JournalTOCs API - articles

Effect of microstructural anisotropy on stress corrosion cracking of hot rolled duplex stainless steels

Chasse K R; Singh, P M

Effect of microstructural anisotropy on stress corrosion cracking of hot rolled duplex stainless steels
Chasse K R; Singh, P M
Corrosion Engineering, Science and Technology, Vol. 47, No. 3 () pp. 170 - 176
Authors: Chasse K R; Singh, P M Article URL: http://www.ingentaconnect.com/content/maney/cest/2012/00000047/00000003/art00005 Citation: Vol 47 No. 3pp 170 176

The Role of Chloride Ion on the Atmospheric Corrosion of Steel and Corrosion Resistance of Sn-bearing Steel

2012-05-15T23:03:26Z

The Role of Chloride Ion on the Atmospheric Corrosion of Steel and Corrosion Resistance of Sn-bearing Steel

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science T. Kamimura, K. Kashima, K. Sugae, H. Miyuki, T. Kudo In order to clarify the role of chloride ion on the atmospheric corrosion of steels, the minute anode chamber simulating local anode sites on steels was set up, and the pH change was measured. The pH was affected by the chloride concentration, and decreased to 1.5 with the formation of β-FeOOH. The role of chloride ion on the corrosion is discussed from the viewpoint of solubility and hydrolysis of Fe3+-species. An atmospheric corrosion model under high chloride content environments is proposed. Based on the model, it was found that Sn-bearing steel exhibits the superior atmospheric corrosion resistance.

Determination of solid fraction-temperature relation and latent heat using full scale casting experiments: application to corrosion resistant steels and nickel based alloys

Carlson K D; Beckermann, C

Determination of solid fraction-temperature relation and latent heat using full scale casting experiments: application to corrosion resistant steels and nickel based alloys
Carlson K D; Beckermann, C
International Journal of Cast Metals Research, Vol. 25, No. 2 () pp. 75 - 92
Authors: Carlson K D; Beckermann, C Article URL: http://www.ingentaconnect.com/content/maney/ijcmr/2012/00000025/00000002/art00002 Citation: Vol 25 No. 2pp 75 92

Brugal® thin organic coatings: effective and gainful alternative to traditional methods of protection of steels from corrosion

O. Roos — Fri, 09 Dec 2011 06:48:52 GMT

Brugal® thin organic coatings: effective and gainful alternative to traditional methods of protection of steels from corrosion
O. Roos
Metal Science and Heat Treatment, Vol. , No. (2011) pp. 350 - 352
The advantages of the use of thin organic coatings for protecting steels from corrosion are considered. Main applications of steels with such coatings are presented. The considerable economic effect due to the use of steels with thin organic coatings instead of dyed galvanized steel is described.

Effects of Si as alloying element on corrosion resistance of weathering steel

2012-04-25T23:03:31Z

Effects of Si as alloying element on corrosion resistance of weathering steel

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science, Volume 59 J.A. Mejía Gómez, J. Antonissen, C.A. Palacio, E. De Grave The corrosion resistance in saline conditions of weathering steel with different concentrations of Si (1, 2 and 3wt.%) exposed to dip dry tests (simulating wet/dry cycles of atmospheric corrosion) was studied by weight loss, X-ray diffraction, Mössbauer spectroscopy and transmission electron microscopy. The results showed that the steels exhibit better corrosion performance with increasing Si concentration. The formation of Fe-oxides such as goethite, lepidocrocite and magnetite was observed. Superparamagnetic goethite is the dominant phase in the rust developed on the Si steels, indicating that Si favors the formation of goethite with small particle size.

Corrosion resistance of bonding zone of AISI 316L-304 stainless steels joined with iron based glass ribbon interlayer: microstructural effects

Corrosion resistance of bonding zone of AISI 316L-304 stainless steels joined with iron based glass ribbon interlayer: microstructural effects
Verduzco J A; Verduzco, V H; Dzib-Perez, L; Gonzalez-Sanchez, J; Lopez, V H; Solis, J
Corrosion Engineering, Science and Technology, Vol. 47, No. 3 () pp. 233 - 241
Authors: Verduzco J A; Verduzco, V H; Dzib-Perez, L; Gonzalez-Sanchez, J; Lopez, V H; Solis, J Article URL: http://www.ingentaconnect.com/content/maney/cest/2012/00000047/00000003/art00012 Citation: Vol 47 No. 3pp 233 241

A new steel with good low‐temperature sulfuric acid dew point corrosion resistance

A new steel with good low‐temperature sulfuric acid dew point corrosion resistance

Materials and Corrosion, Vol. , No. () pp. -
In this work, new steels (1#, 2#, and 3#) were developed for low‐temperature sulfuric acid dew point corrosion. The mass loss rate, macro‐ and micro‐morphologies and compositions of corrosion products of new steels in 10, 30, and 50% H2SO4 solutions at its corresponding dew points were investigated by immersion test, scanning electron microscopy (SEM) and energy‐dispersive spectrometry (EDS). The results indicated that mass loss rate of all the tested steels first strongly increased and then decreased as H2SO4 concentration increased, which reached maximum at 30%. Corrosion resistance of 2# steel is the best among all specimens due to its fine and homogeneous morphologies of corrosion products. The electrochemical corrosion properties of new steels in 10 and 30% H2SO4 solutions at its corresponding dew points were studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results demonstrated that corrosion resistance of 2# steel is the best among all the experimental samples due to its lowest corrosion current density and highest charge transfer resistance, which is consistent with the results obtained from immersion tests.

Corrosion of steel by carbonate‐bicarbonate solution for CO2 capture

Corrosion of steel by carbonate‐bicarbonate solution for CO2 capture

Materials and Corrosion, Vol. , No. () pp. -
Hot alkaline solutions, such as potassium/sodium carbonate solutions, have been used for carbon dioxide removal and capture processes. This survey summarizes the available corrosion data of steels in the solution with carbon dioxide dissolved. Plant operating experiences and laboratory testing results are considered. The corrosion mechanisms, important factors, inhibitor effects, and corrosion cracking are analyzed.

Effect of alloying and thermoplastic treatment on the phase composition and properties of corrosion-resistant steels with metastable austenite

Thu, 05 Apr 2012 06:14:56 GMT

Effect of alloying and thermoplastic treatment on the phase composition and properties of corrosion-resistant steels with metastable austenite
L. A. Maltseva V. A. Sharapova ; T. V. Maltseva ; S. V. Gladkovskii ; A. V. Levina
Metal Science and Heat Treatment, Vol. , No. (2012) pp. 1 - 9
Special features of formation of structure and properties of high-alloy corrosion-resistant steels with different contents of the main components are studied after hardening from various temperatures and deformation with various degrees of reduction.

Shortening of the process of nitriding of corrosion-resistant steels

V. A. Aleksandrov A. V. Grachev ; S. I. Barabanov — Tue, 13 Dec 2011 17:05:43 GMT

Shortening of the process of nitriding of corrosion-resistant steels
V. A. Aleksandrov A. V. Grachev ; S. I. Barabanov
Metal Science and Heat Treatment, Vol. , No. (2011) pp. 344 - 346
The microstructure, the thickness of the nitrided layer, and the microhardness of a group of corrosion-resistant steels are studied after diffusion saturation in an ammonia-air atmosphere. It is shown that the use of such an atmosphere makes it possible to reduce the duration of the process of nitriding by a factor of 3.5 – 4 as compared to nitriding in dissociated ammonia.

Effect of preparation method for two-layer corrosion-resistant steels on their production and operating properties

Mon, 19 Mar 2012 17:10:06 GMT

Effect of preparation method for two-layer corrosion-resistant steels on their production and operating properties
I. G. Rodionova O. N. Baklanova ; A. V. Amezhnov ; T. I. Strizhakova ; A. A. Pavlov
Chemical and Petroleum Engineering, Vol. , No. (2012) pp. 1 - 9
Comparative analysis is provided for two-layer steels prepared by different methods. A method is proposed for thermal cycling tests as an evaluation of the operational reliability of equipment made from two-layer steels.

