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Sample records for corrosion resistant steel

  1. Pitting corrosion resistant austenite stainless steel

    Science.gov (United States)

    van Rooyen, D.; Bandy, R.

    A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

  2. Corrosion Mechanism of Corrosion-Resistant Steel Developed for Bottom Plate of Cargo Oil Tanks

    Institute of Scientific and Technical Information of China (English)

    Feilong SUN; Xiaogang LI; Fan ZHANG; Xuequn CHENG; Cheng ZHOU; Nianchun WU; Yuqun YIN

    2013-01-01

    A new type of corrosion-resistant steel consisting of ferrite and bainite phases was developed for cargo oil tanks of crude oil tankers.The corrosion rate of this new steel was 0.22 mm/a,which was equivalent to ca.1/5 of the criterion (≤ 1 mm/a) for corrosion-resistant steels.The composition and element distribution of the corrosion products were investigated by micro-Raman spectrometry and energy dispersive spectrometer.The results demonstrated that the corrosion product was composed of α-FeOOH,Fe3O4 and a continuous Cu enrichment layer.This kind of corrosion product was protective to the steel matrix and accounted for the enhancement of the corrosion resistance of the new developed steel.

  3. Plastic deformation effect of the corrosion resistance in case of austenitic stainless steel

    Science.gov (United States)

    Haraszti, F.; Kovacs, T.

    2017-02-01

    The corrosion forms are different in case of the austenitic steel than in case of carbon steels. Corrosion is very dangerous process, because that corrosion form is the intergranular corrosion. The austenitic stainless steel shows high corrosion resistance level. It knows that plastic deformation and the heat treating decrease it’s resistance. The corrosion form in case of this steel is very special and the corrosion tests are difficult. We tested the selected steel about its corrosion behaviour after high rate deformation. We wanted to find a relationship between the corrosion resistance decreasing and the rate of the plastic deformation. We wanted to show this behaviour from mechanical and electrical changing.

  4. Formation of Surface Corrosion-Resistant Nanocrystalline Structures on Steel.

    Science.gov (United States)

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha; Slobodyan, Zvenomyra; Tsyrulnyk, Oleksandr

    2016-12-01

    Engineering materials with nanocrystalline structure could be exploited under simultaneous action of mechanical loading and corrosion environments; therefore, their corrosion resistance is important. Surface nanocrystalline structure was generated on middle carbon steels by severe plastic deformation using the method of mechanical pulse friction treatment. This treatment additionally includes high temperature phase transformation and alloying. Using a complex of the corrosive, electrochemical and physical investigations, it was established that nanocrystalline structures can be characterized by lower or increased corrosion resistance in comparison with the reference material. It is caused by the action of two confronting factors: arising energy level and anticorrosive alloying of the surface layer.

  5. Corrosion resistance of high strength modified 13Cr steel

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Mitsuo; Miyata, Yukio; Yamane, Yasuyoshi; Toyooka, Takaaki; Nakano, Yoshifumi [Kawasaki Steel Corp., Handa, Aichi (Japan). Technical Research Labs.; Murase, Fumio [Kawasaki Steel Corp., Handa, Aichi (Japan). Chita Works

    1997-08-01

    A new 13Cr martensitic stainless steel (0.025C-13Cr-Ni-Mo) with excellent resistance to CO{sub 2} corrosion and good resistance to SSC is developed and its application limit in oil and gas environments is clarified. The CO{sub 2} corrosion rate of the 13Cr steels with Ni and Mo is less than 0.3 mm/yr at 180 C (356 F) in 20% NaCl. It is less than that of the conventional 13Cr steel (0.2C-13Cr). The corrosion rate of the steel slightly decreases with the increase in Mo and Ni content. The SSC resistance improves with the increase in Mo content. The critical partial pressure of H{sub 2}S for the 2% Mo steel is greater than 0.005 MPa at the pH value of 3.5. The effects of Ni and Cu on SSC are not distinctive for this kind of steel. These results depends on the hydrogen permeability. The critical H{sub 2}S partial pressure for the 110 grade steel is the same as that of the 95 grade steel at the pH values of 4.5 and 3.0, and is slightly lower at the pH values between 3.0 and 4.5. The new 13Cr steel proves to have excellent properties in the sweet and slightly sour environment.

  6. 78 FR 15376 - Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea

    Science.gov (United States)

    2013-03-11

    ... COMMISSION Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea On the basis... Korea and the antidumping duty orders on corrosion-resistant carbon steel flat products from Germany and... Corrosion-Resistant Carbon Steel Flat Products from Germany and Korea: Investigation Nos. 701-TA-350 and...

  7. Influence of Trace Alloying Elements on Corrosive Resistance of Cast Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    DUAN Han-qiao; YAN Xiang; WEI Bo-kang; LIN Han-tong

    2005-01-01

    The influences of trace alloying elements niobium, vanadium and zirconium on the corrosive resistance of 18-8 type cast stainless steel have been studied in deta() orthogonal design experiments. The results show that zirconium is mainly in the form of compound inclusions, which is unfavorable to promote the corrosive resistance of the cast stainless steel. It can alleviate the disadvantageous influence of carbon addition on corrosive resistance when some elements such as vanadium and niobium exist in the steel, and niobium has a remarkable influence on the intergranular corrosive resistance but unobvious on the pitting corrosion, and vanadium has a slightly favorable influence on the corrosive resistance of the steel.

  8. Corrosion resistance of zinc-magnesium coated steel

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, N.C. [Ford Motor Company Ltd., Dunton Engineering Centre, Room GB15/GM-D01, Laindon, Basildon, Essex SS15 6EE (United Kingdom) and School of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)]. E-mail: niamh.hosking@gmail.com; Stroem, M.A. [Volvo Car Corporation, Building VCPC, Maildrop PV 1B, Volvo Jacobs vag, Goeteborg SE-405 31 (Sweden); Shipway, P.H. [School of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Rudd, C.D. [School of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2007-09-15

    A significant body of work exists in the literature concerning the corrosion behaviour of zinc-magnesium coated steel (ZMG), describing its enhanced corrosion resistance when compared to conventional zinc-coated steel. This paper begins with a review of the literature and identifies key themes in the reported mechanisms for the attractive properties of this material. This is followed by an experimental programme where ZMG was subjected to an automotive laboratory corrosion test using acidified NaCl solution. A 3-fold increase in time to red rust compared to conventional zinc coatings was measured. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the corrosion products formed. The corrosion products detected on ZMG included simonkolleite (Zn{sub 5}Cl{sub 2}(OH){sub 8} . H{sub 2}O), possibly modified by magnesium uptake, magnesium hydroxide (Mg(OH){sub 2}) and a hydroxy carbonate species. It is proposed that the oxygen reduction activity at the (zinc) cathodes is reduced by precipitation of alkali-resistant Mg(OH){sub 2}, which is gradually converted to more soluble hydroxy carbonates by uptake of atmospheric carbon dioxide. This lowers the surface pH sufficiently to allow thermodynamically for general precipitation of insoluble simonkolleite over the corroding surface thereby retarding the overall corrosion reactions, leaving only small traces of magnesium corrosion products behind. Such a mechanism is consistent with the experimental findings reported in the literature.

  9. A liquid aluminum corrosion resistance surface on steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wang Deqing; Shi Ziyuan; Zou Longjiang

    2003-05-31

    The process of hot dipping pure aluminum on a steel substrate followed by oxidation was studied to form a surface layer of aluminum oxide resistant to the corrosion of aluminum melt. The thickness of the pure aluminum layer on the steel substrate is reduced with the increase in temperature and time in initial aluminizing, and the thickness of the aluminum layer does not increase with time at given temperature when identical temperature and complete wetting occur between liquid aluminum and the substrate surface. The thickness of the Fe-Al intermetallic layer on the steel base is increased with increasing bath temperature and time. Based on the experimental data and the mathematics model developed by the study, a maximum exists in the thickness of the Fe-Al intermetallic at certain dipping temperature. X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis reveals that the top portion of the steel substrate is composed of a thin layer of {alpha}-Al{sub 2}O{sub 3}, followed by a thinner layer of FeAl{sub 3}, and then a much thicker one of Fe{sub 2}Al{sub 5} on the steel base side. In addition, there is a carbon enrichment zone in diffusion front. The aluminum oxide surface formed on the steel substrate is in perfect condition after corrosion test in liquid aluminum at 750 deg. C for 240 h, showing extremely good resistance to aluminum melt corrosion.

  10. Corrosion resistance properties of sintered duplex stainless steel

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2006-09-01

    Full Text Available Purpose: of this paper was to examine the corrosion resistance of duplex stainless steels using electrochemical methods in 1M NaCl solution. The influence of powder mixes preparation and cooling cycle after sintering on corrosion properties was evaluated.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies behind the preparation of mixes, Schaeffler’s diagram was taken into consideration. Prepared mixes have been compacted at 800 MPa and sintered in a vacuum furnace with argon backfilling at 1260°C for 1 h. After sintering two different cooling cycles were applied: rapid cooling with an average cooling rate of 245 °C/min and slow cooling of 5 °C/min in argon atmosphere. Produced duplex stainless steels have been studied by scanning and optical microscopy and EDS chemical analysis of microstructure components. Corrosion properties have been studied through electrochemical methods in 1M NaCl water solutionFindings: According to achieved results, it was affirmed that applied sintering method as well as powder mixes preparation allows for manufacturing the sintered duplex steels with good corrosion properties which depends on austenite/ferrite ratio in the microstructure and elements partitioning between phases. Corrosion resistance of sintered stainless steels is strictly connected with the density and the pore morphology present in the microstructure too. The highest resistance to pitting corrosion in 1M NaCl solution was achieved for composition with approximate balance of ferrite and austenite in the microstructure.Research limitations/implications: According to the powders characteristic, the applied fast cooling rate seems to be a good compromise for corrosion properties and microstructures, nevertheless further tests should be carried out in

  11. Nanocrystallization of aluminized surface of carbon steel for enhanced resistances to corrosion and corrosive wear

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C. [Dept. of Materials Physical and Chemical, University of Science and Technology Beijing, Beijing 100083 (China); Dept. of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Li, D.Y., E-mail: dongyang.li@ualberta.c [Dept. of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Shang, C.J. [Dept. of Materials Physical and Chemical, University of Science and Technology Beijing, Beijing 100083 (China)

    2009-12-15

    Aluminizing is often used to improve steel's resistances to corrosion, oxidation and wear. This article reports our recent attempts to further improve aluminized carbon steel through surface nanocrystallization for higher resistances to corrosion and corrosive wear. The surface nanocrystallization was achieved using a process combining sandblasting and recovery heat treatment. The entire surface modification process includes dipping carbon steel specimens into a molten Al pool to form an Al coat, subsequent diffusion treatment at elevated temperature to form an aluminized layer, sandblasting to generate dislocation network or cells, and recovery treatment to turn the dislocation cells into nano-sized grains. The grain size of the nanocrystallized aluminized surface layer was in the range of 20-100 nm. Electrochemical properties, electron work function (EWF), and corrosive wear of the nanocrystalline alloyed surfaces were investigated. It was demonstrated that the nanocrystalline aluminized surface of carbon steel exhibited improved resistances to corrosion, wear and corrosive wear. The passive film developed on the nanocrystallized aluminized surface was also evaluated in terms of its mechanical properties and adherence to the substrate.

  12. Wear resistance and corrosion resistance of VCp particle reinforced stainless steel composites

    Institute of Scientific and Technical Information of China (English)

    YAO Xiu-rong; HAN Jie-cai; ZUO Hong-bo; LIU Zhao-jing; LI Feng-zhen; REN Shan-zhi

    2005-01-01

    The VCp reinforced stainless steel composite was produced by in-situ reaction casting. The composite was tested for its wear resistance under the wet abrasive condition and corrosion resistance, compared with the wear-resistant white iron and stainless steel. The results show that the wear resistance of the composite is slightly inferior to that of the white iron, but much better than that of the stainless steel under the wet grinding abrasive condition. The corrosion resistance of the composite is much better than that of the white iron in the acid medium,and a little worse than that of the stainless steel. Thus the composite exhibits superior properties of wear resistance and corrosion resistance.

  13. Corrosion Resistance of Ceramic Coating on Steel Substrate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fe/Al2O3 ceramic coating was made by spraying and sol-gel. The corrosion resistance between Fe/Al2O3 ceramic coating and steel 45# was studied. By microscope and X-ray diffraction, the binding and the composition of the interface were also analyzed. The results showed that Fe/Al2O3 ceramic coating had dense structure, less porosity and better binding with the substrate which was effective to prevent erosive liquor immersing into the inside of ceramic coating. Some substances that distributed homogeneously in Fe/Al2O3 ceramic coating,such as α-Al2O3, FeAlO3 and Fe3Al, could improve the corrosion resistance of this material.

  14. Corrosion resistance of kolsterised austenitic 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Abudaia, F. B., E-mail: fabudaia@yahoo.com; Khalil, E. O., E-mail: ekhalil9@yahoo.com; Esehiri, A. F., E-mail: Hope-eseheri@hotmail.co.uk; Daw, K. E., E-mail: Khawladaw@yahoo.com [University of Tripoli Department of Materials and Metallurgical Eng, Tripoli-Libya P.O.Box13589 (Libya)

    2015-03-30

    Austenitic stainless suffers from low wear resistance in applications where rubbing against other surfaces is encountered. This drawback can be overcome by surface treatment such as coating by hard materials. Other treatments such as carburization at relatively low temperature become applicable recently to improve hardness and wear resistance. Carburization heat treatment would only be justified if the corrosion resistance is unaffected. In this work samples of 304 stainless steels treated by colossal supersaturation case carburizing (known as Kolsterising) carried out by Bodycote Company was examined for pitting corrosion resistance at room temperature and at 50 °C. Comparison with results obtained for untreated samples in similar testing conditions show that there is no deterioration in the pitting resistance due to the Kolsterising heat treatment. X ray diffraction patterns obtained for Kolsterising sample showed that peaks correspond to the austenite phase has shifted to lower 2θ values compared with those of the untreated sample. The shift is an indication for expansion of austenite unit cells caused by saturation with diffusing carbon atoms. The XRD of Kolsterising samples also revealed additional peaks appeared in the patterns due to formation of carbides in the kolsterised layer. Examination of these additional peaks showed that these peaks are attributed to a type of carbide known as Hagg carbide Fe{sub 2}C{sub 5}. The absence of carbides that contain chromium means that no Cr depletion occurred in the layer and the corrosion properties are maintained. Surface hardness measurements showed large increase after Kolsterising heat treatment.

  15. Corrosion resistance of kolsterised austenitic 304 stainless steel

    Science.gov (United States)

    Abudaia, F. B.; Khalil, E. O.; Esehiri, A. F.; Daw, K. E.

    2015-03-01

    Austenitic stainless suffers from low wear resistance in applications where rubbing against other surfaces is encountered. This drawback can be overcome by surface treatment such as coating by hard materials. Other treatments such as carburization at relatively low temperature become applicable recently to improve hardness and wear resistance. Carburization heat treatment would only be justified if the corrosion resistance is unaffected. In this work samples of 304 stainless steels treated by colossal supersaturation case carburizing (known as Kolsterising) carried out by Bodycote Company was examined for pitting corrosion resistance at room temperature and at 50 °C. Comparison with results obtained for untreated samples in similar testing conditions show that there is no deterioration in the pitting resistance due to the Kolsterising heat treatment. X ray diffraction patterns obtained for Kolsterising sample showed that peaks correspond to the austenite phase has shifted to lower 2θ values compared with those of the untreated sample. The shift is an indication for expansion of austenite unit cells caused by saturation with diffusing carbon atoms. The XRD of Kolsterising samples also revealed additional peaks appeared in the patterns due to formation of carbides in the kolsterised layer. Examination of these additional peaks showed that these peaks are attributed to a type of carbide known as Hagg carbide Fe2C5. The absence of carbides that contain chromium means that no Cr depletion occurred in the layer and the corrosion properties are maintained. Surface hardness measurements showed large increase after Kolsterising heat treatment.

  16. Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

    Science.gov (United States)

    Park, Jong-Hee; Natesan, Krishnamurti; Rink, David L.

    2010-03-16

    An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

  17. Influence of Heat Treatments on the Corrosion Resistance of Medium -Carbon Steel using Sulfuric Spring Water

    Directory of Open Access Journals (Sweden)

    Ikhlas Basheer

    2013-04-01

    Full Text Available The corrosion is one of the important problems that may be occur to the parts of machinery and equipment after manufactured and when used as a result of exposure to corrosive media. Plain-carbon steel is considered as one of the most common minerals used in industrial applications. Some of heat treatments can have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. Therefore, to adopt one of kinds of the plain-carbon steel and the most commonly used in industry to be study subject, that is medium carbon steel and took samples of this steel has been treated thermally in three methods which the normalising, annealing, and hardening .The corrosive media used in the research is Sulfuric Spring, it contains many chemical compounds to show its influence on the corrosion of steel. The weight loss method is used to determine corrosion rate and to compare between the results obtained, show that the greatest corrosion resistance of the annealed steel and the corrosion resistance of the hardened steel is the lowest while the corrosion  resistance of the normalised steel is in-between them.         Calcium carbonate was formed on the metal surface which acts as an isolating layer which decrease corrosion rate with time

  18. 75 FR 55745 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results...

    Science.gov (United States)

    2010-09-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea) for the period of... preliminary results of the instant administrative review. See Corrosion-Resistant Carbon Steel Flat Products...

  19. 77 FR 24221 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission...

    Science.gov (United States)

    2012-04-23

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission... countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to lead...

  20. 77 FR 72827 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea: Final...

    Science.gov (United States)

    2012-12-06

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... on certain corrosion- resistant carbon steel flat products (``CORE'') from Germany and the Republic... Reviews'' section of this notice. \\1\\ Corrosion-Resistant Carbon Steel Flat Products From Germany and the...

  1. 77 FR 44213 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea...

    Science.gov (United States)

    2012-07-27

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... certain corrosion-resistant carbon steel flat products (``CORE'') from Germany and the Republic of Korea..., Director, Office 3, on ``Sunset Reviews of the Antidumping Duty Orders on Corrosion-Resistant Carbon Steel...

  2. 78 FR 55057 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2013-09-09

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea... antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea.... See Corrosion-Resistant Carbon Steel Flat Products from Germany and the Republic of Korea: Revocation...

  3. 78 FR 16832 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea: Revocation...

    Science.gov (United States)

    2013-03-19

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... corrosion-resistant carbon steel flat products (``CORE'') from Germany and the Republic of Korea (``Korea...-Year (``Sunset'') Review, 77 FR 85 (January 3, 2012). \\2\\ See Corrosion-Resistant Carbon Steel Flat...

  4. 77 FR 301 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea: Institution of Five-Year...

    Science.gov (United States)

    2012-01-04

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea: Institution of Five-Year Reviews Concerning the Countervailing Duty Order on Corrosion-Resistant Carbon Steel Flat Products From Korea and the Antidumping Duty Orders on Corrosion-Resistant Carbon Steel Flat Products From Germany and...

  5. 78 FR 16247 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea; Final Results of...

    Science.gov (United States)

    2013-03-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea... section entitled ``Final Results of Review.'' \\1\\ See Certain Corrosion-Resistant Carbon Steel Flat...

  6. 76 FR 3613 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2011-01-20

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... review of the countervailing duty (CVD) order on corrosion-resistant carbon steel flat products (CORE..., 2008. See Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary...

  7. 76 FR 77775 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2011-12-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea... countervailing duty order on corrosion-resistant carbon steel flat products from the Republic of Korea covering the period January 1, 2009, through December 31, 2009. See Corrosion-Resistant Carbon Steel Flat...

  8. 77 FR 13093 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2012-03-05

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... administrative review of the countervailing duty (``CVD'') order on corrosion-resistant carbon steel flat... Review'' below. \\1\\ See Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea...

  9. 77 FR 31877 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five...

    Science.gov (United States)

    2012-05-30

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five... duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to lead to...

  10. Corrosion-resistant Foamed Cements for Carbon Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Gill, S.; Pyatina, T., Muraca, A.; Keese, R.; Khan, A.; Bour, D.

    2012-12-01

    The cementitious material consisting of Secar #80, Class F fly ash, and sodium silicate designed as an alternative thermal-shock resistant cement for the Enhanced Geothermal System (EGS) wells was treated with cocamidopropyl dimethylamine oxide-based compound as foaming agent (FA) to prepare numerous air bubble-dispersed low density cement slurries of and #61603;1.3 g/cm3. Then, the foamed slurry was modified with acrylic emulsion (AE) as corrosion inhibitor. We detailed the positive effects of the acrylic polymer (AP) in this emulsion on the five different properties of the foamed cement: 1) The hydrothermal stability of the AP in 200 and #61616;C-autoclaved cements; 2) the hydrolysis-hydration reactions of the slurry at 85 and #61616;C; 3) the composition of crystalline phases assembled and the microstructure developed in autoclaved cements; 4) the mechanical behaviors of the autoclaved cements; and, 5) the corrosion mitigation of carbon steel (CS) by the polymer. For the first property, the hydrothermal-catalyzed acid-base interactions between the AP and cement resulted in Ca-or Na-complexed carboxylate derivatives, which led to the improvement of thermal stability of the AP. This interaction also stimulated the cement hydration reactions, enhancing the total heat evolved during cement’s curing. Addition of AP did not alter any of the crystalline phase compositions responsible for the strength of the cement. Furthermore, the AP-modified cement developed the porous microstructure with numerous defect-free cavities of disconnected voids. These effects together contributed to the improvement of compressive-strength and –toughness of the cured cement. AP modification of the cement also offered an improved protection of CS against brine-caused corrosion. There were three major factors governing the corrosion protection: 1) Reducing the extents of infiltration and transportation of corrosive electrolytes through the cement layer deposited on the underlying CS

  11. A Study on Corrosion Resistance of Coating System on Steel

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Hwan Seon; Lee, Hyeon Ju; Kim, Kang Seok [Korea Electricity Power Research Institute, Daejeon (Korea, Republic of); Lee, Chul Woo [KEPCO E and Co., Yongin (Korea, Republic of)

    2007-04-15

    The design purpose of architectural finish on steel structures is to prevent corrosion in the respect of structural durability, function, beauty and economy. In particular, as structures located on shores is easily degraded due to damage from salt, it is necessary to evaluate the applied coating systems on steel structures. This study is focused on anti-corrosive tests of both steel surfaces and high strength bolts. Two kinds of tests were conducted on each specimen under the condition of outdoor exposure and salt spray comparatively during 760 hours. In case of coating systems on steel surfaces, three layered coating system showed the best function among the various coating systems. Regarding the coating systems on high strength bolts, the coating system composed of zinc dust on hot dip galvanized coating was found to be the best against corrosion.

  12. Evaluation of stainless steels for their resistance to intergranular corrosion

    Science.gov (United States)

    Korostelev, A. B.; Abramov, V. Ya.; Belous, V. N.

    1996-10-01

    Austenitic stainless steels are being considered as structural materials for first wall/blanket systems in the International Thermonuclear Reactor (ITER). The uniform corrosion of stainless steels in water is well known and is not a critical issue limiting its application for the ITER design. The sensitivity of austenitic steels to intergranular corrosion (IGC) can be estimated rather accurately by means of calculation methods, considering structure and chemical composition of steel. There is a maximum permissible carbon content level, at which sensitization of stainless steel is eliminated: K = Cr eff - αC eff, where α-thermodynamic coefficient, Cr eff-effective chromium content (regarding molybdenum influence) and C eff-effective carbon content (taking into account nickel and stabilizing elements). Corrosion tests for 16Cr11Ni3MoTi, 316L and 316LN steel specimens, irradiated up to 2 × 10 22 n/cm 2 fluence have proved the effectiveness of this calculation technique for determination of austenitic steels tendency to IGC. This method is directly applicable in austenitic stainless steel production and enables one to exclude complicated experiments on determination of stainless steel susceptibility to IGC.

  13. Evaluation of stainless steels for their resistance to intergranular corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Korostelev, A.B. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation); Abramov, V.Ya. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation); Belous, V.N. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation)

    1996-10-01

    Austenitic stainless steels are being considered as structural materials for first wall/blanket systems in the international thermonuclear reactor (ITER). The uniform corrosion of stainless steels in water is well known and is not a critical issue limiting its application for the ITER design. The sensitivity of austenitic steels to intergranular corrosion (IGC) can be estimated rather accurately by means of calculation methods, considering structure and chemical composition of steel. There is a maximum permissible carbon content level, at which sensitization of stainless steel is eliminated: K=Cr{sub eff}-{alpha}C{sub eff}, where {alpha}-thermodynamic coefficient, Cr{sub eff}-effective chromium content (regarding molybdenum influence) and C{sub eff}-effective carbon content (taking into account nickel and stabilizing elements). Corrosion tests for 16Cr11Ni3MoTi, 316L and 316LN steel specimens, irradiated up to 2 x 10{sup 22} n/cm{sup 2} fluence have proved the effectiveness of this calculation technique for determination of austenitic steels tendency to IGC. This method is directly applicable in austenitic stainless steel production and enables one to exclude complicated experiments on determination of stainless steel susceptibility to IGC. (orig.).

  14. 77 FR 58512 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2012-09-21

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... conducting an administrative review of the countervailing duty (CVD) order on corrosion-resistant carbon... Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Notice of Extension of...

  15. 76 FR 54209 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2011-08-31

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... conducting an administrative review of the countervailing duty (CVD) order on corrosion-resistant carbon... CORE from Korea with regard to Dongbu and POSCO. See Corrosion-Resistant Carbon Steel Flat Products...

  16. 78 FR 19210 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2013-03-29

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) has completed its administrative review of the countervailing duty (CVD) order on corrosion-resistant...\\ See Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

  17. Martensitic stainless steel seamless linepipe with superior weldability and CO{sub 2} corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Y.; Kimura, M.; Koseki, T.; Toyooka, T.; Murase, F. [Kawasaki Steel Corp., Handa, Aichi (Japan)

    1997-08-01

    Two types of new martensitic stainless steel with good weldability and superior corrosion resistance have been developed for line pipe application. Both steels are suitable for welding without preheating owing to lowering C and N contents, and they show good low temperature toughness in welds without PWHT. One is applied to sweet environments. It gives better resistance to CO{sub 2} corrosion than the 13Cr martensitic stainless steel for OCTG. Lowering C and addition of Ni contribute to reduction of general corrosion rate in the CO{sub 2} environment. The addition of Cu improves the pitting resistance. The other is applied to light sour environments. It gives good SSC resistance in welds owing to the improvement of the pitting resistance due to Mo addition. The seamless pipes of these martensitic stainless steels are applicable as substitutes for a part of duplex stainless steel flow lines.

  18. Nanostructure and Properties of Corrosion Resistance in C+Ti Multi-Ion-Implanted Steel

    Institute of Scientific and Technical Information of China (English)

    张通和; 吴瑜光; 刘安东; 张旭; 王晓妍

    2003-01-01

    The corrosion and pitting corrosion resistance of C+ Ti dual and C+Ti+C ternary implanted H13 steel were studied by using a multi-sweep cyclic voltammetry and a scanning electron microscope. The effects of phase formation on corrosion and pitting corrosion resistance were explored. The x-ray diffraction analysis shows that the nanometer-sized precipitate phases consist of compounds of Fe2 Ti, TiC, Fe2C and Fe3 C in dual implanted layer and even in ternary implanted layer. The passivation layer consists of these nanometer phases. It has been found that the corrosion and pitting corrosion resistance of dual and ternary implanted H13 steel are improved extremely. The corrosion resistance of ternary implanted layer is better than that of dual implantations and is enhanced with the increasing ion dose. When the ion dose of Ti is 6 × 1017/cm2 in the ternary implantation sample, the anodic peak current density is 95 times less than that of the H13 steel. The pitting corrosion potential of dual and ternary implantation samples is in the range from 55mV to 160mV which is much higher than that of the H13 steel. The phases against the corrosion and pitting corrosion are nanometer silkiness phases.

  19. Effect of Rare Earths on Corrosion Resisting Properties of Carbon-Manganese Clean Steels

    Institute of Scientific and Technical Information of China (English)

    郭锋; 林勤; 孙学义

    2004-01-01

    Electrochemistry experiments were made on carbon-manganese clean steel with rare earths Ce and La respectively to observe corrosion parameters such as corrosion current icorr, and characteristic potential of pitting Eb. The results indicate that the rare earths have effect on corrosion resisting properties of carbon-manganese clean steel, and the optimum contents of La is about 0.011% (mass fraction) and Ce about 0.014% (mass fraction) respectively. The change of corrosion resistance is related to the action of rare earths on microstructure and effect on surface state of samples in the process of polarization.

  20. Contribution to the Study of Effects of Surface State of Welded Joints in Stainless Steel Upon Resistance Towards Pitting Corrosion

    Directory of Open Access Journals (Sweden)

    Juraga, I.

    2007-01-01

    Full Text Available Successful corrosion resistance of stainless steels is based on their natural ability of passivation, i.e. formation of film of chromium oxides that prevents corrosion in many environments. Any nonuniformity of surface layers may be initial spot for corrosion processes and damages. In this contribution, beside real corrosion damages occurred in practice, results of testing of pitting corrosion resistance of weld beads made applying TIG process on AISI 316L steel grade are presented. SEM and EDX testing, as well as electrochemical corrosion testing confirmed adverse effects of heat tints zones upon corrosion resistance of stainless steels.

  1. Corrosion resistance of premodeled wires made of stainless steel used for heart electrotherapy leaders

    Science.gov (United States)

    Przondziono, J.; Walke, W.; Młynarski, R.; Szatka, W.

    2012-05-01

    The purpose of the study is to evaluate resistance to electrochemical corrosion of wire made of X10CrNi18-8 stainless steel designed for use in cardiology treatment. The influence of strain formed in the premodeling process and methods of wire surface preparation to corrosive resistance in artificial plasma solution were analysed. Wire corrosion tests were carried out in the solution of artificial plasma. Resistance to electrochemical corrosion was evaluated on the ground of recorded curves of anodic polarization by means of potentiodynamic method. Potentiodynamic tests carried out enabled to determine how the resistance to pitting corrosion of wire changes, depending on strain formed in the premodeling process as well as on the method of wire surface preparation. For evaluation of phenomena occurring on the surface of tested steel, electrochemical impedance spectroscopy (EIS) was applied. Deterioration of corrosive properties of wire along with the increase in the formed strain hardening was observed.

  2. Improvement of Microhardness and Corrosion Resistance of Stainless Steel by Nanocomposite Coating

    OpenAIRE

    Hiba Husam Ismail; Kareem Neamah Sallomi; Hamid S. Mahdi

    2014-01-01

    Stainless steel (AISI 304) has good electrical and thermal conductivities, good corrosion resistance at ambient temperature, apart from these it is cheap and abundantly available; but has good mechanical properties such as hardness. To improve the hardness and corrosion resistance of stainless steel its surface can be modified by developing nanocomposite coatings applied on its surface. The main objective of this paper is to study effect of electroco-deposition method on microhardness and cor...

  3. Corrosion Resistant Steels for Structural Applications in Aircraft

    Science.gov (United States)

    2007-11-02

    Nitriding Trials ........................................................................................203 LIST OF TABLES Table 1 Property...25% min. transverse KIC 50 ksi√in min. Fatigue Similar to 300M Cleanliness AMS 2300, ASTM E45 SCC Superior to 300M Corrosion Resistance Better...those that have a high deformation resistance associated with very hard and thermal resistant multi-layer PVD titanium aluminum nitride coatings

  4. Heat Treatment and Properties of Nitrogen Alloyed, Martensitic,Corrosion-resistant Steels

    Institute of Scientific and Technical Information of China (English)

    Reinhold Schneider; Klaus Sammt; Roland Rabitsch; Michael Haspel

    2004-01-01

    This paper gives a short introduction to the typical process route and material properties of these steels in comparison to standard martensitic corrosion-resistant steels. The typical response of these steels to various heat treatment parameters is shown and explained using the three grades M333, N360 and M340 (all made by Bohler Edelstahl GmbH) as examples, and the physical metallurgy of these steels and its consequences for practical heat treatment is explained. The correlation between tempering parameters and their effect on the toughness and corrosion properties is explained in particular detail, showing that these new steels not only offer far better property combinations under the usual heat treatment parameters than standard martensitic corrosion-resistant steels, but that they also open the door to extending heat treatment combinations and properties.

  5. 76 FR 4291 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Partial Rescission of...

    Science.gov (United States)

    2011-01-25

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... administrative review of the countervailing duty order on corrosion- resistant carbon steel flat products from... ] requests for administrative review and partial revocation of the countervailing duty order on corrosion...

  6. 76 FR 69703 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Science.gov (United States)

    2011-11-09

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) published a notice of initiation of the administrative review of the antidumping duty order on corrosion... results of this review. See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of...

  7. 77 FR 25141 - Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea: Extension of Time...

    Science.gov (United States)

    2012-04-27

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea... of the antidumping duty (AD) orders on corrosion-resistant carbon steel flat products (CORE) from... Countervailing Duty Operations, Office 3, regarding ``Sunset Reviews of the Antidumping Duty Orders on Corrosion...

  8. 75 FR 77615 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Science.gov (United States)

    2010-12-13

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) published a notice of initiation of the administrative review of the antidumping duty order on corrosion... results of this review. See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of...

  9. A new steel with good low-temperature sulfuric acid dew point corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, X.Q.; Li, X.G. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Key Laboratory of Corrosion and Protection (Ministry of Education), Beijing (China); Sun, F.L. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Lv, S.J. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Equipment and Power Department, Shijiazhuang Refine and Chemical Company Limited, SINOPEC, Shijiazhuang (China)

    2012-07-15

    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% H{sub 2}SO{sub 4} 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 H{sub 2}SO{sub 4} 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% H{sub 2}SO{sub 4} 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. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Enhanced corrosion resistance properties of radiofrequency cold plasma nitrided carbon steel: Gravimetric and electrochemical results

    Energy Technology Data Exchange (ETDEWEB)

    Bouanis, F.Z. [Laboratoire des Procedes d' Elaboration des Revetements Fonctionnels, PERF-LSPES UMR-CNRS 8008, ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France); Bentiss, F. [Laboratoire de Chimie de Coordination et d' Analytique, Faculte des Sciences, Universite Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); Traisnel, M. [Laboratoire des Procedes d' Elaboration des Revetements Fonctionnels, PERF-LSPES UMR-CNRS 8008, ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France); Jama, C. [Laboratoire des Procedes d' Elaboration des Revetements Fonctionnels, PERF-LSPES UMR-CNRS 8008, ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France)], E-mail: charafeddine.jama@ensc-lille.fr

    2009-03-01

    Cold plasma nitriding treatment was performed to improve the corrosion resistance of C38 carbon steel. Nitriding process was conducted using a radiofrequency nitrogen plasma discharge for different times of treatment on non-heated substrates. The modification of the corrosion resistance characteristic of the C38 steel due to the treatment in acid medium (1 M HCl) were investigated by gravimetric and electrochemical tests such as potentiodynamic polarisation curves and electrochemical impedance spectroscopy (EIS). It was shown that the plasma nitriding treatment improves the corrosion resistance. Indeed, in the gravimetric tests, nitrided samples showed lower weight loss and lower corrosion rate in comparison to untreated one. In the Tafel polarisation tests, the nitrided samples showed greatly reduced corrosion current densities, anodic dissolution and also retarded the hydrogen evolution reaction. Using EIS method, an adequate structural model of the interface was used and the values of the corresponding parameters were calculated and discussed. The results obtained from weight loss and electrochemical studies were in reasonable agreement. X-ray photoelectron spectroscopy (XPS) was carried out to establish the mechanism of corrosion inhibition of nitrided C38 steel in 1 M HCl medium. The enhancement of the corrosion resistance is believed to be related to the iron nitride compound layer formed on the C38 steel surface during plasma nitriding, which protected the underlying metal from corrosive attack in the aggressive solutions.

  11. Improving Corrosion Resistance of Q235 Steel by Ni-Cr Alloyed Layer

    Institute of Scientific and Technical Information of China (English)

    HUANG Jun; ZHANG Pingze; WU Hongyan; BI Qiang

    2012-01-01

    Ni-Cr alloyed layer was formed on surface of Q235 steel by double glow plasma surface metallurgy to improve the corrosion resistance of substrate.The composition and microstructure of alloyed layer was analyzed by SEM and XRD.Potentiodynamic polarization and electrochemical impedance spectroscopy was applied to evaluate the corrosion resistance of the alloyed layer.The results showed working pressure had a great effect on structure of Ni-Cr alloyed layer,and the dense and smooth alloyed layer was prepared at 50 Pa working pressure.Compared with substrate,Ni-Cr alloyed layer exhibited higher corrosion potential,lower corrosion current density and larger charge transfer resistance,which indicated that Ni-Cr alloyed layer significantly modified the corrosion resistance of Q235 steel.

  12. Is cell viability always directly related to corrosion resistance of stainless steels?

    Science.gov (United States)

    Salahinejad, E; Ghaffari, M; Vashaee, D; Tayebi, L

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals.

  13. Corrosion Resistance and Pitting Behaviour of Low-Carbon High-Mn Steels in Chloride Solution

    Directory of Open Access Journals (Sweden)

    Grajcar A.

    2016-06-01

    Full Text Available Corrosion resistance of the X4MnSiAlNbTi27-4-2 and X6MnSiAlNbTi26-3-3 type austenitic steels, after hot deformation as well as after cold rolling, were evaluated in 3.5% NaCl solution using potentiodynamic polarization tests. A type of nonmetallic inclusions and their pitting corrosion behaviour were investigated. Additionally, the effect of cold deformation on the corrosion resistance of high-Mn steels was studied. The SEM micrographs revealed that corrosion damage formed in both investigated steels is characterized by various shapes and an irregular distribution at the metallic matrix, independently on the steel state (thermomechanically treated or cold worked. Corrosion pits are generated both in grain interiors, grain boundaries and along the deformation bands. Moreover, corrosion damage is stronger in cold deformed steels in comparison to the thermomechanically treated specimens. EDS analysis revealed that corrosion pits preferentially nucleated on MnS and AlN inclusions or complex oxysulphides. The morphology of corrosion damage in 3.5% NaCl supports the data registered in potentiodynamic tests.

  14. Corrosion of Carbon Steel and Corrosion-Resistant Rebars in Concrete Structures Under Chloride Ion Attack

    Science.gov (United States)

    Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

    2013-03-01

    Corrosion of reinforced concrete is the most challenging durability problem that threatens reinforced concrete structures, especially structures that are subject to severe environmental conditions (i.e., highway bridges, marine structures, etc.). Corrosion of reinforcing steel leads to cracking and spalling of the concrete cover and billions of dollars are spent every year on repairing such damaged structures. New types of reinforcements have been developed to avoid these high-cost repairs. Thus, it is important to study the corrosion behavior of these new types of reinforcements and compare them to the traditional carbon steel reinforcements. This study aimed at characterizing the corrosion behavior of three competing reinforcing steels; conventional carbon steel, micro-composite steel (MMFX-2) and 316LN stainless steel, through experiments in carbonated and non-carbonated concrete exposed to chloride-laden environments. Synthetic pore water solutions have been used to simulate both cases of sound and carbonated concrete under chloride ions attack. A three-electrode corrosion cell is used for determining the corrosion characteristics and rates. Multiple electrochemical techniques were applied using a Gamry PC4™ potentiostat manufactured by Gamry Instruments (Warminster, PA). DC corrosion measurements were applied on samples subjected to fixed chloride concentration in the solution.

  15. Electrochemical and pitting corrosion resistance of AISI 4145 steel subjected to massive laser shock peening treatment with different coverage layers

    Science.gov (United States)

    Lu, J. Z.; Han, B.; Cui, C. Y.; Li, C. J.; Luo, K. Y.