Use of corrosion-resistant steels and alloys in sulfuric acid media

A. S. Zholud A. S. Derbyshev ; Yu. N. Dulepov — Thu, 02 Feb 2012 17:57:56 GMT

Use of corrosion-resistant steels and alloys in sulfuric acid media
A. S. Zholud A. S. Derbyshev ; Yu. N. Dulepov
Chemical and Petroleum Engineering, Vol. , No. (2012) pp. 627 - 631
Within the chemical industry, and also in some other branches, there is extensive use of sulfuric acid solutions of different concentration and corrosiveness, containing metal ions of varied valency (Cu2+, Fe3+, Ni2+, Cr3+, etc.), which appear in a medium, for example, as a result of equipment corrosion, etc. In sulfuric acid media, corrosion can be uniform or local, i.e., pitting, spot corrosion, intercrystalline corrosion (ICC). Whereas uniform corrosion develops as a gradual reduction in the thickness of an original vessel, equipment, and machine component elements, whose corrosion rate may be calculated previously from existing data for the corrosion resistance of structural materials in specific production media, it is almost impossible to predict ICC development, and therefore in many cases it leads to sudden structural breakdown. In order to predict corrosion, it is recommended to use for article manufacture corrosion-resistant steels and alloys with alloying providing in sulfuric acid solutions resistance to uniform and local corrosion with the required heat treatment and monitoring for ICC resistance.

Corrosion fatigue initiation and short crack growth behaviour of austenitic stainless steels under light water reactor conditions

2012-04-25T23:03:31Z

Corrosion fatigue initiation and short crack growth behaviour of austenitic stainless steels under light water reactor conditions

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science, Volume 59 H.P. Seifert, S. Ritter, H.J. Leber The corrosion fatigue initiation and short crack growth behaviour of different wrought low-carbon and stabilised austenitic stainless steels was characterised under simulated boiling water reactor and pressurised water reactor primary water conditions by cyclic fatigue tests with sharply notched fracture mechanics specimens. The special emphasis was placed to the behaviour at low corrosion potentials and, in particular, to hydrogen water chemistry conditions. The major parameter effects and critical conjoint threshold conditions, which result in relevant environmental reduction and acceleration of fatigue initiation life and subsequent short crack growth, respectively, are discussed and summarised. The observed corrosion fatigue behaviour is compared with the fatigue evaluation procedures in codes and regulatory guidelines.

Electrodeposition of zinc-doped silane films for corrosion protection of mild steels

2012-04-25T23:03:31Z

Electrodeposition of zinc-doped silane films for corrosion protection of mild steels

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science, Volume 59 Lian-Kui Wu, Ji-Ming Hu, Jian-Qing Zhang Organosilane/zinc composite films are prepared by one-step electrodeposition onto cold-rolled steels for corrosion protection. Electrochemical impedance spectroscopy measurement, bulk solution immersion and wet heat tests all show that the composite films have improved corrosion performance. X-ray photoelectron spectroscopy measurement suggests the successful encapsulation of metallic zinc. The embedding of metallic zinc results in negative shift in open-circuit potential of the film-covered electrodes. Such cathodic protection effect given by the metallic zinc provides the improved corrosion resistance of the composite films.

Influence of heat treatments at 475 and 400 °C on the pitting corrosion resistance and sensitization of UNS S32750 and UNS S32760 superduplex stainless steels

Influence of heat treatments at 475 and 400 °C on the pitting corrosion resistance and sensitization of UNS S32750 and UNS S32760 superduplex stainless steels

Materials and Corrosion, Vol. , No. () pp. -
Some precipitation reactions of superduplex stainless steels (SDSS) can improve hardness, yield, and ultimate strength, but with substantial decrease of corrosion resistance. One of these reactions is the spinodal decomposition of ferrite into Cr‐rich fine precipitates (α′) and Cr‐depleted matrix during low temperature aging. In this work, the effect of the α′ precipitation on the pitting corrosion resistance was investigated. The results showed that short duration heat treatments at 475 °C do not decrease the pitting corrosion resistance, but increase the hardness of UNS S32750 and S32760 SDSS. The limits of heat treatment duration for both steels were determined.

Naphthenic corrosion resistance, mechanical properties and microstructure evolution of experimental Cr-Mo steels with high Mo content

Naphthenic corrosion resistance, mechanical properties and microstructure evolution of experimental Cr-Mo steels with high Mo content

Materials Research, Vol. , No. () pp. -
One method to face the effects of naphthenic acid corrosion in petroleun refining plants is to use alloys with good resistance to this kind of corrosion. For this purpose, molybdenum additions to chromium containing steels are specially recommended. In this work, experimental Fe-9Cr-xMo (x = 5, 7 and 9 wt. (%)) ingots were cast, forged and hot rolled before being tested in a naphthenic acid environment. Evolution of the mechanical properties with composition is presented. The precipitation and dissolution of phases were investigated with the help of Thermocalc and electron backscattered diffraction (EBSD).

Corrosion resistance of different steel grades in the geothermal fluid of Molasse Basin

Corrosion resistance of different steel grades in the geothermal fluid of Molasse Basin

Materials and Corrosion, Vol. , No. () pp. -
Long‐term corrosion resistance of carbon steels grade API L80 and API Q125 has been evaluated by means of electrochemical measurements and exposure tests in the Molasse Basin, one of the most important geothermal fluids in Europe. In addition, the localized corrosion resistance of the duplex stainless steel alloy 2205 and the austenitic stainless steel grade 316L was determined at 100 and 150 °C. In general, investigated materials showed a remarkable resistance to uniform and localized corrosion. Their corrosion behaviour at service conditions is discussed in this paper.

Influence of Processing and Heat Treatment on Corrosion Resistance and Properties of High Alloyed Steel Coatings

Horst Hill Sebastian Weber ; Ulrich Raab ; Werner Theisen ; Lothar Wagner — Wed, 25 Apr 2012 06:09:08 GMT

Influence of Processing and Heat Treatment on Corrosion Resistance and Properties of High Alloyed Steel Coatings
Horst Hill Sebastian Weber ; Ulrich Raab ; Werner Theisen ; Lothar Wagner
Journal of Thermal Spray Technology, Vol. , No. (2012) pp. 1 - 8
Corrosion and abrasive wear are two important aspects to be considered in numerous engineering applications. Looking at steels, high-chromium high-carbon tool steels are proper and cost-efficient materials. They can either be put into service as bulk materials or used as comparatively thin coatings to protect lower alloyed construction or heat treatable steels from wear and corrosion. In this study, two different corrosion resistant tool steels were used for the production of coatings and bulk material. They were processed by thermal spraying and super solidus liquid phase sintering as both processes can generally be applied to produce coatings on low alloyed substrates. Thermally sprayed (high velocity oxygen fuel) coatings were investigated in the as-processed state, which is the most commonly used condition for technical applications, and after a quenching and tempering treatment. In comparison, sintered steels were analyzed in the quenched and tempered condition only. Significant influence of alloy chemistry, processing route, and heat treatment on tribological properties was found. Experimental investigations were supported by computational thermodynamics aiming at an improvement of tribological and corrosive resistance.

A practical application of thermal desorption mass spectrometry for studying inhibitors and corrosion products

A. K. Buryak T. M. Serdyuk ; A. V. Ul’yanov — Sun, 09 Nov 2008 10:10:33 GMT

A practical application of thermal desorption mass spectrometry for studying inhibitors and corrosion products
A. K. Buryak T. M. Serdyuk ; A. V. Ul’yanov
Protection of Metals, Vol. , No. (2008) pp. -
In the present review, examples of the practicality of applying thermal desorption mass spectrometry (TDMS) to study inhibitors and corrosion products are given. It is shown that the highly informative aspect of the method allows regularities of the processes occurring in volume, on surfaces, and in near-surface layers of steels and alloys to be established. The TDMS method makes it possible to identify adsorbed and chemisorbed inhibitors and corrosion products, as well as products of their destruction.