    2017-02-01

    The effects of massive laser shock peening (LSP) treatment with different coverage layers on residual stress, pitting morphologies in a standard corrosive solution and electrochemical corrosion resistance of AISI 4145 steel were investigated by pitting corrosion test, potentiodynamic polarisation test, and SEM observations. Results showed massive LSP treatment can effectively cause an obvious improvement of pitting corrosion resistance of AISI 4145 steel, and increased coverage layer can also gradually improve its corrosion resistance. Massive LSP treatment with multiple layers was shown to influence pitting corrosion behaviour in a standard corrosive solution.

  16. Is cell viability always directly related to corrosion resistance of stainless steels?

    Energy Technology Data Exchange (ETDEWEB)

    Salahinejad, E., E-mail: salahinejad@kntu.ac.ir [Faculty of Materials Science and Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Ghaffari, M. [Bruker AXS Inc., 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Vashaee, D. [Electrical and Computer Engineering Department, North Carolina State University, Raleigh, NC 27606 (United States); Tayebi, L. [Department of Developmental Sciences, Marquette University School of Dentistry, Milwaukee, WI 53201 (United States); Department of Engineering Science, University of Oxford, Oxford OX1 3PJ (United Kingdom)

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn–Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn–Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. - Highlights: • Cell viability vs. corrosion resistance for medical-grade stainless steels • The stainless steel samples were prepared by powder metallurgy. • Unpenetrated additive played a critical role in the correlation.

  17. Effect of silicate pretreatment, post-sealing and additives on corrosion resistance of phosphated galvanized steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Sodium silicate (water glass) pretreatment before phosphating, silicate post-sealing after phosphating and adding silicate to a traditional phosphating solution were respectively carried out to obtain the improved phosphate coatings with high corrosion resistance and coverage on hot-dip galvanized(HDG) steel. The corrosion resistance, morphology and chemical composition of the coatings were investigated using neutral salt spray(NSS) tests, scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The results show that pretreatment HDG steel with silicate solutions, phosphate coatings with finer crystals and higher coverage are formed and the corrosion resistance is enhanced. Adding silicate to a traditional phosphating solution, the surface morphology of the coatings is nearly unchanged. The corrosion resistance of the coatings is mainly dependent on phosphating time.Phosphating for a longer time (such as 5 min), the corrosion resistance, increasing with concentration of silicate, is improved significantly. Post-sealing the phosphated HDG steel with silicate solutions, the pores among the zinc phosphate crystals are sealed with the films containing Si, P, O and Zn and the continuous composite coatings are formed. The corrosion resistance of the composite coatings, related to the pH value, contents of hydrated gel of silica and Si2O52- and post-sealing time, is increased markedly. The improved coatings with optimal corrosion resistance are obtained for phosphating 5 min and post-sealing with 5 g/L silicate solution for 10 min.

  18. Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels

    Science.gov (United States)

    Yenilmez, A.; Karakan, M.; Çelik, İ.

    2017-01-01

    Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens' structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.

  19. Mechanical and corrosion resistant properties of martensitic stainless steel plasma nitrocarburized with rare earths addition

    Institute of Scientific and Technical Information of China (English)

    LIU Ruiliang; QIAO Yingjie; YAN Mufu; FU Yudong

    2012-01-01

    In order to improve surface hardness and corrosion resistant property of 17-4PH martensitic stainless steel,the steel was plasma nitrocarburized at 560 ℃ for 2-24 h in a gas mixture of nitrogen,hydrogen and ethanol with rare earths (RE) addition.The experimental results showed that the modified layer was characterized by a compound layer containing two distinct zones (i.e.out ‘dark zone’ and inner ‘white zone’).The inner ‘white zone’ was almost a precipitation free zone and had high hardness as well as good corrosion resistance.Anodic polarization test results showed that the specimens plasma nitrocarburized with RE addition had good corrosion resistance resulted mainly from their higher corrosion potentials,lower corrosion current densities and larger passive regions as compared with those of the untreated one.

  20. Improved corrosion resistance of 316L stainless steel by nanocrystalline and electrochemical nitridation in artificial saliva solution

    Science.gov (United States)

    Lv, Jinlong; Liang, Tongxiang

    2015-12-01

    The fluoride ion in artificial saliva significantly changed semiconductor characteristic of the passive film formed on the surface of 316L stainless steels. The electrochemical results showed that nanocrystalline α‧-martensite improved corrosion resistance of the stainless steel in a typical artificial saliva compared with coarse grained stainless steel. Moreover, comparing with nitrided coarse grained stainless steel, corrosion resistance of the nitrided nanocrystalline stainless steel was also improved significantly, even in artificial saliva solution containing fluoride ion. The present study showed that the cryogenic cold rolling and electrochemical nitridation improved corrosion resistance of 316L stainless steel for the dental application.

  1. Comparison of surface fractal dimensions of chromizing coating and P110 steel for corrosion resistance estimation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Naiming, E-mail: lnmlz33@163.com [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Guo, Junwen [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Xie, Faqin [School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China); Zou, Jiaojuan; Tian, Wei [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Yao, Xiaofei [School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Zhang, Hongyan; Tang, Bin [Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2014-08-30

    Highlights: • Continuous chromizing coating was synthesized on P110 steel by pack cementation. • The chromizing coating showed better corrosion resistance. • Comparison of surface fractal dimensions can estimate corrosion resistance. - Abstract: In the field of corrosion research, mass gain/loss, electrochemical tests and comparing the surface elemental distributions, phase constitutions as well as surface morphologies before and after corrosion are extensively applied to investigate the corrosion behavior or estimate the corrosion resistance of materials that operated in various environments. Most of the above methods are problem oriented, complex and longer-period time-consuming. However from an object oriented point of view, the corroded surfaces of materials often have self-similar characterization: fractal property which can be employed to efficiently achieve damaged surface analysis. The present work describes a strategy of comparison of the surface fractal dimensions for corrosion resistance estimation: chromizing coating was synthesized on P110 steel surface to improve its performance via pack cementation. Scanning electron microscope (SEM) was used to investigate the surface morphologies of the original and corroded samples. Surface fractal dimensions of the detected samples were calculated by binary images related to SEM images of surface morphologies with box counting algorithm method. The results showed that both surface morphologies and surface fractal dimensions of P110 steel varied greatly before and after corrosion test, but the chromizing coating changed slightly. The chromizing coating indicated better corrosion resistance than P110 steel. Comparison of surface fractal dimensions of original and corroded samples can rapidly and exactly realize the estimation of corrosion resistance.

  2. Nano-phases and corrosion resistance of C+Mo dual implanted steel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The corrosion resistance of C+Mo dual-implanted H13 steel wasstudied using multi-sweep cyclic voltammetry. The phase formation conditions for corrosion resistance and its effects were researched. The super-saturation solid station solution of Mo+ and C+ atoms was formed in Mo+C dual implanted steel. Precipitate phase with nanometer size Fe2Mo, FeMo, MoC, Fe5C3 and Fe7C3 were formed in dual implanted layer. The passivation layer consisted of these nanometer phases. The corrosion resistance of the dual implanted layer was better than that of single Mo implantation. Jp of the Mo implanted sample is 0.55 times that of H13 steel. The corrosion resistance of the dual implantation was enhanced when ion dose increased. When the Mo+ ion dose was 6×1017/cm2 in the dual implantation, Jp of the dual implanted sample was only 0.11 times that in H13 steel. What is important is that pitting corrosion properties of dual implanted steel were improved obviously.

  3. Nanostructure Formations and Improvement in Corrosion Resistance of Steels by Means of Pulsed Electron Beam Surface Treatment

    Directory of Open Access Journals (Sweden)

    K. M. Zhang

    2013-01-01

    Full Text Available The corrosion of steels has long been the topic for materials scientists. It is established that surface treatment is an efficient way to improve the corrosion resistance of steels without changing the bulk properties and with low costs. In the present paper, different kinds of surface treatment techniques for steels are briefly reviewed. In particular, the surface modification involving nanostructure formations of steels by using a low energy high pulsed electron beam (LEHCPEB treatment is lightened in the case of an AISI 316L stainless steel and D2 steel. The overall results demonstrate the high potential of the LEHCPEB technique for improving the corrosion performance of steels.

  4. Effect of ultrafine grain on tensile behaviour and corrosion resistance of the duplex stainless steel.

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Limin, Dong

    2016-05-01

    The ultrafine grained 2205 duplex stainless steel was obtained by cold rolling and annealing. The tensile properties were investigated at room temperature. Comparing with coarse grained stainless steel, ultrafine grained sample showed higher strength and plasticity. In addition, grain size changed deformation orientation. The strain induced α'-martensite was observed in coarse grained 2205 duplex stainless steel with large strain. However, the grain refinement inhibited the transformation of α'-martensite;nevertheless, more deformation twins improved the strength and plasticity of ultrafine grained 2205 duplex stainless steel. In addition, the grain refinement improved corrosion resistance of the 2205 duplex stainless steel in sodium chloride solution.

  5. Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Łępicka Magdalena

    2014-09-01

    Full Text Available Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18 stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively in two different temperature ranges (380 or 450°C specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

  6. Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

    Institute of Scientific and Technical Information of China (English)

    YUE

    2010-01-01

    The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.

  7. Effect of Deleterious Phases on Corrosion Resistance of Duplex Stainless Steel (2205

    Directory of Open Access Journals (Sweden)

    AbdulKadar M. Godil

    2013-07-01

    Full Text Available Duplex stainless steel is a Ferritic(BCC-Austenitic(FCC steel, covers the advantages of both Austenitic and Ferritic Stainless steels. They having good mechanical and corrosion resistance properties are widely used in many industries like chemical plants, refineries for critical equipments such as pressure vessels, heatexchangers, water heaters. Major problem occurs with duplex steels when they are worked or heated above about temperature of 280°C. Detrimental phases like Sigma, Chi, Laves and Alpha prime form when the Duplex steels are treated above this temperature and they retard the properties of Duplex stainless steels. They also cause embrittlement above temperature of 475°C called “475°C embrittlement”. During welding of duplex steels, Secondary austenite also forms, which is also one of the harmful phases in duplex steels. Among all of these phases, Sigma (σ is extremely harmful to the corrosion resistance of steel. Due to these limitations duplexgrades are not used above certain temperature ranges. In this experimental work a plate of duplex grade 2205 in hot worked condition was procured from TCR Advanced Engineering Pvt. Ltd., GIDC, Vadodara. Initially chemical composition of the plate was checked with emission spectrometer, tensile test and hardness tests werecarried out for comparing with the standard data. As there was no Sigma phase detected when tested with ASTM 930 in the received sample, Sigma phase was intentionally produced by giving heat treatment in the range of 700-850°C. Sigma phases were quantified with ASTM 930 practice A, by electrolytic etching with 40% NaOH. The effect of Sigma phase on corrosion resistance was measured by ASTM G48. The pitting corrosion resistance was evaluated in terms of average pit depth and overall corrosion rate.

  8. In vitro corrosion resistance of Lotus-type porous Ni-free stainless steels.

    Science.gov (United States)

    Alvarez, Kelly; Hyun, Soong-Keun; Fujimoto, Shinji; Nakajima, Hideo

    2008-11-01

    The corrosion behavior of three kinds of austenitic high nitrogen Lotus-type porous Ni-free stainless steels was examined in acellular simulated body fluid solutions and compared with type AISI 316L stainless steel. The corrosion resistance was evaluated by electrochemical techniques, the analysis of released metal ions was performed by inductively coupled plasma mass spectrometry (ICP-MS) and the cytotoxicity was investigated in a culture of murine osteoblasts cells. Total immunity to localized corrosion in simulated body fluid (SBF) solutions was exhibited by Lotus-type porous Ni-free stainless steels, while Lotus-type porous AISI 316L showed very low pitting corrosion resistance evidenced by pitting corrosion at a very low breakdown potential. Additionally, Lotus-type porous Ni-free stainless steels showed a quite low metal ion release in SBF solutions. Furthermore, cell culture studies showed that the fabricated materials were non-cytotoxic to mouse osteoblasts cell line. On the basis of these results, it can be concluded that the investigated alloys are biocompatible and corrosion resistant and a promising material for biomedical applications.

  9. 9% Cr steel high temperature oxidation. Solutions investigated for improving corrosion resistance of the steel

    Energy Technology Data Exchange (ETDEWEB)

    Evin, Harold Nicolas; Heintz, Olivier; Chevalier, Sebastien [UMR 5209 CNRS-Bourgogne Univ. (France). Lab. Interdisciplinaire Carnot de Bourgogne; Foejer, Cecilia; Jakani, Saad; Dhont, Annick; Claessens, Serge [OCAS N.V. ArcelorMittal Global R and D, Gent (Belgium)

    2010-07-01

    The improvement of high temperature oxidation resistance of low chromium content steels, such as T/P91, is of great interest in regards with their application in thermal power generating plants. Indeed, they possess good creep properties, but are facing their limits of use at temperature higher than 600 C, due to accelerated corrosion phenomena. Good knowledge of the mechanisms involved during their oxidation process is needed to prevent the degradation of the materials and to extend life time of the power plants components. Oxide layers thermally grown, on 9% Cr steels (provided by OCAS N.V), during isothermal tests between 600 C and 750 C in laboratory air under atmospheric pressure were investigated, by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The oxidation behaviour appeared very limited at 750 C, due to the presence of a breakaway, which can be linked to iron porous oxide grown over the surface of the samples. ''In situ'' X-ray Photoelectron spectroscopy (XPS) analyses were performed in air at 600 C after short exposures (between 5 min and 25 h). A complex mixture of iron oxide, Cr{sub 2}O{sub 3} and Cr (VI) species were characterized in the scales. The in-situ analyses were compared and related to XPS analyses performed on thick oxide scales formed on samples oxidized in air at 600 C for 100h. An oxidation mechanism is then proposed to understand the oxide scale growth in the temperature range 600 - 750 C. The second step of this study consists in improving the high temperature corrosion resistance of these steels without modifying their mechanical properties. Thus several solutions were investigated such as MOCVD coatings, pack cementation coatings, and tested in cycle conditions prior. (orig.)

  10. CORROSION RESISTANCE OF HOT DIP GALVANIZED STEEL PRETREATED WITH BIS-FUNCTIONAL SILANES MODIFIED WITH NANOALUMINA

    Institute of Scientific and Technical Information of China (English)

    F.J.Shan; C.S.Liu; S.H.Wang; G.C.Qi

    2008-01-01

    The corrosion behavior of hot dip galvanized steel pretreated with bis-[triethoxy-silylpropyl]tetrasulfide (BTESPT) modified with alumina particles was studied.The corrosion resistance of the passiving films was evaluated by Tafel polarization curve and electrochemical impedance spectroscopy.The films formed on the galvanized steel substrate were characterized by Fourier transform infrared spectroscopy and energy dispersive X-ray spectrometry.The surface morphology of the treated hot dip galva-nized steel samples was observed by Field Emission Scanning Electron Microscope. The results show that the pretreatments on the basis of silane films modified with nanoalumina particles have reduced both anodic and cathodic current densities,and increased total impedance in the measured frequency,consequently,improving cor-rosion protection for hot dip galvanized steel during immersion in NaCl solutions compared to chromate films and silane films.

  11. 78 FR 55241 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2013-09-10

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) is conducting an administrative review of the countervailing duty (CVD) order on corrosion-resistant.... SUPPLEMENTARY INFORMATION: Scope of the Order The merchandise covered by this Order \\2\\ is certain corrosion...

  12. Theoretical considerations on the supposed linear relationship between concrete resistivity and corrosion rate of steel reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Gulikers, J. [Research Department, Rijkswaterstaat Bouwdienst, Ministry of Transport, Public Works and Water Management, P.O. Box 20000, 3502 LA Utrecht (Netherlands)

    2005-06-01

    Traditionally, the assessment of service life of steel reinforced concrete structures has been focused on the prediction of the time required to achieve a transition from passive to active corrosion rather than to accurately estimate the subsequent corrosion rates. However, the propagation period, i.e. the time during which the reinforcing steel is actively corroding, may add significantly to the service life. Consequently, ignoring the propagation period may prove to be a conservative approach. On the other hand the prediction of the corrosion rate may result in a very complex task in view of the electrochemical nature of corrosion and the numerous parameters involved. In order to account for the various influences an essentially empirical model has been introduced in which the electrolytic resistivity of the concrete environment serves as the major parameter. This model will be discussed for carbonation-induced corrosion based on the commonly accepted theory of aqueous corrosion. An alternative model for microcell corrosion is proposed which is based on the commonly accepted view that anodic and cathodic sites are microscopic and their locations change randomly with time. In line with this view electrolytic resistivity can be incorporated and thus may play a significant role in the kinetics of the corrosion process. For a wide range of corrosion current densities the relationship between corrosion current density, log(i{sub corr}), and concrete resistance, log(R{sub con}), can then be approximated by an almost ideal linear relationship. Assuming a fixed geometrical arrangement of anodic and cathodic sites on the steel surface, this linear relationship is also valid for concrete resistivity, {rho}{sub con}. However, from the theoretical treatment of the electrochemical processes underlying reinforcement corrosion it becomes evident that a linear relationship between corrosion current density and concrete resistivity does not necessarily imply that concrete

  13. Evaluation of High Temperature Corrosion Resistance of Finned Tubes Made of Austenitic Steel And Nickel Alloys

    Directory of Open Access Journals (Sweden)

    Turowska A.

    2016-06-01

    Full Text Available The purpose of the paper was to evaluate the resistance to high temperature corrosion of laser welded joints of finned tubes made of austenitic steel (304,304H and nickel alloys (Inconel 600, Inconel 625. The scope of the paper covered the performance of corrosion resistance tests in the atmosphere of simulated exhaust gases of the following chemical composition: 0.2% HCl, 0.08% SO2, 9.0% O2 and N2 in the temperature of 800°C for 1000 hours. One found out that both tubes made of austenitic steel and those made of nickel alloy displayed good resistance to corrosion and could be applied in the energy industry.

  14. Evaluation of the corrosion resistance of plasma nitrided austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Mareci, Daniel; Bolat, Georgiana [Technical Univ. Iasi (Romania). Faculty of Chemical Engineering and Environmental Protection; Strugaru, Sorin Iacob; Munteanu, Corneliu [Technical Univ. Iasi (Romania). Faculty of Mechanical Engineering; Souto, Ricardo M. [Univ. of La Laguna, Tenerife (Spain). Dept. of Chemistry

    2015-03-15

    Plasma nitriding at 500 C for 14 h was applied to austenitic 304 stainless steel for surface hardening. The effect of surface treatment on the corrosion resistance of the material was investigated in naturally-aerated 0.5 M NaCl solution for 30 days using linear potentiodynamic polarization and electrochemical impedance spectroscopy methods. Both as-cast and plasma nitrided stainless steel samples underwent spontaneous passivation, though the nitrided sample exhibited more positive zero current potential, higher breakdown potential, and lower anodic current densities than the as-cast material. Impedance spectra were interpreted in terms of a duplex passive film, corrosion resistance mainly arising from a thin inner compact layer, whereas the outer layer was more porous and less sealing. Capacitive behaviour and high corrosion resistance were observed in the low and medium frequency ranges for the nitrided samples.

  15. Enhanced wear and corrosion resistance of plasma electrolytic carburized layer on T8 carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie; Wang, Bin; Zhang, Yifan; Liu, Run [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xia, Yuan; Li, Guang [Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2016-03-01

    A hardening layer of 70 μm on T8 carbon steel was fabricated by plasma electrolytic carburizing (PEC) in glycerol solution at 380 V with 3 min treatment. The discharge process was characterized using optical emission spectroscopy (OES), and the electron temperature in plasma envelope was determined. Meanwhile, diffusion coefficient of carbon was calculated on the basis of carbon concentration profile. The tribological property of carburized steel under dry sliding against ZrO{sub 2} ball was measured by a ball-disc friction and wear tester. The corrosion behaviors were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). It was found that the carburized layer mainly contained α-Fe and Fe{sub 3}C phases with maximum hardness of 620 HV. The PEC treatment significantly decreased the friction coefficient from 0.4 to 0.1. The wear rate of PEC treated steel was about 5.86 × 10{sup −6} mm{sup 3}/N·m, which was less than 1/4 of T8 steel substrate. After PEC treatment, the wear and corrosion resistance of T8 steel were improved. Particularly, the pitting corrosion of steel substrate was obviously suppressed. - Highlights: • Electron temperature in plasma electrolytic carburizing process is determined. • Diffusion coefficient of carbon in PEC is higher than conventional carburizing. • Wear and corrosion resistance of T8 steel are both improved after PEC treatment. • Pitting corrosion of steel substrate is obviously suppressed by PEC treatment.

  16. PRODUCTION OF POROUS POWDER MATERIALS OF SPHERICAL POWDERS OF CORROSION-RESISTANT STEEL

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevskij

    2012-01-01

    Full Text Available Production of porous powder materials from spherical powders of corrosion-resistant steel 12Х18н10Т with formation at low pressures 120–140 mpa in the mold with the subsequent activated sintering became possible due to increase of duration of process of spattering and formation of condensate particles (Si–C or (Mo–Si on surface.

  17. Steel corrosion resistance in model solutions and reinforced mortar containing wastes

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.

    2012-01-01

    This work reports on the corrosion resistance of steel in alkaline model solutions and in cement-based materials (mortar). The model solutions and the mortar specimens were Ordinary Portland Cement (OPC) based. Further, hereby discussed is the implementation of an eco-friendly approach of waste

  18. Steel corrosion resistance in model solutions and reinforced mortar containing wastes

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.

    2012-01-01

    This work reports on the corrosion resistance of steel in alkaline model solutions and in cement-based materials (mortar). The model solutions and the mortar specimens were Ordinary Portland Cement (OPC) based. Further, hereby discussed is the implementation of an eco-friendly approach of waste util

  19. Plasma nitriding of a precipitation hardening stainless steel to improve erosion and corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Cabo, Amado, E-mail: cabo@ionar.com.ar [IONAR S.A., Buenos Aires (Argentina); Bruhl, Sonia P.; Vaca, Laura S.; Charadia, Raul Charadia, E-mail: sonia@frcu.utn.erdu.ar, E-mail: vacal@frcu.utn.edu.ar, E-mail: charadia@frcu.urn.edu.ar, E-mail: dalibone@frcu.utn.edu.ar [Surface Engineering Group (GIS), Universidad Tecnologica Nacional, Facultad Regional Concepcion del Uruguay (Argentina)

    2010-07-01

    Precipitation hardening stainless steels are used as structural materials in the aircraft and the chemical industry because of their good combination of mechanical and corrosion properties. The aim of this work is to analyze the structural changes produced by plasma nitriding in the near surface of Thyroplast PH X Supra®, a PH stainless steel from ThyssenKrupp, and to study the effect of nitriding parameters in wear and corrosion resistance. Samples were first aged and then nitriding was carried out in an industrial facility at two temperatures, with two different nitrogen partial pressures in the gas mixture. After nitriding, samples were cut, polished, mounted in resin and etched with Vilella reagent to reveal the nitrided case. Nitrided structure was also analyzed with XRD. Erosion/Corrosion was tested against sea water and sand flux, and corrosion in a salt spray fog (ASTM B117). All nitrided samples presented high hardness. Samples nitrided at 390 deg C with different nitrogen partial pressure showed similar erosion resistance against water and sand flux. The erosion resistance of the nitrided samples at 500 deg C was the highest and XRD revealed nitrides. Corrosion resistance, on the contrary, was diminished; the samples suffered of general corrosion during the salt spray fog test. (author)

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

    Science.gov (United States)

    Hill, Horst; Weber, Sebastian; Raab, Ulrich; Theisen, Werner; Wagner, Lothar

    2012-09-01

    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.

  1. CO{sub 2} corrosion resistance of carbon steel in relation with microstructure changes

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa, Nathalie, E-mail: nochoa@usb.ve [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Vega, Carlos [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Pébère, Nadine; Lacaze, Jacques [Université de Toulouse, CIRIMAT, UPS/INPT/CNRS, ENSIACET, 4 Allée Emile Monso, CS 44362, 31030 Toulouse Cedex 4 (France); Brito, Joaquín L. [Laboratorio de Físico-química de Superficies, Centro de Química, Instituto Venezolano de Investigaciones Cientificas (IVIC), Carretera Panamericana, Km 11, Altos de Pipe, Estado Miranda (Venezuela, Bolivarian Republic of)

    2015-04-15

    The microstructural effects on the corrosion resistance of an API 5L X42 carbon steel in 0.5 M NaCl solution saturated with CO{sub 2} was investigated. Four microstructures were considered: banded (B), normalized (N), quenched and tempered (Q&T), and annealed (A). Electrochemical measurements (polarization curves and electrochemical impedance spectroscopy) were coupled with surface analyses (scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS)) to characterize the formation of the corrosion product layers. Electrochemical results revealed that corrosion resistance increased in the following order: B < N < Q&T < A. From the polarization curves it was shown that specifically, cathodic current densities were affected by microstructural changes. SEM images indicated that ferrite dissolved earlier than cementite and a thin layer of corrosion products was deposited on the steel surface. XPS analyses revealed that this layer was composed of a mixture of iron carbonate and non-dissolved cementite. It was also found that the quantity of FeCO{sub 3} content on the steel surface was greater for Q&T and A microstructures. These results, in agreement with the electrochemical data, indicate that the deposition mechanism of iron carbonate is closely related to the morphology of the non-dissolved cementite, determining the protective properties of the corrosion product layers. - Highlights: • The effect of change in microstructure on CO{sub 2} corrosion resistance was evaluated. • An API 5LX 42 carbon steel was immersed in a 0.5 M NaCl solution saturated with CO{sub 2}. • Banded, normalized, quenched-tempered and annealed microstructures were considered. • Electrochemical measurements were coupled with surface analysis. • Morphology and distribution of undissolved Fe{sub 3}C control corrosion kinetics.

  2. The corrosion resistance of Eurofer 97 and ODS-Eurofer steels for nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Terada, M. [Escola Politecnica da Univ. de Sao Paulo, Dept. de Engenharia Metalurgica e de Materiais, Sao Paulo-SP (Brazil); Zschommler Sandim, H.R. [Sao Paulo Univ., Dept. de Engenharia de Materiais, Polo Urbo-Industrial, Lorena-SP (Brazil); Costa, I. [Instituto de Pesquisas Energeticas e Nucleares IPEN-CCTM, Sao Paulo - SP (Brazil); Padilha, A.F. [Escola Politecnica da Universidade de Sao Paulo, Dept. de Engenharia Metalurgica e de Materiais, Sao Paulo-SP (Brazil)

    2009-07-01

    Reduced-activation-ferritic-martensitic (RAFM) steels are considered for application in fusion technology as structural materials for the first wall of future fusion reactors DEMO. Ferritic-martensitic steels show reasonably good thermo-physical and mechanical properties, low sensitivity to radiation-induced swelling and helium embrittlement under (fission) neutron irradiation and good compatibility with major cooling and breeding materials. In recent years, reduced activation versions of this type of steels have been developed in Japan and Europe in laboratory scale and tested with equivalent or even better mechanical properties. In result of a systematic development of reduced activation ferritic-martensitic (RAFM) steels in Europe, the 9% CrWVTa alloy EUROFER was specified, and industrial batches have been produced in a variety of different semi-finished product forms. The EUROFER 97 alloy was developed on the basis of the experience gained with steels of the OPTIFER, MANET and F82H-modified type. Oxide dispersion to strengthen (ODS) alloys have been used in order to increase the working temperature of RAFM steels increasing their potentiality for applications in fusion reactors that operate at temperatures higher than 650 C. The literature on the corrosion properties of these alloys is scarce. In the present work the corrosion resistance of EUROFER 97 and ODS-EUROFER was tested in solutions containing H{sub 2}SO{sub 4} and KSCN at 25 C. The results were compared to those of AISI 430 ferritic and AISI 410 martensitic conventional stainless steels. The as-received samples were tested by electrochemical techniques, specifically, potentiodynamic polarization curves and double loop electrochemical potentio-kinetic reactivation tests. The surfaces were observed by scanning electron microscopy (SEM) after exposure to corrosive media. The results showed that EUROFER 97 and ODS-EUROFER present similar corrosion resistance but lower than that of ferritic AISI 430 and

  3. Impact of the nanostructuration on the corrosion resistance and hardness of irradiated 316 austenitic stainless steels

    Science.gov (United States)

    Hug, E.; Prasath Babu, R.; Monnet, I.; Etienne, A.; Moisy, F.; Pralong, V.; Enikeev, N.; Abramova, M.; Sauvage, X.; Radiguet, B.

    2017-01-01

    The influence of grain size and irradiation defects on the mechanical behavior and the corrosion resistance of a 316 stainless steel have been investigated. Nanostructured samples were obtained by severe plastic deformation using high pressure torsion. Both coarse grain and nanostructured samples were irradiated with 10 MeV 56Fe5+ ions. Microstructures were characterized using transmission electron microscopy and atom probe tomography. Surface mechanical properties were evaluated thanks to hardness measurements and the corrosion resistance was studied in chloride environment. Nanostructuration by high pressure torsion followed by annealing leads to enrichment in chromium at grain boundaries. However, irradiation of nanostructured samples implies a chromium depletion of the same order than depicted in coarse grain specimens but without metallurgical damage like segregated dislocation loops or clusters. Potentiodynamic polarization tests highlight a definitive deterioration of the corrosion resistance of coarse grain steel with irradiation. Downsizing the grain to a few hundred of nanometers enhances the corrosion resistance of irradiated samples, despite the fact that the hardness of nanocrystalline austenitic steel is only weakly affected by irradiation. These new experimental results are discussed in the basis of couplings between mechanical and electrical properties of the passivated layer thanks to impedance spectroscopy measurements, hardness properties of the surfaces and local microstructure evolutions.

  4. Influence of silicon addition on the mechanical properties and corrosion resistance of low-alloy steel

    Indian Academy of Sciences (India)

    M Hebda; H Dębecka; J Kazior

    2015-12-01

    The addition of silicon to low-alloy steel allows to modify the materials' microstructure and thus to improve their corrosion resistance and mechanical properties. The influence of adding different amounts of silicon on the properties (density, transverse rupture strength, microhardness and corrosion resistance) and microstructure of low-alloy steel was investigated. Samples were prepared via the mechanical alloying process, which is the most useful method to homogeneously introduce silicon to low-alloy steel. Sintering was performed by using the spark plasma sintering (SPS) technique. After the SPS process, half of each of the obtained samples was heat-treated in a vacuum furnace. The results show that high-density materials were achieved, and a homogeneous and fine microstructure was obtained. The investigated compositions containing 1 wt% of silicon had better corrosion resistance than samples with 3 wt% of silicon addition. Furthermore, corrosion resistance as well as the mechanical and plastic properties of the samples with 1 wt% of silicon can be further improved by applying heat treatment.

  5. Evaluation of the corrosion resistance of the galvanized SS400 steel in NaCl solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seung Mo; Jang, Chang Heui; Kim, In Sup [KAIST, Taejon (Korea, Republic of); Lee, Kyung Ho; Choi, Byung Il [Korea Hydro and Nuclear Power Co., Taejon (Korea, Republic of)

    2006-07-01

    A typical CANDU plant generates about 5,000 spent fuel bundles annually, which are stored in a spent fuel pool. Because the storage capacity of a spent pool is 10 years of spent fuel bundles, the Silo type storage modules are used to store the extra fuel bundles. In a multi-unit site like Wolsong, the extra space needed for the Silo type storage modules are ever increasing with the operating years. Therefore a more space effective storage system is necessary to accommodate all the extra spent fuels from the four CANDU units at site. A new dry storage system, MACSTOR/KN-400 (M/KN- 400) that is based upon MACSTOR design concept was developed. M/KN-400 will be built at the seaside in Wolsong site and galvanized carbon steel will be used for storage cylinder material to protect from the corrosion. Generally, galvanized carbon steels, in which the Zn layer on the surface acts as a sacrificial anode, are known to have good corrosion resistance in the atmospheric or aqueous conditions. However, in the brine condition containing chloride ions or steam environment, the Zn layer can be damaged. Therefore, considering the seaside atmosphere in which the storage system are located, the integrity of the storage cylinder is likely to be affected by the corrosion caused by the salt included in the atmosphere. In this study, electrochemical corrosion tests were performed on the galvanized carbon steels to estimate the corrosion resistance of the storage cylinder.

  6. Improvement of Microhardness and Corrosion Resistance of Stainless Steel by Nanocomposite Coating

    Directory of Open Access Journals (Sweden)

    Hiba Husam Ismail

    2014-12-01

    Full Text Available Stainless steel (AISI 304 has good electrical and thermal conductivities, good corrosion resistance at ambient temperature, apart from these it is cheap and abundantly available; but has good mechanical properties such as hardness. To improve the hardness and corrosion resistance of stainless steel its surface can be modified by developing nanocomposite coatings applied on its surface. The main objective of this paper is to study effect of electroco-deposition method on microhardness and corrosion resistance of stainless steel, and to analyze effect of nanoparticles (Al2O3, ZrO2 , and SiC on properties of composite coatings. In this paper employed Electroco-deposition process to develop a composite coating with (Ni matrix and Ceramic oxide particles: Al2O3 (135nm, ZrO2 (40nm, and SiC (80nm as reinforcements. The coatings were developed with 10 g/L, and 20 g/L concentrations in bath, at four different current densities (0.5, 1, 2, 3 A/dm2 using Watts bath to study the effect of current density and particle concentration in bath, on structure and properties of the coatings developed. The surface morphology of nanocomposite coating was characterized by Scanning Electron Microscopy (SEM. The hardness of the nanocoating was carried out using Digital Vickers microhardness tester. The corrosion resistance property of nanocomposite coating was carried out in 3.5% NaCl solution used Open circuit potential (OCP and potentialastic polarization. The results showed the nanocomposites coating have a smooth and compact surface and have higher hardness than the uncoated stainless steel (2.3 times, and also found that the nanocomposite coating improves the corrosion resistance significantly (89.25%.

  7. Effect of Pyrrole and N-Methylpyrrole Coatings on Corrosion Resistance of Mild Steel

    Institute of Scientific and Technical Information of China (English)

    AliAshrafi; M.A.Golozarl; S.Mallakpour; AliGhasemi

    2004-01-01

    Electrochemical polymerizations of various ratios of pyrrole and methylpyrrole monomers were performed in aqueous toluene-4-sulfinic acid sodium salt (T4SNa) electrolyte, using galvanostatic method, pH of electrolyte was adjusted by p-toluene sulfonic acid (PTSA). In order to prevent corrosion of mild steel substrates during coating deposition, specimens were pretreated in 0.5M oxalic acid solution, employing galvanostatic method. This would passivate the steel substrate and facilitate the coating process as well. Corrosion resistance of coated substrates was investigated in 1M NaCl solution using Tafel polarization technique. In addition, using scanning electron microscopy (SEM), morphological characterization of coatings produced, was investigated. Regarding the corrosion characteristics, results obtained revealed that the ratio of 1 to 1(Pyrrole/Methylpyrrole) could play an important role.

  8. Effect of Pyrrole and N-Methylpyrrole Coatings on Corrosion Resistance of Mild Steel

    Institute of Scientific and Technical Information of China (English)

    Ali Ashrafi; M.A.Golozar; S.Mailakpour; Ali Ghasemi

    2004-01-01

    Electrochemical polymerizations of various ratios of pyrrole and methylpyrrole monomers were performed in aqueous toluene-4-sulfinic acid sodium salt (T4SNa) electrolyte, using galvanostatic method. pH of electrolyte was adjusted by p-toluene sulfonic acid (PTSA). In order to prevent corrosion of mild steel substrates during coating deposition,specimens were pretreated in 0.5M oxalic acid solution, employing galvanostatic method. This would passivate the steel substrate and facilitate the coating process as well. Corrosion resistance of coated substrates was investigated in 1M NaCl solution using Tafel polarization technique. In addition, using scanning electron microscopy (SEM), morphological characterization of coatings produced, was investigated. Regarding the corrosion characteristics, results obtained revealed that the ratio of 1 to 1 (Pyrrole/Methylpyrrole) could play an important role.

  9. 75 FR 18153 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2010-04-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on corrosion-resistant...

  10. 77 FR 16810 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2012-03-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on corrosion-resistant...

  11. 76 FR 20954 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2011-04-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on corrosion-resistant...

  12. A Magnetic Properties and Corrosion Resistance of Fe-Si Alloy Coating Prepared on Mild Steel

    Directory of Open Access Journals (Sweden)

    Yi WANG

    2014-12-01

    Full Text Available The present work deals with preparation of Fe3Si coatings on mild steel and evaluation of its magnetic property and corrosion behavior. Magnetic property of coatings was measured using a vibrating sample magnetometer, the result shows that the saturation magnetization reached to the maximum value (214.1 emu•g-1 and the coercivity fell to the lowest (23.11 Oe in 1000oC. Corrosion behaviour of the coatings was studied using polarization in 3.5%NaCl solution. It was found that the corrosion current density (icorr decreased with increasing of heat treatment temperature up to 1000oC, indicating an improvement in corrosion resistance. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6446

  13. 77 FR 67395 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Revised Schedule for the...

    Science.gov (United States)

    2012-11-09

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Revised Schedule for the Subject Reviews AGENCY: United States International Trade Commission. ACTION: Notice. DATES: Effective...

  14. Prediction of microsegregation and pitting corrosion resistance of austenitic stainless steel welds by modelling

    Energy Technology Data Exchange (ETDEWEB)

    Vilpas, M. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity

    1999-07-01

    The present study focuses on the ability of several computer models to accurately predict the solidification, microsegregation and pitting corrosion resistance of austenitic stainless steel weld metals. Emphasis was given to modelling the effect of welding speed on solute redistribution and ultimately to the prediction of weld pitting corrosion resistance. Calculations were experimentally verified by applying autogenous GTA- and laser processes over the welding speed range of 0.1 to 5 m/min for several austenitic stainless steel grades. Analytical and computer aided models were applied and linked together for modelling the solidification behaviour of welds. The combined use of macroscopic and microscopic modelling is a unique feature of this work. This procedure made it possible to demonstrate the effect of weld pool shape and the resulting solidification parameters on microsegregation and pitting corrosion resistance. Microscopic models were also used separately to study the role of welding speed and solidification mode in the development of microsegregation and pitting corrosion resistance. These investigations demonstrate that the macroscopic model can be implemented to predict solidification parameters that agree well with experimentally measured values. The linked macro-micro modelling was also able to accurately predict segregation profiles and CPT-temperatures obtained from experiments. The macro-micro simulations clearly showed the major roles of weld composition and welding speed in determining segregation and pitting corrosion resistance while the effect of weld shape variations remained negligible. The microscopic dendrite tip and interdendritic models were applied to welds with good agreement with measured segregation profiles. Simulations predicted that weld inhomogeneity can be substantially decreased with increasing welding speed resulting in a corresponding improvement in the weld pitting corrosion resistance. In the case of primary austenitic

  15. Development of Custom 465® Corrosion-Resisting Steel for Landing Gear Applications

    Science.gov (United States)

    Daymond, Benjamin T.; Binot, Nicolas; Schmidt, Michael L.; Preston, Steve; Collins, Richard; Shepherd, Alan

    2016-04-01

    Existing high-strength low-alloy steels have been in place on landing gear for many years owing to their superior strength and cost performance. However, there have been major advances in improving the strength of high-performance corrosion-resisting steels. These materials have superior environmental robustness and remove the need for harmful protective coatings such as chromates and cadmium now on the list for removal under REACH legislation. A UK government-funded collaborative project is underway targeting a refined specification Custom 465® precipitation hardened stainless steel to replace the current material on Airbus A320 family aircraft main landing gear, a main fitting component developed by Messier-Bugatti-Dowty. This is a collaborative project between Airbus, Messier-Bugatti-Dowty, and Carpenter Technology Corporation. An extensive series of coupon tests on four production Heats of the material have been conducted, to obtain a full range of mechanical, fatigue, and corrosion properties. Custom 465® is an excellent replacement to the current material, with comparable tensile strength and fracture toughness, better ductility, and very good general corrosion and stress corrosion cracking resistance. Fatigue performance is the only significant area of deficit with respect to incumbent materials, fatigue initiation being often related to carbo-titanium-nitride particles and cleavage zones.