Corrosion of aluminium, stainless steels and AISI 680 nickel alloy in nitrogen‐based fuels

Corrosion of aluminium, stainless steels and AISI 680 nickel alloy in nitrogen‐based fuels

Materials and Corrosion, Vol. , No. () pp. -
Nitrogen‐based compounds can potentially be used as alternative non‐carbon or low‐carbon fuels. Nevertheless, the corrosion of construction materials at high temperatures and pressures in the presence of such fuel has not been reported yet. This work is focused on the corrosion of AISI Al 6061, 1005 carbon steel (CS), 304, 316L, 310 austenitic stainless steels (SS) and 680 nickel alloy in highly concentrated water solution of ammonium nitrate and urea (ANU). The corrosion at 50 °C and ambient pressure and at 350 °C and 20 bar was investigated to simulate storage and working conditions. Sodium chloride was added to the fuel (0–5 wt%) to simulate industrial fertilizers and accelerated corrosion environment. Heavy corrosion of CS was observed in ANU solution at 50 °C, while Al 6061, 304 and 316L SS showed high resistance both to uniform and pitting corrosion in ANU containing 1% of sodium chloride. Addition of 5% sodium chloride caused pitting of Al 6061 but had no influence on the corrosion of SS. Tests in ANU at 350 °C and 20 bar showed pitting on SS 304 and 316L and 680 nickel alloy. The highest corrosion resistance was found for SS 310 due to formation of stable oxide film on its surface.

Study of sensitization and different heating cycles on stainless steels used for automotive exhaust components

Study of sensitization and different heating cycles on stainless steels used for automotive exhaust components

Materials and Corrosion, Vol. , No. () pp. -
In order to achieve a reasonable lifetime of automotive exhaust components, a large number of high alloyed ferritic and austenitic stainless steels are used nowadays. It is a common concept that the lifetime of a component is directly related to the performance of steel against corrosion. The components are divided into different sections depending on their service temperatures. High temperature oxidation resistance is one of the properties which are required in different sections. The effect of material sensitization on corrosion resistance of stainless steels is well understood from the literature. Besides, sensitization materials in exhaust systems have to withstand different cyclic heating and cooling phases. The objective of this study was to develop a basic understanding that can determine the influence of different temperature treatments on stainless steels. A fundamental understanding on the interaction of sensitization and cyclic heat impacts are presented in the paper.

Specific features of hydrogen-induced corrosion degradation of steels of gas and oil pipelines and oil storage reservoirs

E. I. Kryzhanivs’kyi H. M. Nykyforchyn — Wed, 16 Nov 2011 16:47:48 GMT

Specific features of hydrogen-induced corrosion degradation of steels of gas and oil pipelines and oil storage reservoirs
E. I. Kryzhanivs’kyi H. M. Nykyforchyn
Materials Science, Vol. , No. (2011) pp. 127 - 136
We analyze general regularities of degradation of the mechanical and corrosion-mechanical properties of steels of oil and gas main pipelines and oil storage reservoirs after 28–40 years of operation. The transported oil product not only causes corrosion damages of the internal surface of pipelines and reservoirs, but also becomes a source of hydrogenation of the metal. As a result, it degrades already under the long joint action of mechanical load and hydrogen. Changes in (degradation of) the mechanical properties of the sections of a pipe or a reservoir that contact with the transported medium during operation indicate this fact. First of all, this manifests itself as embrittlement of the metal, i.e., as decreases in the plasticity and resistance to fracture. Comparison assessment of operated and nonoperated steels showed the high sensitivity of the electrochemical properties to the state of the metal, which offers prospects for the development of electrochemical methods for assessing its in-service degradation.

Modeling steel corrosion under supercritical CO2 conditions

Modeling steel corrosion under supercritical CO2 conditions

Materials and Corrosion, Vol. , No. () pp. -
Corrosion in the presence of CO2 was studied under supercritical conditions (high pressure and moderate temperature) using different carbon steels and various corrosion resistant alloys (CRA's). An objective of this work was, among others, to put the results in perspective relative to various CO2 corrosion models that have been developed and published over the years. In particular, the NORSOK, FREECORP, and OLI models were used for comparison, while others were discussed as well. The systems investigated were (a) supercritical CO2 (SC CO2) saturated with water (no separate water phase), (b) a water mist phase in equilibrium with SC CO2, (c) a water/brine phase in equilibrium with SC CO2. It was found that the OLI model best simulates the experimental corrosion rates observed in system (c) where coupons were corroded in the aqueous phase at high velocities in the rotating cage. The varying susceptibility of different carbon steels to corrosion under these conditions is highlighted. CRA steels are comparatively more resistant.

Physicochemical properties of steel surfaces with titanium nitride ion-plasma sprayed coating

A. I. Kostrzhitskii T. V. Cheban ; R. A. Podolyan — Sun, 09 Nov 2008 10:10:30 GMT

Physicochemical properties of steel surfaces with titanium nitride ion-plasma sprayed coating
A. I. Kostrzhitskii T. V. Cheban ; R. A. Podolyan
Protection of Metals, Vol. , No. (2008) pp. -
Abstract In nutral media, the regularities of the electrochemical corrosion of a steel, that had been sprayed by ionic plasma with titanium nitride, are studied. It is shown that the coating porosity is the principal factor determining its protective properties. Quantitative data on the effect of operation conditions on the coating porosity and corrosion-electrochemical behavior in liquids are given. Empirical formulas describing the kinetics of increasing the number of corrosion craters are obtained. Guidelines concerning the using of the ion-plasma coatings in the protecting of lean alloy steels against corrosion are formulated.

Comparison of hydrogen embrittlement in three pipeline steels in high pressure gaseous hydrogen environments

2012-04-25T23:03:31Z

Comparison of hydrogen embrittlement in three pipeline steels in high pressure gaseous hydrogen environments

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science, Volume 59 N.E. Nanninga, Y.S. Levy, E.S. Drexler, R.T. Condon, A.E. Stevenson, A.J. Slifka The tensile properties of X52, X65, and X100 pipeline steels have been measured in a high-pressure (13.8MPa) hydrogen gas environment. Significant decreases in elongation at failure and reduction of area were observed when testing in hydrogen as compared with air, and those changes were accompanied by noticeable changes in fracture morphology. In addition to baseline characterization of the effects of strength and microstructure on the X52, X65, and X100 alloys, the influence of strain rate and hydrogen gas pressure was studied for only the X100 alloy.

Study on the Corrosion Mechanism of Zn-5Al-0.5Mg-0.08Si Coating

Study on the Corrosion Mechanism of Zn-5Al-0.5Mg-0.08Si Coating

Journal of Metallurgy, Vol. , No. () pp. -
A new type of hot-dip Zn-5Al-0.5Mg-0.08Si and Zn-5Al alloy coatings was performed on the cold rolled common steel. The hot-dip process was executed by self-made hot-dip galvanising simulator. SEM and EDS test results demonstrated that Mg was mainly distributed in crystal boundaries. XRD test results showed that the corrosion product of Zn-5Al-0.5Mg-0.08Si alloy coating was almost Zn5(OH)8C12⋅H2O. The features of Zn5(OH)8C12⋅H2O are low electric conductivity, insolubility and good adhesion.The corrosion resistance of alloy-coated steels was detected by neutral salt spray test. The microstructural characterization of the coating surface after neutral salt spray test and removing the corrosion products revealed that the corrosion process of Zn-5Al-0.5Mg-0.08Si coating was uniform and the coating surface was almost flat. As a result, the corrosion resistance of Zn-5Al-0.5Mg-0.08Si coating has a remarkable improvement with a factor of 9.2 compared with that of Zn-5Al coating.