  16. Effects of Alloy Element and Microstructure on Corrosion Resistant Property of Deposited Metals of Weathering Steel

    Institute of Scientific and Technical Information of China (English)

    Xiao-ming XIAO; Yun PENG; Cheng-yong MA; Zhi-ling TIAN

    2016-01-01

    Alloy element and microstructure are key factors that dominate mechanical and corrosion resistant properties of weathering steel.The effect of Mo on microstructure,mechanical properties and corrosion resistant property of depos-ited metal was investigated.Experimental results show that with the increase of Mo content in deposited metals,the phase transformation temperature decreases,and the ferrite zone in CCT diagram moves rightward,resulting in en-larged bainite zone and reduced ferrite and pearlite zone.The addition of 0�24 mass% Mo in deposited metal results in the increase of tensile strength,more M-A constituent and less high angle grain which reduce the low temperature toughness.It is found that Mo can raise the weathering resistance of deposited metal in industrial atmosphere.Analy-sis indicates that Mo may enrich in the inner rust layer,produce MoO3 ,enhance the formation of compact rust film and impede the anode dissolution reaction.Granular bainite in deposited metals displays better corrosion resistance than acicular ferrite during the initial corrosion stage,but its long-term influence on the corrosion resistance is limited.

  17. A facile electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yi [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China); He, Yi, E-mail: chemheyi@swpu.edu.cn [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China); Luo, Pingya, E-mail: luopy@swpu.edu.cn [State Key Lab of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Rd. 8, Xindu District, Chengdu City, Sichuan Province 610500 (China); Chen, Xi; Liu, Bo [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu City, Sichuan Province 610500 (China)

    2016-04-15

    Graphical abstract: - Highlights: • A facile fabrication of superhydrophobic film was obtained on carbon steel. • Composition of superhydrophobic film is iron palmitate. • The film exhibits excellent chemical stability and good self-cleaning effect. • Corrosion of C45 steel is significantly inhibited with superhydrophobic surface. - Abstract: Superhydrophobic Fe film with hierarchical micro/nano papillae structures is prepared on C45 steel surface by one-step electrochemical method. The superhydrophobic surface was measured with a water contact angle of 160.5 ± 0.5° and a sliding angle of 2 ± 0.5°. The morphology of the fabricated surface film was characterized by field emission scanning electron microscopy (FE-SEM), and the surface structure seems like accumulated hierarchical micro-nano scaled particles. Furthermore, according to the results of Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS), the chemical composition of surface film was iron complex with organic acid. Besides, the electrochemical measurements showed that the superhydrophobic surface improved the corrosion resistance of carbon steel in 3.5 wt.% NaCl solution significantly. The superhydrophobic layer can perform as a barrier and provide a stable air–liquid interface which inhibit penetration of corrosive medium. In addition, the as-prepared steel exhibited an excellent self-cleaning ability that was not favor to the accumulation of contaminants.

  18. Corrosion Resistance of Zn and Cu Coated Steel Pipes as a Substitute for Cu Pipe in an Air Conditioner System

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae Gyeong; Park, Chan Jin; Hong, Sung Kil [Chonnam National University, Gwangju (Korea, Republic of)

    2009-02-15

    We investigated the corrosion resistance of Zn and Cu coated steel pipes as a substitute for Cu pipe in an air-conditioner system. In addition, the galvanic corrosion tendency between two dissimilar metal parts was studied. The corrosion resistance of the Cu electroplated steel was similar to that of Cu, while the corrosion rate of the Zn electro-galvanized and the galvalume (Zn-55 % Al) coated steels was much higher and not suitable for Cu substitute in artificial sea water and acidic rain environments. Furthermore, the galvanic difference between Cu electroplated steel and Cu was so small that the Cu coated steel pipe can be used as a substitute for Cu pipe in an air-conditioner system.

  19. Atomic-scale decoration for improving the pitting corrosion resistance of austenitic stainless steels

    Science.gov (United States)

    Zhou, Y. T.; Zhang, B.; Zheng, S. J.; Wang, J.; San, X. Y.; Ma, X. L.

    2014-01-01

    Stainless steels are susceptible to the localized pitting corrosion that leads to a huge loss to our society. Studies in the past decades confirmed that the pitting events generally originate from the local dissolution in MnS inclusions which are more or less ubiquitous in stainless steels. Although a recent study indicated that endogenous MnCr2O4 nano-octahedra within the MnS medium give rise to local nano-galvanic cells which are responsible for the preferential dissolution of MnS, effective solutions of restraining the cells from viewpoint of electrochemistry are being tantalizingly searched. Here we report such a galvanic corrosion can be greatly resisted via bathing the steels in Cu2+-containing solutions. This chemical bath generates Cu2-δS layers on the surfaces of MnS inclusions, invalidating the nano-galvanic cells. Our study provides a low-cost approach via an atomic scale decoration to improve the pitting corrosion resistance of stainless steels in a volume-treated manner.

  20. Corrosion Resistance of Galvanized Steel in the Environment of a Bioreactor

    Directory of Open Access Journals (Sweden)

    Šustr Michal

    2016-06-01

    Full Text Available The article deals with monitoring the corrosion resistibility of welded materials in the anaerobic fermenter (bioreactor. The main goal of this research is to assess the change of hardness after degradation. The change of hardness occurs in the corrosion environment and it correlates with the corrosion resistibility of material. The purpose of this experiment is to recognize the possibilities of using the CMT welded materials in the defined environment. As an innovative technology the acoustic emission method is used for assessment of surface layer disruption during hardness testing. Aluminium alloy with galvanized steel (AluZinc was used as an experimental material. The basic materials were welded by the filler material AlSi3.

  1. Corrosion resistance and development length of steel reinforcement with cementitious coatings

    Science.gov (United States)

    Pei, Xiaofei

    This research program focused on the corrosion resistance and development length of reinforcing steel coated with Cementitious Capillary Crystalline Waterproofing (CCCW) materials. The first part of this research program involved using the half-cell potential method to evaluate the corrosion resistance of CCCW coating materials. One hundred and two steel bars were embedded in concrete cylinders and monitored. In total, 64 steel reinforcing bars were coated with CCCW prior to embedment, 16 mortar cylinders were externally coated with CCCW, and 22 control (uncoated) samples were tested. All the samples were immersed in a 3.5% concentration chloride solution for a period of one year. Three coating types were studied: CCCW-B, CCCW-B+ C and CCCW-C+D. The test results showed that the CCCW coating materials delayed the corrosion activity to varying degrees. In particular, CCCW-C+D applied on the reinforcing steel surface dramatically delayed the corrosion activity when compared to the control samples. After being exposed to the chloride solution for a period of one year, no sign of corrosion was observed for the cylinders where the concrete surface was coated. The second part of this research evaluated the bond strength and development length of reinforcing steel coated with two types of CCCW coating materials (CCCW-B+C and CCCW-C+D) using a modified pull-out test method. A self-reacting inverted T-shaped beam was designed to avoid compression in the concrete surrounding the reinforcing steel. Steel reinforcing bars were embedded along the web portion of the T-beam with various embedded lengths and were staggered side by side. In total, six T-beams were fabricated and each beam contained 8 samples. Both short-term (7 days) and long-term (3 months) effects of water curing were evaluated. The reinforcing steel bars coated with CCCW-B+C demonstrated a higher bond strength than did samples coated with CCCW-C+D. However, the bond strengths of samples with coating materials

  2. CORROSION INHIBITOR FOR CARBON STEELS

    African Journals Online (AJOL)

    corrosion inhibitor for carbon steel in 3% ac]neon.s' NaCl solution (pH 6) ... compared to stainless steels (Buchweishaija & Hagen 1997). Organic compounds are ... resistant dust for break and clutch linings, wood binders and mould (Gedam.

  3. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    Science.gov (United States)

    Zhang, Zhe; Yu, Ting; Kovacevic, Radovan

    2017-07-01

    Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%-40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V8C7, M7C3, and M23C6 were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content. No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. The corrosion resistance of the clads was decreased with the increase in the VC content, demonstrating the negative effect of VC on the corrosion resistance of AISI 420 stainless steel

  4. Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings

    Science.gov (United States)

    Jones, John Eric; Chen, Meng; Yu, Qingsong

    2015-01-01

    To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20–25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH3/O2 plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O-and N-contents on the surfaces were substantially increased after NH3/O2 plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH3/O2 plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electro-chemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. PMID:24500866

  5. Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings.

    Science.gov (United States)

    Eric Jones, John; Chen, Meng; Yu, Qingsong

    2014-10-01

    To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20-25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH₃/O₂ plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O- and N-contents on the surfaces were substantially increased after NH₃/O₂ plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH₃/O₂ plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. © 2014 Wiley Periodicals, Inc.

  6. Bacterial exopolysaccharides for corrosion resistance on low carbon steel

    Science.gov (United States)

    Corrosion is a global issue that affects safety and economics. There is an increasing demand for bio-based polymers for industrial applications and production of polymers by microorganisms is especially attractive. This work reports on the electrochemical and physical properties of exopolysaccharide...

  7. Review on Improving Wear and Corrosion Resistance of Steels via Plasma Electrolytic Saturation Technology

    Science.gov (United States)

    Lin, Naiming; Xie, Ruizhen; Zhou, Peng; Zou, Jiaojuan; Ma, Yong; Wang, Zhenxia; Han, Pengju; Wang, Zhihua; Tang, Bin; Tian, Wei

    2016-03-01

    Plasma electrolytic saturation (PES) technique which holds the advantages of short treating time and limited heating influence and immediate quenching effect is conducted under high voltage power supply in some electrolyte has been extensively applied to enhance the surface performance of metallic materials. Steel is widely used in various fields thanks to its promising merits of easy workability, plasticity, toughness and weldability. It accounts for a large proportion in the application scope of the metal materials. Steel surfaces with good corrosion resistance, promising wear resistance and high hardness would be obtained by PES. Meanwhile, uniformed coatings can be formed without special requirements for substrate geometries using the PES. This paper first presents a brief introduction of the technological principle of PES. The status on studies and applications of PES for improving surface performance of steels has been reviewed.

  8. Effect Of Heat Treatment On The Corrosion Resistance Of Aluminized Steel Strips

    Directory of Open Access Journals (Sweden)

    Żaba K.

    2015-09-01

    Full Text Available The paper presents the results of corrosion resistance of heat treated aluminized steel strips. Products coated by Al-10Si alloy are used among others in a manufacturing process of welded pipes as the elements of the car exhaust systems, working in high temperatures and different environments (eg. wet, salty. The strips and tubes high performance requirements are applied to stability, thickness and roughness of Al-Si coating, adhesion and corrosion resistance. Tubes working in elements of exhaust systems in a wide range of temperatures are exposed to the effects of many aggressive factors, such as salty snow mud. It was therefore decided to carry out research on the impact of corrosion on the environmental influence on heat treated aluminized steel strips. The heat treatment was carried out temperatures in the range 250-700°C for 30, 180, 1440 minutes. Then the coatings was subjected to cyclic impact of snow mud. Total duration of treatment was 12 months and it was divided into three stages of four months and at the end of each stage was made the assessment of factor of corrosion. The results are presented in the form of macroscopic, microscopic (using a scanning electron microscope observations and the degree and type of rusty coating.

  9. Microstructure and Corrosion Resistance of Laser Additively Manufactured 316L Stainless Steel

    Science.gov (United States)

    Trelewicz, Jason R.; Halada, Gary P.; Donaldson, Olivia K.; Manogharan, Guha

    2016-03-01

    Additive manufacturing (AM) of metal alloys to produce complex part designs via powder bed fusion methods such as laser melting promises to be a transformative technology for advanced materials processing. However, effective implementation of AM processes requires a clear understanding of the processing-structure-properties-performance relationships in fabricated components. In this study, we report on the formation of micro and nanoscale structures in 316L stainless steel samples printed by laser AM and their implications for general corrosion resistance. A variety of techniques including x-ray diffraction, optical, scanning and transmission electron microscopy, x-ray fluorescence, and energy dispersive x-ray spectroscopy were employed to characterize the microstructure and chemistry of the laser additively manufactured 316L stainless steel, which are compared with wrought 316L coupons via electrochemical polarization. Apparent segregation of Mo has been found to contribute to a loss of passivity and an increased anodic current density. While porosity will also likely impact the environmental performance (e.g., facilitating crevice corrosion) of AM alloys, this work demonstrates the critical influence of microstructure and heterogeneous solute distributions on the corrosion resistance of laser additively manufactured 316L stainless steel.

  10. Evaluation of the stress corrosion cracking resistance of several high strength low alloy steels

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1980-01-01

    The stress corrosion cracking resistance was studied for high strength alloy steels 4130, 4340, for H-11 at selected strength levels, and for D6AC and HY140 at a single strength. Round tensile and C-ring type specimens were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, salt spray, the atmosphere at Marshall Space Flight Center, and the seacoast at Kennedy Space Center. Under the test conditions, 4130 and 4340 steels heat treated to a tensile strength of 1240 MPa (180 ksi), H-11 and D6AC heat treated to a tensile strength of 1450 MPa (210 ksi), and HY140 (1020 MPa, 148 ksi) are resistant to stress corrosion cracking because failures were not encountered at stress levels up to 75 percent of their yield strengths. A maximum exposure period of one month for alternate immersion in salt water or salt spray and three months for seacoast is indicated for alloy steel to avoid false indications of stress corrosion cracking because of failure resulting from severe pitting.

  11. 77 FR 25405 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2012-04-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on corrosion...

  12. 75 FR 25841 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2010-05-10

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on corrosion...

  13. 76 FR 21332 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2011-04-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on corrosion...

  14. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Science.gov (United States)

    Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhang, Jianli

    2017-02-01

    The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N2 in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr2N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitro`gen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T1). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N2-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential corrosion. The Cr2N precipitation led to relatively poor resistance to pitting corrosion in three HAZs and pure Ar shielding GTAW weld root. The N2-supplemented shielding gas improved pitting corrosion resistance of GTAW joint by increasing PREN of secondary austenite and suppressing Cr2N precipitation. In addition, the FCAW WM had much poorer resistance to pitting corrosion than the GTAW WM due to many O-Ti-Si-Mn inclusions. In the BM, since the austenite with lower PREN compared

  15. Significance of steel electrical resistance method in the evaluation of reinforcement corrosion in cementitious systems

    Directory of Open Access Journals (Sweden)

    Krajci, L.

    2004-06-01

    Full Text Available The suitable detection system of steel reinforcement corrosion in concrete structures contributes to the reduction of their maintenance costs. Method of steel electrical resistance represents non-destructive monitoring of steel in cementitious systems. Specially prepared and arranged test specimen of steel as a corrosion sensor is embedded in mortar specimen. Verification tests of this method based on chloride corrosion of steel in mortars as well as its visual inspection are introduced. Significance of steel electrical resistance method lies in the expression of steel corrosion by these quantitative parameters: reduction of cross-section of steel, thickness of corroded layer and loss of weight of steel material. This method is an integral method that allows the indirect determination of mentioned corrosion characteristics. The comparison of verified method with gravimetric evaluation of steel corrosion gives a good correspondence. Test results on mortars with calcium chloride dosages between 0.5% and 4.0% by weight of cement prove high sensitiveness and reliability of steel electrical resistance method.

    La utilización de un sistema de detección de la corrosión de las armaduras en estructuras de hormigón puede contribuir a la reducción de sus costes de mantenimiento. El método de la resistencia eléctrica del acero consiste en la monitorización no-destructiva realizada sobre el acero en sistemas cementantes. Dentro de la muestra de mortero se coloca el sistema de detección, especialmente preparado y fijado, actuando como un sensor de la corrosión. En este trabajo se presentan ensayos de verificación de este método, junto con inspecciones visuales, en morteros sometidos a corrosión de armaduras por efecto de los cloruros. La efectividad de este método de la resistencia eléctrica del acero se expresa, en la corrosión de armaduras, de acuerdo a los siguientes parámetros cuantitativos: reducción de la sección transversal del

  16. Development of Modified 304 Stainless Steel Resistant to Stress Corrosion Cracking in Chloride Environment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This was a feasibility study for a modified 304 steel resistant to stress corrosion cracking (SCC) in aqueous environment containing chloride. SCC tests were conducted potentiostaticaly with spot-welded specimens, which had both crevice and residual stress, mainly in 3 % NaCl solution at various temperatures to determine the critical temperature for SCC at and below which the steel would not suffer from SCC. The effects of individual alloying element of silicon, manganese and copper on SCC of 18Cr-14Ni steels which phosphor content is 0.002 % and molybdenum content is 0.01 % were examined. Addition of 1 or 2 % of copper has beneficial effect on resistance to SCC, while increasing silicon or manganese content has no significant effect. Critical temperature of the steel with 0.002 % of phosphor and 2 % of copper is 150 ℃, which is markedly higher than 50 ℃ of 304L steel. However, the beneficial effect of copper is reduced with increasing phosphor content. From practical viewpoint, the modified steel with good SCC resistance should have 0.01 %-0.015 % of phosphor and 0.3 % or more of molybdenum, because it is very difficult to reduce phosphor content below 0.008 % industrially and such molybdenum content is inevitably introduced through cost-saving melting process using return steel. Aluminium is to be added as another alloying element and 3 % of aluminium combined with 2 % of copper has been found to negate the deleterious effects of increased phosphor and molybdenum content. As a candidate steel at this stage, 14Cr-16Ni-0.013P-2Cu-1Al-(0.3-1)Mo steel has critical temperature of 110 ℃.

  17. Raising the Corrosion Resistance of Low-Carbon Steels by Electrolytic-Plasma Saturation with Nitrogen and Carbon

    Science.gov (United States)

    Kusmanov, S. A.; Grishina, E. P.; Belkin, P. N.; Kusmanova, Yu. V.; Kudryakova, N. O.

    2017-05-01

    Structural features of the external oxide layer and internal nitrided, carbonitrided and carburized layers in steels 10, 20 and St3 produced by the method of electrolytic plasma treatment are studied. Specimens of the steels are tested for corrosion in a naturally aerated 1-N solution of sodium chloride. The condition of the metal/sodium chloride solution interface is studied by the method of electrochemical impedance spectroscopy. It is shown that the corrosion resistance of low-carbon steels can be raised by anode electrolytic-plasma saturation with nitrogen and carbon. Recommendations are given on the choice of carbonitriding modes for structural steels.

  18. High corrosion resistance of austenitic stainless steel alloyed with nitrogen in an acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Metikos-Hukovic, M., E-mail: mmetik@fkit.h [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Babic, R. [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Grubac, Z. [Department of General and Inorganic Chemistry, Faculty of Chemistry and Technology, University of Split, 21000 Split (Croatia); Petrovic, Z. [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Lajci, N. [Faculty of Mine and Metallurgy, University of Prishtina, 10000 Prishtina, Kosovo (Country Unknown)

    2011-06-15

    Highlights: {yields} ASS alloyed with nitrogen treated at 1150 {sup o}C exhibits microstructure homogeneity. {yields} Passivation peak of ASS corresponds to oxidation of metal and absorbed hydrogen. {yields} Transfer phenomena and conductivity depend on the film formation potential. {yields} Electronic structure of the passive film and its corrosion resistance correlate well. {yields} Passive film on ASS with nitrogen is low disordered and high corrosion resistant. - Abstract: Passivity of austenitic stainless steel containing nitrogen (ASS N25) was investigated in comparison with AISI 316L in deareated acid solution, pH 0.4. A peculiar nature of the passivation peak in a potentiodynamic curve and the kinetic parameters of formation and growth of the oxide film have been discussed. The electronic-semiconducting properties of the passive films have been correlated with their corrosion resistance. Alloying austenitic stainless steel with nitrogen increases its microstructure homogeneity and decreases the concentration of charge carriers, which beneficially affects the protecting and electronic properties of the passive oxide film.

  19. Microbial consortium influence upon steel corrosion rate, using polarisation resistance and electrochemical noise techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Gayosso, M.J.; Zavala Olivares, G.; Ruiz Ordaz, N.; Juarez Ramirez, C.; Garcia Esquivel, R.; Padilla Viveros, A

    2004-10-01

    The microbiologically influenced corrosion (MIC) is a process, which affects the oil industry, particularly the hydrocarbons extraction, transport and storage. MIC evaluation has been normally based upon microbiological tests, and just a few references mention alternating methods, such as the electrochemical techniques, which can be used as criteria for their evaluation. In this work, two different electrochemical laboratory techniques, polarisation resistance and electrochemical noise were used, in order to determine the corrosion behaviour of a microbial consortium, obtained from a gas transporting pipeline, located in the southeast of Mexico. The bacteria population growth was found to be different for sessile and plancktonic microorganisms. Moreover, long incubation times were required to reach the maximum concentration of sessile bacteria. The electrochemical techniques used in this study exhibited a similar tendency on the corrosion rate behaviour with time, and values above 0.3 mm year{sup -1} were observed at the end of the experiments. The experiments were complemented with surface analysis. Scanning electron microscope observation of APIXL52 steel coupons, exposed to the consortium action, revealed bacteria presence, as well as a damaged steel surface. A type of localized corrosion was observed on the metal surface, and it was associated to the bacteria effect.

  20. Influence of Organic Inhibitor on Corrosion Resistance of Steel in Simulated Concrete Pore Solution

    OpenAIRE

    Cai, Jingshun S.; C. C. CHEN; Liu, J. Z.; Liu, J. P.

    2014-01-01

    Organic corrosion inhibitor is one of lower cost technologies that limit the deterioration of concrete structures. The influence of a newly prepared organic corrosion inhibitor on the corrosion behavior of carbon steel in simulated concrete pore solution was investigated by polarization curves, electrochemical impedance spectroscopy, and so on. The effect of organic corrosion inhibitors on concrete working performance was also studied. The results show that the corrosion rate decreases with t...

  1. Effect of Mn Content and Solution Annealing Temperature on the Corrosion Resistance of Stainless Steel Alloys

    Directory of Open Access Journals (Sweden)

    Ihsan-ul-Haq Toor

    2014-01-01

    Full Text Available The corrosion behavior of two specially designed austenitic stainless steels (SSs having different Nickel (Ni and Manganese (Mn contents was investigated. Prior to electrochemical tests, SS alloys were solution-annealed at two different temperatures, that is, at 1030°C for 2 h and 1050°C for 0.5 h. Potentiodynamic polarization (PD tests were carried out in chloride and acidic chloride, whereas linear polarization resistance (LPR and electrochemical impedance spectroscopy (EIS was performed in 0.5 M NaCl solution at room temperature. SEM/EDS investigations were carried out to study the microstructure and types of inclusions present in these alloys. Experimental results suggested that the alloy with highest Ni content and annealed at 1050°C/0.5 hr has the highest corrosion resistance.

  2. Nanotextured stainless steel for improved corrosion resistance and biological response in coronary stenting

    Science.gov (United States)

    Mohan, Chandini C.; Prabhath, Anupama; Cherian, Aleena Mary; Vadukumpully, Sajini; Nair, Shantikumar V.; Chennazhi, Krishnaprasad; Menon, Deepthy

    2014-12-01

    Nanosurface engineering of metallic substrates for improved cellular response is a persistent theme in biomaterials research. The need to improve the long term prognosis of commercially available stents has led us to adopt a `polymer-free' approach which is cost effective and industrially scalable. In this study, 316L stainless steel substrates were surface modified by hydrothermal treatment in alkaline pH, with and without the addition of a chromium precursor, to generate a well adherent uniform nanotopography. The modified surfaces showed improved hemocompatibility and augmented endothelialization, while hindering the proliferation of smooth muscle cells. Moreover, they also exhibited superior material properties like corrosion resistance, surface integrity and reduced metal ion leaching. The combination of improved corrosion resistance and selective vascular cell viability provided by nanomodification can be successfully utilized to offer a cell-friendly solution to the inherent limitations pertinent to bare metallic stents.

  3. The Influence of Modes of Deposition of Coatings on the Corrosion Resistance of Welded Joints of Steels in Acidic Media;

    Science.gov (United States)

    Saraev, Yu N.; Bezborodov, V. P.; Selivanov, Y. V.

    2016-08-01

    In this work, effect of welding on corrosion of welded joints of austenitic steel 12KH18N10T. It is shown that the use of pulsed - arc welding steel 12KH18N10T allows you to create a protective coating with dispersed structure with less thermal impact on the zone of the welded joint. Coating is of such structure allows 1.5 to 6 times to reduce the corrosion rate of welded joints of steel 12KH18N10T in active chemical environments. Pulse the process of deposition of coatings on welded joint of steels can be effectively used for the protection against corrosion in the repair of equipment of chemical industry. The results obtained can be recommended for use when welding a protective corrosion - resistant coatings on working surfaces of equipment of chemical productions.

  4. In vitro corrosion resistance of plasma source ion nitrided austenitic stainless steels.

    Science.gov (United States)

    Le, M K; Zhu, X M

    2001-04-01

    Plasma source ion nitriding has emerged as a low-temperature, low-pressure nitriding approach for low-energy implanting nitrogen ions and then diffusing them into steel and alloy. In this work, a single high nitrogen face-centered-cubic (f.c.c.) phase (gammaN) formed on the 1Cr18Ni9Ti and AISI 316L austenitic stainless steels with a high nitrogen concentration of about 32 at % was characterized using Auger electron spectroscopy, electron probe microanalysis, glancing angle X-ray diffraction, and transmission electron microscopy. The corrosion resistance of the gammaN-phase layer was studied by the electrochemical cyclic polarization measurement in Ringer's solutions buffered to pH from 3.5 to 7.2 at a temperature of 37 degrees C. No pitting corrosion in the Ringer's solutions with pH = 7.2 and 5.5 was detected for the gammaN-phase layers on the two stainless steels. The high pitting potential for the gammaN-phase layers is higher, about 500 and 600 mV, above that of the two original stainless steels, respectively, in the Ringer's solution with pH = 3.5. The corroded surface morphologies of the gammaN-phase layers observed by scanning electron microscopy are consistent with the results of the electrochemical polarization measurement.

  5. Electrochemical methods for characterisation of thermal spray corrosion resistant stainless steel coatings

    NARCIS (Netherlands)

    Hofman, R.; Vreijling, M.P.W.; Ferrari, G.M.; Wit, J.H.W. de

    1998-01-01

    The use of thermal spray stainless steel coatings for protection of low alloyed steels against different types of corrosion is limited due to high porosity levels and oxide inclusions. In this paper electrochemical methods like corrosion potential monitoring and cyclic voltammetry are reported to mo

  6. Electrochemical methods for characterisation of thermal spray corrosion resistant stainless steel coatings

    NARCIS (Netherlands)

    Hofman, R.; Vreijling, M.P.W.; Ferrari, G.M.; Wit, J.H.W. de

    1998-01-01

    The use of thermal spray stainless steel coatings for protection of low alloyed steels against different types of corrosion is limited due to high porosity levels and oxide inclusions. In this paper electrochemical methods like corrosion potential monitoring and cyclic voltammetry are reported to

  7. Corrosion resistance enhancement of SAE 1020 steel after Chromium implantation by nitrogen ion recoil

    Directory of Open Access Journals (Sweden)

    Geraldo Francisco Gomes

    2005-12-01

    Full Text Available SAE 1020 construction steel is widely used as mortar reinforcement and small machine parts, but aside good surface properties as high ductility, hardness and wear resistance, its surface is prone to severe corrosion. As it is known, Chromium in amount over 12%-13% in the Fe alloys renders them resistance to several corrosive attacks. SAE 1020 samples were recovered with Chromium film and then bombarded either by nitrogen Ion Beam (IB or Plasma Immersion Ion Implantation (PIII to recoil implant Cr atoms in the Fe matrix. Samples treated by 100 keV N+ IB showed irregular, thin Cr profile, remaining a part of the film on the surface, to about 10 nm. Samples treated by 40 kV N PIII presented Cr layer of about 18% at., ranging to around 90 nm. Cr of the film was implanted in the Fe matrix in an almost flat profile. Results of corrosion test showed good performance of the PIII treated sample. The IB treated sample showed some enhancement over the non-treated reference and the only Cr film deposited sample showed no modification on the corrosion behavior as compared to the non-treated reference sample.

  8. Influence of silver additions to type 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tseng, I-Sheng; Møller, Per;

    2010-01-01

    techniques. The microstructure of these 316 stainless steels was examined, and the influences of silver additions to 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance were investigated. This study suggested that silver-bearing 316 stainless steels could be used......Bacterial contamination is a major concern in many areas. In this study, silver was added to type 316 stainless steels in order to obtain an expected bacteria inhibiting property to reduce the occurrence of bacterial contamination. Silver-bearing 316 stainless steels were prepared by vacuum melting...

  9. Microstructure and intergranular corrosion resistance of UNS S17400 (17-4PH) stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, S.S.M., E-mail: ssmtavares@terra.com.b [Universidade Federal Fluminense - Programa de Pos-graduacao em Engenharia Mecanica (PGMEC), Rua Passo da Patria, 156 - CEP 24210-240 - Niteroi/RJ (Brazil); Silva, F.J. da; Scandian, C. [Universidade Federal do Espirito Santo - Departamento de Engenharia Mecanica - Av. Fernando Ferrrari, 514 - CEP 29075-910 - Vitoria/ES (Brazil); Silva, G.F. da [Universidade Federal Fluminense - Programa de Pos-graduacao em Engenharia Mecanica (PGMEC), Rua Passo da Patria, 156 - CEP 24210-240 - Niteroi/RJ (Brazil); Abreu, H.F.G. de [Universidade Federal do Ceara - Departamento de Engenharia Metalurgica e Materiais - Campus do Pici, Bloco 702 - CEP 60455-760 - Fortaleza/CE (Brazil)

    2010-11-15

    UNS S17400 or 17-4PH is a precipitation hardening martensitic stainless steel with many industrial applications. Quite different mechanical properties can be produced in this material by varying the aging temperature. In this work, the influence of aging temperature on the intergranular corrosion susceptibility was evaluated by electrochemical and metallographic tests. The microstructural features were investigated by X-ray diffraction, optical and scanning electron microscopy. Intergranular chromium carbide precipitation occurs in specimens aged at high temperatures, although NbC carbides were also observed. The results obtained by double loop electrochemical potentiodynamic reactivation tests (DL-EPR) show that the susceptibility to intergranular corrosion resistance increases with the increase of aging temperature. Healing due to Cr diffusion in the 600-650 {sup o}C range was not observed by DL-EPR tests.

  10. Influence of Laser Peening on Phase Transformation and Corrosion Resistance of AISI 321 steel

    Science.gov (United States)

    Karthik, D.; Swaroop, S.

    2016-07-01

    The objective of this study is to investigate the influence of laser peening without coating (LPwC) on austenitic to martensitic (γ → α') phase transformation and corrosion behavior of austenitic stainless steel AISI 321 in 3.5% NaCl environment. Results indicate that LPwC induces a large compressive residual stresses of nearly -854 MPa and γ → α' phase transformation of about 18% (volume fraction). Microstructures of peened surface confirmed the γ → α' phase transformation and showed no grain refinement. Hardness increased slightly with a case depth of 900 μm. Despite the smaller surface roughness introduced, corrosion resistance improved after peening due to compressive residual stresses.

  11. Corrosion resistant PEM fuel cell

    Science.gov (United States)

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  12. A facile electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on carbon steel

    Science.gov (United States)

    Fan, Yi; He, Yi; Luo, Pingya; Chen, Xi; Liu, Bo

    2016-04-01

    Superhydrophobic Fe film with hierarchical micro/nano papillae structures is prepared on C45 steel surface by one-step electrochemical method. The superhydrophobic surface was measured with a water contact angle of 160.5 ± 0.5° and a sliding angle of 2 ± 0.5°. The morphology of the fabricated surface film was characterized by field emission scanning electron microscopy (FE-SEM), and the surface structure seems like accumulated hierarchical micro-nano scaled particles. Furthermore, according to the results of Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS), the chemical composition of surface film was iron complex with organic acid. Besides, the electrochemical measurements showed that the superhydrophobic surface improved the corrosion resistance of carbon steel in 3.5 wt.% NaCl solution significantly. The superhydrophobic layer can perform as a barrier and provide a stable air-liquid interface which inhibit penetration of corrosive medium. In addition, the as-prepared steel exhibited an excellent self-cleaning ability that was not favor to the accumulation of contaminants.

  13. Mechanism of selective corrosion in electrical resistance seam welded carbon steel pipe

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Fajardo, Pedro; Godinez Salcedo, Jesus; Gonzalez Velasquez, Jorge L. [Instituto Politecnico Nacional, Mexico D.F., (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas. Dept. de Ingenieria Metalurgica

    2009-07-01

    In this investigation the studies of the mechanism of selective corrosion in electrical resistance welded (ERW) carbon steel pipe was started. Metallographic characterizations and evaluations for inclusions were performed. The susceptibility of ERW pipe to selective corrosion in sea water (NACE 1D182, with O{sub 2} or CO{sub 2} + H{sub 2}S) was studied by the stepped potential Potentiostatic electrochemical test method in samples of 1 cm{sup 3} (ASTM G5) internal surface of the pipe (metal base-weld). The tests were looking for means for predicting the susceptibility of ERW pipe to selective corrosion, prior to placing the pipeline in service. Manganese sulfide inclusions are observed deformed by the welding process and they are close to the weld centerline. A slight decarburization at the weld line is observed, and a distinct out bent fiber pattern remains despite the post-weld seam annealing. The microstructure of the weld region consists of primarily polygonal ferrite grains mixed with small islands of pearlite. It is possible to observe the differences of sizes of grain of the present phases in the different zones. Finally, scanning electron microscopic observation revealed that the corrosion initiates with the dissolution of MnS inclusions and with small crack between the base metal and ZAC. (author)

  14. Reduced platelet adhesion and improved corrosion resistance of superhydrophobic TiO₂-nanotube-coated 316L stainless steel.

    Science.gov (United States)

    Huang, Qiaoling; Yang, Yun; Hu, Ronggang; Lin, Changjian; Sun, Lan; Vogler, Erwin A

    2015-01-01

    Superhydrophilic and superhydrophobic TiO2 nanotube (TNT) arrays were fabricated on 316L stainless steel (SS) to improve corrosion resistance and hemocompatibility of SS. Vertically-aligned superhydrophilic amorphous TNTs were fabricated on SS by electrochemical anodization of Ti films deposited on SS. Calcination was carried out to induce anatase phase (superhydrophilic), and fluorosilanization was used to convert superhydrophilicity to superhydrophobicity. The morphology, structure and surface wettability of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The effects of surface wettability on corrosion resistance and platelet adhesion were investigated. The results showed that crystalline phase (anatase vs. amorphous) and wettability strongly affected corrosion resistance and platelet adhesion. The superhydrophilic amorphous TNTs failed to protect SS from corrosion whereas superhydrophobic amorphous TNTs slightly improved corrosion resistance of SS. Both superhydrophilic and superhydrophobic anatase TNTs significantly improved corrosion resistance of SS. The superhydrophilic amorphous TNTs minimized platelet adhesion and activation whereas superhydrophilic anatase TNTs activated the formation of fibrin network. On the contrary, both superhydrophobic TNTs (superhydrophobic amorphous TNTs and superhydrophobic anatase TNTs) reduced platelet adhesion significantly and improved corrosion resistance regardless of crystalline phase. Superhydrophobic anatase TNTs coating on SS surface offers the opportunity for the application of SS as a promising permanent biomaterial in blood contacting biomedical devices, where both reducing platelets adhesion/activation and improving corrosion resistance can be effectively combined.

  15. Improvement of the Corrosion Resistance of High Alloyed Austenitic Cr-Ni-Mo Stainless Steels by Solution Nitriding

    Institute of Scientific and Technical Information of China (English)

    Christine Eckstein; Heinz- Joachim Spies; Jochen Albrecht

    2004-01-01

    Characteristic features of austenitic steel grades combine a good corrosion resistance with a low hardness, wear resistance and scratch resistance. An interesting possibility for improving the wear behaviour of these steels without loss of their corrosion resistance lies in enriching the near surface region with nitrogen. The process of a solution nitriding allows the rise of the solution of nitrogen in the solid phase. On this state nitrogen increases the corrosion resistance and the tribilogical load-bearing capacity. The aim of the study was, to investigate the improvement of the pitting corrosion behaviour by solution nitriding. A special topic was to observe the effect of nitrogen by different molybdenum content. So austenitic stainless steels (18% Cr, 12% Ni, Mo gradation between 0.06 to 3.6%) had been solution nitrided. The samples could be prepared with various surface content of nitrogen from 0.04 to 0.45% with a step-by-step grinding. The susceptibility against pitting corrosion of these samples had been tested by determination of the stable pitting potential in 0.5M and 1M NaCl at 25℃. For the investigated steel composition and the used corrosion system there is no influence of molybdenum on the effectiveness of nitrogen. The influence of nitrogen to all of the determined parameters can be corrosion tests. Additionally surface investigations with an acid elektolyte (0,1M HCl + 0,4M NaCI) were performed. In this case the passivation effective nitrogen content increases markedly with rising molybdenum concentration of the steel.Obviously an interaction of Mo and N is connected with a strongly acid electrolyte.

  16. Influence of Alloying Elements Corrosion Resistance of Cold on Mechanical Properties and Rolled C-Mn-Si TRIP Steels

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling-yun; WU Di; LI Zhuang

    2012-01-01

    The rust layer plays an important role in the corrosion of steel in chlorinated environments. Salt spray, po- tentiodynamic polarization curve and tensile test were conducted in laboratory for the specimens after two-stage heat treatment. The influence of the alloying elements on mechanical properties and corrosion resistance of three kinds of steels was investigated by observing the microstructure and the morphologies of rust layer. The results show that the highest value (29%) of total elongation for steel A is obtained. The mechanical property of the specimen for steel C exhibits best strength ductility balance (21 384 MPa ·%) because of the presence of the multiphase microstructures after a two-stage heat treatment and the addition of the alloying elements. The corrosion products are known to be a complex mixture of Fe3O4 , Fe2O3 and α-FeOOH for steel C. The presence of the alloying elements results in the for mation of compact and dense rust layers in steel B and C. Passive film protects the substrate of TRIP (transformation induced plasticity) steel containing a complex mix of multiphase. Superior corrosion performance is exhibited for steel C with low alloying contents due to the enrichment of alloying elements within the rust layers.

  17. Effects of laser heat treatment on salt spray corrosion of 1Cr5Mo heat resistant steel welding joints

    Institute of Scientific and Technical Information of China (English)

    孔德军; 郭卫

    2015-01-01

    The surface of 1Cr5Mo heat-resistant steel welding joint was processed with CO2 laser, and the corrosion behaviors before and after laser heat treatment (LHT) were investigated in the salt spray corrosion environments. The microstructures, phases, residual stresses and retained austenite content of 1Cr5Mo steel welding joint before and after LHT were analyzed with optical microscope and X-ray diffraction, respectively. The cracking morphologies and chemical compositions of corrosion products after salt spray corrosion were analyzed with field emission scanning electron microscopy (FESEM) and energy disperse spectroscopy (EDS), respectively, the polarization curves were measured on a PS-268A type electrochemical workstation, and the mechanism of corrosion resistance by LHT was investigated as well. The results show that the passive film of original sample is destroyed owing to the corrosive media penetrating into the subsurface, resulting in the redox reaction. The content of residual austenite in the surface and the self-corrosion potential are increased by LHT, which is contributed to improving the capability of salt spray corrosion resistance.