Stress-corrosion failures of main pipelines

A. Ya. Krasovskii I. V. Lokhman ; I. V. Orynyak — Thu, 10 May 2012 06:06:46 GMT

Stress-corrosion failures of main pipelines
A. Ya. Krasovskii I. V. Lokhman ; I. V. Orynyak
Strength of Materials, Vol. , No. (2012) pp. 1 - 15
The basic peculiarities of stress corrosion fracture cases of main pipelines are analyzed. The authors consider structure, mechanical properties, Charpy energy, fracture toughness, corrosion fatigue, and fracture mechanisms of steel Kh70 (from transit gas pipeline “Urengoy–Pomary– Uzhgorod”) in three conditions: as received (archive), after 24 and 26 years of service. The service degradation of steel is revealed, which manifests itself in considerable drop of Charpy energy, fracture toughness and resistance to the corrosion fatigue crack growth. The analysis is performed of the resistance of the pipeline steels to the corrosion fatigue crack nucleation and growth and the respective recommendations are provided concerning the avoidance of the stress corrosion failure of transit gas pipelines.

Influence of alloying elements and density on aqueous corrosion behaviour of some sintered low alloy steels

2012-04-30T00:34:19Z

Influence of alloying elements and density on aqueous corrosion behaviour of some sintered low alloy steels

Materials & Design, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Materials & Design, Volume 40 T.K. Kandavel, R. Chandramouli, P. Karthikeyan Low alloy steels produced through powder metallurgy route of sintering followed by forging are promising candidate materials for high strength small components. Porosity in such steels poses a real challenge during acid pickling treatment, which is one of the processing steps during manufacturing. The present research work attempts to investigate the mechanism underlying the acid corrosion behaviour of some sintered low alloy steels under induced acid pickling conditions. Sintered-forged low alloy steel samples containing molybdenum (Mo), copper (Cu) and titanium (Ti) were subjected to aqueous corrosion attack by immersing the samples in 18% HCl (Hydrochloric acid) solution for 25h. Sample weight loss and Fe (Iron) loss were estimated for the corroded samples. The morphology of the corroded surfaces was studied through metallography and scanning electron microscopy. Higher porosity alloys underwent enhanced corrosion rates. Both corrosion rate and iron loss are found to decrease linearly with reduction in porosity in all cases of the alloys. The alloying elements Mo, Ti and Cu, when added in combination, have played a complementary role in the reduction of corrosion rate by almost one order of magnitude compared to unalloyed steel. Presence of carbides of the carbide forming elements Mo and Ti played a positive role on the corrosion behaviour of the low alloy steels.

A comparative study of critical pitting temperature (CPT) of stainless steels by electrochemical impedance spectroscopy (EIS), potentiodynamic and potentiostatic techniques

2012-04-25T23:03:31Z

A comparative study of critical pitting temperature (CPT) of stainless steels by electrochemical impedance spectroscopy (EIS), potentiodynamic and potentiostatic techniques

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science, Volume 59 N. Ebrahimi, M. Momeni, A. Kosari, M. Zakeri, M.H. Moayed In this study critical pitting temperature (CPT) of two stainless steels is compared using EIS, potentiodynamic and potentiostatic techniques. Two types of stainless steels including DSS2205 and 20Cr–28Ni were chosen. EIS measurements were carried at anodic potential of 600mV/SCE and the results were compared with those of potentiodynamic and potentiostatic polarisations. The results revealed that the CPT of DSS2205 and 20Cr–28Ni was between 45–55°C and 35–45°C in potentiodynamic polarisation, respectively. It was 60 and 55°C for potentiostatic method and between 55–60°C and 45–55°C in EIS method for DSS2205 and 20Cr–28Ni, respectively.

Electrochemical investigations on corrosion protection oils

Electrochemical investigations on corrosion protection oils

Materials and Corrosion, Vol. , No. () pp. -
Tribologically affected surfaces of high‐strength steels often only may be protected against corrosion by the use of specific protecting oils. The protective effectiveness of these products is usually assessed by neutral salt spray test during qualification. As this test method takes a long time and because the reproducibility is poor a new test method was developed based on electrochemistry. It could be shown that a distinction was possible between well and nonprotecting oils based on current density curves and electrochemical impedance spectroscopy.

Influence of microstructure on mechanical properties and corrosion behavior of 3%Cr steel in CO2 environment

Influence of microstructure on mechanical properties and corrosion behavior of 3%Cr steel in CO2 environment

Materials and Corrosion, Vol. , No. () pp. -
Corrosion behavior and mechanical properties of two 3%Cr pipeline steels were studied which have same chemical compositions but different microstructures, bainite‐ferrite and ferrite‐pearlite microstructures. Analysis of chemical compositions and surface morphology of the corrosion scale were performed using X‐ray diffraction and scanning electron microscopy in conjunction with energy dispersive X‐ray spectroscopy. The semi‐passive character of corrosion scale was investigated using polarization curves measurements. The influence of microstructure on the chromium enrichment in the corrosion scale for different test periods was investigated. The microstructure was observed to affect the corrosion behavior even when the steel surface has been covered with corrosion scales and continue to have an effect until the corrosion scale possessing semi‐passive character. Possessing both good strength and corrosion resistance, 3%Cr steel with bainite‐ferrite microstructure was very promising for pipeline steel applications.

Protection of carbon steels against atmospheric corrosion in a wet tropical climate using gas-plasma metallization with aluminum

R. A. Tupikov Yu. G. Dragunov ; I. L. Kharina ; D. S. Zmienko — Sun, 09 Nov 2008 10:10:34 GMT

Protection of carbon steels against atmospheric corrosion in a wet tropical climate using gas-plasma metallization with aluminum
R. A. Tupikov Yu. G. Dragunov ; I. L. Kharina ; D. S. Zmienko
Protection of Metals, Vol. , No. (2008) pp. -
Results of testing for resistance to atmospheric corrosion in a humid-tropical climate (in experimental chambers and under outdoor conditions) have been performed for templates of ribbed pipes made of a carbon steel with various types of anticorrosion (paint, diffusional, metallic) coatings. An optimum type of coating has been determined, its properties have been investigated, and the optimum thickness was found that proved to be good at corrosion resistance in ribbed pipes and allowed for the specificity of structural and service features of the equipment to be protected.

Acoustic emission monitoring of micro cell corrosion testing in type 304 stainless steels

Fri, 18 Nov 2011 16:47:44 GMT

Acoustic emission monitoring of micro cell corrosion testing in type 304 stainless steels

Strength, Fracture and Complexity, Vol. , No. (2011) pp. -

A new method of acoustic emission (AE) monitoring was proposed to study the corrosion and stress corrosion cracking (SCC) by chloride ion. It is a combination of the small chloride droplet corrosion, SCC testing method and AE waveform measurement system with a high sensitivity AE sensor, all of which have been developed by our group. Three types of corrosion were observed in the corrosion testing, which were the open pitting, the covered pitting and snake-like corrosion, respectively. There were many AE events in the covered pitting and snake-like corrosion. On the contrary, there was no AE event in the open pitting. Meanwhile, the cross section of the snake-like corrosion was analyzed by EBSD. It shows that under the corrosion surface, there were some cracks at the {111} interface of Σ3 coincidence boundary and annealing twins. Based on these experiment results, it indicated that the microstructure generated by the covered pitting and snake-like corrosion during corrosion is the initiation site of stress corrosion cracking. Besides, the micro cell corrosion and SCC testing in thin plate specimens of SUS304 stainless steel by the AE monitoring were effective for evaluation of the progression process of them.