  18. Improved Corrosion and Abrasion Resistance of Organic-Inorganic Composite Coated Electro-galvanized Steels for Digital TV Panels

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Du-Hwan; Noh, Sang-Geol; Park, Jong-Tae; Kang, Choon-Ho [POSCO Technical Research Laboratories, Pohang (Korea, Republic of)

    2015-10-15

    Recently, household electronic industries require environmentally-friendly and highly functional steels in order to enhance the quality of human life. Customers especially require both excellent corrosion and abrasion resistant anti-fingerprint steels for digital TV panels. Thus POSCO has developed new functional electro-galvanized steels, which have double coated layers with organic-inorganic composites on the zinc surface of the steel for usage as the bottom chassis panel of TVs. The inorganic solution for the bottom layer consists of inorganic phosphate, magnesium, and zirconium compounds with a small amount of epoxy binder, and affords both improved adhesion properties by chemical conversion reactions and corrosion resistance due to a self-healing effect. The composite solution for the top layer was prepared by fine dispersion of organic-inorganic ingredients that consist of a urethane modified polyacrylate polymer, hardener, silica sol and a titanium complex inhibitor in aqueous media. Both composite solutions were coated on the steel surface by using a roll coater and then cured through an induction furnace in the electro-galvanizing line. New anti-fingerprint steel was evaluated for quality performance through such procedures as the salt spray test for corrosion resistance, tribological test for abrasion resistance, and conductivity test for surface electric conductance regarding to both types of polymer resin and coating weight of composite solution. New composite coated anti-fingerprint steels afford both better corrosion resistance and abrasion properties compared to conventional anti-fingerprint steel that mainly consists of acrylate polymers. Detailed discussions of both composite solutions and experimental results suggest that urethane modifications of acrylate polymers of composite solutions play a key role in enhanced quality performances.

  19. Corrosion Resistance of The Bearing Steel 67SiMnCr6-6-4 with Nanobainitic Structure

    Directory of Open Access Journals (Sweden)

    Skołek E.

    2015-04-01

    Full Text Available The paper describes a comparative study of the corrosion resistance of bearing steel 67SiMnCr6-6-4 after two kinds of nanostructuring treatments and two kinds of conventional quenching and tempering treatments. The nanostructuring treatment consisted of austempering with an isothermal quenching at 240°C and 300°C. The conventional heat treatment consisted on quenching and tempering at 350°C for 1 h and quenching and tempering at 550°C for 1 h. Time and temperature of tempering was chosen so that the hardness of both samples (nanostructured as well as quenched and tempered was similar. The microstructure of steel after each heat treatment was described with the use of transmission electron microscopy (TEM. It was shown, that the austempering conducted at 240°C produced homogenous nanobainitic structure consisting of carbide-free bainite plates with nanometric thickness separated by the layers of retained austenite. The austempering at 300°C produced a sub-micrometric carbide-free bainite with retained austenite in form of layers and small blocks. The conventional heat treatments led to a tempered martensite microstructure. The corrosion resistance study was carried out in Na2SO4 acidic and neutral environment using potentiodynamic and electrochemical impedance spectroscopy (EIS methods. The corrosion resistance of nanostructured steel samples were compared to the steel samples with tempered martensite. The obtained results indicate, that the corrosion resistance of bearing steel with nanobainitic structure is similar to steel with tempered martensite in both acidic and neutral environment. This means that the high density of intercrystalline boundaries in nanobinite does not deteriorate the corrosion properties of the bearing steel.

  20. Nanophase formation and its behavior of corrosion resistance in C+Ti dual implanted steel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    [1]Zhang Huixing,Zhang Xiaoji,Zhou Fengsheng et al.,High current metal-ion source for ion implantation,Rev.Sci.Instrum.,1990,61(1): 574.[2]Zhang Tonghe,Ji Chengzhou,Shen Jinghua et al.,Surface modification of steel by high-dose pulse-ion implantation of titanium,tungsten,molybdenum and carbon,Nucl.Instrum.Methods,1991,B59/60: 828.[3]Zhang Tonghe,Ji Chengzhou,Shen Jinghua et al.,The influence of Ti,N and Ti+N implantation on phase change,microstructure,growth of metallic compounds and correlated effects in hardness and wear resistance in H13 steel,Nucl.Instrum.Methods,1993,B72: 409-420.[4]Zhang Tonghe,Huang Huapeng,Ji Chengzhou et al.,The formation of metallic silicides of Ti,Y,Fe,Mo and W using metal vapor vacuum arc implantation,Surf.Coat.Technol.,1994,66: 355-360.[5]Zhang Tonghe,Ji Chengzhou,Shen Jinghua et al.,Formation of intermetallic compounds with a high flux pulse molybdenum ion beam in steel and aluminum,Surf.Coat.Technol.,1992,51:455-460.[6]Zhang Tonghe,Wang Xiaoyan,Liang Hong et al.,Behavior of MEVVA metal ion implantation for surface modification of materials,Surf.Coat.Technol.,1996,83: 280-283.[7]Zhang Tonghe,Wang Xiaoyan,Liang Hong et al.,Behavior of MEVVA metal ion implantation for surface modification of materials,Surf.Coat.Technol.,1996,83: 280-283.[8]Takakashi,K.,Waki,M.I.,Chemical and electrochemical properties of ion implanted metals,Surf.Coat.Technol.,1994,65:57-63.[9]Wolf,G K.,An historical perspective of ion bombardment research for corrosion studies,Surf.Coat.Technol.,1996,83: 1-9.[10]Zhang Tonghe,Wu Yuguang,Deng Zhiwei et al.,The corrosion behavior of nanometer embedded phase in Ti implanted H13 steel,Science in China,Ser.E,1999,42(6): 623-630.[11]Zhang Tonghe,Wu Yuguang,Yi Zhongzhen et al.,Nanophase formation and its behavior of corrosion resistance in C+Mo dual implanted steel,Science in China,Ser.E,2001,4(4): 383-388.[12]Zhang Tonghe,Wu Yuguang,Deng Zhiwei et al.Properties of corrosion

  1. Comparison of resistance to corrosion on haz of a ferritic stainless steel by different surface finishings

    Directory of Open Access Journals (Sweden)

    Juvenilson Costa Damascena

    2015-10-01

    Full Text Available Certain techniques, comprising machining and GTAW dressing, have been used in the weld bead edge (region of the welded joint between the weld metal and the base metal to increase the fillet radius of the region by reducing the stress concentrator factor, decreasing roughness, and increasing the life of weldings. Moreover, TIG Dressing may also provide a smooth change in the radius of the curvature and change the average grain size and promote a microstructural variation through the reflow of this region. Current study analyzes the effect of surface finish of the Heat Affected Zone (HAZ on resistance to corrosion of welded joints of simple deposition under plate by using machining techniques with sandpaper of different particle sizes and GTAW Dressing, comparing the effect of the two techniques in the resistance to corrosion in environments with chloride ions. ACE P410D ferritic stainless steel was employed as base metal and austenitic wire 308L for welding. Results showed that the condition sweetened with GTAW Dressing with pure argon at current 100A generated the lowest mass loss among the conditions under analysis.

  2. Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062

    Science.gov (United States)

    Rosemann, P.; Müller, C.; Baumann, O.; Modersohn, W.; Halle, T.

    2017-03-01

    The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polished or blasting depending on the application and the requested corrosion resistance. Blasted surfaces are often used in industrial practice due to the easier and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the different performed corrosion tests (potential measurement, KorroPad-test and pitting potential) on welding seams with different surface treatments.

  3. Improvement of the linear polarization resistance method for testing steel corrosion inhibitors

    Science.gov (United States)

    Faritov, A. T.; Rozhdestvenskii, Yu. G.; Yamshchikova, S. A.; Minnikhanova, E. R.; Tyusenkov, A. S.

    2016-11-01

    The linear polarization resistance method is used to improve the technique of corrosion control in liquid conducting according to GOST 9.514-99 (General Corrosion and Aging Protection System. Corrosion Inhibitors for Metals in Water Systems. Electrochemical Method of Determining the Protective Ability). Corrosion monitoring is shown to be performed by electronic devices with real-time data transfer to industrial controllers and SCADA systems.

  4. Corrosive-wear resistance of stainless steels for the impeller of slurry pump used in zinc hydrometallurgy process

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper presents corrosive-wear (C-W) behaviors of three kinds of steels under the simulating condition of traditional zinc hydrometallurgy process by using a self-made rotating disk apparatus. Result shows that pure wear loss rate is significantly larger than pure corrosion loss rate. Under this C-W condition, the ranking of C-W resistance is S2 > S3 > S1 (S1: austenite stainless steel; S2: CD-4MCu duplex stainless steel; S3:17-4PH stainless steel). S2 has excellent C-W resistance due to strong surface deformation strengthening effect of high-density dislocations of the γphase. S3 also has excellent C-W resistance owing to high hardness and strength. However, S1 does not show good C-W resistance under strong erosion of liquid-solid slurry because of its single-phase austenitic structure and very low hardness. As a result, duplex stainless steels as well as 17-4 PH stainless steel can be used as impeller candidate materials in the zinc hydrometallurgy process due to their excellent C-W resistance and lower cost.

  5. Corrosive-wear resistance of stainless steels for the impeller of slurry pump used in zinc hydrometallurgy process

    Directory of Open Access Journals (Sweden)

    Ping LI

    2005-08-01

    Full Text Available This paper presents corrosive-wear (C-W behaviors of three kinds of steels under the simulating condition of traditional zinc hydrometallurgy process by using a self-made rotating disk apparatus. Result shows that pure wear loss rate is significantly larger than pure corrosion loss rate. Under this C-W condition, the ranking of C-W resistance is S2 > S3 > S1 (S1: austenite stainless steel; S2: CD-4MCu duplex stainless steel; S3 :17-4PH stainless steel. S2 has excellent C-W resistance due to strong surface deformation strengthening effect of high-density dislocations of the γ phase. S3 also has excellent C-W resistance owing to high hardness and strength. However, S1 does not show good C-W resistance under strong erosion of liquid-solid slurry because of its single-phase austenitic structure and very low hardness. As a result, duplex stainless steels as well as 17-4 PH stainless steel can be used as impeller candidate materials in the zinc hydrometallurgy process due to their excellent C-W resistance and lower cost.

  6. Corrosion resistance of steel fibre reinforced concrete – a literature review

    DEFF Research Database (Denmark)

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

    2016-01-01

    the existence of a critical crack width, below 0.20 mm, where corrosion of carbon-steel fibres is not critical and the structural integrity of the exposed SFRC can be ensured over the long-term. A doctoral project investigating chloride-induced corrosion of steel fibres on cracked SFRC has been initiated......Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of prefabricated segmental linings for bored tunnels, since it entails simplified production processes and higher quality standards. However, international standards and guidelines are not consistent regarding...... the consideration of steel fibres for the structural verification of SFRC elements exposed to corrosive environments, hampering the development of civil infrastructure built of SFRC. In particular, the long-term effect of exposure to chlorides is in focus and under discussion. This paper reviews the existing...

  7. Growth and corrosion resistance of molybdate modified zinc phosphate conversion coatings on hot-dip galvanized steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The modified zinc phosphate conversion coatings(ZPC) were formed on hot-dip galvanized(HDG) steel when 1.0 g/L sodium molybdate were added in a traditional zinc phosphate solution. The growth performance and corrosion resistance of the modified ZPC were investigated by SEM, open circuit potential(OCP), mass gain, potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) measurements and compared with those of the traditional ZPC. The results show that if sodium molybdate is added in a traditional zinc phosphate solution, the nucleation of zinc phosphate crystals is increased obviously; zinc phosphate crystals are changed from bulky acicular to fine flake and a more compact ZPC is obtained. Moreover, the mass gain and coverage of the modified ZPC are also boosted. The corrosion resistance of ZPI is increased with an increase in coverage, and thus the corrosion protection ability of the modified ZPC for HDG steel is more outstanding than that of the traditional ZPC.

  8. Corrosion-erosion resistance of Zn-Al co-cementation coatings on carbon steels in aqueous media

    Institute of Scientific and Technical Information of China (English)

    李德志; 何业东; 王德仁; 张召恩; 齐慧滨; 高唯

    2002-01-01

    A novel Zn-Al co-cementation coating was obtained by a pack cementation method. This coating possesses a two-layered structure. The outer layer is mainly composed of Fe2Al5 and FeAl intermetallics with a small amount of Zn, and the inner layer consists of Zn, Fe and a small amount of Al. The corrosion-erosion resistance of Zn-Al co-cementation coatings on carbon steel was studied by a rotary corrosion method in various NaCl and H2S containing solutions and relevant SiO2 containing media. The experimental results are compared with those of carbon steels and the sherardizing and aluminizing coatings, showing that the Zn-Al co-cementation coatings have excellent corrosion-erosion resistance in various aqueous media.

  9. Corrosion resistance of ERW (Electric Resistance Welded) seam welds as compared to metal base in API 5L steel pipes

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Velasquez, Jorge L.; Godinez Salcedo, Jesus G.; Lopez Fajardo, Pedro [Instituto Politecnico Nacional (IPN), Mexico D.F. (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE). Dept. de Ingenieria Metalurgica

    2009-07-01

    The corrosion resistance of ERW seam welds and the base metal in API 5L X70 steel pipes was evaluated by Tafel tests. The procedure was according to ASTM G3 standard. The study was completed with metallographic and chemical characterization of the tested zones, that is, the welded zone and the base metal away of the weld. All tests were made on the internal surface of the pipe in order to assess the internal corrosion of an in-service pipeline made of the API 5L X70 steel. The test solution was acid brine prepared according to NACE Publications 1D182 and 1D196. The results showed that the ERW seam weld corrodes as much as three times faster than the base material. This behavior is attributed to a more heterogeneous microstructure with higher internal energy in the ERW seam weld zone, as compared to the base metal, which is basically a ferrite pearlite microstructure in a normalized condition. This result also indicates that pipeline segments made of ERW steel pipe where the seam weld is located near or at the bottom of the pipe are prone to a highly localized attack that may form channels of metal loss if there is water accumulation at the bottom of the pipeline. (author)

  10. Analysis of the Long-Term Corrosion Behavior of X80 Pipeline Steel in Acidic Red Soil Using Electrical Resistance Test Technique

    Directory of Open Access Journals (Sweden)

    Shuaixing Wang

    2015-01-01

    Full Text Available The long-term corrosion rate of X80 steel in an acidic red soil was monitored in situ by using a precise electrical resistance (ER test system. The corrosion characteristics of X80 steel were examined via SEM, EDS, and XRD. The results indicated that the corrosion rate determined from ER test was very similar to that obtained from the mass loss test. The ER test technique made it possible to predict the long-term corrosion rate of steel in soil in situ. The corrosion rate of X80 steel in acidic red soil was about 0.0902 mm/a at 38 weeks, but the corrosion rate was dropped to 0.0226 mm/a after 5 years. The final corrosion product layer was composed mainly of FeOOH, γ-Fe2O3, and FeCO3.

  11. Corrosion Resistance of Galvanized Steel in the Environment of a Bioreactor

    OpenAIRE

    Šustr Michal; Dostál Petr; Začal Jaroslav

    2016-01-01

    The article deals with monitoring the corrosion resistibility of welded materials in the anaerobic fermenter (bioreactor). The main goal of this research is to assess the change of hardness after degradation. The change of hardness occurs in the corrosion environment and it correlates with the corrosion resistibility of material. The purpose of this experiment is to recognize the possibilities of using the CMT welded materials in the defined environment. As an innovative technology the acoust...

  12. CORROSION RESISTANT CERAMIC COATING FOR X80 PIPELINE STEEL BY LOW-TEMPERATURE PACK ALUMINIZING AND OXIDATION TREATMENT

    OpenAIRE

    HUANG MIN; FU QIAN-GANG; WANG YU; ZHONG WEN-WU

    2013-01-01

    In this paper, we discuss the formation of ceramic coatings by a combined processing of low-temperature pack aluminizing and oxidation treatment on the surface of X80 pipeline steel substrates in order to improve the corrosion resistance ability of X80 pipeline steel. First, Fe-Al coating consisting of FeAl3 and Fe2Al5 was prepared by a low-temperature pack aluminizing at 803 K which was fulfilled by adding zinc in the pack powder. Pre-treatment of X80 pipeline steel was carried out through s...

  13. Structure and mechanical properties of the three-layer material based on a vanadium alloy and corrosion-resistant steel

    Science.gov (United States)

    Nikulin, S. A.; Rozhnov, A. B.; Nechaikina, T. A.; Rogachev, S. O.; Zavodchikov, S. Yu.; Khatkevich, V. M.

    2014-10-01

    The quality of three-layer pipes has been studied; they are manufactured by hot pressing of a three-layer assembly of tubular billets followed by forging and cold rolling. The operating core is made from a V-4Ti-4Cr alloy. The protective claddings are made from corrosion-resistant steels of two grades, 08Kh17T and 20Kh13. The results of investigation into the structure and microhardness of the junction zone of steel and the vanadium alloy, which includes a contact zone and a transition diffusion layer, are reported. The 08Kh17T steel is shown to be a preferred cladding material.

  14. Laser gas assisted treatment of steel 309: Corrosion and scratch resistance of treated surface

    Science.gov (United States)

    Toor, Ihsan-ul-Haq; Yilbas, B. S.; Ahmed, Junaid; Karatas, C.

    2017-10-01

    Laser gas assisted surface treatment of steel 309 is carried out and the characteristics of the resulting surface are analyzed using the analytical tools. Scanning electron and 3-D optical microscopes are used to assess the morphological and metallurgical changes in the laser treated layer. Energy spectroscopy and X-ray diffraction are carried out to determine the elemental composition and compounds formed on the laser treated surface. The friction coefficient of the laser treated surface is measured using the micro-tribometer and compared to that of the as received surface. The corrosion resistance of the laser treated and as received surfaces is measured incorporating the electrochemical tests. It is found that laser treatment results in a dense layer and formation of nitride compounds at the surface. This enhances the microhardness at the laser treated surface. The friction coefficient attains lower values at the laser treated surface than that corresponding to the as received surface. The corrosion rate of the surface reduces significantly after the laser treatment process, which can be attributed to the passive layer at the surface via formation of a dense layer and nitride compounds in the surface vicinity. In addition, the number of pit sites decreased for the laser treated surface than that of as received surface.

  15. Corrosion resistance of a steel under an oxidizing atmosphere in a fluid catalytic cracking regenerator

    Directory of Open Access Journals (Sweden)

    Ieda Caminha

    2004-03-01

    Full Text Available In the present work, the corrosion resistance of an ASTM A 387 G11 steel was evaluated under two conditions: an oxidizing atmosphere in a fluid catalytic cracking regenerator of a petroleum processing unit and a simulated atmosphere in the laboratory, at temperatures of 650 °C and 700 °C. The characterization of the phases present in the oxidized layer was carried out by X-ray diffraction (XRD, optical microscopy (OM and scanning electron microscopy (SEM with X-ray energy dispersive analysis (EDS. Severe corrosion was observed after exposure to both the real and simulated conditions, with formation of several iron oxides (Fe2O3, Fe3O4 and FeO in the product scale layer, as well as a slight inner oxidation and sulfidation of chromium in the substrate. Internal nitridation of the silicon and the manganese was observed only in the real condition, probably related to the long-term exposure inside the regenerator.

  16. Corrosion resistance of stainless steels and high Ni-Cr alloys to acid fluoride wastes

    Energy Technology Data Exchange (ETDEWEB)

    Smith, H.D.; Mackey, D.B.; Pool, K.H. [Pacific Northwest Lab., Richland, WA (United States); Schwenk, E.B. [Westinghouse Hanford Co., Richland, WA (United States)

    1992-04-01

    TRUEX processing of Hanford Site waste will utilize potentially corrosive acid fluoride processing solutions. Appropriate construction materials for such a processing facility need to be identified. Toward this objective, candidate stainless steels and high Ni-Cr alloys have been corrosion tested in simulated acid fluoride process solutions at 333K. The high Ni-Cr alloys exhibited corrosion rates as low as 0.14 mm/y in a solution with an HF activity of about 1.2 M, much lower than the 19 to 94 mm/y observed for austenitic stainless steels. At a lower HF activity (about 0.008 M), stainless steels display delayed passivation while high Ni-Cr alloys display essentially no reaction.

  17. Inhibition of Staphylococcus aureus biofilm by a copper-bearing 317L-Cu stainless steel and its corrosion resistance.

    Science.gov (United States)

    Sun, Da; Xu, Dake; Yang, Chunguang; Chen, Jia; Shahzad, M Babar; Sun, Ziqing; Zhao, Jinlong; Gu, Tingyue; Yang, Ke; Wang, Guixue

    2016-12-01

    The present study investigated the antibacterial performance, corrosion resistance and surface properties of antibacterial austenitic 317L-Cu stainless steel (317L-Cu SS). After 4.5wt% copper was added to 317L stainless steel (317L SS), the new alloy underwent solid solution and aging heat treatment. Fluorescent staining using 4',6-diamidino-2-phenylindole (DAPI) revealed that the 317L-Cu SS showed strong antibacterial efficacy, achieving a 99% inhibition rate of sessile Staphylococcus aureus cells after 5days. The corrosion data obtained by potentiodynamic polarization curves indicated that in comparison with 317L SS, the pitting potential and corrosion current density of 317L-Cu slightly decreased due to the addition of Cu. The 317L-Cu SS exhibited no cytotoxicity against zebrafish (Danio rerio) embryos. The experimental results in this study demonstrated that the new alloy has potential applications in medical and daily uses.

  18. EVALUATION OF CORROSION RESISTANCE OF STEEL SHEETS FOR AUTOMOTIVE INDUSTRY WITH THE USE OF THE SPOTFACE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Alberto Nei Carvalho Costa

    2013-03-01

    Full Text Available Innovation, leading to weight and cost reduction, is a key word concerning the design of steel auto body for auto makers that aim to keep and improve their market share worldwide. On the other hand, auto body life, which is related to the corrosion resistance of the materials employed, should always be considered. The latter has led the auto makers to team up with suppliers to find the best solutions concerning the materials selection. The end result always points towards different sets of steels either zinc-coated or zinc alloyed-coated. Taking all these aspects into consideration, the overall challenge the auto makers face is to mitigate the time required for selection and narrow down the options available. This paper studies the corrosion resistance of several materials applied on steel auto bodies using the technique named spotface, which main advantage is reducing the time required by the traditional scribe to evaluate and compare different materials, when they are submitted either to accelerated or field corrosion testing. Concerning the accelerated corrosion testing, they were performed according to the General Motors do Brasil’s requirements.

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

    Directory of Open Access Journals (Sweden)

    Lorena Braga Moura

    2012-04-01

    Full Text Available 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.

  20. Corrosion resistance of Zn-Co-Fe alloy coatings on high strength steel

    NARCIS (Netherlands)

    Lodhi, Z.F.; Mol, J.M.C.; Hovestad, A.; Hoen-Velterop, L. 't; Terryn, H.; Wit, J.H.W.de

    2009-01-01

    The corrosion properties of electrodeposited zinc-cobalt-iron (Zn-Co-Fe) alloys (up to 40 wt.% Co and 1 wt.% Fe) on steel were studied by using various electrochemical techniques and compared with zinc (Zn) and cadmium (Cd) coatings in 3.5% NaCl solution. It was found that with an increase in Co con

  1. Corrosion resistance of multilayer hybrid sol-gel coatings deposited on the AISI 316L austenitic stainless steel

    Science.gov (United States)

    Caballero, Y. T.; Rondón, E. A.; Rueda, L.; Hernández Barrios, C. A.; Coy, A.; Viejo, F.

    2016-02-01

    In the present work multilayer hybrid sol-gel coatings were synthesized on the AISI 316L austenitic stainless steel employed in the fabrication of orthopaedic implants. Hybrid sols were obtained from a mixture of inorganic precursor, TEOS, and organic, GPTMS, using ethanol as solvent, and acetic acid as catalyst. The characterization of the sols was performed using pH measurements, rheological tests and infrared spectroscopy (FTIR) for different ageing times. On the other hand, the coatings were characterized by scanning electron microscopy (SEM), while the corrosion resistance was evaluated using anodic potentiodynamic polarization in SBF solution at 37±2°C. The results confirmed that sol-gel synthesis employing TEOS-GPTMS systems produces uniform and homogeneous coatings, which enhanced the corrosion resistance with regard to the parent alloy. Moreover, corrosion performance was retained after applying more than one layer (multilayer coatings).

  2. The development of high strength corrosion resistant precipitation hardening cast steels

    Science.gov (United States)

    Abrahams, Rachel A.

    Precipitation Hardened Cast Stainless Steels (PHCSS) are a corrosion resistant class of materials which derive their properties from secondary aging after a normalizing heat treatment step. While PHCSS materials are available in austenitic and semi-austenitic forms, the martensitic PHCSS are most widely used due to a combination of high strength, good toughness, and corrosion resistance. If higher strength levels can be achieved in these alloys, these materials can be used as a lower-cost alternative to titanium for high specific strength applications where corrosion resistance is a factor. Although wrought precipitation hardened materials have been in use and specified for more than half a century, the specification and use of PHCSS has only been recent. The effects of composition and processing on performance have received little attention in the cast steel literature. The work presented in these investigations is concerned with the experimental study and modeling of microstructural development in cast martensitic precipitation hardened steels at high strength levels. Particular attention is focused on improving the performance of the high strength CB7Cu alloy by control of detrimental secondary phases, notably delta ferrite and retained austenite, which is detrimental to strength, but potentially beneficial in terms of fracture and impact toughness. The relationship between age processing and mechanical properties is also investigated, and a new age hardening model based on simultaneous precipitation hardening and tempering has been modified for use with these steels. Because the CB7Cu system has limited strength even with improved processing, a higher strength prototype Fe-Ni-Cr-Mo-Ti system has been designed and adapted for use in casting. This prototype is expected to develop high strengths matching or exceed that of cast Ti-6Al-4V alloys. Traditional multicomponent constitution phase diagrams widely used for phase estimation in conventional stainless steels

  3. Antibacterial Properties and Corrosion Resistance of Nitrogen-doped TiO2 Coatings on Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Hefeng Wang; Bin Tang; Xiuyan Li; Yong Ma

    2011-01-01

    The Nitrogen-doped TiO2 (N-TiO2) coatings were fabricated on 304 austenitic stainless steel (SS) substrates by oxidation of titanium nitride coatings, which were prepared by plasma surface alloying technique. Microstructural investigation, corrosion tests and antibacterial tests were conducted to study the properties of N-TiO2 coatings. Composition analysis shows that the SS substrates were shielded by the N-TiO2 coatings entirely. The N-TiO2 coatings are anatase in structure as characterized by X-ray diffraction. The corrosion properties of N-TiO2 coated SS samples in Hanks' solution were investigated by a series of tests. The electrochemical measurements indicate that the corrosion potential positively shifts from -0.275 V for untrated SS to -0.267 V for N-TiO2, while the corrosion current density decreases from 1.3× 10-5 A/cm2 to 4.1×10-6A/cm2. The corrosion resistance obtained by fitting the impedance spectra also reveals that the N-TiO2 coatings provide good protection for SS substrate against corrosion in Hanks' solution. Electrochemistry noise tests indicate that the N-TiO2 coatings effectively retard the local pitting and crevice corrosion of the SS substrate. The results of the antibacterial test reveal that N-TiO2 coatings give 304 austenitic SS an excellent antibacterial property.

  4. Synergy effects of Cu and Sn on pitting corrosion resistance of ultra-purified medium chromium ferritic stainless steel

    Science.gov (United States)

    Zhang, XiangJun; Liu, ZhenYu

    2017-03-01

    The influence of combination of Cu and Sn on pitting resistance of ultra-purified medium chromium ferritic stainless steel in 3.5 wt.% NaCl at 25°C was investigated by using electrochemical method. The results show that there is synergy effect between Cu and Sn, and the strong interaction between Cu and Sn in ferritic stainless steels clearly affects their pitting corrosion behaviour in 3.5% NaCl. A mechanism of the synergy of Cu and Sn was discussed.

  5. Influence of the pulsed plasma treatment on the corrosion resistance of the low-alloy steel plated by Ni-based alloy

    Science.gov (United States)

    Dzhumaev, P.; Yakushin, V.; Kalin, B.; Polsky, V.; Yurlova, M.

    2016-04-01

    This paper presents investigation results of the influence of high temperature pulsed plasma flows (HTPPF) treatment on the corrosion resistance of low-alloy steel 0.2C-Cr-Mn- Ni-Mo cladded by the rapidly quenched nickel-based alloy. A technique that allows obtaining a defect-free clad layer with a good adhesion to the substrate was developed. It is shown that the preliminary treatment of steel samples by nitrogen plasma flows significantly increases their corrosion resistance in the conditions of intergranular corrosion test in a water solution of sulfuric acid. A change of the corrosion mechanism of the clad layer from intergranular to uniform corrosion was observed as a result of sub-microcrystalline structure formation and homogeneous distribution of alloying elements in the plasma treated surface layer thus leading to the significant increase of the corrosion resistance.

  6. High Corrosion-Resistance Double-Layer Ni-P Coating on Steels

    Institute of Scientific and Technical Information of China (English)

    JIANG Hai; LIU Xian-li; JIANG Zhang-hao; LI Guang-yu; LIAN Jian-she; GU Chang-dong

    2004-01-01

    Double-layer Ni-P alloy coating with a thickness about 20 μm and different Ni-P layers was prepared by electroless deposition and its corrosion resistance was studied. The microstructure and corrosion-resistance of the coatings were analyzed by SEM, XRD, electrochemical polarization measurements and salt spray tests. The salt spray tests showed that the double-layer coating exhibits better corrosion resistance. The time of the emergence of the first red rust spot on the coating surface can reach 384 hours, and the gray rusts were firstly emergered during the salt spray tests. The electrochemical analysis revealed that the difference in the corrosion potential between the double layers plays a very important role in protecting the substrate from rusting.

  7. Influence of femtosecond laser marking on the corrosion resistance of stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Valette, S. [Universite Jean Monnet, LTSI, 10 rue Barrouin, F42000 Saint Etienne (France)]. E-mail: stephane.valette@ec-lyon.fr; Steyer, P. [INSA de Lyon, LPCI, 20 Av. A. Einstein, F69621 Villeurbanne Cedex (France); Richard, L. [Ecole des Mines de St. Etienne, Centre CIS, 158 cours Fauriel, F42000 Saint Etienne (France); Forest, B. [Ecole des Mines de St. Etienne, Centre CIS, 158 cours Fauriel, F42000 Saint Etienne (France); Donnet, C. [Universite Jean Monnet, LTSI, 10 rue Barrouin, F42000 Saint Etienne (France); Audouard, E. [Universite Jean Monnet, LTSI, 10 rue Barrouin, F42000 Saint Etienne (France)

    2006-04-30

    Marking is of prime importance in the field of biomaterials to allow the identification of surgical tools as well as prostheses. Nowadays, marking is often achieved by means of laser beam, which may modify the characteristics of the treated surfaces. The use of laser devices delivering nanosecond pulses is known to induce dramatic corrosion degradations during sterilization or decontamination processes of the biomaterials. The aim of the present study is to investigate the ability of femtosecond (pulse duration in the 10{sup -15} s range) laser treatments to avoid preferential corrosion processes of the marked areas, in order to extend the durability and the reliability of biomaterials. Experiments have been performed on martensitic Z30C13 and austenitic 316L stainless steels. Electrochemical measurements (cyclic polarization curves) were carried out to determine the passive state of samples before and after engraving, their corrosion rate and their susceptibility to localized corrosion. Further protracted immersion tests were also carried out to evaluate the natural long-term degradation of engraved parts. The electrochemical behavior is then explained on the basis of surface characterizations. Femtosecond laser marking is shown to provide an electrochemical ennoblement. Moreover, the chemical composition is not affected so that the passive character of both stainless steels is maintained, even improved if we consider the susceptibility to localized corrosion.

  8. Corrosion resistance of various bio-films deposited on austenitic cast steel casted by lost-wax process and in gypsum mould

    Directory of Open Access Journals (Sweden)

    J. Gawroński

    2010-01-01

    Full Text Available This work is the next of a series concerning the improvement of austenitic cast steel utility predicted for use in implantology for complicated long term implants casted by lost-wax process and in gypsum mould. Austenitic cast steel possess chemical composition of AISI 316L medical steel used for implants. In further part of present work investigated cast steel indicated as AISI 316L medical steel. Below a results of electrochemical corrosion resistance of carbon layer and bi-layer of carbon/HAp deposited on AISI 316L researches are presented. Coatings were manufactured by RF PACVD and PLD methods respectively. Obtained results, unequivocally indicates on the improvement of this type of corrosion resistance by substrate material with as deposited carbon layer. While bi-layer of carbon/HAp are characterized by very low corrosion resistance.

  9. Corrosion Resistance of a Sand Particle-Modified Enamel Coating Applied to Smooth Steel Bars

    Directory of Open Access Journals (Sweden)

    Fujian Tang

    2014-09-01

    Full Text Available The protective performance of a sand particle-modified enamel coating on reinforcing steel bars was evaluated in 3.5 wt% NaCl solution by electrochemical impedance spectroscopy (EIS. Seven percentages of sand particles by weight were investigated: 0%, 5%, 10%, 20%, 30%, 50% and 70%. The phase composition of the enamel coating and sand particles were determined with the X-ray diffraction (XRD technique. The surface and cross-sectional morphologies of the sand particle-modified enamel coating were characterized using scanning electron microscopy (SEM. XRD tests revealed three phases of sand particles: SiO2, CaCO3 and MgCO3. SEM images demonstrated that the enamel coating wetted well with the sand particles. However, a weak enamel coating zone was formed around the sand particles due to concentrated air bubbles, leading to micro-cracks as hydrogen gas pressure builds up and exceeds the tensile strength of the weak zone. As a result, the addition of sand particles into the enamel coating reduced both the coating and corrosion resistances.

  10. Effect of boron addition on pitting corrosion resistance of modified 9Cr-1Mo steel: Application of electrochemical noise

    Energy Technology Data Exchange (ETDEWEB)

    Pujar, M.G., E-mail: pujar55@gmail.com [Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603102 (India); Das, C.R.; Thirunavukkarasu, S.; Kamachi Mudali, U.; Bhaduri, A.K. [Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603102 (India); Brijitta, J.; Tata, B.V.R. [Materials Science Group (MSG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603102 (India)

    2011-10-17

    Highlights: {yields} Weibull probability plots separate pitting and passive corrosion events. {yields} Gumbel distribution analysis gives maximum metastable pit depths. {yields} Addition of boron results in superior pitting corrosion resistance in 0.1 M NaCl. {yields} Incorporation of B into M{sub 23}C{sub 6} carbides refines them and improves pitting resistance. {yields} Coarse M{sub 23}C{sub 6} carbides and delta-ferrite result in inferior pitting resistance. - Abstract: 9Cr-1Mo steels indigenously melted with the addition of boron (Alloy B) and without it (Alloy D) along with Alloy C (without boron addition with minor changes in the trace element concentrations) were studied for their pitting corrosion resistance in 0.001 M, 0.01 M, 0.05 M and 0.1 M sodium chloride solutions using electrochemical noise (EN) technique. Weibull probability plots were used to determine the pit embryo generation rates. Gumbel extreme value analysis was conducted to determine the maximum metastable as well as stable pit radii. The analysis of the data showed superior pitting corrosion resistance of the Alloy B compared to Alloy C as well as Alloy D.

  11. Influence of C, N and Ti concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M.C.; Carboneras, M.; Coy, A.E.; Viejo, F.; Arrabal, R.; Munoz, J.A. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040, Madrid (Spain)

    2004-07-01

    The influence of Ti, C, and N concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel has been studied. A kinetic study of the corrosion process has been carried out using gravimetric tests according to ASTM A-262 practices B and C (Streicher and Huey, respectively). The TTS diagrams were drawn as a function of alloying elements concentration (C, N and Ti). Materials characterization under several test conditions was carried out using Scanning Electron Microscopy (SEM) analysing microstructural characteristics and the attack microstructure. The chemical resistance of these steels to intergranular test was function of N, C and Ti concentration. High Ti and N concentration favoured the precipitation of TiN during the material manufacture process. N forms TiN very stable, causing the removal of Ti from the matrix and, indirectly, favouring the Cr{sub 23}C{sub 6} precipitation during the sensitization process and increasing the corrosion rate. In order to inhibit the intergranular corrosion in these materials the N and Ti concentrations must be optimised. (authors)

  12. Passive behaviour of alloy corrosion-resistant steel Cr10Mo1 in simulating concrete pore solutions with different pH

    Science.gov (United States)

    Ai, Zhiyong; Jiang, Jinyang; Sun, Wei; Song, Dan; Ma, Han; Zhang, Jianchun; Wang, Danqian

    2016-12-01

    The passive behaviour of new alloy corrosion-resistant steel Cr10Mo1 and plain carbon steel (as a comparison) in simulating concrete pore solutions of different pH (ranging from 13.5 to 9.0) under open circuit potential conditions, was evaluated by various electrochemical techniques: potentiodynamic polarization, capacitance measurements and electrochemical impedance spectroscopy. The chemical composition and structure of passive films were investigated by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The electrochemical responses of passive films show that Cr10Mo1 steel has an increasing passivity with pH decreasing while carbon steel dose conversely, revealing carbonation does no negative effect on passivation of the corrosion-resistant steel. SIMS reveals that the passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer mainly consisting of Fe oxides and hydroxides, and an inner layer enriched in Cr species, while only a Fe-concentrated layer for carbon steel. According to the XPS analysis results, as the pH decreases, more stable and protective Cr oxides are enriched in the film on Cr10Mo1 steel while Fe oxides gradually decompose. Higher content of Cr oxides in the film layer provides Cr10Mo1 corrosion-resistant steel more excellent passivity at lower pH.

  13. Waste of cleaning emulsion sewage as inhibitors of steel corrosion

    Science.gov (United States)

    Fazullin, D. D.; Mavrin, G. V.; Shaikhiev, I. G.

    2016-06-01

    The article describes the corrosion test of steel of the brand 20 in the stratal water. To increase corrosion resistance as a corrosion inhibitor the concentrate waste emulsion of the mark "Incam- 1" was provided. The article presents studies of the corrosion rate with different dosages of corrosion inhibitor in the stratal water. Based on these research results are revealed that the degree of protection of steel is 27% at a dosage of 3.8 g / dm3.

  14. Optimum temperature on corrosion resistance for plasma ion nitrided 316L stainless steel in sea water solution

    Science.gov (United States)

    Chong, Sang-Ok; Kim, Seong-Jong

    2017-01-01

    The aim of this research is to investigate the optimum plasma ion nitriding temperature on corrosion resistance in natural sea water for plasma ion nitrided 316L stainless steel. Plasma ion nitriding was conducted at different temperatures of 350, 400, 450, and 500 °C with a mixture of 75% of nitrogen and 25% of hydrogen during 10 h. In conclusion of anodic polarization test, a wide passive potential region and a high corrosion potential were observed at a plasma ion nitriding temperature of 450 °C. Moreover, relatively less damage depth and clean surface micrographs were observed at 450 °C as results of observation of three-dimensional (3D) microscope and scanning electron microscope (SEM) after polarization experiments. In addition, higher corrosion potential and lower corrosion current density were indicated at plasma ion nitrided samples than the value of untreated substrate after Tafel analysis. Hence, plasma ion nitrided at 450 °C in sea water solution represented optimum corrosion resistance among the all the plasma ion nitriding temperature parameters.

  15. The effect of σ-phase precipitation at 800°C on the corrosion resistance in sea-water of a high alloyed duplex stainless steel

    NARCIS (Netherlands)

    Wilms, M.E.; Gadgil, V.J.; Krougman, J.M.; Ijsseling, F.P.

    1994-01-01

    Super-duplex stainless steels are recently developed high alloyed stainless steels that combine good mechanical properties with excellent corrosion resistance. Because of a high content of chromium and molybdenum, these alloys are susceptible to σ-phase precipitation during short exposure to

  16. PREPARATION AND CORROSION RESISTANCE OF NiP/TiO2 COMPOSITE FILM ON CARBON STEEL IN SULFURIC ACID SOLUTION

    Institute of Scientific and Technical Information of China (English)

    L.Z. Song; S.Z. Song; J. Zhao

    2006-01-01

    A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM (environmental scanning electron microscopy)and EIS (electrochemical impedance spectroscopy) measurements. Results showed that the NiP/TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS (X-ray photoelectron spectroscopy) spectrum, and an anticorrosion mechanism of the composite film was discussed.