Content Type Journal Article
Pages 71-78
DOI 10.3233/SFC-2011-0125
Authors
- Mitsuharu Shiwa, National Institute for Materials Science, Ibaraki, Japan
- Hiroyuki Masuda, National Institute for Materials Science, Ibaraki, Japan
- Hisasi Yamawaki, National Institute for Materials Science, Ibaraki, Japan
- Kaita Ito, Department of Materials Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
- Manabu Enoki, Department of Materials Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan

Journal Strength, Fracture and Complexity
Online ISSN 1875-9262
Print ISSN 1567-2069

Journal Volume Volume 7

Journal Issue Volume 7, Number 1 / 2011

On the Stress Corrosion Cracking and Hydrogen Embrittlement Behavior of Austenitic Stainless Steels in Boiling Saturated Magnesium Chloride Solutions

On the Stress Corrosion Cracking and Hydrogen Embrittlement Behavior of Austenitic Stainless Steels in Boiling Saturated Magnesium Chloride Solutions

International Journal of Corrosion, Vol. , No. () pp. -
The stress corrosion cracking (SCC) and hydrogen embrittlement (HE) behaviors for types 304, 310, and 316 austenitic stainless steels were investigated in boiling saturated magnesium chloride solutions using a constant load method under different conditions including test temperature, applied stress, and sensitization. Both of type 304 and type 316 stainless steels showed quite similar behavior characteristics, whereas type 310 stainless steel showed a different behavior. The time to failure (tf) parameter was used among other parameters to characterize the materials behavior in the test solution and to develop a mathematical model for predicting the time to failure in the chloride solution. The combination of corrosion curve parameters and fracture surface micrographs gave some explanation for the cracking modes as well as an indication for the cracking mechanisms. On the basis of the results obtained, it was estimated that intergranular cracking was resulted from hydrogen embrittlement due to strain-induced formation of martensite along the grain boundaries, while transgranular cracking took place by propagating cracks nucleated at slip steps by dissolution.

Corrosion at the urea injection in SCR‐system during component test

Corrosion at the urea injection in SCR‐system during component test

Materials and Corrosion, Vol. , No. () pp. -
The corrosion behaviour of the austenitic stainless steels 304L and 904L was investigated after component testing in diesel exhaust urea environment. Cross‐sectional analyses and depth profiling of corrosion products were performed with Auger electron spectroscopy (AES) and X‐ray photoelectron spectroscopy (XPS). The samples of both materials displayed high amounts of silicon oxide on their surfaces, though this did not appear to have an active role in the corrosion. The higher alloyed 904L exhibited only small signs of corrosion and the inner oxide below the silicon oxide was chromium rich. Substantial nitrogen uptake was detected, presumably due to the presence of NH3, cyanates and similar species. The lower alloyed 304L showed more severe corrosion. The oxide on the 304L samples mainly consisted of iron oxide apart from the silicon oxide present. The nitrogen uptake was less pronounced and possibly connected to presence of nitride precipitates. The most pronounced corrosion was detected at sites where deposits frequently form and decompose. Those deposits are a probable nitrogen source and may also form compounds enabling the breakdown of the oxide.

Corrosion of stainless steel grades in H2O/KOH 50% at 120 °C: AISI304 austenitic and 2205 duplex

Corrosion of stainless steel grades in H2O/KOH 50% at 120 °C: AISI304 austenitic and 2205 duplex

Materials and Corrosion, Vol. , No. () pp. -
We report on the corrosion of austenitic (AISI304) and duplex (2205) stainless steels in H2O/KOH 50% at 120 °C. The research is based on a combination of electrochemical, structural and compositional analyses, aimed at assessing the surface modifications resulting from anodic attack and their impact on corrosion resistance. Linear sweep voltammetry and electrochemical impedance spectrometry measurements were carried out in an air‐tight high‐temperature cell. In‐plane and cross‐sectional SEM micrography, X‐ray diffractometry and EDX profiling were used to characterise samples attacked under electrochemically controlled conditions. Electrochemical results have shown that AISI304 exhibits a complex passivating behaviour, while the anodic electrokinetics of the duplex is characterised by mixed kinetic control. AISI304 was found to fail by intergranular corrosion and to be covered: in passive conditions by acicular compounds and in transpassive conditions by a compact layer of corrosion products. Duplex samples, instead, exhibit an uniform form of corrosion morphology and bear a compact layer of corrosion products both in passive and in transpassive conditions.

A Method for determining safe concentrations of chloride ions in pitting corrosion of steels in nitrate media

V. P. Razygraev M. V. Lebedeva ; I. I. Korchak — Sun, 09 Nov 2008 10:10:33 GMT

A Method for determining safe concentrations of chloride ions in pitting corrosion of steels in nitrate media
V. P. Razygraev M. V. Lebedeva ; I. I. Korchak
Protection of Metals, Vol. , No. (2008) pp. -
Features of how pitting corrosion develops on steels in nitrate-chloride media are analyzed, and the disadvantages of certain well-known electrochemical methods used to determine safe ratios of components under such conditions are found. A principally new approach to determining these parameters is proposed, based on the induction of intense pitting in definitely aggressive media with subsequent suppression of this process by continuously dilution of the solution or by gradual addition of an inhibitor. Equations are obtained for determining safe component concentrations depending on the volume of solution passing through the cell. Using the proposed method, safe ratios of components are determined for 12Kh18N10T chromium-nickel steel at chloride ion concentrations within 0.02–2.0 M.

Corrosion of stainless steels in simulated diesel exhaust environment with urea

Corrosion of stainless steels in simulated diesel exhaust environment with urea

Materials and Corrosion, Vol. , No. () pp. -
Laboratory exposures have been performed simulating a selective catalytic reduction (SCR) system with urea injection for NOx reduction in diesel exhaust after‐treatment. The corrosion behaviour of three ferritic and one austenitic stainless steel was examined using X‐ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Continuous exposure to condensate did not cause any corrosion. Results show that cyclic interaction between high temperature and condensation aggravates the corrosion compared to isothermal exposure at 450 °C. All ferritic alloys exhibited more or less the same behaviour, while the austenitic steel performed better. In fact, the presence of urea decreased the corrosion compared to the environment without urea. The cyclic samples exposed with urea displayed iron sulphate on the surface. The sulphate appeared to decrease the oxide thickness. A sulphur enrichment in the form of sulphide also occurred in the inner chromium‐rich oxides of all cyclically exposed samples, both with and without urea. Thus, sulphidation is presumed to be involved in the corrosion process.

22Cr High-Mn-N Low-Ni Economical Duplex Stainless Steels

2012-03-16T04:35:25Z

22Cr High-Mn-N Low-Ni Economical Duplex Stainless Steels

Journal of Iron and Steel Research, International, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Journal of Iron and Steel Research, International, Volume 19, Issue 2 Da-wei JIANG, Chang-sheng GE, Xiang-juan ZHAO, Jun LI, Lu-lu SHI, Xue-shan XIAO A new family of economical duplex stainless steels in which N or Mn was substituted for Ni with composition of 22Cr-8.0Mn-xNi-1.0Mo-0.7Cu-0.7W-0.3N (x = 0.5 – 2.0) have been developed by examining the micro-structure, mechanical and corrosion properties of these alloys. The results show that these alloys have a balanced ferrite-austenite relation. In addition, the alloys are free of precipitation of sigma phase and Cr-nitride when solution-treated at 750 to 1300°C for 30 min. The yield strength, tensile strength and fracture elongation values of experimental alloys solution-treated at 1050°C for 30 min are about 500, 750 MPa and 40.0%, respectively. Low-temperature impact properties can be improved distinctly with the increase of nickel content. Among the designed DSS alloys, the alloy with Ni of 2.0% is found to be an optimum alloy with proper phase proportion, better low-temperature impact properties and higher pitting corrosion resistance compared with those of other alloys. The mechanical and corrosion properties and lower production cost of the designed DSSs are better than those of AISI 304.

Study of the correlation between corrosion resistance and semi‐conducting properties of the passive film of AISI 316L stainless steel in physiological solution

Study of the correlation between corrosion resistance and semi‐conducting properties of the passive film of AISI 316L stainless steel in physiological solution

Materials and Corrosion, Vol. , No. () pp. -
In this work the corrosion resistance of AISI 316L biomedical stainless steel was assessed through electrochemical impedance spectroscopy (EIS) measurements in Hanks' solution at 37 °C. Specimens were immersed in the electrolyte during 21 days. Semi‐conducting properties of the passive film naturally formed on the surface of the metallic material during the test were evaluated through the Mott–Schottky approach. The aim was to investigate the correlation between corrosion resistance and semi‐conducting properties in the physiological solution. The corrosion resistance was found to decrease with the immersion time. The density of defects in the passive film increased accordingly as indicated by the Mott–Schottky plots. The passive film presented a semi‐conducting behavior with a duplex character. Above the flat band potential the behavior was typical of an n‐type semiconductor whilst below such value it was typical of a p‐type semiconductor. The results from EIS measurements and Mott–Schottky were in good agreement, suggesting that the corrosion resistance of biomedical stainless steels may be associated with the semi‐conducting properties of the passive films formed during immersion in physiological medium.

Effect of electro discharge machining (EDM) on the AISI316L SS white layer microstructure and corrosion resistance

Wed, 02 May 2012 05:48:24 GMT

Effect of electro discharge machining (EDM) on the AISI316L SS white layer microstructure and corrosion resistance
Habib Sidhom Farhat Ghanem ; Tidiane Amadou ; Gonzalo Gonzalez ; Chedly Braham
The International Journal of Advanced Manufacturing Technology, Vol. , No. (2012) pp. 1 - 13
Abstract The localised corrosion resistance of austenitic stainless steels is strongly influenced by the quality of finished surface. EDM machining induces substantial changes by the high thermal gradients generated by electric sparks. Experimental techniques such as roughness measurement, scanning electron microscopy (SEM), energy dispersive microanalysis (EDX) and X-ray diffraction technique, reveal micro-geometrical, microstructural, chemical and mechanical changes. These changes lead to white and heat-affected layers with a depth less than 100 μm. The white layer is a melted material characterised by dendritic structure and constituted by austenite, chromium carbide and ε-carbide. The heat-affected layer is characterised by very large grain size comparatively to the bulk material. Electrochemical test coupled with metallographic examinations using SEM reveals a weakening of the resistance to pitting and intergranular corrosion comparatively to diamond polished surface. This weakening is correlated to differences in structure and chemical composition of white layer. Susceptibility to stress corrosion cracking has been attributed to the field of tensile residual stresses resulting from thermal effects. The removal of the white layer material by polishing or wire brushing restores the corrosion resistance of the AISI316L SS.

Corrosion of ZrO2 treated type 304 stainless steels in high temperature pure water with various amounts of hydrogen peroxide

2012-03-11T03:07:05Z

Corrosion of ZrO2 treated type 304 stainless steels in high temperature pure water with various amounts of hydrogen peroxide

Progress in Nuclear Energy, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Progress in Nuclear Energy, Volume 57 Tsung-Kuang Yeh, Po-I. Wu, Chuen- Horng Tsai As boiling water reactors (BWRs) age, intergranular stress corrosion cracking (IGSCC) of the structural materials in the reactor piping systems and vessel internals has become a major degradation problem. Several approaches to mitigating IGSCC in the structural components have been developed and investigated. Among them, the technique of inhibitive protective coatings is deemed the most promising one since it is expected to work even in the absence of the well-known hydrogen water chemistry technology. Following our earlier work on exploring the electrochemical characteristics of important oxidizing species on zirconium oxide (ZrO2) treated Type 304 stainless steels (SSs), we targeted on the characteristics of hydrogen peroxide, which is another strongly oxidizing species in the reactor coolant other than oxygen, in this study. Tests were conducted to determine electrochemical parameters such as electrochemical corrosion potential (ECP), corrosion current density, exchange current density and Tafel constant of the reduction reaction of hydrogen peroxide on 304 SS specimens before and after the ZrO2 treatment. The surface morphologies of the treated and untreated specimens were examined by scanning electron microscopy, energy dispersive X-ray spectroscopy, and laser Raman spectra. Furthermore, the corrosion mitigation efficiency of ZrO2 treatment was evaluated by electrochemical polarization tests in simulated BWR environments. Test results showed that there were no significant differences in ECP between the untreated and ZrO2 treated specimens in the test environments of various hydrogen peroxide concentrations. However, it was found via polarization analysis that the exchange current density of the reduction reaction on and the corrosion current density of the treated specimens were markedly lower than those on and of the untreated ones in the same environments. The ZrO2 treatment was able to deter the reduction rate of hydrogen peroxide on the Type 304 SS surface.

Corrosion of materials in hydrochloric acid solutions

A. S. Derbyshev A. N. Suriev ; A. N. Efimov ; I. A. Beresneva ; F. A. Ladygin — Thu, 02 Feb 2012 17:57:57 GMT

Corrosion of materials in hydrochloric acid solutions
A. S. Derbyshev A. N. Suriev ; A. N. Efimov ; I. A. Beresneva ; F. A. Ladygin
Chemical and Petroleum Engineering, Vol. , No. (2012) pp. 632 - 634
Hydrochloric acid solutions, particularly at elevated temperature, are very corrosive media and cause rapid corrosion of the majority of metals, steels, and alloys, and also chemical breakdown of many nonmetallic materials. Under laboratory conditions in 2% hydrochloric acid solution at 20–25°C the corrosion resistance is studied for specimens of steels 12Kh18N10T, 10Kh17N13M3T, alloy 06KhN28MDT, and titanium VT1-0, and also in 20% hydrochloric acid solution at 95–100°C for specimens of nickel-molybdenum alloys N70MFV-VI (EP814A-VI), alloy N65M-VI (EP982), titanium-palladium alloy 4200 (Ti–0.2%Pd), zirconium, and tantalum, as well as nonmetallic materials, i.e., fluoroplastic, glass, porcelain, faolite, graphite, polypropylene, cross-linked polyethylene, acrylic plastic, silicon carbide composite, and vinyl plastic. The test duration is 1000 h. In 2% hydrochloric acid solution at 20–25°C high resistance is exhibited by titanium VT1-0, alloy 06KhN28MDT, and corrosion-resistant chromium-nickel-molybdenum alloy 10Kh17N13M3T, from which it is possible to manufacture equipment and engineering pipelines in contact with low-concentration hydrochloric acid solutions operating at ambient temperature. In hydrochloric acid solution with a weight concentration of 20% at 95–100°C high resistance to uniform and local corrosion is exhibited by zirconium and tantalum, and the rate of corrosion penetration for alloy N70MFV-VI (EP814A) is 0.447 mm/yr, for alloy KhN63MB it is 1.441 mm/yr, for alloy KhN65MV it is 13.931 mm/yr, and for alloy 4200 it is 3.403 mm/yr. Of the nonmetallic materials, alongside fluoroplastic, high chemical resistance is exhibited by polypropylene, and cross-linked polyethylene.

Characterization of Uncoated Stainless Steel as Proton Exchange Membrane Fuel Cell Bipolar Plates Material

Characterization of Uncoated Stainless Steel as Proton Exchange Membrane Fuel Cell Bipolar Plates Material

Fuel Cells, Vol. , No. () pp. -
Thanks to their high conductivity, important gas tightness, good corrosion resistance, and low‐cost manufacturing pathways, stainless steels are considered as good candidates for proton exchange membrane fuel cell (PEMFC) bipolar plates materials. In this study, a proprietary alloy was identified as very promising: its initial electrical contact resistance (ECR) with the gas diffusion layer was low, while its corrosion resistance in simulated PEMFC environment was sufficient. Furthermore, the ECR did not increase dramatically during long‐term potentiostatic and potentiodynamic polarizations in simulated PEMFC cathode and anode environments. Finally, the stainless steel was successfully tested for 3,000 h in a commercial system using a 16‐cell stack, without detrimental cell voltage losses.