  17. Effect of thermal treatment on the corrosion resistance of Type 316L stainless steel exposed in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Y. [Department of Materials Science & Engineering, McMaster University, Hamilton, ON (Canada); Zheng, W. [CanmetMATERIALS, Natural Resources Canada, Hamilton, ON (Canada); Guzonas, D.A. [Canadian Nuclear Laboratories Chalk River Laboratories, ON (Canada); Cook, W.G. [Department of Chemical Engineering, University of New Brunswick, Fredericton, NB (Canada); Kish, J.R., E-mail: kishjr@mcmaster.ca [Department of Materials Science & Engineering, McMaster University, Hamilton, ON (Canada)

    2015-09-15

    There are still unknown aspects about the growth mechanism of oxide scales formed on candidate stainless steel fuel cladding materials during exposure in supercritical water (SCW) under the conditions relevant to the Canadian supercritical water-cooled reactor (SCWR). The tendency for intermetallic precipitates to form within the grains and on grain boundaries during prolonged exposure at high temperatures represents an unknown factor to corrosion resistance, since they tend to bind alloyed Cr. The objective of this study was to better understand the extent to which intermetallic precipitates affects the mode and extent of corrosion in SCW. Type 316L stainless steel, used as a model Fe–Cr–Ni–Mo alloy, was exposed to 25 MPa SCW at 550 °C for 500 h in a static autoclave for this purpose. Mechanically-abraded samples were tested in the mill-annealed (MA) and a thermally-treated (TT) condition. The thermal treatment was conducted at 815 °C for 1000 h to precipitate the carbide (M{sub 23}C{sub 6}), chi (χ), laves (η) and sigma (σ) phases. It was found that although relatively large intermetallic precipitates formed at the scale/alloy interface locally affected the oxide scale formation, their discontinuous formation did not affect the short-term overall apparent corrosion resistance.

  18. Effect of thermal aging on pitting corrosion resistance of 16Cr - 5Ni - 1Mo precipitation hardening stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Karim, R.; Dawood, M.M.A.L.; Mahallawi, I.S.E.L.; Koussy, M.R.E.L. [Cairo University (Egypt). Dept. of Mining, Petroleum and Metallurgy

    2004-12-15

    Specimens of precipitation hardening 16-5-1 stainless steel were solution treated at 1050{sup o}C for 1 h followed by aging at temperatures in the range 400 - 750{sup o}C for various holding times (1 - 16 h). After heat treatment, two types of corrosion test (accelerated and immersion testing) were conducted in 6% ferric chloride solution. The results showed that the pitting corrosion resistance was affected by austenite content, {delta} ferrite and precipitation of molybdenum and chromium carbides. Three critical temperature ranges were identified, which were related to the phases formed: (a) high corrosion rate at 475{sup o}C ({delta} ferrite and M{sub o}2 C); (b) low corrosion rate at 550 - 625{sup o}C (reversed austenite and Laves phase); (c) intermediate corrosion rate at 750{sup o}C (Cr{sub 23} C{sub 6} and TiC). The morphology of the pitting was dependent on the form of the {delta} ferrite and carbides. (author)

  19. Tribological and corrosion behaviors of carburized AISI 4340 steel

    Science.gov (United States)

    Thong-on, Atcharawadi; Boonruang, Chatdanai

    2016-01-01

    AISI 4340 steel is widely used in automotive and aircraft industries as gear components. In such applications, surface hardening processes such as carburizing are required in order to improve the life time of the components. There are many studies showing the tribological behavior of the carburized steel, but the corrosion behavior has not yet been clarified. This paper reports on both tribological and corrosion behaviors of the carburized AISI 4340 steel. Factor associated with carburizing, such as the quantities of deposited carbon, dissolved carbon, and formed Cr23C6 and Fe3C, affect the tribological and corrosion behaviors of the steel by improving hardness, friction, lubrication, and wear resistance; but corrosion resistance is reduced. The dissolved carbon affects the formation of the oxide layer of the carburized steel, by obstructing the continuous oxide layer formation and by decreasing the chromium content of the steel, leading to the decrease in the corrosion resistance of the steel.

  20. Erosion-corrosion resistance of electroplated Co-Pd film on 316L stainless steel in a hot sulfuric acid slurry environment

    Science.gov (United States)

    Li, Sirui; Zuo, Yu; Ju, Pengfei

    2015-03-01

    A Co-Pd film was deposited on 316L stainless steel by electroplating. The erosion-corrosion behavior of the Co-Pd plated samples in hot sulfuric acid solution with SiO2 particles was investigated. The results showed that there was a significant synergistic effect between erosion and corrosion. At higher stirring speed, even in such strong corrosive environment the erosion-corrosion rate of Co-Pd plated samples was controlled mainly by the erosion resistance. The erosion-corrosion resistance of pure Pd plated sample decreased rapidly with increasing stirring speed, whereas that of Co-Pd plated sample kept almost stable under the tested conditions due to the high micro-hardness and good corrosion resistance of the film.

  1. A study on corrosion resistant graphene films on low alloy steel

    Directory of Open Access Journals (Sweden)

    A. S. Sai Pavan

    2016-04-01

    Full Text Available Abstract Graphene nanosheets were produced after synthesizing graphene oxide via Hummer’s method and a modified Hummer’s method. The obtained graphene after reduction was dispersed in 1-propanol to get a coating solution. Mild steel coupons were coated with the graphene solution via dip coating method. Corrosion studies were carried out at different environments like water (pH 6.0, HCl (0.1 N, NaCl (3.5 wt% and NaOH (1 M. Tafel analysis showed a reduction in the corrosion rate up to 99 % after three layer deposition with the graphene developed using the modified Hummer’s method. X-ray diffraction and Raman Spectroscopy confirmed the presence of graphene.

  2. A study on corrosion resistant graphene films on low alloy steel

    Science.gov (United States)

    Sai Pavan, A. S.; Ramanan, Sutapa Roy

    2016-11-01

    Graphene nanosheets were produced after synthesizing graphene oxide via Hummer's method and a modified Hummer's method. The obtained graphene after reduction was dispersed in 1-propanol to get a coating solution. Mild steel coupons were coated with the graphene solution via dip coating method. Corrosion studies were carried out at different environments like water (pH 6.0), HCl (0.1 N), NaCl (3.5 wt%) and NaOH (1 M). Tafel analysis showed a reduction in the corrosion rate up to 99 % after three layer deposition with the graphene developed using the modified Hummer's method. X-ray diffraction and Raman Spectroscopy confirmed the presence of graphene.

  3. Formation of Chromium Coating and Comparative Examination on Corrosion Resistance with 13Cr Steel in CO2-SATURATED Simulated Oilfield Brine

    Science.gov (United States)

    Zou, Jiaojuan; Xie, Faqin; Lin, Naiming; Yao, Xiaofei; Tian, Wei; Tang, Bin

    2013-07-01

    In order to enhance the surface properties of P110 oil casing tube steel and increase its usage during operation, chromium coating was fabricated by pack cementation. Scanning electron microscope, energy dispersive spectrometry and X-ray diffraction were used to investigate the surface morphology, cross-sectional microstructure, element distribution and phase constitutions of the coating. Comparative examinations on corrosion resistance between chromium coating and 13Cr stainless steel in CO2-saturated simulated oilfield brine were carried out via electrochemical measurements. The results showed that the obtained coating was uniform and compact, mainly consisted of CrxCy and doped with minor Cr2N. Chromizing treatment made it possible to create on the working surface of P110 steel with enhanced corrosion resistance, and the chromium coating indicated lower pitting corrosion sensitivity than that of 13Cr stainless steel.

  4. Influence of mill scale and rust layer on the corrosion resistance of low-alloy steel in simulated concrete pore solution

    Science.gov (United States)

    Shi, Jin-jie; Ming, Jing

    2017-01-01

    Electrochemical impedance spectroscopy, cyclic potentiodynamic polarization measurements, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to investigate the influence of mill scale and rust layer on the passivation capability and chloride-induced corrosion behaviors of conventional low-carbon (LC) steel and low-alloy (LA) steel in simulated concrete pore solution. The results show that mill scale exerts different influences on the corrosion resistance of both steels at various electrochemical stages. We propose that the high long-term corrosion resistance of LA steel is mainly achieved through the synergistic effect of a gradually formed compact, adherent and well-distributed Cr-enriched inner rust layer and the physical barrier protection effect of mill scale.

  5. A study of the evolution of rust on Mo-Cu-bearing fire-resistant steel submitted to simulated atmospheric corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Hao Long [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62, Shenyang 110016 (China); Zhang Sixun [College of Material and Metallurgy, Northeastern University, Wenhua Road 3, Shenyang 110004 (China); Technical Centre of Laiwu Steel Group, Ltd., Changsheng Road 23, Laiwu 271104 (China); Dong Junhua, E-mail: jhdong@imr.ac.cn [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62, Shenyang 110016 (China); Ke Wei [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Wencui Road 62, Shenyang 110016 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer The rusting evolution of a Mo-Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated. Black-Right-Pointing-Pointer The rusting evolution of the steel is related to the rust composition, structure, and electrochemical characteristics. Black-Right-Pointing-Pointer Increased content of {alpha}-FeOOH and decreased {gamma}-FeOOH and Fe{sub 3}O{sub 4} indicate the enhanced resistance of the rust. Black-Right-Pointing-Pointer Mo and Cu are involved in the formation of molybdate and Cu(I)-bearing compounds in the rust. - Abstract: The corrosion evolution of a Mo-Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated by corrosion weight gain, XRD, EPMA, XPS, and polarization curves. The results indicate that the corrosion kinetics is closely related to the rust composition and electrochemical properties. As the corrosion proceeds, the relative content of {gamma}-FeOOH and Fe{sub 3}O{sub 4} decreases and {alpha}-FeOOH increases, and the rust layer becomes compact and adherent to steel substrate. Molybdenum and copper enrich in the inner rust layer, especially at the bottom of the corrosion nest, forming non-soluble molybdate and Cu(I)-bearing compounds responsible for enhanced corrosion resistance of the rust layer.

  6. Pitting corrosion resistance and bond strength of stainless steel overlay by friction surfacing on high strength low alloy steel

    Directory of Open Access Journals (Sweden)

    Amit Kumar Singh

    2015-09-01

    Full Text Available Surface modification is essential for improving the service properties of components. Cladding is one of the most widely employed methods of surface modification. Friction surfacing is a candidate process for depositing the corrosion resistant coatings. Being a solid state process, it offers several advantages over conventional fusion based surfacing process. The aim of this work is to identify the relationship between the input variables and the process response and develop the predictive models that can be used in the design of new friction surfacing applications. In the current work, austenitic stainless steel AISI 304 was friction surfaced on high strength low alloy steel substrate. Friction surfacing parameters, such as mechtrode rotational speed, feed rate of substrate and axial force on mechtrode, play a major role in determining the pitting corrosion resistance and bond strength of friction surfaced coatings. Friction surfaced coating and base metal were tested for pitting corrosion by potentio-dynamic polarization technique. Coating microstructure was characterized using optical microscopy, scanning electron microscopy and X-ray diffraction. Coatings in the as deposited condition exhibited strain-induced martensite in austenitic matrix. Pitting resistance of surfaced coatings was found to be much lower than that of mechtrode material and superior to that of substrate. A central composite design with three factors (mechtrode rotational speed, substrate traverse speed, axial load on mechtrode and five levels was chosen to minimize the number of experimental conditions. Response surface methodology was used to develop the model. In the present work, an attempt has been made to develop a mathematical model to predict the pitting corrosion resistance and bond strength by incorporating the friction surfacing process parameters.

  7. Electrochemical corrosion behavior of steel wires in a coalmine with a corrosive medium

    Institute of Scientific and Technical Information of China (English)

    Wang Songquan; Zhang Dekun; Wang Dagang; Zhang Zefeng

    2011-01-01

    A 6 × 19 point-contact hoisting cable was used as our research object to examine the progress of corrosion of steel wires in a laboratory, simulating the actual working conditions in a coalmine. An electrochemical method was used to investigate the corrosion behavior of steel wires with different surface treatments of a corrosive acid solution. The results show that anode activation of steel wire mainly occurs during pre-corrosion, where the anode activation process of bare steel wires is the fastest as is their corresponding corrosion speed, while the anode activation process of oil coated steel wires and their corresponding corrosion speed are the lowest. During the intermediate and late immersion periods,a passive film is generated on the surface of steel wires, which are gradually damaged with the passage of time. Local pitting corrosion occurs easily on the surface of steel wires with a high-polarization potential.Suitable equivalent circuits were chosen to fit the electrochemical impedance spectroscopy (EIS) of steel wires over various corrosive times and different surface treatments, which indicate good fitting results.The double electrical layer charge-transfer resistance increases in the sequence: bare steel wire,untreated steel wire and oil coated steel wire and their corrosion resistance decreases in turn, which is consistent with their polarization curves. The oil layer provides a certain protective effect on untreated steel wires, but its effect is not entirely clear.

  8. Effect of Copper and Bronze Addition on Corrosion Resistance of Alloyed 316L Stainless Steel Cladded on Plain Carbon Steel by Powder Metallurgy

    Institute of Scientific and Technical Information of China (English)

    Wenjue CHEN; Yueying WU; Jianian SHEN

    2004-01-01

    A sandwich structure with cladding alloyed 316L stainless steel on plain carbon steel was prepared by means of powder metallurgy (PM) processing. Electrolytic Cu and prealloyed bronze (95Cu wt pct, 5Sn wt pct) were added in different contents up to 15% into the surface cladded 316L layers and the effect of alloying concentrations on the corrosion resistance of the 316L cladding layers was studied. The corrosion performances of the cladding samples were studied by immersion tests and potentio-dynamic anodic polarization tests in H2SO4 and FeCl3 solutions. Both 316L and alloyed 316L surface layers with 1.0 mm depth produced by PM cladding had an effect to improve corrosion resistance in H2SO4 and FeCl3 solutions. Small Cu and bronze addition (4%) had a positive effect in H2SO4 and FeCl3 solutions. 4% Cu alloyed 316L surface layer produced by PM cladding showed similar anodic polarization behaviour to the 316L cladding layer in H2SO4 and FeCl3 solutions.

  9. Some peculiarities of corrosion of wheel steel

    Directory of Open Access Journals (Sweden)

    Alexander SHRAMKO

    2009-01-01

    Full Text Available Corrosion mechanism and rate of different chemical composition and structural condition of wheel steel were investigated. It was shown that “white layers”, variation in grain size and banding of wheel steel structure results in corrosion rate. Microstructure of steel from different elements of railway wheels after operation with corrosion was investigated. Wheel steel with addition of vanadium corroded more quickly than steel without vanadium. Non-metallic inclusions are the centre of corrosion nucleation and their influence on corrosion depends on type of inclusion. Mechanism of corrosion of wheel steel corrosion was discussed.

  10. Corrosion Resistance and Mechanical Properties of TIG and A-TIG Welded Joints of Lean Duplex Stainless Steel S82441 / 1.4662

    OpenAIRE

    Brytan Z.; Niagaj J.

    2016-01-01

    This paper presents results of pitting corrosion resistance of TIG (autogenous and with filler metal) and A-TIG welded lean duplex stainless steel S82441/1.4662 evaluated according to ASTM G48 method, where autogenous TIG welding process was applied using different amounts of heat input and shielding gases like pure Ar and Ar+N2 and Ar+He mixtures. The results of pitting corrosion resistance of the welded joints of lean duplex stainless steel S82441 were studied in as weld conditions and afte...

  11. CORROSION RESISTANCE OF Fe–Al/Al2O3 DUPLEX COATING ON PIPELINE STEEL X80 IN SIMULATED OIL AND GAS WELL ENVIRONMENT

    OpenAIRE

    MIN HUANG; YU WANG; PING-GU WANG; QIN-YI SHI; MENG-XIAN ZHANG

    2015-01-01

    Corrosion resistant Fe–Al/Al2O3 duplex coating for pipeline steel X80 was prepared by a combined treatment of low-temperature aluminizing and micro-arc oxidation (MAO). Phase composition and microstructure of mono-layer Fe–Al coating and Fe–Al/Al2O3 duplex coating were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) with energy dispersive spectrometer (EDS). Corrosion resistance of the coated pipeline steel X80 in a simulated oil and gas well condition was also investig...

  12. Proposal for an alternative operative method for determination of polarisation resistance for the quantitative evaluation of corrosion of reinforcing steel in concrete cooling towers

    Energy Technology Data Exchange (ETDEWEB)

    Mitzithra, M.E., E-mail: me.mitzithra@gmail.com [EDF R& D, 6 quai Watier, 78401 Chatou Cedex (France); Université de Toulouse, UPS, INSA, LMDC, 135, Avenue de Rangueil, 31077 Toulouse Cedex 4 (France); Deby, F.; Balayssac, J.P. [Université de Toulouse, UPS, INSA, LMDC, 135, Avenue de Rangueil, 31077 Toulouse Cedex 4 (France); Salin, J. [EDF R& D, 6 quai Watier, 78401 Chatou Cedex (France)

    2015-07-15

    This paper summarises the results obtained from numerical simulations of an operational measurement mode of polarisation resistance adapted for evaluating corrosion of reinforcing steel in concrete on cooling towers. A simple operational measurement mode of R{sub p} is proposed, adapted for cooling towers prone to corrosion due to carbonation. By means of numerical experimentations, calculation diagrams and semi-empirical equations are built involving the different influencing parameters: concrete cover to steel reinforcement, concrete resistivity and current intensity injected from the counter electrode. Finally, a first application of the proposed procedure for calculating the real value of R{sub p} in laboratory conditions is presented.

  13. Influence of pre-deformation, sensitization and oxidation in high temperature water on corrosion resistance of AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Jinlong, E-mail: ljltsinghua@126.com [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Liang, Tongxiang [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Luo, Hongyun [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Xueyuan Road 37, Beijing 100191 (China)

    2016-12-01

    Highlights: • The pre-strain accelerated desensitization and sensitization for austenitic stainless steels. • Low temperature sensitization (carbide precipitation) induced α′-martensite. • The sensitization level could affect directly corrosion resistance of the oxide film. - Abstract: The effects of pre-deformation on sensitization of AISI 304 stainless steel were investigated by the double loop electrochemical potentiokinetic reactivation test. The effects of pre-deformation and sensitization on high temperature oxidized film formed in high temperature water were analyzed by a XRD and SEM. The electrochemical impedance spectroscopy at room temperature was used to study corrosion resistance of oxidized film. The point defect density of oxidized film was calculated by Mott–Schottky plots. The results showed that the value of the degree of sensitization first decreased and then slight increased with the increasing of engineering strain. Moreover, low temperature promoted to form sensitization induced “secondary” α′-martensite. The sample with 20% engineering strain had higher impedance value than other samples. The result was supported by further Mott–Schottky experiments. Considering increased α′-martensite with the increasing of strain, the results of the impedance were more consistent with values of the degree of sensitization.

  14. Effect of electromagnetic interaction during fusion welding of AISI 2205 duplex stainless steel on the corrosion resistance

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; González-Sánchez, J.; García-Hernández, R.; Dzib-Pérez, L.; Curiel-López, F. F.

    2017-02-01

    The effect of electromagnetic interaction of low intensity (EMILI) applied during fusion welding of AISI 2205 duplex stainless steel on the resistance to localised corrosion in natural seawater was investigated. The heat affected zone (HAZ) of samples welded under EMILI showed a higher temperature for pitting initiation and lower dissolution under anodic polarisation in chloride containing solutions than samples welded without EMILI. The EMILI assisted welding process developed in the present work enhanced the resistance to localised corrosion due to a modification on the microstructural evolution in the HAZ and the fusion zone during the thermal cycle involved in fusion welding. The application of EMILI reduced the size of the HAZ, limited coarsening of the ferrite grains and promoted regeneration of austenite in this zone, inducing a homogeneous passive condition of the surface. EMILI can be applied during fusion welding of structural or functional components of diverse size manufactured with duplex stainless steel designed to withstand aggressive environments such as natural seawater or marine atmospheres.

  15. Improvement in nano-hardness and corrosion resistance of low carbon steel by plasma nitriding with negative DC bias voltage

    Science.gov (United States)

    Alim, Mohamed Mounes; Saoula, Nadia; Tadjine, Rabah; Hadj-Larbi, Fayçal; Keffous, Aissa; Kechouane, Mohamed

    2016-10-01

    In this work, we study the effect of plasma nitriding on nano-hardness and corrosion resistance of low carbon steel samples. The plasma was generated through a radio-frequency inductively coupled plasma source. The substrate temperature increased (by the self-induced heating mechanism) with the treatment time for increasing negative bias voltages. X-rays diffraction analysis revealed the formation of nitride phases (ɛ-Fe2-3N and γ'-Fe4N) in the compound layer of the treated samples. A phase transition occurred from 3.5 kV to 4.0 kV and was accompanied by an increase in the volume fraction of the γ'-Fe4N phase and a decrease in that of the ɛ-Fe2-3N phase. Auger electron spectroscopy revealed a deep diffusion of the implanted nitrogen beyond 320 nm. The nano-hardness increased by ~400% for the nitrogen-implanted samples compared to the untreated state, the nitride phases are believed to participate to the hardening. Potentiodynamic polarization measurements revealed that the plasma nitriding has improved the corrosion resistance behavior of the material. When compared to the untreated state, the sample processed at 4.0 kV exhibits a shift of +500 mV and a reduction to 3% in its corrosion current. These results were obtained for relatively low bias voltages and short treatment time (2 h).

  16. Corrosion Behavior of S450EW Low-alloy Weathering Steel in Cyclically Alternate Corrosion Environments

    Institute of Scientific and Technical Information of China (English)

    Jun-shan WANG; Pei-yang SHI; Cheng-jun LIU; Mao-fa JIANG

    2015-01-01

    Weathering steel is widely used in various ifelds due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450EW weathering steel is closely related to chromium content. The addition of chromium signiif-cantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m−2·h−1. The rust of S450EW weathering steel was mainly constituted of FeOOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-FeOOH. The ifne precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneifcial for the cure of original defects and cracks of the rust layer via the enrich-ment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.

  17. Energy Saving Melting and Revert Reduction (E-SMARRT): Optimization of Heat Treatments on Stainless Steel Castings for Improved Corrosion Resistance and Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    John N. DuPont; Jeffrey D. Farren; Andrew W. Stockdale; Brett M. Leister

    2012-06-30

    It is commonly believed that high alloy steel castings have inferior corrosion resistance to their wrought counterparts as a result of the increased amount of microsegregation remaining in the as-cast structure. Homogenization and dissolution heat treatments are often utilized to reduce or eliminate the residual microsegregation and dissolve the secondary phases. Detailed electron probe microanalysis (EPMA) and light optical microscopy (LOM) were utilized to correlate the amount of homogenization and dissolution present after various thermal treatments with calculated values and with the resultant corrosion resistance of the alloys.The influence of heat treatment time and temperature on the homogenization and dissolution kinetics were investigated using stainless steel alloys CN3MN and CK3MCuN. The influence of heat treatment time and temperature on the impact toughness and corrosion reistance of cast stainless steel alloys CF-3, CF-3M, CF-8, and CF-8M was also investigated.

  18. Evaluation of the corrosion resistance of AISI 316 stainless steel filters

    Directory of Open Access Journals (Sweden)

    Luzinete Pereira Barbosa

    2005-06-01

    Full Text Available In this investigation, the corrosion resistance of AISI 316 SS filters prepared with powders in the size ranges 74-44 µm and 210-105 µm and compacted with pressures of 300 MPa and 400 MPa has been evaluated in naturally aerated 0.5 M H2SO4 solution at 25 °C. Weight loss of filters manufactured with compacting pressure of 400 MPa were significantly higher than that of filters compacted at 300 MPa. The filter compacted at 400 MPa had higher carbon and nitrogen contents compared to those compacted at 300 MPa. The former also had chromium rich precipitates and oxides in the grain boundaries. The pores in filters compacted at 400 MPa were smaller than in filters compacted at 300 MPa. Smaller pores favor the formation of concentration cells and consequently, increased crevice corrosion.

  19. Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jiang; Zhuo Chengzhi; Tao Jie; Liu Linlin [Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China); Jiang Shuyun [Department of Mechanical Engineering, Southeast University, 2 Sipailou, Nanjing 210096 (China)], E-mail: xujiang73@nuaa.edu.cn

    2009-01-07

    In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO{sub 2} predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 deg. C) conditions, amorphous nano-SiO{sub 2} particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr{sub 6.5}Ni{sub 2.5}Si and Cr{sub 23}C{sub 6}. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO{sub 2} particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix

  20. Enhanced corrosion resistance of mild steel in hydrochloric acid solution by new thiadiazole derivatives: Electrochemical, theoretical and XPS studies

    Energy Technology Data Exchange (ETDEWEB)

    Bentiss, Fouad; Lebrini, Mounim; Lagrenee, Michel [Laboratoire de Cristallochimie et Physicochimie du Solide, CNRS UMR 8012, ENSCL, BP. 108, F-59652 Villeneuve d' Ascq Cedex (France); Herve, Vezin [Laboratoire de Chimie Organique et Macromoleculaire, CNRS UMR 8009, USTL Bat C3, F-59655 Villeneuve d' Ascq Cedex (France)

    2004-07-01

    In this work, a new class of thiadiazole derivatives, namely 3,5-bis(2-thienyl)-1,3,4-thiadiazole (2-TTH) and 3,5-bis(3-thienyl)-1,3,4-thiadiazole (3-TTH), have been studied as possible corrosion inhibitors for mild steel in molar hydrochloric acid (1M HCl). Polarisation curves and AC impedance methods have been used. These studies have shown that the thiadiazole derivatives were very good inhibitors for mild steel in 1M HCl. Comparison of results showed that 3-TTH was the best inhibitor. The potential of zero charge (PZC) of mild steel was studied by ac impedance method, and the mechanism of adsorption has been predicted. X-ray photoelectron spectroscopy surface analysis with thiadiazole derivatives shows that it chemisorbed at the mild steel/HCl interface. The adsorption of these inhibitors followed Langmuir's adsorption isotherm. The electronic properties of 2-TTH and 3-TTH, obtained using the AM1 semi-empirical quantum chemical approach, were correlated with their experimental efficiencies using the linear resistance model (LR). (authors)

  1. Passivation Characteristics of Alloy Corrosion-Resistant Steel Cr10Mo1 in Simulating Concrete Pore Solutions: Combination Effects of pH and Chloride

    Directory of Open Access Journals (Sweden)

    Zhiyong Ai

    2016-09-01

    Full Text Available The electrochemical behaviour for passivation of new alloy corrosion-resistant steel Cr10Mo1 immersed in alkaline solutions with different pH values (13.3, 12.0, 10.5, and 9.0 and chloride contents (0.2 M and 1.0 M, was investigated by various electrochemical techniques: linear polarization resistance, electrochemical impedance spectroscopy and capacitance measurements. The chemical composition and structure of passive films were determined by XPS. The morphological features and surface composition of the immersed steel were evaluated by SEM together with EDS chemical analysis. The results evidence that pH plays an important role in the passivation of the corrosion-resistant steel and the effect is highly dependent upon the chloride contents. In solutions with low chloride (0.2 M, the corrosion-resistant steel has notably enhanced passivity with pH falling from 13.3 to 9.0, but does conversely when in presence of high chloride (1.0 M. The passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer enriched in Fe oxides and hydroxides, and an inner layer, rich in Cr species. The film composition varies with pH values and chloride contents. As the pH drops, more Cr oxides are enriched in the film while Fe oxides gradually decompose. Increasing chloride promotes Cr oxides and Fe oxides to transform into their hydroxides with little protection, and this is more significant at lower pH (10.5 and 9.0. These changes annotate passivation characteristics of the corrosion-resistant steel in the solutions of different electrolyte.

  2. Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa

    Science.gov (United States)

    Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam

    2015-07-01

    The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.

  3. Effect of chromium and molybdenum on corrosion resistance of super 13Cr martensitic stainless steel in CO{sub 2} environment

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, Hisashi; Kondo, Kunio; Hirata, Hiroyuki [Sumitomo Metal Industries, Ltd., Amagasaki (Japan). Corporate R and D Labs.; Ueda, Masakatsu; Mori, Tomoki [Sumitomo Metal Industries, Ltd., Wakayama (Japan). Wakayama Steel Works

    1998-12-31

    The effect of Cr and Mo on the corrosion resistance of super 13Cr stainless steel in CO{sub 2} environment has been investigated by the electrochemical technique and the surface film analysis. The corrosion rate in CO{sub 2} environment at elevated temperatures is reduced with the increase in the effective Cr content. The pitting resistance is improved by the addition of more than 0.25 mass% Mo, because Mo is effective to stabilize the passive film in the CO{sub 2} environment. The effect of the Mo content on the SSC susceptibility in CO{sub 2} environment with a little amount of H{sub 2}S has been also studied. Mo is also effective to improve the SSC resistance by the formation of Mo sulfide in the outer layer of the surface film, because the Mo sulfide film can assist the formation and/or stabilization of the Cr oxide passive film in the inner layer even in the CO{sub 2} environment with a little amount of H{sub 2}S at room temperature. Based on these results, O.O1C-13Cr-5.2Ni-0.7Mo steel chemical compositions has been determined to improve the corrosion resistance of 13Cr martensitic stainless steel. The applicable environment of the developed steel will be discussed compared with super 13Cr stainless steel containing 2mass% Mo and conventional 13Cr steel.

  4. Corrosion of Steels in Steel Reinforced Concrete in Cassava Juice

    Science.gov (United States)

    Oluwadare, G. O.; Agbaje, O.

    The corrosion of two types of construction steels, ST60Mn and RST37-2♦, in a low cyanide concentration environment (cassava juice) and embedded in concrete had been studied. The ST60 Mn was found to be more corrosion resistant in both ordinary water and the cassava juice environment. The cyanide in cassava juice does not attack the steel but it provides an environment of lower pH around the steel in the concrete which leads to breakdown of the passivating film provided by hydroxyl ions from cement. Other factors such as the curing time of the concrete also affect the corrosion rates of the steel in the concrete. The corrosion rate of the steel directly exposed to cassava juice i.e., steel not embedded in concrete is about twice that in concrete. Long exposure of concrete structure to cassava processing effluent might result in deterioration of such structures. Careful attention should therefore be paid to disposal of cassava processing effluents, especially in a country like Nigeria where such processing is now on the increase.

  5. Corrosion Resistance and Mechanical Properties of TIG and A-TIG Welded Joints of Lean Duplex Stainless Steel S82441 / 1.4662

    Directory of Open Access Journals (Sweden)

    Brytan Z.

    2016-06-01

    Full Text Available This paper presents results of pitting corrosion resistance of TIG (autogenous and with filler metal and A-TIG welded lean duplex stainless steel S82441/1.4662 evaluated according to ASTM G48 method, where autogenous TIG welding process was applied using different amounts of heat input and shielding gases like pure Ar and Ar+N2 and Ar+He mixtures. The results of pitting corrosion resistance of the welded joints of lean duplex stainless steel S82441 were studied in as weld conditions and after different mechanical surface finish treatments. The results of the critical pitting temperature (CPT determined according to ASTM G48 at temperatures of 15, 25 and 35°C were presented. Three different surface treatment after welding were applied: etching, milling, brushing + etching. The influence of post weld surface treatment was studied in respect to the pitting corrosion resistance, basing on CPT temperature.

  6. Effects of X-rays Radiation on AISI 304 Stainless Steel Weldings with AISI 316L Filler Material: A Study of Resistance and Pitting Corrosion Behavior

    Directory of Open Access Journals (Sweden)

    Francisco Javier Cárcel-Carrasco

    2016-04-01

    Full Text Available This article investigates the effect of low-level ionizing radiation, namely X-rays, on the micro structural characteristics, resistance, and corrosion resistance of TIG-welded joints of AISI 304 austenitic stainless steel made using AISI 316L filler rods. The welds were made in two different environments: natural atmospheric conditions and a closed chamber filled with inert argon gas. The influence of different doses of radiation on the resistance and corrosion characteristics of the welds is analyzed. Welded material from inert Ar gas chamber TIG showed better characteristics and lesser irradiation damage effects.

  7. Effect of heat input on the microstructure, residual stresses and corrosion resistance of 304L austenitic stainless steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Unnikrishnan, Rahul, E-mail: rahulunnikrishnannair@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Idury, K.S.N. Satish, E-mail: satishidury@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Ismail, T.P., E-mail: tpisma@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Bhadauria, Alok, E-mail: alokbhadauria1@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Shekhawat, S.K., E-mail: satishshekhawat@gmail.com [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay (IITB), Powai, Mumbai 400076, Maharashtra (India); Khatirkar, Rajesh K., E-mail: rajesh.khatirkar@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Sapate, Sanjay G., E-mail: sgsapate@yahoo.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India)

    2014-07-01

    Austenitic stainless steels are widely used in high performance pressure vessels, nuclear, chemical, process and medical industry due to their very good corrosion resistance and superior mechanical properties. However, austenitic stainless steels are prone to sensitization when subjected to higher temperatures (673 K to 1173 K) during the manufacturing process (e.g. welding) and/or certain applications (e.g. pressure vessels). During sensitization, chromium in the matrix precipitates out as carbides and intermetallic compounds (sigma, chi and Laves phases) decreasing the corrosion resistance and mechanical properties. In the present investigation, 304L austenitic stainless steel was subjected to different heat inputs by shielded metal arc welding process using a standard 308L electrode. The microstructural developments were characterized by using optical microscopy and electron backscattered diffraction, while the residual stresses were measured by X-ray diffraction using the sin{sup 2}ψ method. It was observed that even at the highest heat input, shielded metal arc welding process does not result in significant precipitation of carbides or intermetallic phases. The ferrite content and grain size increased with increase in heat input. The grain size variation in the fusion zone/heat affected zone was not effectively captured by optical microscopy. This study shows that electron backscattered diffraction is necessary to bring out changes in the grain size quantitatively in the fusion zone/heat affected zone as it can consider twin boundaries as a part of grain in the calculation of grain size. The residual stresses were compressive in nature for the lowest heat input, while they were tensile at the highest heat input near the weld bead. The significant feature of the welded region and the base metal was the presence of a very strong texture. The texture in the heat affected zone was almost random. - Highlights: • Effect of heat input on microstructure, residual

  8. Influence of nitrogen on the stress corrosion cracking resistance of austenitic stainless steels in chloride environment; Influence de l'azote sur la resistance a la corrosion sous contrainte d'aciers inoxydables austenitiques en milieu chlorure

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, S

    2001-11-01

    The aim of this study is to investigate the influence of nitrogen additions on the Stress Corrosion Cracking (SSC) resistance of austenitic stainless steel in chloride environment. The investigation was carried out in two part: first, an experimental investigation with model industrial steels was carried out and secondly, numerical simulations based on the Corrosion Enhanced Plasticity Model were developed. Both slow strain rate tensile tests and constant load test of the different steels in boiling MgCl{sub 2} (153 deg C) at free potential show that, for a given plastic strain rate, nitrogen addition increases the critical stress for crack initiation without influencing the crack propagation rate. We observed that the creep rate under constant load was affected by the nitrogen content. As a consequence, the SCC behaviour (cracks density and propagation rate) depends on the nitrogen content. We thus confirm that the nitrogen content influences the corrosion - deformation interaction mechanisms via its positive contribution to the flow stress. These experimental results are reproduced semi-quantitatively by means of numerical simulations at the scale of crack. - dislocation interactions. The presence of nitrogen is modelled by an increased lattice friction stress, which in turn affects the dynamics of crack tip shielding by dislocation pile-ups. We conclude that nitrogen addition in austenitic stainless steels increases the SC crack initiation stress in proportion of the increased flow stress, without penalty in terms of SC crack propagation rate. (author)

  9. Effects of heat treatment on the corrosion resistance of carbon steel coated with LaMgAl11O19 thermal barrier coatings

    Institute of Scientific and Technical Information of China (English)

    Liang-liang Huang; Hui-min Meng; Li-kang Liang; Sen Li; Jin-hui Shi

    2015-01-01

    LaMgAl11O19 thermal barrier coatings (TBCs) were applied to carbon steels with a NiCoCrAlY bond coat by plasma spraying. The effects of heat treatment on the corrosion resistance of carbon steel coated with LaMgAl11O19 TBCs were investigated in 3.5wt% NaCl solution using polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and X-ray diffrac-tion (XRD). The results show that a large number of cracks are found in the LaMgAl11O19 TBCs after the samples are heat-treated, including some through-thickness cracks. The corrosion forms of the as-sprayed and heat-treated TBCs are uniform corrosion and pitting corrosion, respectively. The as-sprayed TBCs exhibit three EIS time constants after being immersed for less than 7 d, and then a new time constant ap-pears because of steel substrate corrosion. When the immersion time is increased to 56 d, a Warburg impedance (W) component appears in the EIS data. The EIS data for the heat-treated TBCs exhibit only two time constants after the samples are immersed for less than 14 d, and a new time constant appears when the immersion time is increased further. The heat treatment reduces the corrosion resistance of carbon steel coated with LaMgAl11O19 TBCs. The corrosion products are primarilyγ-FeOOH and Fe3O4.

  10. Corrosion resistance of weldable super 13Cr stainless steel in H{sub 2}S containing CO{sub 2} environments

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, M.; Amaya, H.; Kondo, K. [Sumitomo Metal Industries, Ltd., Amagasaki (Japan). Iron and Steel Research Labs.; Ogawa, K. [Sumitomo Metal Industries, Ltd., Osaka (Japan); Mori, T. [Wakayama Steel Works (Japan)

    1996-08-01

    The weldable super 13Cr stainless steel was investigated because of the application for flow line in CO{sub 2} environments with a little amount of H{sub 2}S. TIG welding in the condition of no post weld heat treatment (PWHT) was used as the welding technique. The lowering of C content less than 0.01 mass% in the weldable steel decreased a maximum hardness in the heat-affected zone(HAZ) and mitigated the sulfide stress cracking (SSC) susceptibility. The increasing of Mo content from 2.0 mass% of the super 13Cr stainless steel OCTG (0.02C-12Cr-5.5Ni-2Mo) to 2.5 mass% improved SSC resistance in the HAZ. Based on these results, the weldable super 13Cr stainless steel, which consisted of 0.007C-12Cr-6Ni-2.5Mo-Ti, has been developed. The welded-joint with the yield strength of 550 MPa (80 ksi) and enough corrosion resistance was completed by using the welding material of super duplex stainless steel which had 25Cr-9Ni-3Mo-2W-0.3N. The corrosion resistance to SSC at room temperatures and localized-corrosion at elevated temperatures of the welded-joint was the same as the super 13Cr stainless steel OCTG. The improvement effect of the corrosion resistance by means of Mo addition was discussed based on the stability of Cr oxide passive film, the analysis results of the surface film formed in the CO{sub 2} environment containing H{sub 2}S, and calculated-solubility of oxides, FeCO{sub 3} and sulfides in that environment. It was clarified that Mo assisted the formation of the Cr oxide passive film in the inner layer of the surface film and the formation of Mo sulfide in the outer layer.

  11. Pre-oxidized and nitrided stainless steel alloy foil for proton exchange membrane fuel cell bipolar plates: Part 1. Corrosion, interfacial contact resistance, and surface structure

    Science.gov (United States)

    Brady, M. P.; Wang, H.; Turner, J. A.; Meyer, H. M.; More, K. L.; Tortorelli, P. F.; McCarthy, B. D.

    Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr 2N, CrN, TiN, V 2N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of scale-up studies to determine the feasibility of extending the nitridation approach to thin 0.1 mm stainless steel alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. Developmental Fe-20Cr-4V alloy and type 2205 stainless steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. As-treated Fe-20Cr-4V foil exhibited target (low) ICR values, whereas 2205 foil suffered from run-to-run variation in ICR values, ranging up to 2× the target value. Pre-oxidized and nitrided surface structure examination revealed surface-through-layer-thickness V-nitride particles for the treated Fe-20Cr-4V, but near continuous chromia for treated 2205 stainless steel, which was linked to the variation in ICR values. Promising corrosion resistance was observed under simulated aggressive PEMFC anode- and cathode-side bipolar plate conditions for both materials, although ICR values were observed to increase. The implications of these findings for stamped bipolar plate foils are discussed.

  12. Effect of copper addition on mechanical properties, corrosion resistance and antibacterial property of 316L stainless steel.

    Science.gov (United States)

    Xi, Tong; Shahzad, M Babar; Xu, Dake; Sun, Ziqing; Zhao, Jinlong; Yang, Chunguang; Qi, Min; Yang, Ke

    2017-02-01

    The effects of addition of different Cu content (0, 2.5 and 3.5wt%) on mechanical properties, corrosion resistance and antibacterial performance of 316L austenitic stainless steel (SS) after solution and aging treatment were investigated by mechanical test, transmission electron microscope (TEM), X-ray diffraction (XRD), electrochemical corrosion, X-ray photoelectron spectroscopy (XPS) and antibacterial test. The results showed that the Cu addition and heat treatment had no obvious influence on the microstructure with complete austenite features. The yield strength (YS) after solution treatment was almost similar, whereas the aging treatment obviously increased the YS due to formation of tiny Cu-rich precipitates. The pitting and protective potential of the solution treated Cu-bearing 316L SS in 0.9wt% NaCl solution increased with increasing Cu content, while gradually declined after aging, owing to the high density Cu-rich precipitation. The antibacterial test proved that higher Cu content and aging were two compulsory processes to exert good antibacterial performance. The XPS results further indicated that aging enhanced the Cu enrichment in passive film, which could effectively stimulate the Cu ions release from the surface of passive film.

  13. An Industrial Perspective on Environmentally Assisted Cracking of Some Commercially Used Carbon Steels and Corrosion-Resistant Alloys

    Science.gov (United States)

    Ashida, Yugo; Daigo, Yuzo; Sugahara, Katsuo

    2017-08-01

    Commercial metals and alloys like carbon steels, stainless steels, and nickel-based super alloys frequently encounter the problem of environmentally assisted cracking (EAC) and resulting failure in engineering components. This article aims to provide a perspective on three critical industrial applications having EAC issues: (1) corrosion and cracking of carbon steels in automotive applications, (2) EAC of iron- and nickel-based alloys in salt production and processing, and (3) EAC of iron- and nickel-based alloys in supercritical water. The review focuses on current industrial-level understanding with respect to corrosion fatigue, hydrogen-assisted cracking, or stress corrosion cracking, as well as the dominant factors affecting crack initiation and propagation. Furthermore, some ongoing industrial studies and directions of future research are also discussed.

  14. A novel method to prepare superhydrophobic, UV resistance and anti-corrosion steel surface

    KAUST Repository

    Isimjan, Tayirjan T.

    2012-11-01

    Both TiO 2 and SiO 2 coated steel surfaces containing micro- and nanoscale binary structures with different surface roughness were successfully fabricated by means of a facile layer by layer deposition process followed by heat treatment. The resulting surfaces were modified by the low free energy chemical PTES (1H,1H,2H,2H-Perfluorodecyltriethoxysilane). The experimental results of wettability exhibit that such modified surfaces have a strong repulsive force to water droplets, their static contact angles exceed 165°, receding angle>160°, advanced angles>170° and slide angle<1°. The resulting surfaces not only exhibit superhydrophobic properties but also show strong UV resistance (after coating SiO 2 on top of TiO 2) and strong stability to various solvents including 0.01% HCl solution. © 2012 Elsevier B.V.

  15. Effect of Aging on Precipitation Behavior and Pitting Corrosion Resistance of SAF2906 Super Duplex Stainless Steel

    Science.gov (United States)

    Li, Jianchun; Li, Guoping; Liang, Wei; Han, Peide; Wang, Hongxia

    2017-09-01

    The effect of aging temperature and holding time on the precipitation of secondary phases and pitting corrosion resistance of SAF2906 super duplex stainless steel was examined. Chromium nitride and σ phase were observed to preferentially precipitate at the ferrite/austenite interface. An amount of nitrides was also observed within the ferrite grain. The precipitation of chromium nitride occurred before the σ phase. The increase in aging temperature and holding time did not affect the concentration of the nitrides but increased the area fraction of the σ phase at a faster rate. The Cr2N precipitation in SAF2906 is more evident than that of the other duplex stainless steels. The variation tendency of the precipitation concentrations is primarily consistent with the prediction results of Thermo-Calc software. The electrochemical results showed that Cr2N and σ phase significantly reduced the pitting potential. Scanning electron microscope observations revealed that pits appear mainly in regions adjacent to sigma phase and Cr2N.

  16. Enhancement of corrosion resistance for plasma nitrided AISI 4140 steel by plain air plasma post-oxidizing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jiqiang; Liu, Han; Ye, Xuemei [Jiangsu Key Laboratory of Materials Surface Technology, Changzhou University, Changzhou 213164 (China); Chai, Yating [Materials Research and Education Center, Auburn University, AL 36849 (United States); Hu, Jing, E-mail: jinghoo@126.com [Jiangsu Key Laboratory of Materials Surface Technology, Changzhou University, Changzhou 213164 (China); Materials Research and Education Center, Auburn University, AL 36849 (United States)

    2015-05-25

    Highlights: • Plain air was primarily used for plasma post-oxidation for AISI 4140 steel. • A thin iron oxide layer composed of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} was formed on top of the compound layer. • The ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} was closely related to the post-oxidizing conditions. • Post-oxidizing at 673 K for 60 min brought out highest ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} and optimum corrosion resistance. - Abstract: Plasma post-oxidizing was conducted immediately after plasma nitriding in the same equipment for AISI 4140 steel, and plain air was used as the oxygen bearing gas. The cross-sectional microstructures of the treated samples were observed by optical metallography and scanning electron microcopy (SEM), and the thickness of compound layer was measured accordingly. The phases were determined by X-ray diffraction (XRD), corrosion resistance was evaluated by electrochemical polarization, and the surface morphology before and after polarization test was also observed by SEM. Meanwhile, standard Gibbs free energy of the oxidation reactions existed in Fe–O system was calculated. The results show that a thin iron oxide layer composed of magnetite (Fe{sub 3}O{sub 4}) and hematite (Fe{sub 2}O{sub 3}) is formed on top of the compound layer during plasma post-oxidizing process, and the ratio of magnetite (Fe{sub 3}O{sub 4}) to hematite (Fe{sub 2}O{sub 3}) is depended on plasma post-oxidizing temperature and time. Highest ratio of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3} is obtained while post-oxidizing at 673 K for 60 min due to lower standard Gibbs free energy and appropriate forming rate for the formation of Fe{sub 3}O{sub 4} at this temperature. The thin oxide layer brings out significant enhancement of corrosion resistance, especially at higher ratios of Fe{sub 3}O{sub 4} to Fe{sub 2}O{sub 3}, due to the dense and adherent characteristic of Fe{sub 3}O{sub 4} oxide. Surface images of the post-oxidizing specimen

  17. MICROSCOPIC CORROSION STUDIES OF DUPLEX STAINLESS STEELS

    Institute of Scientific and Technical Information of China (English)

    C.Leygraf; J.Pan; M.Femenia

    2004-01-01

    Electrochemical scanning tunneling microscopy and scanning electrochemical microscopy have been used for in situ monitoring of localized corrosion processes of different Duplex stainless steels (DSS) in acidic chloride solutions. The techniques allow imaging of local dissolution events with micrometer resolution, as opposed to conventional electrochemical techniques, which only give an overall view of the corrosion behavior. In addition, combined scanning Kelvin probe force microscopy and magnetic force microscopy were used for mapping the Volta potential variation over the surface of DSSs. A significant difference in Volta potential between the austenite and ferrite phases suggests galvanic interaction between the phases. A compositional gradient appears within 2 micrometers across the phase boundary, as seen with scanning Auger microscopy (SAM). In all, the studies suggest that higher alloyed DSS exhibit a more homogeneous dissolution behavior than lower alloyed DSS, due to higher and more similar corrosion resistance of the two phases, and enhanced resistance of the ferrite/austenite phase boundary regions.

  18. Corrosion Behavior and Durability of Low-Alloy Steel Rebars in Marine Environment

    Science.gov (United States)

    Liu, Ming; Cheng, Xuequn; Li, Xiaogang; Yue, Pan; Li, Jun

    2016-10-01

    The corrosion resistance of Cr-modified low-alloy steels and HRB400 carbon steel was estimated using the open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopic, and weight loss methods in simulated concrete pore solution. Results show that Cr-modified steels exhibit a higher corrosion resistance with a higher critical chloride level (CTL), lower corrosion current density, and higher impedance than carbon steel. The CTL of the steels significantly reduces with increasing temperature. Weight loss measurement shows that the Cr-modified steels exhibit low corrosion rates and small corrosion pitting. The primary constituents of the corrosion scales are Fe2O3, Fe3O4, β-FeOOH, γ-FeOOH, and α-FeOOH. A large amount of α-FeOOH could be detected in the Cr-modified steel corrosion products. Moreover, the Cr-modified steels demonstrate a higher durability than HRB400 carbon steel.

  19. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  20. Research on Pitting Corrosion-resistant of Stainless Steel/Carbon Steel Welding Jiont%不锈钢/碳钢复合钢板焊接接头耐点蚀性能研究

    Institute of Scientific and Technical Information of China (English)

    贡志林

    2015-01-01

    The corrosion resistance of bade metal, weld and heat affected zone of stainless steel-carbon steel laminated composite material in 3. 5% NaCl solution, 30% CH3 COOH solution, 60% CH3 COOH solution and 98%CH3 COOH solution was studied respectively through electrochemical test. It was obtained that the corrosion resistance of weld was the better then the base metal, but the corrosion resistance of heat affected zone was the worst. Besides, in the four solution base metal and weld showed poor corrosion resistance in 3. 5%NaCl solution. A theoretical and experimental foundation for stainless steel-carbon steel laminated composite material was supplied.%采用电化学测试方法评价了不锈钢复合板母材、焊缝及热影响区在3.5%NaCl溶液、30%CH3 COOH溶液、60%CH3 COOH溶液、98%CH3 COOH溶液中的耐点蚀性能。结果显示在以上各种溶液中焊缝的抗腐蚀性能最优、母材其次而热影响区抗腐蚀性能最弱。此外在这四种溶液中母材跟焊区在3.5%NaCl溶液溶液中的耐腐蚀性能最弱。

  1. Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

    Institute of Scientific and Technical Information of China (English)

    Shengrong Wang; Cuiwei Dun; Xiaogang Li; Zhiyong Liunn; Min Zhu; Dawei Zhang

    2015-01-01

    The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface.α-FeOOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorr decreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy (EIS) are consistent with potentiodynamic polarization tests.

  2. Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

    Directory of Open Access Journals (Sweden)

    Shengrong Wang

    2015-06-01

    Full Text Available The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy (SEM,energy dispersive X-ray spectroscopy (EDS, and X-ray diffraction (XRD. The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface. α-FeOOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorr decreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy (EIS are consistent with potentiodynamic polarization tests.

  3. Investigations of the corrosion fatigue behaviour at a super pure martensitic stainless steel (X 5 CrNiCuNb 17 4 PH) in comparison to the soft martensitic stainless steel X 4 CrNiMo 16 5 1 ESR in chloride containing aqueous media. Pt. 1. Corrosion investigations and stress corrosion tests to optimize the heat treatment according to the stress corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt-Thomas, K.G.; Wunderlich, R.; Happle, T.

    1989-06-01

    The stress corrosion was investigated for all heat-treatments of the 17-4 PH in 22% NaCl(pH3) solution. The precipitation hardening steel was most resistant to stress corrosion in concentrated NaCl-solution after a three-stage heat-treatment. There was no improvement of corrosion fatigue resistance after metallurgical aftertreatment of soft martensitic steel compared to the untreated material. This is due to the instable passive behaviour of the material which led to crack initiation, especially during the 150/sup 0/C experiments, at chloride-induced places of pitting. The investigation of the electrochemical corrosion behaviour of both materials showed that the pH-value hardly influences corrosion resistance. An increase of the salt content leads to higher pitting induction. At temperatures of 80/sup 0/C in a saturated NaCl-solution the material showed no corrosion resistance. In potentiokinetic investigations, a direct transition from the active area to the pitting potential was observed. In accordance with both the corrosion fatigue and the stress corrosion cracking investigations, it was found that pitting at the martensite precipitator starts primarily around Cu-containing or oxidic inclusions. (orig./MM).

  4. Evaluation of steel corrosion by numerical analysis

    OpenAIRE

    Kawahigashi, Tatsuo

    2017-01-01

    Recently, various non-destructive and numerical methods have been used and many cases of steel corrosion are examined. For example, methods of evaluating corrosion through various numerical methods and evaluating macrocell corrosion and micro-cell corrosion using measurements have been proposed. However, there are few reports on estimating of corrosion loss with distinguishing the macro-cell and micro-cell corrosion and with resembling an actuality phenomenon. In this study, for distinguishin...

  5. The effects of carbon and nitrogen on the corrosion resistance of type 316 stainless steel to liquid lithium

    Science.gov (United States)

    Barker, M. G.; Frankham, S. A.

    1982-06-01

    Type 316 stainless steel plates have been exposed at 600°C to liquid lithium containing carbon and nitrogen at various chemical activities for periods of up to 672 h. The corrosion products Li 9CrN 5 and M 23C 6 have been identified on the plate surfaces and in the grain boundaries. Scanning electron microscopy has shown preferential nickel and chromium depletion at the steel surface in lithium with high nitrogen content. The diffusion coefficient of carbon in type 316 stainless steel from a lithium source was found to be 6.5 × 10 t 1¯5 m 2/s.

  6. Electrochemical Fabrication and Characterization of Corrosion-Resistant, Ternary, Lead-Based Alloys as a New Material for Steel Surface Protection

    Science.gov (United States)

    Aliyev, A. Sh.; Tahirli, H. M.; Elrouby, Mahmoud; Soltanova, N. Sh.; Tagiev, D. B.

    2016-06-01

    This article presents the study of the synthesis of the ternary Pb-Sb-Te alloy on the stainless steel substrate via electrochemical method. The corrosion resistance of the electrodeposited alloy has been investigated via subjecting the electro-synthesized alloy to a corrosive medium containing sulfide ions; this medium is similar to the petroleum refining environment. The resulting film of the electrodeposited alloy was analyzed by the scanning electron microscope, energy-dispersive X-ray analysis, and X-ray diffraction to determine the morphology and the phase structure of the electrodeposited film. It was found that the electrodeposited Pb-Sb-Te alloy thin film is a multiphase composition. The obtained data reveal that the most corrosion-resistant phase is the PbSb2Te4 alloy.

  7. Laser surface alloying of FeCoCrAlNi high-entropy alloy on 304 stainless steel to enhance corrosion and cavitation erosion resistance

    Science.gov (United States)

    Zhang, S.; Wu, C. L.; Zhang, C. H.; Guan, M.; Tan, J. Z.

    2016-10-01

    FeCoCrAlNi high-entropy alloy coating was synthesized with premixed high-purity Co, Cr, Al and Ni powders on 304 stainless steel by laser surface alloying, aiming at improving corrosion and cavitation erosion resistance. Phase constituents, microstructure and microhardness were investigated using XRD, SEM, and microhardness tester, respectively. The cavitation erosion and electrochemical corrosion behavior of FeCoCrAlNi coating in 3.5% NaCl solution were also evaluated using an ultrasonic vibrator and potentiodynamic polarization measurement. Experimental results showed that with appropriate laser processing parameters, FeCoCrAlNi coating with good metallurgical bonding to the substrate could be achieved. FeCoCrAlNi coating was composed of a single BCC solid solution. The formation of simple solid solutions in HEAs was the combined effect of mixing entropy (ΔSmix), mixing enthalpy (ΔHmix), atom-size difference (δ) and valence electron concentration (VEC), and the effect of ΔSmix was much larger than that of the other factors. The microhardness of the FeCoCrAlNi coating was ~3 times that of the 304 stainless steel. Both the corrosion and cavitation erosion resistance of the coating were improved. The cavitation erosion resistance for FeCoCrAlNi HEA coating was ~7.6 times that of 304 stainless steel. The corrosion resistance was also improved as reflected by a reduction in the current density of one order of magnitude as compared with 304 stainless steel.

  8. The corrosion resistance of composite arch wire laser-welded by NiTi shape memory alloy and stainless steel wires with Cu interlayer in artificial saliva with protein.

    Science.gov (United States)

    Zhang, Chao; Sun, Xinhua; Hou, Xu; Li, Hongmei; Sun, Daqian

    2013-01-01

    In this paper, the corrosion resistance of laser-welded composite arch wire (CoAW) with Cu interlayer between NiTi shape memory alloy and stainless steel wire in artificial saliva with different concentrations of protein was studied. It was found that protein addition had a significant influence on the corrosion behavior of CoAW. Low concentration of protein caused the corrosion resistance of CoAW decrease in electrochemical corrosion and immersion corrosion tests. High concentration of protein could reduce this effect.

  9. The Corrosion Resistance of Composite Arch Wire Laser-Welded By NiTi Shape Memory Alloy and Stainless Steel Wires with Cu Interlayer in Artificial Saliva with Protein

    Science.gov (United States)

    Zhang, Chao; Sun, Xinhua; Hou, Xu; Li, Hongmei; Sun, Daqian

    2013-01-01

    In this paper, the corrosion resistance of laser-welded composite arch wire (CoAW) with Cu interlayer between NiTi shape memory alloy and stainless steel wire in artificial saliva with different concentrations of protein was studied. It was found that protein addition had a significant influence on the corrosion behavior of CoAW. Low concentration of protein caused the corrosion resistance of CoAW decrease in electrochemical corrosion and immersion corrosion tests. High concentration of protein could reduce this effect. PMID:23801895

  10. Microbial Corrosion and Cracking in Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    1998-01-01

    and corrosion products (ferrous sulphides) on the metal surface. Experiments have been conducted on carbon steel exposed in near neutral (pH 6 to 8.5) saline hydrogen sulphide environment (0 to 100 mg/l total dissolved sulphide) for a period of 14 days. Furthermore coupons have been exposed in a bioreactor...... for a period of up to 120 days in sulphide-producing environment controlled by biological activity of (SRB).Electrochemical studies have been conducted in order to characterise the electrochemical response of the biofilm / ferrous sulphide / metal interface and clarify whether the tested electrochemical...... and not electrochemically active film. The polarisation resistance increases with the film resistance and an small underestimation of corrosion rate is possible, if film resistance is large.· An electrochemically reactive film (ferrous sulphides) results in current contributions that will be added to the metal dissolution...

  11. Finishes for Metals. Paintability of Galvanized Steel, Corrosion Resistance of Metallized Coatings.

    Science.gov (United States)

    Building Research Inst., Inc., Washington, DC.

    Two papers are presented. The first, "Report of the AISI Research Project on the Paintability of Galvanized Steel," was a project aimed at determining optimum procedures for painting bright-spangled galvanized sheet steel products using three classes of trade sales paints--metallic zinc-dust, portland cement-in-oil, and water base emulsion paints.…

  12. Influence of surface roughness of stainless steel on microbial adhesion and corrosion resistance

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Bagge-Ravn, Dorthe; Kold, John;

    2003-01-01

    Abstract The aim of this study was to evaluate if hygienic characteristics of stainless steel used in the food industry could be improved by smoothing surface roughness from an Ra of 0.9 to 0.01 ƒÝm. The adherence of Pseudomonas sp., Listeria monocytogenes and Candida lipolytica to stainless steel...

  13. Grain boundary engineering for intergranular corrosion resistant austenitic stainless steel%抗晶间腐蚀奥氏体不锈钢的晶界工程

    Institute of Scientific and Technical Information of China (English)

    粉川博之

    2005-01-01

    Sensitization by chromium depletion due to chromium carbide precipitation at grain boundaries in austenitic stainless steels can not be prevented perfectly only by previous conventional techniques, such as reduction of carbon content, stabilization-treatment, local solution-heat-treatment, etc. Recent studies on grain boundary structure have revealed that the sensitization depends strongly on grain boundary character and atomic structure, and that low energy grain boundaries such as coincidence-site-lattice (CSL) boundaries have strong resistance to intergranular corrosion. The concept of 'grain boundary design and control' has been developed as grain boundary engineering (GBE). GBEed materials are characterized by high frequencies of CSL boundaries which are resistant to intergranular deterioration of materials, such as intergranular corrosion. A thermomechanical treatment was tried to improve the resistance to the sensitization by GBE. A type 304 austenitic stainless steel was cold-rolled and solution-heat-treated, and then sensitization-heat-treated. The grain boundary character distribution was examined by orientation imaging microscopy (OIM). The intergranular corrosion resistance was evaluated by electrochemical potentiokinetic reactivation (EPR) and ferric sulfate-sulfuric acid tests. The sensitivity to intergranular corrosion was reduced by the thermomechanical treatment and indicated a minimum at a small roll-reduction. The frequency of CSL boundaries indicated a maximum at the small reduction. The ferric sulfate-sulfuric acid test showed much smaller corrosion rate in the thermomechanical-treated specimen than in the base material. A high density of annealing twins were observed in the thermomechanical-treated specimen. The results suggest that the therrmomechanical treatment can introduce low energy segments in the grain boundary network by annealing twins and can arrest the percolation of intergranular corrosion from the surface. The effects of carbon

  14. Corrosion resistance of plasma sprayed NiCrAl + (ZrO2 + Y2O3 ) thermal barrier coating on 18 -8 steel surface

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei; L(U) Tao; DING Hua-dong; ZHOU Hai; LIU Kai

    2005-01-01

    The corrosion resistance of NiCrAl +(ZrO2 + Y2 O3 )thermal barrier coating, formed with the plasma spraying technique, on the 18 - 8 steel surface was investigated. The phase structure and morphology of the coating were analyzed by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM). The electrochemical corrosion behavior of the coating in 1.0 mol/L H2 SO4 solution was studied by using electrochemical measurement methods. The results show that the gradient plasma spraying coating is composed of the NiCrAlY primer coating and the (ZrO2 + Y2O3 ) top coating, and the coating thickness is 360 μm. The microhardness of coating reaches 1 100 HV. The corrosion resistance of the plasma sprayed coating of the 18 - 8 steel surface is about 5 times as great as that of the original pattern. The corrosion resistance of the coating is enhanced notably.

  15. Improving Corrosion Resistance of Stainless Steel by Yttrium Addition: An AES Analysis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of Y addition on the distribution of element concentrations in the passive film of high silicon stainless steel formed in 93% H2SO4 was comparatively studied by using auger electron spectroscopy (AES). The results show that 0.2%Y addition increases the SiO2 proportion in the passive film of stainless steel so that the formation of SiO2 enriched passive film from silicon in the alloy is brought into full play.

  16. Electrochemical evaluation for corrosion resistance of bacterial exopolysaccharides on low carbon steel

    Science.gov (United States)

    Corrosion is a global issue that affects safety and economics. There is an increasing demand for bio-based polymers for industrial applications and production of polymers by microorganisms is especially attractive. This work reports on the electrochemical and physical properties of 29 strains or fr...

  17. Development of WELDABLE12CR stainless steel seamless pipe with superior weldability and corrosion resistance for linepipe application; Yosetsusei oyobi taishokusei ni sugureta linepipe yo stainless keimokumukokan WELDABLE12CR no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Y.; Kimura, M.; Toyooka, T.; Nakano, Y.; Murase, F. [Kawasaki Steel Corp., Tokyo (Japan)

    1998-06-20

    Severe corrosive circumstance of oil wells and gas wells including high temperature, high CO2 partial pressure, high chlorine ion concentration, and further H2S are becoming more and more serious in recent years. Measures to prevent CO2 corrosion and sulfide stress crack are necessary for pipelines called flowlines and gathering line for transporting oil or gas which has severe corrosivity before treatment. WELDABLE12CR steel pipe which is seamless martensite stainless steel with excellent weldability and corrosion resistance is developed by the present authors. There two kinds of such steel pipes, one is 11Cr steel (0.01C-11Cr-1.5Ni-0.5Cu-0.01N-based steel) that is superior in corrosion resistance to 13Cr steel for oil well so that it can be used in CO2 circumstance, and the other one is 12Cr steel (0.01C-12Cr-5Ni-2Mo-0.01N-based steel) that has excellent SSC-resistance thus being used in the circumstance containing CO2 and a trace quantity of H2S. 5 refs., 4 figs., 3 tabs.

  18. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: crazyfim@gmail.com [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); López-Morelos, V.H., E-mail: vhlopez@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); García-Hernández, R., E-mail: rgarcia@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); Dzib-Pérez, L., E-mail: luirdzib@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); García-Ochoa, E.M., E-mail: emgarcia@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); González-Sánchez, J., E-mail: jagonzal@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico)

    2014-12-01

    Highlights: • Electromagnetic interaction in welding improved localised corrosion resistance. • Electromagnetic interaction in welding enhanced γ/δ phase balance of DuplexSS. • Welding under Electromagnetic interaction repress formation and growth of detrimental phases. • Welds made with gas protection (2% O{sub 2} + 98% Ar) have better microstructural evolution during welding. - Abstract: The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O{sub 2} (M1) and 97% Ar + 3% N{sub 2} (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  19. Characterization of the Reinforcing Steel Corrosion by Potentialdynamic Scan Approach

    Institute of Scientific and Technical Information of China (English)

    QIAO Guofu; LIU Tiejun

    2012-01-01

    Reinforcement corrosion is the major cause of damage and early failure of reinforced concrete structures worldwide with subsequent enormous costs for maintenance,restoration and replacement.Many methods used today for assessment of reinforcement corrosion are based on electrochemical techniques that determine the free corrosion potential or polarization resistance.Most of these methods always consider the B value in Stern-Geary equation as constant.However,B changes with different condition.In this paper,potentialdynamic method is used to characterize the corrosion of reinforcing steel.The corrosion rate of Q235 carbon steel is measured with concrete environment.B is calculated real-time.By this way,the error of reinforcement corrosion rate is minimized.

  20. 电位、电阻率与钢筋腐蚀率关系研究%POTENTIAL, RESISTIVITY AND THE RELATIONSHIP BETWEEN THE CORROSION RATE OF STEEL

    Institute of Scientific and Technical Information of China (English)

    聂志虎; 吴瑾

    2011-01-01

    the half-cell potential and concrete resistivity can only qualitatively estimate the reinforcement corrosion in the concrete, but it can' t quantitative detect the corrosion level of steel rebar. Quantitative relationship of potential, resistivity and steel corrosion rate is researched with the help of these two methods. By studying and analysising on the concrete, the new evaluation based on potential method and resistivity is proposed, and tested in engineering practice.%半电池电位法、电阻率法都是定性地估计混凝土结构中钢筋腐蚀的状态,而不能定量检测钢筋腐蚀率.本文借助这两种方法来研究电位、电阻率与钢筋腐蚀率之间的定量关系.通过对混凝土构件进行的试验研究和分析总结,得出电位法、电阻率法新的评价方法,并在工程实践中得到验证.

  1. Synergy between molybdenum and nitrogen on the pitting corrosion and passive film resistance of austenitic stainless steels as a pH-dependent effect

    Energy Technology Data Exchange (ETDEWEB)

    Loable, Carole, E-mail: carole.loable@lepmi.grenoble-inp.fr [Univ. Grenoble Alpes, LEPMI, F-38000 Grenoble (France); CNRS, LEPMI, F-38000 Grenoble (France); Dep. Eng. Quimica, Instituto Superior Técnico-Universidade de Lisboa, Av. Rovisco Pais, 1049 001 Lisbon (Portugal); Viçosa, Isadora N., E-mail: inogueira@poli.ufrj.br [Univ. Grenoble Alpes, LEPMI, F-38000 Grenoble (France); CNRS, LEPMI, F-38000 Grenoble (France); Mesquita, Thiago J., E-mail: Thiago.mesquita@total.com [CRU Ugitech, Avenue Paul Girod, 73403 Ugine Cedex (France); Mantel, Marc, E-mail: Marc.Mantel@ugitech.com [CRU Ugitech, Avenue Paul Girod, 73403 Ugine Cedex (France); Université Grenoble Alpes, SIMAP, F-38000 Grenoble (France); CNRS, SIMAP, F-38000 Grenoble (France); Nogueira, Ricardo P., E-mail: rnogueira@pi.ac.ae [Univ. Grenoble Alpes, LEPMI, F-38000 Grenoble (France); CNRS, LEPMI, F-38000 Grenoble (France); Department of Chemical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Berthomé, Gregory, E-mail: gregory.berthome@simap.grenoble-inp.fr [Université Grenoble Alpes, SIMAP, F-38000 Grenoble (France); CNRS, SIMAP, F-38000 Grenoble (France); Chauveau, Eric, E-mail: eric.chauveau@ugitech.fr [Department of Chemical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Roche, Virginie, E-mail: virginie.roche@lepmi.grenoble-inp.fr [Univ. Grenoble Alpes, LEPMI, F-38000 Grenoble (France); CNRS, LEPMI, F-38000 Grenoble (France)

    2017-01-15

    This paper brings up some insights upon the pH dependence of the synergistic effect of Mo and N on the localized corrosion resistance of austenitic stainless steels. The objective of this work is to study the synergetic effect of Mo and N additions on corrosion and passive film properties of austenitic grades. A comparison between Mo containing (3 wt% Mo); Mo and N containing (3 wt% Mo and 0.1% N) and free Mo or free Mo and N grades of highly controlled laboratory heats was done considering their localized corrosion resistance and oxide film formation in different aggressive conditions, from neutral to alkaline pH. The passive layer was characterized by EIS and XPS analyses. The combined effect of Mo and N on the pitting potential was confirmed to be synergistic, and not just the addition of their individual effects. Moreover, this effect was found to be pH-dependent, being very positive in acid to neutral conditions whereas it was almost inexistent in high pH. - Highlights: • Laboratory austenitic stainless steels with Mo and/or N were tested. • Mo and N acted synergistically to improve pitting resistance. • Synergistic effect is pH-dependent. • N clearly enhanced the repassivation of austenitic SS in presence of Mo.

  2. Corrosion-resistant uranium

    Science.gov (United States)

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  3. Structural changes in corrosion-resistant steel 03Kh26N6T with initial anisotropy

    Science.gov (United States)

    Akhmed Fuad, M. F.; Tsepin, M. A.; Lobach, A. A.; Smirnov, O. M.

    1991-09-01

    Resultant analytic curves (2) and (3) are an accurate mathematical model describing the anisotropy characteristics in steel 03Kh26N6T and their variation during superplastic deformation. In this case, the phenomenological laws governing structural changes are based on fully defined physical notions concerning the diffusion nature of the processes that take place in this case. Analysis of the structural changes in the steel with initial metallographic anisotropy indicates that in designing and calculating processes involving the superplastic deformation of hollow articles formed from sheet blanks, it is necessary to consider the different magnitude of the structural components in the characteristic directions and, accordingly, the different rate of structural changes. This may determine to a significant degree both the quality of the components produced (for example, variations in thickness) and variations in the optimal superplastic-deformation regime. The new quantitative data on steel anisotropy, which were obtained in this study, should be considered in developing mathematical models of the superplastic deformation process, which describe the shape variation of structurally sensitive materials with a high accuracy. It is obvious that to determine the range of optimal temperature-rate coditions of superplasticity, the relationships presented in the study make it possible to assess the activation energy of structural variations and, in turn, to ascertain not only the controlling mechanisms of superplastic deformation but also to solve the temperature problem of selecting the SPD regime.

  4. Corrosion resistant coating

    Science.gov (United States)

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  5. CORROSION RESISTANCE OF PACK ALUMINIZED SUS304 STAINLESS STEEL%SUS304ss包埋粉末渗铝的耐蚀性能

    Institute of Scientific and Technical Information of China (English)

    罗宏

    2009-01-01

    In order to research the corrosion resistance of SUS304 stainless steels with pack aluminized process,the corrosion resistance tests in 0.33 mol/L FeCl_3+0.05 mol/L HCl,the oxidation tests at 1000℃, and the corrosion resistance tests in deposition of alkali-chloride and sulphate at 500℃were conducted.The corrosion resistance was comprehensively evaluated by weight loss method and electrochemical tests etc.The experimental results indicated that aluminized layer of SUS304ss was dense,and the thickness was 50μm;the pitting corrosion resistance of almuinized SUS304ss was better than that of unaluminized one;the oxidation properties of aluminized SUS304ss increased 5 times at 1000℃;the corrosion resistance of aluminized SUS304 in deposition of alkali-chloride and sulphate increased about 20 times at 500℃;the corrosion potential of aluminized SUS304 was higher than that of unaluminized one,which had better corrosion resistance.%展开了SUS304ss及其渗铝后在0.33 mol/L FeCl_3+0.05 mol/L HCl溶液中的耐蚀性实验、1000℃下的抗高温氧化实验及表面沉积碱金属氯化物和硫酸盐在500℃下的耐蚀性实验,用失重法和电化学方法等综合评定了SUS304ss渗铝后的耐蚀性.研究表明:渗铝SUS304ss表面渗铝层结构致密,厚度为50 μm;在0.33mol/L FeCl3+0.05 mol/L HCl溶液中SUS304ss发生了严重孔蚀,渗铝后表而发生轻微孔蚀;渗铝SUS304ss在1000℃下加热,表面和截面形貌完好,耐高温氧化性提高了约5倍;在500℃下表面沉积盐碱混合物,渗铝SUS304ss耐腐蚀性约提高20倍;渗铝后SUS304ss的腐蚀电位大于未渗铝钢,耐蚀性提高.

  6. Effects of carbon and nitrogen on the corrosion resistance of type 316 stainless steel to liquid lithium

    Energy Technology Data Exchange (ETDEWEB)

    Barker, M.G.; Frankham, S.A. (Nottingham Univ. (UK). Dept. of Chemistry)

    1982-06-01

    Type 316 stainless steel plates have been exposed at 600/sup 0/C to liquid lithium containing carbon and nitrogen at various chemical activities for periods of up to 672 h. The corrosion products Li/sub 9/CrN/sub 5/ and M/sub 23/C/sub 6/ have been identified on the plate surfaces and in the grain boundaries. Scanning electron microscopy has shown preferential nickel and chromium depletion at the steel surface in lithium with high nitrogen content. The diffusion coefficient of carbon in type 316 stainless steel from a lithium source was found to be 6.5 x 10/sup -15/ m/sup 2//s.

  7. Effects of Strain Energy and Grain Size on Corrosion Resistance of Ultrafine Grained Fe-20%Cr Steels with Extremely low C and N Fabricated by ECAP

    Directory of Open Access Journals (Sweden)

    Muhammad Rifai

    2015-01-01

    Full Text Available Effect of strain energy and grain size on corrosion resistance of ultrafine grained (UFG Fe-20%Cr steels with extremely low C and N fabricated by equal channel angular pressing (ECAP was investigated. UFG structures of initial grain size of 144 nm exhibited the typical three-stage softening comprising recovery, recrystallization, and grain growth. Potentiodynamic polarization measurements were carried out with a conventional three-electrode cell to evaluate pitting potential. Pitting potential in 1000 mol·m−3 NaCl solution was nobler in UFG state, but pitting potential started to decrease monotonously at lower temperature compared to hardness. The degradation of corrosion resistance in the early stage of annealing is attributed to stability change of passivation by recovery of dislocation structures inside grains and in nonequilibrium grain boundaries. We therefore conclude that nobler potentials of UFG states were realized by not only grain size reduction but also defective deformation-induced UFG.

  8. MICROSTRUCTURE AND CORROSION RESISTANCE OF CHROMIUM NITRIDES OBTAINED BY VACUUM GAS NITRIDING OF ELECTROLYTIC CHROMIUM DEPOSITED ON AISI H13 STEEL

    Directory of Open Access Journals (Sweden)

    H. Cifuentes

    2013-06-01

    Full Text Available In this scientific research paper, the microstructure and corrosion resistance of chromium nitrides obtained from a duplex treatment consisting of an electroplated hard chromium coating applied on a steel AISI H13 follow by a thermochemical treatment in vacuum using NH3 as precursor gas of nitrogen, is evaluated. This type of duplex treatments combine the benefits of each individual treatment in order to obtain, with this synergic effect, compounds type CrxN more economic than those obtained by other kind of treatments e.g. physical vapor deposition (PVD. The results obtained by X-Ray Diffraction (XRD indicate the surface and subsurface transformation of the electrolytic hard chromium coating by formation of CrN and Cr2N phases. Likewise, potentiodynamic polarization tests indicate an increase in corrosion resistance of such kind of compounds in comparison with the obtained results with electroplated hard chromium.

  9. Corrosion behavior of corrosion resistant alloys in stimulation acids

    Energy Technology Data Exchange (ETDEWEB)

    Cheldi, Tiziana [ENI E and P Division, 20097 San Donato Milanese Milano (Italy); Piccolo, Eugenio Lo; Scoppio, Lucrezia [Centro Sviluppo Materiali, via Castel Romano 100, 00128 Rome (Italy)

    2004-07-01

    In the oil and gas industry, selection of CRAs for downhole tubulars is generally based on resistance to corrosive species in the production environment containing CO{sub 2}, H{sub 2}S, chloride and in some case elemental sulphur. However, there are non-production environments to which these materials must also be resistant for either short term or prolonged duration; these environments include stimulation acids, brine and completion fluids. This paper reports the main results of a laboratory study performed to evaluate the corrosion and stress corrosion behaviour to the acidizing treatments of the most used CRAs for production tubing and casing. Laboratory tests were performed to simulate both 'active' and 'spent' acids operative phases, selecting various environmental conditions. The selected steel pipes were a low alloyed steel, martensitic, super-martensitic, duplex 22 Cr, superduplex 25 Cr and super-austenitic stainless steels (25 Cr 35 Ni). Results obtained in the 'active' acid environments over the temperature range of 100-140 deg. C, showed that the blend acids with HCl at high concentration and HCl + HF represented too much severe conditions, where preventing high general corrosion and heavy localised corrosion by inhibition package becomes very difficult, especially for duplex steel pipe, where, in some case, the specimens were completely dissolved into the solution. On the contrary, all steels pipes were successfully protected by inhibitor when organic acid solution (HCOOH + CH{sub 3}COOH) were used. Furthermore, different effectiveness on corrosion protection was showed by the tested inhibitors packages: e.g. in the 90% HCl at 12% + 10 CH{sub 3}COOH acid blend. In 'spent' acid environments, all steel pipes showed to be less susceptible to the localised and general corrosion attack. Moreover, no Sulphide Stress Corrosion Cracking (SSC) was observed. Only one super-austenitic stainless steel U-bend specimen showed

  10. Electrospun polystyrene fibres on TiO$_2$ nanostructured film to enhance the hydrophobicity and corrosion resistance of stainless steel substrates

    Indian Academy of Sciences (India)

    Azimirad R; Safa S

    2016-03-01

    A dual layer of dip-coated TiO$_2$ film (top layer) and electrospun polystyrene (bottom layer) was coated on stainless steel (SS) substrates. The morphological and structural studies were performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Their hydrophobicity and corrosion resistance were also investigated using contact angle (CA) and electrochemical corrosion tests in acidic and salt solutions, respectively. Contact angle results showed that the naturally hydrophilic TiO$_2$/SS sample (CA ∼ 66$^\\deg$) turned into a superhydrophic surface (CA ∼ 148$^\\deg$) when it was covered by polystyrene fibres (PS/TiO2/SS). This observation can be attributed to the intrinsic hydrophobicity of organic polystyrene fibres (due to their low surface energy) and also to the existence of trapped air bubbles between fibres. Electrochemical corrosion tests showed that the corrosion rate was substantially decreased by using a protective bilayer (PS/TiO$_2$) from 33 to 0.39 mV/y for bare SS sample and from 0.01 to 0.003 mV/y for PS/TiO$_2$/SS sample in 1 M salt and acidic solutions, respectively. The superhydrophobic protective layer forms an obstacle against ionic exchange interactions. Therefore, it slows down the breaking of the surface oxidic layer on the metal substrate and prevents the metallic surface underneath from further corrosion.