Effect of hydrogen content on the embrittlement in a Fe–Mn–C twinning-induced plasticity steel

2012-04-25T23:03:31Z

Effect of hydrogen content on the embrittlement in a Fe–Mn–C twinning-induced plasticity steel

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science, Volume 59 Motomichi Koyama, Eiji Akiyama, Kaneaki Tsuzaki The hydrogen embrittlement of a Fe–18Mn–0.6C austenitic steel (wt.%) was examined using tensile tests under hydrogen charging at various current densities. The tensile properties deteriorated due to the occurrence of intergranular fracture above a specific current density. The work hardening behavior was not affected by the hydrogen charging, indicating that the embrittlement was independent of the change in behavior of slip deformation, martensitic transformation, and twinning deformation. The relationship between the fracture stresses for the intergranular fracture and the diffusible hydrogen content of the austenitic steel was approximated to the power law similarly to ferritic high strength steels.

Antibacterial properties and corrosion resistance of AISI 420 stainless steels implanted by silver and copper ions

Wed, 28 Mar 2012 05:51:33 GMT

Antibacterial properties and corrosion resistance of AISI 420 stainless steels implanted by silver and copper ions
Hong-wei Ni Han-shuang Zhang ; Rong-sheng Chen ; Wei-ting Zhan ; Kai-fu Huo ; Zhen-yu Zuo
International Journal of Minerals, Metallurgy and Materials, Vol. , No. (2012) pp. 322 - 327
Abstract Silver or copper ions are often chosen as antibacterial agents. But a few reports are concerned with these two antibacterial agents for preparation of antibacterial stainless steel (SS). The antibacterial properties and corrosion resistance of AISI 420 stainless steel implanted by silver and copper ions were investigated. Due to the cooperative antibacterial effect of silver and copper ions, the Ag/Cu implanted SS showed excellent antibacterial activities against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) at a total implantation dose of 2×1017 ions/cm2. Electrochemical polarization curves revealed that the corrosion resistance of Ag/Cu implanted SS was slightly enhanced as compared with that of un-implanted SS. The implanted layer was characterized by X-ray photoelectron spectroscopy (XPS). Core level XPS spectra indicate that the implanted silver and copper ions exist in metallic state in the implanted layer.

Failure analysis of a steel tube joint perforated by corrosion in a well-drilling pipe

2012-05-03T23:09:39Z

Failure analysis of a steel tube joint perforated by corrosion in a well-drilling pipe

Engineering Failure Analysis, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Engineering Failure Analysis Peng Cheng-hong, Liu Zheng-yi, WEI Xing-zhao The corroded steel tube joint belonging to an offshore oil well-drilling pipeline was investigated. All of the pits and punctures distributed along the “steps” are formed by off-centre machining on the internal tube surface, and the pits have a horse’s hoof and hemispherical contour. The metallurgical structure of some spots on non-penetrating corrosion pits and penetrating punctures looked markedly curved, i.e., curved deflections in the banded structure (or streamlines) were visible. The pits contour and metallurgical structure indicate that the pits and punctures are characterised by cavitation erosion. The chemical composition of the corroded steel tube joint is similar to 1320, 1330 and L80-1 steels specified in ASTM standards, and the content of non-metallic impurities in the failed steel tube was identified as Grade 1.0 to 1.5, which is within the permitted range. Corrosion pit surfaces and the tube joint showed a deposit layer and a clay-like substance that was rich in Fe, Mn, Ca, Ti, Cu, C, O, S and Cl, and “crystal sugar –like” appearance observed on location of the penetrating puncture, indicating H2S- and CO2-assisted corrosion mechanisms. These investigations indicated that failure of the pipeline occurred by erosion corrosion, cavitations erosion and chemical corrosion, which is from both mechanical and chemical actions.

Electrochemical investigations on the corrosion behaviour of galvanized reinforcing steels in concrete with chromate‐reduced cements

Electrochemical investigations on the corrosion behaviour of galvanized reinforcing steels in concrete with chromate‐reduced cements

Materials and Corrosion, Vol. , No. () pp. -
The reduction of the chromate contents in cements affects the electrochemical reactions of galvanized reinforcing steels in fresh concrete. By means of electrochemical measurements and bar pull‐out tests the effect of chromates on the formation of protective coatings at the zinc and the bond behaviour have been investigated using chromate‐containing and chromate‐reduced cements. The results have shown that the bond zone was affected as a result of chromate reduction for cement types CEM I and CEM II. The disturbance to the bond zone should be considered as long‐term in relation to the pore structure which is formed. The effects on the bond are largely compensated for as the concrete ages. The results of the related bond strength with displacement paths of 0.1 and 0.5 mm, respectively, are still within the range of expected figures for non‐galvanized reinforcing steel despite the structural disturbance. Under practical aspects it is not necessary that the existing structural disturbance with respect to bond strength is taken into consideration.

A failure study of condenser tube manufactured from low nickel stainless steels

2012-03-13T00:11:05Z

A failure study of condenser tube manufactured from low nickel stainless steels

Engineering Failure Analysis, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Engineering Failure Analysis D.N. Wasnik A failure analysis of condenser tubes manufactured from Type 204 stainless steel was conducted to find the root cause of failures. The failures were observed in the parent materials of the tube rather than from welding or heat-affected zones. A detailed metallography, corrosion test and stress analysis study has been carried out to find out the root cause of failure, and it revealed that the parent materials of the tube were highly sensitized, and post-annealing treatment had been not performed by the manufacturers. The condenser tube failed prematurely due to sensitization and the presence of thermal residual stresses exacerbates this. This study emphasizes the metallurgical analysis performed to identify the root cause of failure of condenser tubes manufactured from Type 204 stainless steel.

Nanomechanical evaluation of the protectiveness of nitrided layers against hydrogen embrittlement

2012-05-15T23:03:26Z

Nanomechanical evaluation of the protectiveness of nitrided layers against hydrogen embrittlement

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science M. Asgari, A. Barnoush, R. Johnsen, R. Hoel In this work, the nitrided layer on austenitic AISI 316L stainless steels were examined by means of in-situ electrochemical nanoindentation, and the effect of electrochemically charged hydrogen on the mechanical properties were investigated. By using this method, changes in the mechanical properties due to the absorption of atomic hydrogen at different nitride layer depths have been traced. One important finding is that hydrogen charging of the nitriding layer can soften the layer and reduce the layer hardness, and the reduction of the nitrogen concentration in the nitride layer reduces this softening effect. Graphical Abstract Graphical abstract Highlights ► Plasma nitride layer of 316 SS was studied by electrochemical nanoindentation. ► H Effect on mechanical properties of the substrate and nitride layer was studied. ► H increases the hardness of 316 SS and has opposite effect on the nitride layer. ► The H induced softening is advantageous for controlling the H embrittlement. ► The H induced softening is dependent on the N concentration.

High temperature behavior of the metal/oxide interface of ferritic stainless steels

2012-04-25T23:03:31Z

High temperature behavior of the metal/oxide interface of ferritic stainless steels

Corrosion Science, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Corrosion Science, Volume 59 Jérôme Issartel, Sébastien Martoia, Frédéric Charlot, Valérie Parry, Guillaume Parry, Rafael Estevez, Yves Wouters Two grades of ferritic stainless steel, a bi-stabilized (Ti, Nb) AISI 441 and a stabilized (Ti) AISI 439, were oxidized at 1060°C under simulated process atmosphere for durations between 45 and 1800s. Focused Ion Beam (FIB) coupled with Field Emission Gun and Scanning Electron Microscopy (FEG/SEM) was used to investigate the morphology of the oxide layer. Particularly, metallic protrusions localized at the metal/oxide interface and bulging out through the silica layer were observed. A model based on stress assisted diffusion of oxygen was employed to estimate the effects of the heterogeneous distribution of silica in the oxide. The oxide layer is thought to induce non-uniform nucleation of silica at the metal/oxide interface. Further lateral growth of the silica layer then leads to the formation of metallic protrusions.