  11. 77 FR 27438 - Certain Corrosion-Resistant Carbon Steel Flat Products From Korea: Final Results of Expedited...

    Science.gov (United States)

    2012-05-10

    ..., plated, or coated with corrosion-resistant metals such as zinc, aluminum, or zinc-, aluminum-, nickel- or... nonmetallic substances in addition to the metallic coating, in coils (whether or not in successively... other nonmetallic substances in addition to the metallic coating. Excluded from the order are...

  12. 76 FR 55004 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary...

    Science.gov (United States)

    2011-09-06

    ... rectangular shape, either clad, plated, or coated with corrosion-resistant metals such as zinc, aluminum, or zinc-, aluminum-, nickel- or iron-based alloys, whether or not corrugated or painted, varnished or coated with plastics or other nonmetallic substances in addition to the metallic coating, in...

  13. 76 FR 15291 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2011-03-21

    ... rectangular shape, either clad, plated, or coated with corrosion-resistant metals such as zinc, aluminum, or zinc-, aluminum-, nickel- or iron-based alloys, whether or not corrugated or painted, varnished or coated with plastics or other nonmetallic substances in addition to the metallic coating, in...

  14. 75 FR 13490 - Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Notice of...

    Science.gov (United States)

    2010-03-22

    ... with corrosion-resistant metals such as zinc, aluminum, or zinc-, aluminum-, nickel- or iron-based... substances in addition to the metallic coating, in coils (whether or not in successively superimposed layers..., varnished or coated with plastics or other nonmetallic substances in addition to the metallic coating....

  15. 77 FR 14501 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2012-03-12

    ... coated with corrosion-resistant metals such as zinc, aluminum, or zinc-, aluminum-, nickel- or iron-based... substances in addition to the metallic coating, in coils (whether or not in successively superimposed layers..., varnished or coated with plastics or other nonmetallic substances in addition to the metallic coating....

  16. Surface treatment and corrosion behaviour of austenitic stainless steel biomaterial

    Science.gov (United States)

    Oravcová, M.; Palček, P.; Zatkalíková, V.; Tański, T.; Król, M.

    2017-02-01

    In this article results from corrosion behaviour of austenitic stainless steel AISI 316L after different surface treatments are published. “As received” surface and surface after grinding resulted in lower resistance to pitting corrosion in physiological solution than electrochemically polished in H3PO4+H2SO4+H2O. Electropolishing also improved the surface roughness in comparison with the “as received” surface. Deposition of Al2O3 nanometric ALD coating improves the corrosion resistance of stainless steel in chloride-containing environment by shifting the breakdown potential toward more positive values. This oxide coating not only improves the corrosion resistance but it also affects the wettability of the surface, resulting in hydrophobic surface.

  17. Fabrication of high nitrogen austenitic stainless steels with excellent mechanical and pitting corrosion properties

    Institute of Scientific and Technical Information of China (English)

    Hua-bing Li; Zhou-hua Jiang; Yang Cao; Zu-rui Zhang

    2009-01-01

    18Cr18Mn2Mo0.9N high nitrogen austenitic stainless steel exhibits high strength and good ductility at room temperature. The steel shows typical duc-tile-brittle transition behavior and excellent pitting corrosion resistance properties.

  18. THE EFFECT OF DEPOSITION PARAMETERS ON THE CHEMICAL COMPOSITION AND CORROSION RESISTANCE OF TICXNY COATINGS PRODUCED ON HIGH-SPEED STEEL SUBSTRATES

    Directory of Open Access Journals (Sweden)

    Senna L.F.

    2001-01-01

    Full Text Available TiCxNy coatings deposited on high-speed steel substrates have been used to enhance the tribological properties of cutting tools (hardness, wear resistance, etc. as well as their corrosion resistance in an aggressive environment. These layers are usually produced by plasma deposition techniques (PVD or CVD, and different coating properties can be obtained with each method. In this work, TiCxNy films were deposited on AISI M2 high-speed steel substrates by the reactive magnetron sputtering technique. A series of samples with a variety of reactive gas mixtures (nitrogen and methane, substrate biases, and deposition temperatures was produced. As a result, coatings with different chemical compositions were deposited for each group of deposition parameters. Gas mixture composition and substrate bias directly affected the chemical composition of the coating, while deposition temperature influenced the chemical composition of TiCxNy layers to a very low extent.

  19. Effect of a nano-sized TiC particle addition on the flow-assisted corrosion resistance of SA 106B carbon steel

    Science.gov (United States)

    Park, Jin-Ju; Park, Eun-Kwang; Lee, Gyoung-Ja; Rhee, Chang-Kyu; Lee, Min-Ku

    2017-09-01

    Carbon steel with dispersed nano-sized TiC ceramic particles was fabricated by the ex-situ introduction of the particles into the melt, with the flow-assisted corrosion (FAC) resistance then investigated in the presence and absence of TiC nanoparticles using a once-through type of FAC loop test. From the potentiodynamic polarization curves, the current density at any given anodic potential was decreased and the open-circuit potential was increased by the addition of TiC nanoparticles. In addition, when the nano-sized TiC particles were added, the FAC rate was 1.38 times lower than that of carbon steel without TiC nanoparticles, indicating an improvement of the FAC resistance due to the homogeneous distribution of the TiC reinforcing nanoparticles.

  20. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  1. Prevention of corrosion in prestressing steels

    NARCIS (Netherlands)

    Polder, R.B.

    1996-01-01

    Corrosion of prestressing steel may lead to sudden, so called brittle failure, due to the special microstructure of the steel and the high tensile forces. Such brittle failure may seriously reduce the load capacity of a prestressed concrete structure. In principle all stressed high strength steel is

  2. Effect of heat treatment on the stress corrosion resistance of a microalloyed pipeline steel

    Energy Technology Data Exchange (ETDEWEB)

    Albarran, J.L. [UNAM, Inst. de Fisica, Cuernavaca (Mexico); Martinez, L. [UNAM, Inst. de Fisica, Cuernavaca (Mexico)]|[U.A.C., Programa de Corrosion del Golfo de Mexico (Mexico); Lopez, H.F. [Wisconsin Univ., Materials Dept., Milwaukee, WI (United States)

    1999-11-01

    In this work, the effect of heat treating on a pipeline steel exposed to a sulfide stress cracking (SSC) environment was investigated using LEFM compact specimens. In the as-received condition, specimens with crack orientations parallel and normal to the rolling direction were exposed to H{sub 2}S saturated synthetic sea water at an applied stress intensity (K{sub 1}) of 30 MPa{center_dot}m{sup 1/2}. In both cases, crack propagation rates were very close to each other (da/dt = 8.77 x 10{sup -9}m/s). as the microstructure was modified by heat treating, the rates of crack growth exhibited appreciable differences under similar applied stress intensities. In the martensitic (as-quenched) condition, crack growth was relatively fast (da/dt = 4.72 x 10{sup -7}m/s) indicating severe hydrogen embrittlement. In the water sprayed, and in the quenched and tempered conditions, the LEFM specimens exhibited crack arrest events. This, in turn, enabled the determination of threshold stress intensity values (K{sub issc}) for the water sprayed, and for the quenched and tempered conditions of 26 and 32 MPa{center_dot}m{sup 1/2}, respectively. In addition, favourable paths for microcrack growth were found to be provided by globular inclusions and grain boundary precipitates. (Author)

  3. Investigation of Fecraly Coating on Corrosion Behaviour of Mild Steel

    Directory of Open Access Journals (Sweden)

    Joseph B. AGBOOLA

    2009-07-01

    Full Text Available Steel has found wide application in hot rolling equipments in the steel industry and the oil rig structures in sea water. These equipments are frequently subjected to corrosive and temperature condition which causes severe damage to them, hence the need to develop steel suitable to withstand these conditions in terms of surface treatment. This research work investigates the effect of FeCrAlY coating on mild steel under high temperature and aggressive environment. Iron based coatings are used due to low cost among other properties such as good corrosion resistance, ease of machining and high ductility when compared to hard metals.Thermal spraying of the specimens was carried out using high velocity oxygen fuel (HVOF. Corrosion test was carried out on both coated and uncoated samples. All samples were subjected to the same high temperature treatment for oxidation test.

  4. Development of novel protective high temperature coatings on heat exchanger steels and their corrosion resistance in simulated coal firing environment; Developpement de revetements pour les aciers d'echangeurs thermiques et amelioration de leur resistance a la corrosion en environnement simulant les fumees de combustion et de charbon

    Energy Technology Data Exchange (ETDEWEB)

    Rohr, V.

    2005-10-15

    Improving the efficiencies of thermal power plants requires an increase of the operating temperatures and thus of the corrosion resistance of heat exchanger materials. Therefore, the present study aimed at developing protective coatings using the pack cementation process. Two types of heat exchanger steels were investigated: a 17% Cr-13% Ni austenitic steel and three ferritic-martensitic steels with 9 (P91 and P92) and 12% Cr (HCM12A). The austenitic steel was successfully aluminized at 950 C. For the ferritic-martensitic steels, the pack cementation temperature was decreased down to 650 C, in order to maintain their initial microstructure. Two types of aluminides, made of Fe{sub 2}Al{sub 5} and FeAl, were developed. A mechanism of the coating formation at low temperature is proposed. Furthermore, combining the pack cementation with the conventional heat treatment of P91 allowed to take benefit of higher temperatures for the deposition of a two-step Cr+Al coating. The corrosion resistance of coated and uncoated steels is compared in simulated coal firing environment for durations up to 2000 h between 650 and 700 C. It is shown that the coatings offer a significant corrosion protection and, thus, an increase of the component lifetime. Finally, the performance of coated 9-12% Cr steels is no longer limited by corrosion but by interdiffusion between the coating and the substrate. (author)

  5. Use of cyclic current reversal polarization voltammetry for investigating the relationship between corrosion resistance and heat-treatment induced variations in microstructures of 400 C martensitic stainless steels

    Science.gov (United States)

    Ambrose, John R.

    1992-01-01

    Software for running a cyclic current reversal polarization voltammagram has been developed for use with a EG&G Princeton Applied Research Model 273 potentiostat/galvanostat system. The program, which controls the magnitude, direction and duration of an impressed galvanostatic current, will produce data in ASCII spreadsheets (Lotus, Quattro) for graphical representation of CCRPV voltammograms. The program was used to determine differences in corrosion resistance of 440 C martenstic stainless steel produced as a result of changes in microstructure effected by tempering. It was determined that tempering at all temperatures above 400 F resulted in increased polarizability of the material, with the increased likelihood that pitting would be initiated upon exposure to marine environments. These results will be used in development of remedial procedures for lowering the susceptibility of these alloys toward the stress corrosion cracking experienced in bearings used in high pressure oxygen turbopumps used in the main engines of space shuttle orbiters.

  6. Effect of surface passivation on corrosion resistance and antibacterial properties of Cu-bearing 316L stainless steel

    Science.gov (United States)

    Zhao, Jinlong; Xu, Dake; Shahzad, M. Babar; Kang, Qiang; Sun, Ying; Sun, Ziqing; Zhang, Shuyuan; Ren, Ling; Yang, Chunguang; Yang, Ke

    2016-11-01

    The resistance for pitting corrosion, passive film stability and antibacterial performance of 316L-Cu SS passivated by nitric acid solution containing certain concentration of copper sulfate, were studied by electrochemical cyclic polarization, electrochemical impedance spectroscopy (EIS) and co-culture with bacteria. Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze the Cu2+ ions release from 316L-Cu SS surface. XPS analysis proved that the enrichment of CuO, Cr2O3 and Cr(OH)3 on the surface of specimen could simultaneously guarantee a better corrosion resistance and stable antibacterial properties. The biocompatibility evaluation determined by RTCA assay also indicated that the 316L-Cu SS after antibacterial passivation was completely biocompatible.

  7. The Effect of La on the Microstructure and Corrosion-resistance of Hot-dipped Aluminizing Steel

    Institute of Scientific and Technical Information of China (English)

    WENJiu-ba; ZHANGWei; LIXiao-yuan; LIQuan-an

    2004-01-01

    The effect of the content of rare-earth La on the microstructure and corrosion-resistance of hot-dipped aluminum was investigated in this paper. The results show that, under the same technology conditions, the thickness of hot-dipped aluminizing layer by adding the appropriate content of rare-earth La is about 2-3 times as much as that without rare-earth La, and the microstructure of hot-dipped aluminizing layer has also greatly changed ,and a great deal of phase Fe3A1 waspreci pitated along the boundary of a phase. The corrosion resistance of the hot-dipped layer with rare-earth is greatly increased.

  8. The Effect of La on the Microstructure and Corrosion-resistance of Hot-dipped Aluminizing Steel

    Institute of Scientific and Technical Information of China (English)

    WEN Jiu-ba; ZHANG Wei; LI Xiao-yuan; LI Quan-an

    2004-01-01

    The effect of the content of rare-earth La on the microstructure and corrosion-resistance of hot-dipped aluminum was investigated in this paper. The results show that, under the same technology conditions, the thickness of hot-dipped aluminizing layer by adding the appropriate content of rare-earth La is about 2~3 times as much as that without rare-earth La, and the microstructure of hot-dipped aluminizing layer has also greatly changed ,and a great deal of phase Fe3Al was precipitated along the boundary of α phase. The corrosion resistance of the hot-dipped layer with rare-earth is greatly increased.

  9. Localized Corrosion of Chromium Coated Steel

    NARCIS (Netherlands)

    Zhang, X.; Beentjes, P.; Mol, A.; Terryn, H.

    2006-01-01

    In this paper, we report on the studies of the local corrosion behaviour of chromium-coated ultra low carbon steel in NaCl solution using polarization, electrochemical impedance spectroscopy (EIS) and SVET.

  10. Corrosion behaviour of sintered duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Utrilla, M. Victoria; Urena, Alejandro; Otero, Enrique; Munez, Claudio Jose [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, C/ Tulipan s/n, 28933 Mostoles, Madrid (Spain)

    2004-07-01

    Duplex austenite-ferrite stainless steels were prepared by mixing austenitic (316L) and ferritic (434L) atomized powders. Although different 316L/434L ratios were prepared, present work centred its study on 50% ferrite - 50% austenite sintered steel. The powders were mixed and pressed at 700 MPa and sintered at 1250 deg. C for 30 min in vacuum. The cooling rate was 5 deg. C/min. Solution treatment was carried out to homogenize the microstructure at 1100 deg. C during 20 min. A microstructural study of the material in solution was performed, evaluating the microstructure, proportion and shape of porosity, and ferrite percentage. This last was measured by two methods, quantitative metallography and Fischer ferrito-metry. The materials were heat treated in the range of 700 to 1000 deg. C, for 10, 30 and 60 min and water quenched, to study the microstructural changes and the influence on the intergranular corrosion resistance. The method used to evaluate the sensitization to the intergranular corrosion was the electrochemical potentio-kinetic reactivation procedure (EPR). The test solution was 0.5 M H{sub 2}SO{sub 4} + 0,01 M KSCN at 30 deg. C. The criterion used to evaluate the sensitization was the ratio between the maximum reactivation density (Ir) and the maximum activation density (Ia). The results of the electrochemical tests were discussed in relation with the microstructures observed at the different heat treatments. (authors)

  11. Research on Aluminized Steel for Resisting Stress Corrosion Cracking and Hydrogen Embrittlement%渗铝钢抗应力腐蚀开裂及抗氢脆性能研究

    Institute of Scientific and Technical Information of China (English)

    吴昊; 李华飞

    2016-01-01

    以30CrMo钢为母体,对30CrMo钢及其渗铝钢分别进行抗硫化氢应力腐蚀开裂实验、抗氯离子应力腐蚀开裂实验,采用Devanathan双电池技术测量氢的扩散系数。实验结果表明:30CrMo钢渗铝后比渗铝前具有更好的抗硫化氢应力腐蚀开裂、抗氢脆性能;单一氯离子对30CrMo钢及其渗铝钢应力腐蚀开裂性能影响较小。%Using 30CrMo steel as the matrix, resistance to hydrogen sulfide stress corrosion cracking test and resistance to chloride ion stress corrosion cracking test were carried out respectively for 30CrMo steel and its aluminized steel.Using Devanathan double cell technology, and we measured hydrogen diffusion coefficient.Experimental results show that, aluminized steel of 30CrMo has better resistance to hydrogen sulfide stress corrosion cracking and hy-drogen embrittlement, and single chloride ion has little influence on the stress corrosion cracking for 30CrMo steel and its aluminized steel.

  12. Microstructure and corrosion resistance of Fe-Al intermetallic coating on 45 steel synthesized by double glow plasma surface alloying technology

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiao-lin; YAO Zheng-jun; GU Xue-dong; CONG Wei; ZHANG Ping-ze

    2009-01-01

    A binary Fe-Al alloyed layer was synthesized on 45 steel by means of double glow plasma surface alloying technique. The corrosion-resisting layer prepared is composed of a sedimentary layer and a diffusion layer, with a total thickness of about 180 μm. The aluminum content of the alloyed layer shows gradual change from surface to the inside of substrate. The ideal profile is beneficial to the metallurgical bonding of the surface alloying layer with substrate materials. The microstructure of both layers consists of the Fe-Al intermetallic compound, which is FeAl with B2 structure in the sedimentary layer and Fe3Al with incompletely ordered DO3 structure in the diffusion layer. The protective film exhibits high micro-hardness. In comparison with the substrate of 45 steel, the corrosion resistance of the aluminized sample is much higher in 2.0% Na2S and 0.05 mol/L Na2SO4 + 0.5 mol/L NaCl mixed solutions.

  13. Investigation of corrosion of welded joints of austenitic and duplex stainless steels

    Science.gov (United States)

    Topolska, S.

    2016-08-01

    Investigation of corrosion resistance of materials is one of the most important tests that allow determining their functional properties. Among these tests the special group consist electrochemical investigations, which let to accelerate the course of the process. These investigations allow rapidly estimating corrosion processes occurring in metal elements under the influence of the analysed environment. In the paper are presented results of investigations of the resistance to pitting corrosion of the steel of next grades: austenitic 316L and duplex 2205. It was also analysed the corrosion resistance of welded joints of these grades of steel. The investigations were conducted in two different corrosion environments: in the neutral one (3.5 % sodium chloride) and in the aggressive one (0.1 M sulphuric acid VI). The obtained results indicate different resistance of analysed grades of steel and their welded joints in relation to the corrosion environment. The austenitic 316L steel characterizes by the higher resistance to the pitting corrosion in the aggressive environment then the duplex 2205 steel. In the paper are presented results of potentiodynamic tests. They showed that all the specimens are less resistant to pitting corrosion in the environment of sulphuric acid (VI) than in the sodium chloride one. The 2205 steel has higher corrosion resistance than the 316L stainless steel in 3.5% NaCl. On the other hand, in 0.1 M H2SO4, the 316L steel has a higher corrosion resistance than the 2205 one. The weld has a similar, very good resistance to pitting corrosion like both steels.

  14. Corrosion Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

    In this paper the corrosion properties of laser welded AISI 316L stainless steel are examined. A number of different welds has been performed to test the influence of the weld parameters of the resulting corrosion properties. It has been chosen to use the potential independent critical pitting...... temperature (CPT) test as corrosion test. The following welding parameters are varied: Welding speed, lsser power, focus point position and laser operation mode (CW or pulsed)....

  15. Friction welding of a nickel free high nitrogen steel: influence of forge force on microstructure, mechanical properties and pitting corrosion resistance

    Directory of Open Access Journals (Sweden)

    Mrityunjoy Hazra

    2014-01-01

    Full Text Available In the present work, nickel free high nitrogen austenitic stainless steel specimens were joined by continuous drive friction welding process by varying the amount of forge (upsetting force and keeping other friction welding parameters such as friction force, burn-off, upset time and speed of rotation as constant at appropriate levels. The joint characterization studies include microstructural examination and evaluation of mechanical (micro-hardness, impact toughness and tensile and pitting corrosion behaviour. The integrity of the joint, as determined by the optical microscopy was very high and no crack and area of incomplete bonding were observed. Welds exhibited poor Charpy impact toughness than the parent material. Toughness for friction weld specimens decreased with increase in forge force. The tensile properties of all the welds were almost the same (irrespective of the value of the applied forge force and inferior to those of the parent material. The joints failed in the weld region for all the weld specimens. Weldments exhibited lower pitting corrosion resistance than the parent material and the corrosion resistance of the weld specimens was found to decrease with increase in forge force.

  16. Development of an aluminized multi-phase steel with dual phase properties for high temperature corrosion resistance applications

    Energy Technology Data Exchange (ETDEWEB)

    Mahieu, J.; Cooman, B.C. de [Lab. for Iron and Steelmaking, Dept. of Metallurgy and Materials Science, Ghent Univ., Zwijnaarde (Belgium); Maki, J. [Yawata R and D Lab., Nippon Steel Corp. (Japan); Fiorucci, M. [Galvalange Sarl, Dudelange (Luxembourg); Claessens, S. [OCAS NV, Zelzate (Belgium)

    2003-04-01

    A high strength, high Mn, Cr-Mo containing multi-phase steel grade was aluminized with a 90 wt% Al-10 wt% Si alloy coating, using a laboratory hot-dip simulator. The adhesion of the coating to the steel strip was evaluated and the microstructure of the as deposited material was assessed. The coated sheet steel was tested at high temperatures by monitoring the weight gain of the samples and their mechanical properties as a function of time. It was found that the thermal properties of the aluminized sheet were excellent. The analysis of the coating/substrate interface revealed the dissolution of brittle intermetallic phases, explaining the excellent high temperature resistance performance of the Al-Si coating up to temperatures as high as 900 C. In addition, the use of a continuous annealing cycle common in current aluminizing lines, resulted in a dual phase microstructure. (orig.)

  17. Demonstration and Validation of Stainless Steel Materials for Critical Above Grade Piping in Highly Corrosive Locations

    Science.gov (United States)

    2017-05-01

    Prepared for Office of the Secretary of Defense (OUSD(AT&L)) Washington, DC 20301-3090 Under Project F07-AR15, “ Advanced Corrosion-Resistant Steel for...world for steel infrastruc- ture . Highly corroded carbon steel pipes at the site were replaced with two grades of stainless steel, and minor corrosion...mitigation modifications were made to pipe supports. After the rehabilitated system was commis- sioned, the pipes were inspected and tested according

  18. Improved Corrosion Resistance of Pulse Plated Nickel through Crystallisation Control

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Watanabe, Tohru; Andersen, Jens Enevold Thaulov

    1995-01-01

    When electrodeposition of nickel is used for corrosion protection of steel two aspects are important. The porosity of the coating and the resistance against corrosion provided by the coating itself. Using simple pulsed current (PC) plating, the size of the deposited crystals can be significantly...... smaller, thereby reducing porosity correspondingly. This usually also leads to improved hardness of the coating. Introducing pulse reversal (PR) plating, the most active crystals are continuously dissolved during the anodic pulse, providing a coating with improved subsequent corrosion resistance in almost...... any corrosive environment. This correlation between film texture and corrosion resistance will be discussed....

  19. Improved Corrosion Resistance of Pulse Plated Nickel through Crystallisation Control

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Watanabe, Tohru; Andersen, Jens Enevold Thaulov

    1995-01-01

    When electrodeposition of nickel is used for corrosion protection of steel two aspects are important. The porosity of the coating and the resistance against corrosion provided by the coating itself. Using simple pulsed current (PC) plating, the size of the deposited crystals can be significantly...... smaller, thereby reducing porosity correspondingly. This usually also leads to improved hardness of the coating. Introducing pulse reversal (PR) plating, the most active crystals are continuously dissolved during the anodic pulse, providing a coating with improved subsequent corrosion resistance in almost...... any corrosive environment. This correlation between film texture and corrosion resistance will be discussed....

  20. Effect of hot dip galvanized coating on the corrosion resistance of the external surface of reinforcement steel

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, Oezlem; Topuz, Polat [Gedik University Vocational School, Istanbul (Turkey)

    2016-02-01

    Studies have been carried out to investigate the performance of hot dip galvanized coating on reinforcement corrosion. The coated and uncoated concrete specimens were subjected to accelerated corrosion to determine the time to corrosion initiation. The accelerated corrosion test results clearly showed that the specimens with hot dip galvanized coatings performed very well against reinforcement corrosion and were better than uncoated specimens.

  1. Marine atmospheric corrosion of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Morcillo, M.; Alcantara, J.; Diaz, I.; Chico, B.; Simancas, J.; Fuente, D. de la

    2015-07-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products formed; (c) corrosion mechanisms of carbon steel in marine atmospheres; (d) exfoliation of rust layers formed in highly aggressive marine atmospheres; (e) long-term corrosion rate prediction; and (f) behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camarinas, Galicia) in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM)/energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Mossbauer spectroscopy and SEM/μRaman spectroscopy. (Author)

  2. Polymeric nano-materials for corrosion control of steel in concrete

    NARCIS (Netherlands)

    Varini, M.; Koleva, D.A.; Denkova, A.G.; Mol, J.M.C.; Terryn, H.; Van Breugel, K.

    2013-01-01

    Polymeric nano-materials utilization in reinforced concrete, aiming to deal with steel corrosion was developed in previous works. Promising results were obtained with PEO–b–PS nano-formations, both in terms of enhanced bulk matrix properties and improved steel corrosion resistance. Recent research h

  3. Corrosion And Thermal Processing In Cold Gas Dynamic Spray Deposited Austenitic Stainless Steel Coatings

    Science.gov (United States)

    2016-06-01

    testing cell . Source: [56]. ............................................................................................................68  Figure 36...for galvanic corrosion [26]. This is shown schematically in Figure 3. 7 Figure 3. Schematic mechanism of pitting corrosion. Source: [29]. The...here is corrosion resistance. The chromium carbide precipitate can form a galvanic couple with the surrounding steel and the depletion of chromium in

  4. Corrosion performance of martensitic stainless steel seamless pipe for linepipe application

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Mitsuo; Miyata, Yukio; Toyooka, Takaaki; Murase, Fumio [Kawasaki Steel Corp., Handa, Aichi (Japan)

    1999-11-01

    The corrosion performance of two types of weldable martensitic stainless steel seamless pipe for pipeline application is investigated. 11Cr steel pipe developed for sweet environment gives better resistance to CO{sub 2} corrosion than the 13Cr martensitic stainless steel for OCTG. 12Cr steel pipe developed for light sour environment shows good SSC resistance in a mild sour environment and superior CO{sub 2} corrosion resistance at high temperature and high CO{sub 2} partial pressure condition. The suitable condition for the 11Cr steel pipe and the 12Cr steel pipe in sweet environment, and the critical pH and H{sub 2}S partial pressure for the 12Cr steel pipe welded joint in sour environment are clarified. Both welded joints have superior resistance to hydrogen embrittlement under the cathodic protection condition in sea water.

  5. Corrosion-resistant metallic coatings

    OpenAIRE

    F. Presuel-Moreno; M.A. Jakab; N. Tailleart; Goldman, M.; J. R. Scully

    2008-01-01

    We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned) to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic i...

  6. Corrosion Behaviors of PI 10 Steel and Chromium Coating in CO2-saturated Simulated Oilfield Brine

    Institute of Scientific and Technical Information of China (English)

    LIN Naiming; XIE Faqin; ZHOU Jun; WU Xiangqing; TIAN Wei

    2011-01-01

    The protective chromium coating was prepared on P110 steel by employing pack cementation. The corrosion behaviors of P110 steel and the obtained coating in CO2-saturated simulated oilfield brine were studied by static complete immersion tests and electrochemical measurements.The corrosion attacks of the samples were determined by mass loss, corroded surface morphologies,corrosion products, and results of electrochemical measurements. The experimental results showed that the coating was uniform, continuous and compact. The chromium coating was slightly corroded,and the mass loss and corrosion rate of the coating were far lower than those of P110 steel. Chromium coating has higher self-corroding potential and lower corrosion current density than P110 steel in accordance with the electrochemical tests results. Taken as a whole, chromizing treatment has significantly improved the corrosion resistance of P110 steel.

  7. Crevice and pitting corrosion behavior of stainless steels in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Zaragoza-Ayala, A.E.; Orozco-Cruz, R. [Univ. Autonoma de Campeche (Mexico). Programa de Corrosion del Golfo de Mexico

    1999-11-01

    Pitting and crevice corrosion tests in natural seawater were performed on a series of stainless steels (i.e., S31603, N08904, S32304, S31803, S32520, N08925 and S31266) in order to determine their resistance to these types of localized corrosion. Open circuit potential (OCP) measurements for these alloys show for short exposure times an ennoblement in the OCP. After a certain time, occasional fall and rise in the OCP values was observed, which can be related to nucleation and repassivation of pits and/or crevices on the metal surface. Analysis of the electrochemical behavior and microscopic observations shows that only S31603 and S32304 alloys were susceptible to crevice and pitting corrosion, whereas the remaining alloys exhibited good resistance. Pitting potentials determined by the potentiodynamic technique also show S3 1603 and S32304 are susceptible to pitting corrosion under the experimental conditions used in this work.

  8. Corrosion of steel structures in sea-bed sediment

    Indian Academy of Sciences (India)

    Xiutong Wang; Jizhou Duan; Yan Li; Jie Zhang; Shide Ma; Baorong Hou

    2005-04-01

    Seabed sediment (SBS) is a special soil that is covered by seawater. With the developments in marine oil exploitation and engineering, more and more steel structures have been buried in SBS. SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this paper, approach in the field of SBS corrosion is reviewed. Electrochemical and microbial corrosion factors, corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and prediction of corrosion are also discussed here.

  9. Pitting corrosion and crevice corrosion behaviors of high nitrogen austenitic stainless steels

    Institute of Scientific and Technical Information of China (English)

    Hua-bing Li; Zhou-hua Jiang; Yan Yang; Yang Cao; Zu-rui Zhang

    2009-01-01

    Pitting corrosion and crevice corrosion behaviors of high nitrogen austenitic stainless steels (HNSS) were investigated by electrochemical and immersion testing methods in chloride solution, respectively. The chemical constitution and composition in the depth of passive films formed on HNSS were analyzed by X-ray photoelectron spectrum (XPS). HNSS has excellent pitting and crevice corrosion resistance compared to 316L stainless steel. With increasing the nitrogen content in steels, pitting potentials and critical pitting temperature (CPT) increase, and the maximum, average pit depths and average weight loss decrease. The CPT of HNSS is correlated with the alloying element content through the measure of alloying for resistance to corrosion (MARC). The MARC can be expressed as an equation of CPT=2.55MARC-29. XPS results show that HNSS exhibiting excellent corrosion resis-tance is attributed to the enrichment of nitrogen on the surface of passive films, which forms ammonium ions increasing the local pH value and facilitating repassivation, and the synergistic effects of molybdenum and nitrogen.

  10. Coating Prospects in Corrosion Prevention of Aluminized Steel and Its Coupling with Magnesium

    Science.gov (United States)

    Sun, Fuyan

    In this study, a plasma electrolytic oxidation (PEO) process was used to form oxide coating on aluminized steel, heated aluminized steel and magnesium. A potentiodynamic polarization corrosion test was employed to investigate the general corrosion properties. Galvanic corrosion of steel samples and magnesium samples was studied by zero resistance ammeter (ZRA) tests and boiling tests. Scanning electron microscopy (SEM) and EDS were used to investigate the coating microstructure and the coating/substrate interface. In general, the PEO coatings on all three substrate can help prevent general corrosion. 6-min coated magnesium with unipolar current mode performs best in most galvanic couplings for preventing both general corrosion and galvanic corrosion. Factors which could influence galvanic corrosion behaviors of tested samples were discussed based on area ratios of anode/cathode and cell potential driving force during the ZRA corrosion tests and boiling tests.

  11. Study of corrosion resistance of AISI 444 ferritic stainless steel for application as a biomaterial; Estudo da resistencia a corrosao do aco inoxidavel ferritico AISI 444 para aplicacao como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Rogerio Albuquerque

    2014-09-01

    Ferritic stainless steels are ferromagnetic materials. This property does not allow their use in orthopedic prosthesis. Nevertheless, in some specific applications, this characteristic is very useful, such as, for fixing dental and facial prostheses by using magnetic attachments. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and Ti and Nb stabilizers, were investigated for magnetic dental attachments application. The ISO 5832-1 (ASTM F-139) austenitic stainless steel and a commercial universal keeper for dental attachment (Neo-magnet System) were evaluated for comparison reasons. The first stainless steel is the most used metallic material for prostheses, and the second one, is a ferromagnetic keeper for dental prostheses (NeoM). In vitro cytotoxicity analysis was performed by the red neutral incorporation method. The results showed that the AISI 444 stainless steel is non cytotoxic. The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. The highest susceptibility to pitting corrosion was associated to the NeoM SS. This steel was also associated to the highest dopant concentration. The comparatively low levels of chromium (nearly 12.5%) and molybdenum (0.3%) of NeoM relatively to the other studied stainless steels are the probable cause of its lower corrosion resistance. The NeoM chemical composition does not match that of the SUS444 standards. The AISI 444 SS pitting resistance was equivalent to the ISO 5832-1 pointing out that it is a potential candidate for replacement of commercial ferromagnetic alloys used

  12. Stainless steel corrosion scale formed in reclaimed water: Characteristics, model for scale growth and metal element release.

    Science.gov (United States)

    Cui, Yong; Liu, Shuming; Smith, Kate; Hu, Hongying; Tang, Fusheng; Li, Yuhong; Yu, Kanghua

    2016-10-01

    Stainless steels generally have extremely good corrosion resistance, but are still susceptible to pitting corrosion. As a result, corrosion scales can form on the surface of stainless steel after extended exposure to aggressive aqueous environments. Corrosion scales play an important role in affecting water quality. These research results showed that interior regions of stainless steel corrosion scales have a high percentage of chromium phases. We reveal the morphology, micro-structure and physicochemical characteristics of stainless steel corrosion scales. Stainless steel corrosion scale is identified as a podiform chromite deposit according to these characteristics, which is unlike deposit formed during iron corrosion. A conceptual model to explain the formation and growth of stainless steel corrosion scale is proposed based on its composition and structure. The scale growth process involves pitting corrosion on the stainless steel surface and the consecutive generation and homogeneous deposition of corrosion products, which is governed by a series of chemical and electrochemical reactions. This model shows the role of corrosion scales in the mechanism of iron and chromium release from pitting corroded stainless steel materials. The formation of corrosion scale is strongly related to water quality parameters. The presence of HClO results in higher ferric content inside the scales. Cl(-) and SO4(2-) ions in reclaimed water play an important role in corrosion pitting of stainless steel and promote the formation of scales. Copyright © 2016. Published by Elsevier B.V.

  13. Effects of cold working on the pitting corrosion behavior s of AISI 304 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kee Min; Kim, Jong Soo; Kim, Young Jun; Kwon, Houk Sang [KAIST, Daejon (Korea, Republic of)

    2015-12-15

    These microstructural changes by cold working can lead improvement of mechanical properties, however from a corrosion resistant point of view, the effects of cold working on the corrosion resistance of stainless steel have been argued. Several studies has been focused on the influence of cold working on the localized corrosion resistance of stainless steels. However, the opinions about the role of cold working on the localized corrosion resistance are highly in consistence. Some studies report that the pitting potential of austenitic stainless steels decreased with cold working level, on the other hands, other studies claimed that the pitting resistance was increased by cold working. Therefore it is necessary to verify how cold working affects pitting corrosion behavior of austenitic stainless steels. In the present work, the influence of cold working on the localized corrosion of AISI 304stainless steel in the neutral chloride solution was studied based on point defect model (PDM). The fraction of deformation-induced martensite was linearly increased with cold rolling level. Through cold rolling, the pitting potential was decreased, the metastable pitting event density was significantly increased and the repassivation potential was decreased. The overall localized corrosion resistance was decreased with cold working, however cold working level increased from 30 % to 50 %, localized corrosion resistance was recovered. The accumulated cation vacancy generates a void at metal/film interface, therefore film breakdown accelerates for cold worked alloys.

  14. Studies on the corrosion resistance of reinforced steel in concrete with ground granulated blast-furnace slag--An overview.

    Science.gov (United States)

    Song, Ha-Won; Saraswathy, Velu

    2006-11-16

    The partial replacement of clinker, the main constituent of ordinary Portland cement by pozzolanic or latent hydraulic industrial by-products such as ground granulated blast furnace slag (GGBFS), effectively lowers the cost of cement by saving energy in the production process. It also reduces CO2 emissions from the cement plant and offers a low priced solution to the environmental problem of depositing industrial wastes. The utilization of GGBFS as partial replacement of Portland cement takes advantage of economic, technical and environmental benefits of this material. Recently offshore, coastal and marine concrete structures were constructed using GGBFS concrete because high volume of GGBFS can contribute to the reduction of chloride ingress. In this paper, the influence of using GGBFS in reinforced concrete structures from the durability aspects such as chloride ingress and corrosion resistance, long term durability, microstructure and porosity of GGBFS concrete has been reviewed and discussed.

  15. CORROSION RESISTANCE OF SHIPBUIDING STEELS IN MARINE ATMOSPHERE%船板钢耐海洋大气腐蚀性能研究

    Institute of Scientific and Technical Information of China (English)

    贾月彩; 牛见青; 刘东升

    2013-01-01

    采用周浸加速腐蚀试验技术,结合电子探针以及XRD物相定量分析等手段对比研究了船板钢F690、F460和普通Q235B C-Mn钢在模拟海洋大气环境中(3.5wt% NaC1水溶液)的耐腐蚀性能.结果表明,F690钢形成的锈层表面平整,除锈后未发现明显的点蚀坑存在,内外锈层分明,锈层较致密,且在内锈层中检测到Cr和Mo的明显富集,其年腐蚀速率也相对较低.F460钢锈层中也观测到少量的Cr元素的富集.Q235B的锈层疏松,内外锈层没有明显分界.船板钢锈层都是由α-FeOOH、β-FeOOH、γ-FeOOH和Fe3O4组成的.F690钢中物相α-CrxFe1-xOOH含量较多,Mo分布于内锈层的裂纹处,使内锈层更加致密.%The corrosion resistances of F690, F460 and Q235B steels in simulated marine atmosphere were investigated by means of accelerated cyclic immersion test, electron probe and phase quantitative analysis of XRD. The results indicated that F690 steel formed flat rust surface, obvious outer and inner compact rust layers, enriched Cr and Mo detected in inner rust layers and no obvious pitting corrosion on the substrate after removing the rust. Enriched Cr was also found in the rust layers of F460. The Q235B steel showed loose rust layers and no clear boundary between inner and outer layers. The rust layers of shipbuilding steels consisted of α-FeOOH, β-FeOOH, γ-FeOOH and Fe3O4. The rust had more α-CrxFe1-xOOH phase and Mo was distributed at the cracks of inner rust layers for the F690 steel, resulting in more compact inner rust layers.

  16. Corrosion fatigue behaviour of 317LN austenitic stainless steel in phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Onoro, J. [Ingenieria y Ciencia de los Materiales, ETSI Industriales, Universidad Politecnica de Madrid, c/Jose Gutierrez Abascal, 2, 28006 Madrid (Spain)], E-mail: javier.onoro@upm.es

    2009-10-15

    The corrosion fatigue crack-growth behaviour of AISI 317LN stainless steel was evaluated in air and in 85% phosphoric acid at 20 deg. C. Austenitic stainless steels with high molybdenum content have high corrosion resistance and good mechanical properties. However, this increase in the molybdenum content and other elements such as nitrogen can also modify the microstructure. This leads to a modification of its mechanical properties. The corrosion fatigue crack-growth rate was higher in phosphoric acid immersion than in air. Austenitic stainless steels with a fully austenitic microstructure were more ductile, tough, and behave better against corrosion fatigue. The higher resistance to corrosion fatigue was directly associated to its higher resistance to corrosion.