Inhibition of hydrogen sulfide corrosion of steel by catamin AB

L. V. Frolova E. V. Tomina ; L. P. Kazanskii ; Yu. I. Kuznetsov — Sun, 09 Nov 2008 10:10:31 GMT

Inhibition of hydrogen sulfide corrosion of steel by catamin AB
L. V. Frolova E. V. Tomina ; L. P. Kazanskii ; Yu. I. Kuznetsov
Protection of Metals, Vol. , No. (2008) pp. -
The protective properties of a quaternary ammonium salt (dimethyl alkyl benzyl ammonium chloride, or catamin AB) have been studied in wide intervals of concentrations of H2S (from 10 to 2000 mg/l) and of the inhibitor (from 25 to 500 mg/l). It is shown that catamin AB, which effectively slows down the corrosion of steels and preserves their plastic properties in aqueous solutions saturated by hydrogen sulfide to approximately CH2 S = 2000 mg/l, does not possess high protective properties in the same solutions at CH2 S = 0.0−50.0 mg/l. According to the results of XPS studies, this fact is connected to the weak adsorption of this inhibitor on the surface of steel in the absence of a film of iron sulfides on it. Based on the XPS data, it has been shown that, in media containing high concentrations of H2S, a thin (a few nanometers thick) film of iron sulfides is formed on steel. This film is covered with a monomolecular layer of catamin AB, impeding the dissolution of the steel and further growth of the sulfide film.

Inhibition investigation and determination of some quantum chemical parameters of 1‐(4‐(dimethylamino)benzylidene)thiosemicarbazide on steel alloys in sulfuric acid medium

Inhibition investigation and determination of some quantum chemical parameters of 1‐(4‐(dimethylamino)benzylidene)thiosemicarbazide on steel alloys in sulfuric acid medium

Materials and Corrosion, Vol. , No. () pp. -
The inhibition effect of 1‐(4‐(dimethylamino)benzylidene)thiosemicarbazide (DBT) on the corrosion behavior of 304 stainless steel and mild steel in 0.5 M sulfuric acid solution was investigated using weight loss and potentiostatic polarization methods. The experimental results suggest that DBT inhibits the corrosion of the steels in acid solution. The inhibition efficiencies increased as the concentration of the compound was increased. The calculated inhibition efficiencies from the two investigated methods were in good agreement. Potentiostatic polarization measurements indicate that DBT acts as a mixed type inhibitor for both alloys. The adsorption of inhibitor on the steel surfaces obeys Langmuir adsorption isotherm. The structure of DBT was optimized using PM3 semi‐empirical method. Highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), energy levels, ELUMO − EHOMO (energy gap), dipole moment (µ), and Mulliken charge densities for this molecule were computed and the adsorption mechanism was discussed. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the surfaces of the alloys.

Cadmium- and chromate-free coating schemes for corrosion protection of 15CDV6 steel

2012-03-09T01:38:48Z

Cadmium- and chromate-free coating schemes for corrosion protection of 15CDV6 steel

Metal Finishing, Vol. , No. (2012) pp. -
Publication year: 2011 Source:Metal Finishing, Volume 109, Issue 3 Indumathi S.N, T. Vasudevan, S. Sundarrajan, B.V. Subba Rao, C.V.S. Murthy, D.R. Yadav Electrodeposits of cadmium- and chromate-based inorganic inhibitor pigments in paint formulations are extensively used in the aerospace industry to provide long-term corrosion protection for high-strength steel hardware. Due to environmental concerns and worker safety issues, there is a pressing need to identify and adopt alternative ecofriendly coatings with equivalent performance. In this work, an ecofriendly cadmium- and chromatefree coating scheme comprised of zinc nickel alloy plating, trivalent chromium- based passivation, followed by a primer based on polyaniline phosphate, is studied for its anticorrosive properties. Long-term performance evaluation studies of this eco-friendly coating scheme were carried out on 15CDV6 steel, an ultra-high- strength steel used in the aerospace industry. For comparative purposes, two extensively used cadmium- and chromate-based schemes complying to aerospace and military specifications comprised of cadmium plating, hexavalent chromium-based passivation followed by two different chromate-based primers were studied on 15CDV6 steel substrate. Electrochemical impedance spectroscopic studies and salt fog exposure tests were carried out to evaluate the anticorrosive properties of the coat- ing schemes. Cadmium- and chromate-free scheme exhibited excellent performance in the long-term corrosion evaluation studies. The results obtained in accelerated tests show the possibility of replacement of cadmium- and chromate-based schemes for corrosion protection of steels with an eco-friendly option.

Comparison between symmetric and asymmetric hot rolling techniques performed on duplex stainless steel 2205

C. Mapelli S. Barella ; D. Mombelli ; C. Baldizzone ; A. Gruttadauria — Wed, 11 Jan 2012 17:57:27 GMT

Comparison between symmetric and asymmetric hot rolling techniques performed on duplex stainless steel 2205
C. Mapelli S. Barella ; D. Mombelli ; C. Baldizzone ; A. Gruttadauria
International Journal of Material Forming, Vol. , No. (2012) pp. 1 - 13
Abstract The use of duplex stainless steel represents one possible efficient alternative of austenitic grade and an interesting resources for its high performance against stress corrosion cracking. Unfortunately such material shows some limitations in their use: for instance the sheets or plates of duplex stainless steels present anomalous and poor formability for plastic deformation processes. Such problems are mainly related to an unsuitable normal anisotropy coefficient, which might cause the “necking” and “earing” phenomena, especially during hot rolling. The study deals with the comparison of symmetric and asymmetric rolling technique on stainless steel duplex 2205 specimens. All the experiments were carried out using a laboratory mill, properly equipped with an individual engine for each rolling cylinder. The experimental parameters considered include three different pre-heating temperatures and two asymmetry ratios, while the reduction level is maintained constant for both rolling configurations. Moreover, the study involves also the analysis of the influence of solubilization quenching and the SEM, SEM-EBSD investigation dedicated to establish the microstructure modifications. The specimens were also studied through tensile tests to determine the influence of the rolling techniques on the mechanical properties of the product, focusing on the definition of the average anisotropy coefficient. The results of the experimental trials allow to conclude that the use of asymmetric rolling process induces an improved formability and increases duplex 2205 tensile properties.

Investigation of hydrogen assisted cracking of a high strength steel using circumferentially notched tensile test

2012-04-30T00:34:45Z

Investigation of hydrogen assisted cracking of a high strength steel using circumferentially notched tensile test

Materials Science and Engineering: A, Vol. , No. (2012) pp. -
Publication year: 2012 Source:Materials Science and Engineering: A, Volume 547 N.R. Raykar, R.K. Singh Raman, S.K. Maiti, Lokesh Choudhary The novel circumferentially notched tensile (CNT) test technique is used for the first time for an investigation of hydrogen assisted stress corrosion cracking. Effect of hydrogen on the fracture strength of high strength steel AS-4340 is examined in neutral 3.5% NaCl solution at room temperature and under hydrogen supply from within the material and/or external environment. A progressive drop in the stress intensity factor at the fracture was observed as a result of: (a) increasing span of hydrogen pre-charging (hence increasing internal hydrogen) and (b) decreasing rate of loading (hence increasing external supply of hydrogen). The measured critical stress intensity factors corresponding to varying degrees of supply of internal hydrogen are consistent with the computed hydrogen concentrations ahead of the crack tip. The experimentally determined threshold for hydrogen embrittlement in the regime of slower loading rates are consistent with the published data. The results presented here establish the usefulness of the CNT test technique for the investigation of HASCC in high strength steel over a wider range of loading rate. Graphical Abstract Highlights ► Novel CNT testing was successfully employed for HASCC study of a high strength steel. ► Effects of both internal and external hydrogen were examined. ► Fracture toughness K Ic H relates to theoretical hydrogen distribution at/around crack tip. ► K Ic H for lower loading rates agree with published threshold fracture toughness data. ► Utility of CNT tests for study of HASCC in steels was established.