  17. Corrosion resistance of stainless steel, nickel-titanium, titanium molybdenum alloy, and ion-implanted titanium molybdenum alloy archwires in acidic fluoride-containing artificial saliva: An in vitro study

    Directory of Open Access Journals (Sweden)

    Venith Jojee Pulikkottil

    2016-01-01

    Full Text Available Objective: (1 To evaluate the corrosion resistance of four different orthodontic archwires and to determine the effect of 0.5% NaF (simulating high fluoride-containing toothpaste of about 2250 ppm on corrosion resistance of these archwires. (2 To assess whether surface roughness (Ra is the primary factor influencing the corrosion resistance of these archwires. Materials and Methods: Four different archwires (stainless steel [SS], nickel-titanium [NiTi], titanium molybdenum alloy [TMA], and ion-implanted TMA were considered for this study. Surface characteristics were analyzed using scanning electron microscopy, atomic force microscopy (AFM, and energy dispersive spectroscopy. Linear polarization test, a fast electrochemical technique, was used to evaluate the corrosion resistance, in terms of polarization resistance of four different archwires in artificial saliva with NaF concentrations of 0% and 0.5%. Statistical analysis was performed by one-way analysis of variance. Results: The potentiostatic study reveals that the corrosion resistance of low-friction TMA (L-TMA > TMA > NiTi > SS. AFM analysis showed the surface Ra of TMA > NiTi > L-TMA > SS. This indicates that the chemical composition of the wire is the primary influential factor to have high corrosion resistance and surface Ra is only secondary. The corrosion resistance of all wires had reduced significantly in 0.5% acidic fluoride-containing artificial saliva due to formation of fluoride complex compound. Conclusion: The presence of 0.5% NaF in artificial saliva was detrimental to the corrosion resistance of the orthodontic archwires. Therefore, complete removal of residual high-fluorinated toothpastes from the crevice between archwire and bracket during tooth brushing is mandatory.

  18. Corrosion resistance of stainless steel, nickel-titanium, titanium molybdenum alloy, and ion-implanted titanium molybdenum alloy archwires in acidic fluoride-containing artificial saliva: An in vitro study

    Science.gov (United States)

    Pulikkottil, Venith Jojee; Chidambaram, S.; Bejoy, P. U.; Femin, P. K.; Paul, Parson; Rishad, Mohamed

    2016-01-01

    Objective: (1) To evaluate the corrosion resistance of four different orthodontic archwires and to determine the effect of 0.5% NaF (simulating high fluoride-containing toothpaste of about 2250 ppm) on corrosion resistance of these archwires. (2) To assess whether surface roughness (Ra) is the primary factor influencing the corrosion resistance of these archwires. Materials and Methods: Four different archwires (stainless steel [SS], nickel-titanium [NiTi], titanium molybdenum alloy [TMA], and ion-implanted TMA) were considered for this study. Surface characteristics were analyzed using scanning electron microscopy, atomic force microscopy (AFM), and energy dispersive spectroscopy. Linear polarization test, a fast electrochemical technique, was used to evaluate the corrosion resistance, in terms of polarization resistance of four different archwires in artificial saliva with NaF concentrations of 0% and 0.5%. Statistical analysis was performed by one-way analysis of variance. Results: The potentiostatic study reveals that the corrosion resistance of low-friction TMA (L-TMA) > TMA > NiTi > SS. AFM analysis showed the surface Ra of TMA > NiTi > L-TMA > SS. This indicates that the chemical composition of the wire is the primary influential factor to have high corrosion resistance and surface Ra is only secondary. The corrosion resistance of all wires had reduced significantly in 0.5% acidic fluoride-containing artificial saliva due to formation of fluoride complex compound. Conclusion: The presence of 0.5% NaF in artificial saliva was detrimental to the corrosion resistance of the orthodontic archwires. Therefore, complete removal of residual high-fluorinated toothpastes from the crevice between archwire and bracket during tooth brushing is mandatory. PMID:27829756

  19. Effect of tempering temperature and Mo content on the corrosion behavior of 13Cr martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Jong Woo; Ahn, Yong Sik; Park, Hwa Soon [Pukyong National Univ., Busan (Korea, Republic of)

    1999-07-01

    Martensitic stainless steel has high strength and hardness in comparison with other stainless steels. But the toughness and corrosion resistance is lower. So lots of researches have been done in order to improve these properties. In the previous study the alloying element of Mo resulted in increasing the toughness at tempered condition of the steel. It has been investigated in this work how the Mo addition and tempering condition influence on the various types of corrosion behavior of 13% Cr martensitic stainless steel. Corrosion resistance was hardly changed by the tempering up to temperature of 500 .deg. C, but decreased at 600 .deg. C due to the formation of Cr carbide on the prior austenite boundary. However, the corrosion resistance increased again at 700 .deg. C, because Cr carbides were resolved and redistributed. Both general corrosion resistance and intergranular corrosion resistance of tempered steel are significantly improved with Mo content.

  20. Electrochemical study of corrosion inhibition of stainless steel in phosphoric medium

    Energy Technology Data Exchange (ETDEWEB)

    Hnini, K.; Chtaini, A. [Laboratoire d' Electrochimie et de Bio Corrosion, Faculte des Sciences et Techniques, Beni-Mellal (Morocco); Khouili, M.; Elbouadili, A. [Laboratoire de Chimie Organique et Analytique, Faculte des Sciences et Techniques, Beni-Mellal (Morocco)

    2004-07-01

    The corrosion of metals represents a terrible waste of both natural resources and money, the failure of some stainless steel resulting from pitting corrosion is some times considered a technological problem, consequently, much effort has been expended in attempting to understand and overcome the corrosion therefore, many stainless steel/ environment combinations have been studied. The use of heterocyclic compounds as inhibitors is one of the most practical methods for protection against corrosion in acidic media. In continuation of our work on development of macrocyclic compounds as corrosion inhibitors we report in our study the corrosion inhibiting behaviour of organic compound Methoxy-2-Allyl-4 Phenol (MAP) containing coordinating and conjugation groups, at three forms (natural, polymerized and chemically treated) on the corrosion of stainless steel in phosphoric acid. This study focused on the comparison for corrosion inhibition proprieties of these different applications using potentiodynamic polarization, electrochemical impedance spectroscopy and SEM. The specimen was evaluated to determine change in his corrosion potential and resistance polarization; These MAP products have exhibited corrosion inhibition by maintaining a high resistance polarization (low corrosion rate) in each application. These results reveal that this compound is efficient inhibitor in all forms; the most inhibition efficiency is obtained with polymerized form. To further evaluate the test data, the steel surfaces were analyzed using scanning electron microscopy, SEM observations of surface treated concrete confirmed presence of inhibitor on the steel surfaces. (authors)

  1. Mechanical Properties and Corrosion Behavior of Low Carbon Steel Weldments

    Directory of Open Access Journals (Sweden)

    Mohamed Mahdy

    2013-01-01

    Full Text Available This research involves studying the mechanical properties and corrosion behavior of “low carbon steel” (0.077wt% C before and after welding using Arc, MIG and TIG welding. The mechanical properties include testing of microhardness, tensile strength, the results indicate that microhardness of TIG, MIG welding is more than arc welding, while tensile strength in arc welding more than TIG and MIG.The corrosion behavior of low carbon weldments was performed by potentiostat at scan rate 3mV.sec-1 in 3.5% NaCl to show the polarization resistance and calculate the corrosion rate from data of linear polarization by “Tafel extrapolation method”. The results indicate that the TIG welding increase the corrosion current density and anodic Tafel slop, while decrease the polarization resistance compared with unwelded low carbon steel. Cyclic polarization were measured to show resistance of specimens to pitting corrosion and to calculate the forward and reveres potentials. The results show shifting the forward, reverse and pitting potentials toward active direction for weldments samples compared with unwelded sample.

  2. A Corrosion Sensor for Monitoring the Early-Stage Environmental Corrosion of A36 Carbon Steel

    Directory of Open Access Journals (Sweden)

    Dong Chen

    2014-08-01

    Full Text Available An innovative prototype sensor containing A36 carbon steel as a capacitor was explored to monitor early-stage corrosion. The sensor detected the changes of the surface- rather than the bulk- property and morphology of A36 during corrosion. Thus it was more sensitive than the conventional electrical resistance corrosion sensors. After being soaked in an aerated 0.2 M NaCl solution, the sensor’s normalized electrical resistance (R/R0 decreased continuously from 1.0 to 0.74 with the extent of corrosion. Meanwhile, the sensor’s normalized capacitance (C/C0 increased continuously from 1.0 to 1.46. X-ray diffraction result indicates that the iron rust on A36 had crystals of lepidocrocite and magnetite.

  3. Stress Corrosion Cracking of Pipeline Steels

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper provides a review of the differences between high pH and near-neutral pH stress corrosion cracking ofpipeline steels, influencing factors, and mechanisms. The characteristics and historical information on both forms ofSCC are discussed. The prospect for research in the future is also presented.

  4. Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline

    Directory of Open Access Journals (Sweden)

    LI Wei

    2007-02-01

    Full Text Available A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303g/L NaOH alkaline solution at 85℃ was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

  5. Corrosion of two kinds of cast steels containing chromium in hot concentrated alkaline

    Institute of Scientific and Technical Information of China (English)

    LI Wei; LIU Jun-quan; TU Xiao-hui

    2007-01-01

    A typical hot concentrated alkaline corrosion environment exists in alumina metallurgical industry, so that steel materials with outstanding alkaline corrosion resistance are strongly demanded for its processing equipment. In this paper, the corrosion resistance of two kinds of martensitic cast steels containing chromium in static 303 g/L NaOH alkaline solution at 85℃ was studied through polarization and potential-time curves, corrosion weight loss and corrosion morphology analysis. Experimental results showed that protection effect by passive film of cast steel containing Cr was temporary. The low carbon steel without Cr content also exhibited chemical passivity in the same solution. The corrosion mode of the tested Cr-containing cast steel was composed of active dissolving corrosion and caustic embrittlement cracking. Dissolving corrosion was the primary mechanism for the induced weight loss, while severe caustic embrittlement cracking was secondary. With the increase of chromium content in the cast steel, the tendency of the caustic embrittlement cracking decreased, while the active dissolving corrosion increased.

  6. Microbial Corrosion and Cracking in Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    1998-01-01

    and for recommendations in regards to electrochemical monitoring of MIC. The work presented here and further studies are also planned to lead to a Ph.D. thesis on "MIC monitoring based on mechanisms of corrosion".The results of laboratory experiments conducted in the period 1995 to 1997 are summarised. Conclusions...... will be based on results from the entire 3 year period, but only selected experimental data primarily from the latest experiments will be presented in detail here.Microbial corrosion of carbon steel under influence of sulphate-reducing bacteria (SRB) is characterised by the formation of both biofilm...... and corrosion products (ferrous sulphides) on the metal surface. Experiments have been conducted on carbon steel exposed in near neutral (pH 6 to 8.5) saline hydrogen sulphide environment (0 to 100 mg/l total dissolved sulphide) for a period of 14 days. Furthermore coupons have been exposed in a bioreactor...

  7. Dependence of corrosion properties of AISI 304L stainless steel on the austenite grain size

    Energy Technology Data Exchange (ETDEWEB)

    Sabooni, Soheil; Rashtchi, Hamed; Eslami, Abdoulmajid; Karimzadeh, Fathallah; Enayati, Mohammad Hossein; Raeissi, Keyvan; Imani, Reihane Faghih [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of). Dept. of Materials Engineering; Ngan, Alfonso Hing Wan [The Univ. of Hong Kong (China). Dept. of Mechanical Engineering

    2017-07-15

    The corrosion resistance of austenitic stainless steels is known to be hampered by the loss of chromium available for passive surface layer formation as a result of chromium carbide precipitation at austenite grain boundaries during annealing treatments. Although high-temperature annealing can promote carbide dissolution leading to better corrosion resistance, grain coarsening also results, which would lead to poorer mechanical properties. Processing methods to achieve both good corrosion resistance and mechanical properties are thus highly desirable for austenitic stainless steels. In the present study, we show that the corrosion resistance of AISI 304L stainless steel can be improved by grain refinement into the ultrafine-grained regime. Specifically, samples with different austenite grain sizes in the range of 0.65-12 μm were studied by potentiodynamic polarization and electrochemical impedance spectroscopy tests in a 3.5 wt.% NaCl solution. All samples showed a typical passive behavior with similar corrosion potential, but the corrosion current density decreased significantly with decreasing grain size. The results show that the sample with the finest grain size had the best corrosion resistance due to a higher resistance of the passive layer to pitting attacks. This study indicates that grain refinement which improves mechanical properties can also significantly improve the corrosion resistance of AISI 304L stainless steel.

  8. Investigation on the explosive welding mechanism of corrosion-resisting aluminum and stainless steel tubes through finite element simulation and experiments

    Science.gov (United States)

    Sui, Guo-Fa; Li, Jin-Shan; Li, Hong-Wei; Sun, Feng; Zhang, Tie-Bang; Fu, Heng-Zhi

    2012-02-01

    To solve the difficulty in the explosive welding of corrosion-resistant aluminum and stainless steel tubes, three technologies were proposed after investigating the forming mechanism through experiments. Then, a 3D finite element model was established for systematic simulations in the parameter determination. The results show that the transition-layer approach, the coaxial initial assembly of tubes with the top-center-point the detonation, and the systematic study by numerical modeling are the key technologies to make the explosive welding of LF6 aluminum alloy and 1Cr18Ni9Ti stainless steel tubes feasible. Numerical simulation shows that radial contraction and slope collision through continuous local plastic deformation are necessary for the good bonding of tubes. Stand-off distances between tubes ( D 1 and D 2) and explosives amount ( R) have effect on the plastic deformation, moving velocity, and bonding of tubes. D 1 of 1 mm, D 2 of 2 mm, and R of 2/3 are suitable for the explosive welding of LF6-L2-1Cr18Ni9Ti three-layer tubes. The plastic strain and moving velocity of the flyer tubes increase with the increase of stand-off distance. More explosives ( R>2/3) result in the asymmetrical distribution of plastic strain and non-bonding at the end of detonation on the tubes.

  9. Corrosion Effects on the Strength Properties of Steel Fibre Reinforced Concrete Containing Slag and Corrosion Inhibitor

    OpenAIRE

    Sivakumar Anandan; Sounthararajan Vallarasu Manoharan; Thirumurugan Sengottian

    2014-01-01

    Corrosion in steel can be detrimental in any steel rebar reinforced concrete as well as in the case of steel fibre reinforced concrete. The process of corrosion occurring in steel fibre incorporated concrete subjected to corrosive environment was systematically evaluated in this study. Concrete specimens were prepared with steel fibre inclusions at 1.5% Vf (volume fraction) of concrete and were added in slag based concrete (containing manufactured sand) and replaced with cement at 20%, 40%, ...

  10. On the corrosion resistance of AISI 316L-type stainless steel coated with manganese and annealed with flow of oxygen

    Science.gov (United States)

    Savaloni, Hadi; Agha-Taheri, Ensieh; Abdi, Fateme

    2016-06-01

    AISI 316L-type stainless steel was coated with 300-nm-thick Mn thin films and post-annealed at 673 K with a constant flow of oxygen (250 cm3/min). The films crystallographic and morphological structures were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM) before corrosion test and scanning electron microscopy (SEM) after corrosion test. Corrosion behavior of the samples in 0.3, 0.5 and 0.6 M NaCl solutions was investigated by means of potentiodynamic and electrochemical impedance spectroscopy (EIS) techniques. Results showed that the corrosion inhibition of annealed Mn/SS316L in all NaCl solutions with different concentrations is higher than that of bare SS316L. A correlation is achieved between the structural variation of the films with the potentiodynamic and EIS corrosion results.

  11. Evaluation of structural behaviour and corrosion resistant of austenitic AISI 304 and duplex AISI 2304 stainless steel reinforcements embedded in ordinary Portland cement mortars; Evaluacion del comportamiento estructural y de resistencia a la corrosion de armaduras de acero inoxidable austenitico AISI 304 y duplex AISI 2304 embebidas en morteros de cemento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Medina, E.; Cobo, A.; Bastidas, D. M.

    2012-07-01

    The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304) and duplex EN 1.4362 (AISI 2304) have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR), of reinforcements embedded in ordinary Portland cement (OPC) mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure. (Author) 26 refs.

  12. Optimization of the pulsed current gas tungsten arc welding (PCGTAW) parameters for corrosion resistance of super duplex stainless steel (UNS S32760) welds using the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Yousefieh, M., E-mail: m.yousefieh@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, M., E-mail: shamanian@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Saatchi, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-01-21

    Research highlights: > Among the four factors and three levels tested, it was concluded that the pulse current had the most significant effect on the pitting potential and the background current had the next most significant effect. The effects of pulse frequency and % on time are less important when compared to the other factors. > The percentage contributions of the pulse current, the background current, % on time, and pulse frequency to the corrosion resistance are 66.28%, 25.97%, 2.71% and 5.04%, respectively. > The optimum conditions within the selected parameter values were found as the second level of pulse current (120 A), second level of background current (60 A), third level of % on time (80%) and third level of pulse frequency (5 Hz). > The confirmation test was carried out at optimum working conditions. Pitting potential was increased to 1.06 V{sub SCE} by setting the control factors. Predicted (1.04 V{sub SCE}) and observed (1.06 V{sub SCE}) pitting potential values are close to each other, which are the highest values obtained in the present study. - Abstract: In the present work, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the pulsed current gas tungsten arc welding (PCGTAW) parameters for the corrosion resistance of super duplex stainless steel (UNS S32760) welds. A L{sub 9} (3{sup 4}) orthogonal array (OA) of Taguchi design which involves nine experiments for four parameters (pulse current, background current, % on time, pulse frequency) with three levels was used. Corrosion resistance in 3.5%NaCl solution was evaluated by anodic polarization tests at room temperature. Analysis of variance (ANOVA) is performed on the measured data and S/N (signal to noise) ratios. The higher the better response category was selected to obtain optimum conditions. The optimum conditions providing the highest pitting potential were estimated. The optimum conditions were found as the second level of pulse current (120 A

  13. Corrosion-resistant metallic coatings

    Directory of Open Access Journals (Sweden)

    F. Presuel-Moreno

    2008-10-01

    Full Text Available We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic inhibitors to protect defects in the coating, by formation of an optimized barrier to local corrosion in Cl− containing environments, as well as by sacrificial cathodic prevention. Further progress in this field could lead to the design of the next generation of adaptive or tunable coatings that inhibit corrosion of underlying substrates.

  14. Corrosion of mild steel and stainless steel by marine Vibrio sp.

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi; Wagh, A.B.

    Microbially induced corrosion (MIC) of stainless steel and mild steel coupons exposed to media with and without a bacterial culture Vibrio sp. was studied using Scanning Electron Microscope (SEM). Pitting type of corrosion was noticed which was more...

  15. Evaluation of the corrosion resistance of latex modified concrete (LMC)

    Energy Technology Data Exchange (ETDEWEB)

    Okba, S.H.; El-Dieb, A.S.; Reda, M.M. [Ain Shams Univ., Cairo (Egypt). Dept. of Structural Engineering

    1997-06-01

    In recent years, various reinforced concrete structures worldwide have suffered rapid deterioration. Therefore, durability of concrete structures especially those exposed to aggressive environments is of great concern. Many deterioration causes and factors have been investigated. Corrosion of steel reinforcement was found to be one of the major deterioration problems. Penetration of chloride ions is one of the main causes which induces corrosion. The objective of this study is to evaluate the corrosion resistance of latex modified concrete (LMC) compared to conventional concrete using an accelerated corrosion cell. The corrosion cell proved to be a good and simple method to evaluate the durability of concretes especially with respect to chloride ion penetration, and the protection of reinforcement against corrosion. The LMC proved to be superior in its corrosion resistance compared to conventional concrete, which recommends its use in structures exposed to severe aggressive environments.

  16. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  17. Corrosion-resistant coating development

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.; Kupp, D.M.; Martin, R.L. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  18. Study of the sulphide stress corrosion cracking (SSCC) resistance of API SL GR B and X60 pipeline steels. Evaluacion de la resistencia al agrietamiento por corrosion-tension en medios sulfhidricos (SSCC) de aceros para tuberias Calidad API 5L Grados B y X60

    Energy Technology Data Exchange (ETDEWEB)

    Bao-Iturbe, C. (Babcock and Wilcox Espaola. S.A. Bilbao (Spain)); Gutierrez de Saiz-Solabarria (Univ. Pais Vasco. Departamento Ingenieria Metalurgica y Control de Materiales. Bilbao (Spain))

    1993-01-01

    A study of the sulphide stress corrosion cracking resistance at room temperature of API 5L Cr B and X60 pipeline steels has been carried out. The theoretical mechanisms in order to explain these phenomena and several operational failures of pipeline steel due to SSCC have been reviewed and the National Association of Corrosion Engineers (NACE) standard concerning SSCC has been described. The main factors of influence of the SSCC have been analysed, results are presented and conclusions are elaborated. (Author) 32 ref.

  19. Atmospheric Corrosion of Q235 Carbon Steel and Q450 Weathering Steel in Turpan,China

    Institute of Scientific and Technical Information of China (English)

    Qiang YU; Chao-fang DONG; Yue-hua FANG; Kui XIAO; Chun-yun GUO; Gang HE; Xiao-gang LI

    2016-01-01

    Q235 carbon steel and Q450 weathering steel were exposed to the hot and dry environment of Turpan, China for three years.The corrosion rates of both steels were calculated and compared.The morphologies of the rust layer products were observed by optical microscopy and scanning electron microscopy.Analyses of the rust layers were performed by X-ray photoelectron spectroscopy,X-ray powder diffraction,and Raman spectroscopy,and anal-ysis results indicate that the compositions of rust are main iron rich oxide such as FeOOH,Fe3 O4 ,and Fe2 O3 .The iron oxide layer content proportion was calculated through a semi-quantitative algorithm.The resistance elements (Cr,Ni,and Cu)enhanced the resistance properties of the Q450 weathering steel matrix.Moreover,the resistance elements increased the proportion of goethite crystals in the corroded rust layer.

  20. Effect of Harmonic Microstructure on the Corrosion Behavior of SUS304L Austenitic Stainless Steel

    Science.gov (United States)

    Rai, Prabhat K.; Shekhar, S.; Nakatani, M.; Ota, M.; Vajpai, S. K.; Ameyama, K.; Mondal, K.

    2016-12-01

    Corrosion behavior of a harmonic structured SUS304L austenitic stainless steel was examined and compared with nonharmonic structured SUS304L stainless steel and conventional 304 stainless steel in 3.5 pct NaCl solution. The study was performed using linear polarization, potentiodynamic polarization, cyclic polarization, and a salt fog exposure test for 30 days. Characterization was accomplished using a scanning electron microscope, an electron probe microanalyzer, and Raman spectroscopy. Improved pitting corrosion resistance was found in the case of the harmonic structured steel as compared to that of the nonharmonic and the conventional 304 stainless steel. Harmonically distributed fine-grained structure, less porosity, and higher fraction of passive α-FeOOH are attributed to the improvement in corrosion resistance of the harmonic structured steel.

  1. Corrosion Resistance of High Nitrogen Superauste nitic Stainless Steel and Influence of Nitrogen%超级高氮奥氏体不锈钢的耐腐蚀性能及氮的影响

    Institute of Scientific and Technical Information of China (English)

    郎宇平; 康喜范

    2001-01-01

    The pitting resistance and the c revice corrosion resistance of superaustenitic stainless steels 00Cr24Ni22Mo7Mn3 CuN(654SMO) were studied in concentrated chloride media by electrochemical and c hemical immersion test.Through changing the concentration of nitrogen, the infl uence of nitrogen on pitting resistance and crevice corrosion resistance of aust enitic stainless steels have been studied.The results showed that nitrogen enha nces noticeably the pitting resistance and the crevice corrosion resistance of a ustenitic stainless steel in combination with suitable content of molybdenum and chromium.With the increase of nitrogen content, the pitting resistance and the crevice corrosion resistance increase.For local corrosion, such as pitting and crevice corrosion, the property of superaustenitic stainless steel is as good a s hastelloy alloy C-276, and even better.%用电化学测试、化学浸泡等方法研究了超级奥氏 体不锈钢00Cr24Ni22Mo7Mn3CuN(654SMO)的耐点腐蚀和耐缝隙腐蚀的性能。通过改变氮含量 ,研究了氮对奥氏体不锈钢的耐点腐蚀和耐缝隙腐蚀性能的影响。结果表明,氮和适量的铬 、钼结合,能显著提高奥氏体不锈钢的耐点腐蚀和缝隙腐蚀的能力,并且随着氮含量的增加 ,奥氏体不锈钢的耐点腐蚀和耐缝隙腐蚀的能力也增强。对比实验表明,超级奥氏体不锈钢 在耐点腐蚀、缝隙腐蚀等局部腐蚀性能方面可以和镍基合金C-276媲美,甚至优于镍基合金。

  2. Corrosion inhibition in 2.0 M sulfuric acid solutions of high strength maraging steel by aminophenyl tetrazole as a corrosion inhibitor

    Science.gov (United States)

    Sherif, El-Sayed M.

    2014-02-01

    The corrosion of high strength maraging steel after varied immersion times in concentrated solution, 2.0 M, of sulfuric acid has been investigated. The work was also extended to study the effect of 5-(3-aminophenyl)-tetrazole (APTA) on the inhibition of the steel corrosion. The study has been carried out using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electron microscope (SEM) along with energy dispersive X-ray analyzer (EDX) investigations. EIS spectra showed that the corrosion and polarization resistances decrease with increasing the immersion time of the steel before measurement and increase in the presence of APTA and the increase of its concentration. Polarization data agreed with the EIS measurements and indicated that the increase of immersion time increases the corrosion of steel by increasing its corrosion current and corrosion rate and lowering its polarization resistance. On the other hand, the addition of APTA and the increase of its concentration minimized the corrosion of steel through decreasing the corrosion current and corrosion rate and increasing the polarization resistance at all exposure test periods. SEM and EDX investigations confirmed that the inhibition of the maraging steel in the 2.0 M H2SO4 solutions is achieved via the adsorption of the APTA molecules onto the steel protecting its surface from being dissolved easily.

  3. 表层混凝土电阻率法检定栓钉腐蚀的适用性研究%Applicability of surface concrete resistivity method to corrosion inspection of studs in steel-concrete composite structures

    Institute of Scientific and Technical Information of China (English)

    路新瀛; 林潮; 樊健生

    2014-01-01

    Surface concrete resistivity method which is usually used to map the rebar corrosion is employed to detect the corrosion of studs in steel-concrete composite structures.After comparing with the destructive testresults ,it is concluded that the surface concrete resis-tivity method is not suitable to judge the corrosion state of studs in the composite structures.%用钢筋腐蚀检测中常用的表层混凝土电阻率检定法,对自然暴露7年的组合构件中的栓钉腐蚀进行了检测研究,对比破损检查结果发现,表层混凝土电阻率法不适于组合结构中栓钉腐蚀的检测和腐蚀状态判定。

  4. Electrochemical and analytical characterization of three corrosion inhibitors of steel in simulated concrete pore solutions

    Science.gov (United States)

    Shi, Jin-Jie; Sun, Wei

    2012-01-01

    Corrosion inhibitors for steel, such as sodium phosphate (Na3PO4), sodium nitrite (NaNO2), and benzotriazole (BTA), in simulated concrete pore solutions (saturated Ca(OH)2) were investigated. Corrosion behaviors of steel in different solutions were studied by means of corrosion potential ( E corr), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). A field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray analysis (EDXA) was used for observing the microstructures and morphology of corrosion products of steel. The results indicate that, compared with the commonly used nitrite-based inhibitors, Na3PO4 is not a good inhibitor, while BTA may be a potentially effective inhibitor to prevent steel from corrosion in simulated concrete pore solutions.

  5. An Electrochemical Study on the Corrosion Inhibition of Stainless Steel by Polyaniline Film

    Institute of Scientific and Technical Information of China (English)

    Hao WANG; Lin NIU; Qiu Hong LI; Su Xiang WU; Feng Hua WEI

    2004-01-01

    Polyaniline(PANI) film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte. The potential sweep rates were changed to achieve the PANI film with different thickness and structures. Protective properties of the PANI film for corrosion of stainless steel in 3% NaCl aqueous solution were investigated by monitoring potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS).The results showed that the PANI film which was formed with lower sweep rate led to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the stainless steel.

  6. Influence of silver additions to type 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tseng, I-Sheng; Møller, Per;

    2010-01-01

    Bacterial contamination is a major concern in many areas. In this study, silver was added to type 316 stainless steels in order to obtain an expected bacteria inhibiting property to reduce the occurrence of bacterial contamination. Silver-bearing 316 stainless steels were prepared by vacuum melti...

  7. Corrosion behavior of Cr/Ni alloy coated ferritic stainless steel in simulated cathodic PEMFC environments

    Energy Technology Data Exchange (ETDEWEB)

    Rendon, M.; Rivas, S.V.; Arriga, L.G.; Orozco, G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Queretaro (Mexico); Perez-Quiroz, J.T. [Inst. Mexicano del Transporte, Queretaro (Mexico); Porcayo, J. [Inst. de Investigaciones Electricas, Morelos (Mexico)

    2008-07-01

    The bipolar plate in a proton exchange membrane fuel cell (PEMFC) must be corrosion resistant and the interfacial contact resistance (ICR) with the gas diffusion layer must be low. For these reasons, stainless steel with high Cr content is considered to be a viable material for use in bipolar plate construction. This study evaluated the corrosion resistance of ferritic stainless steels 441 and 439, with and without a Cr/Ni coating, under simulated cathodic PEMFC conditions. Steel 441 without coating has a low corrosion current density and can be considered as a candidate material to be used as bipolar plate. The study showed that after the Cr/Ni coating was applied by Thermal Spray Metal method, the corrosion current density increased due to selective dissolution of an alloy element. The corrosion current density of the coatings was higher than the DOE target value, rendering them an unfeasible option to be used in bipolar plates for fuel cell applications. However, previous studies have shown that after the coating was applied, a passivation process improved the corrosion resistance. Although steel 441 appears to be a better candidate than steel 316 because of its lower cost, the behaviour of the Ni-Cr alloys was not satisfactory in corrosive acidic medium. 5 refs.

  8. An electrochemical and microstructural characterization of steel-mortar admixed with corrosion inhibitors

    Institute of Scientific and Technical Information of China (English)

    Tuan; Anh; Nguyen; Recep; AVCI

    2009-01-01

    The present research brings new insights on the role of admixed corrosion inhibitors in the processes of cement hydration and rebar corrosion. The admixing of NaCl and the corrosion inhibitors in fresh mortar was found to alter the morphology and microstructure of the hardened mortar at the steel-mortar interfacial region. The admixing of the inhibitors increased the risk of carbonation of cement hydrates at the steel-mortar interfacial region, but partially displaced chloride ions. Chloride and the admixed inhibitors facilitated the formation of different cement hydrates and affected chloride binding at the steel-mortar interfacial region. The admixing of all three inhibitors was found to increase the polarization resistance of steel, indicating reduced corrosion rate of the steel over 48-day exposures to salt ponding.

  9. An electrochemical and microstructural characterization of steel-mortar admixed with corrosion inhibitors

    Institute of Scientific and Technical Information of China (English)

    SHI XianMing; YANG ZhengXian; Tuan Anh Nguyen; SUO ZhiYong; Recep AVCI; SONG ShiZhe

    2009-01-01

    The present research brings new insights on the role of admixed corrosion inhibitors in the processes of cement hydration and rebar corrosion. The admixing of NaCI and the corrosion inhibitors in fresh mortar was found to alter the morphology and microstructure of the hardened mortar at the steel-mor-tar interfacial region. The admixing of the inhibitors increased the risk of carbonation of cement hy-drates at the steel-mortar interracial region, but partially displaced chloride ions. Chloride and the ad-mixed inhibitors facilitated the formation of different cement hydrates and affected chloride binding at the steel-mortar interfacial region. The admixing of all three inhibitors was found to increase the po-larization resistance of steel, indicating reduced corrosion rate of the steel over 48-day exposures to salt ponding.

  10. Progressive Corrosion Study of Metals like Mild Steel, Zinc and Aluminium in an Urban Atmosphere

    Directory of Open Access Journals (Sweden)

    H. K. Kadiya

    2009-01-01

    Full Text Available Corrosion rate (Progressive of mild steel (MS, zinc and aluminum have been determined under outdoor conditions of exposure at Valsad (South Gujarat representing an urban atmosphere. Mild steel (MS, zinc and aluminium plates exposed during November 2005 indicates corrosion rate of 88, 33 and 1.4 mg/sq.dm for one month exposure period and 3668, 968 and 26.1 mg/sq.dm for mild steel, zinc and aluminium respectively for twelve months exposure period. Mild steel panels exposed vertically suffer less corrosion than those exposed at an angle of 45°. The resistivity towards the atmosphere was in the increasing order: mild steel < zinc < aluminium. Corrosion rate of these three metals found more in rainy seasons than the rate of winter and summer season

  11. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo

    2005-01-01

    in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Oxygen entering the system accelerates...

  12. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo

    2007-01-01

    if the biofilm in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemicel impedance spectroscopy (EIS). Oxygen entering the system...

  13. Effect of alloy elements on the anti-corrosion properties of low alloy steel

    Indian Academy of Sciences (India)

    Baorong Hou; Yantao Li; Yanxu Li; Jinglei Zhang

    2000-06-01

    Effect of alloy elements on corrosion of low alloy steel was studied under simulated offshore conditions. The results showed that the elements Cu, P, Mo, W, V had evident effect on corrosion resistance in the atmosphere zone; Cu, P, V, Mo in the splash zone and Cr, Al, Mo in the submerged zone.

  14. Concrete cover cracking with localized corrosion of reinforcing steel

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Acosta, A. A.; Sagues, A. A. [South Florida Univ., Dept of Civil and Environmental Engineering, Tampa FL (United States)

    2000-07-01

    The critical amount of steel corrosion needed for concrete cover cracking of a reinforced concrete element was measured, focusing on cases where only a fraction of the steel bar length is corroding. The amount of corrosion needed to crack the concrete cover was found to range between 49 micrometre to 137 micrometre in specimens of localized corrosion. In contrast, in cases of uniform corrosion of comparable systems the corrosion needed to crack the concrete cover varied from 15 micrometre to 75 micrometer. Based on this and previous work on this problem, an empirical equation is proposed for the critical amount of steel corrosion as a function of specimen dimensions. The model proposed for estimating the critical amount of steel corrosion showed reasonable agreement between estimates of the work of corrosion expansion and the energy required to crack the concrete. 23 refs., 3 tabs., 8 figs.

  15. Corrosion resistance of the welded AISI 316L after various surface treatments

    Directory of Open Access Journals (Sweden)

    Tatiana Liptáková

    2014-01-01

    Full Text Available The main aim of this work is to monitor the surface treatment impact on the corrosion resistance of the welded stainless steel AISI 316L to local corrosion forms. The excellent corrosion resistance of austenitic stainless steel is caused by the existence of stable, thin and well adhering passive layer which quality is strongly influenced by welding. Therefore surface treatment of stainless steel is very important with regard to its local corrosion susceptibility Surfaces of welded stainless steel were treated by various mechanical methods (grinding, garnet blasting. Surface properties were studied by SEM, corrosion resistance was evaluated after exposition tests in chlorides environment using weight and metalographic analysis. The experimental outcomes confirmed that the mechanical finishing has a significant effect on the corrosion behavior of welded stainless steel AISI 316L.

  16. Galvanic corrosion of Mg-Zr fuel cladding and steel immobilized in Portland cement and geopolymer at early ages

    Science.gov (United States)

    Rooses, Adrien; Lambertin, David; Chartier, David; Frizon, Fabien

    2013-04-01

    Galvanic corrosion behaviour of Mg-Zr alloy fuel cladding and steel has been studied in Ordinary Portland cement and Na-geopolymer. Portland cements implied the worse magnesium corrosion performances due to the negative effects of cement hydrates, grinding agents and gypsum on the galvanic corrosion. Galvanic corrosion in Na-geopolymer paste remains very low. Silicates and fluoride from the geopolymer activation solution significantly improve the corrosion resistance of the magnesium alloy while coupling with a cathode.

  17. Corrosion-resistant sulfur concretes

    Science.gov (United States)

    McBee, W. C.; Sullivan, T. A.; Jong, B. W.

    1983-04-01

    Sulfur concretes have been developed by the Bureau of Mines as construction materials with physical and mechanical properties that suit them for use in acid and salt corrosive environments where conventional concretes fail. Mixture design methods were established for preparing sulfur concretes using different types of aggregates and recently developed mixed-modified sulfur cements. Bench-scale testing of the sulfur concretes has shown their potential value. Corrosion resistance, strength, and durability of sulfur concrete are superior to those of conventional materials. Field in situ evaluation tests of the sulfur concretes as replacement for conventional concrete materials are in progress in corrosive areas of 24 commercial chemical, fertilizer, and metallurgical plants.

  18. The effect of organic matter associated with the corrosion products on the corrosion of mild steel in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Wagh, A.B.

    the corrosion of mild steel and the temperature and dissolved oxygen of seawater. In contrast to this, the corrosion and mild steel was inversely related to the organic carbon and water extractable carbohydrates associated with the corrosion products of mild...

  19. Interplay of microbiological corrosion and alloy microstructure in stress corrosion cracking of weldments of advanced stainless steels

    Indian Academy of Sciences (India)

    R K Singh Raman

    2003-06-01

    This paper presents an overview of the phenomenon of stress corrosion cracking (SCC) of duplex stainless steels and their weldments in marine environments and the potential role of microbial activity in inducing SCC susceptibility. As a precursor to the topic the paper also reviews the performance of the traditional corrosion-resistant alloys and their weldments and the necessity of using duplex stainless steels (DSS), in order to alleviate corrosion problems in marine environments. Given that the performance of weldments of such steels is often unsatisfactory, this review also assesses the research needs in this area. In this context the paper also discusses the recent reports on the role of microorganisms in inducing hydrogen embrittlements and corrosion fatigue.

  20. Marine corrosion protective coatings of hexagonal boron nitride thin films on stainless steel.

    Science.gov (United States)

    Husain, Esam; Narayanan, Tharangattu N; Taha-Tijerina, Jose Jaime; Vinod, Soumya; Vajtai, Robert; Ajayan, Pulickel M

    2013-05-22

    Recently, two-dimensional, layered materials such as graphene and hexagonal boron nitride (h-BN) have been identified as interesting materials for a range of applications. Here, we demonstrate the corrosion prevention applications of h-BN in marine coatings. The performance of h-BN/polymer hybrid coatings, applied on stainless steel, were evaluated using electrochemical techniques in simulated seawater media [marine media]. h-BN/polymer coating shows an efficient corrosion protection with a low corrosion current density of 5.14 × 10(-8) A/cm(2) and corrosion rate of 1.19 × 10(-3) mm/year and it is attributed to the hydrofobic, inert and dielectric nature of boron nitride. The results indicated that the stainless steel with coatings exhibited improved corrosion resistance. Electrochemical impedance spectroscopy and potentiodynamic analysis were used to propose a mechanism for the increased corrosion resistance of h-BN coatings.

  1. Corrosion properties of S-phase layers formed on medical grade austenitic stainless steel.

    Science.gov (United States)

    Buhagiar, Joseph; Dong, Hanshan

    2012-02-01

    The corrosion properties of S-phase surface layers formed in AISI 316LVM (ASTM F138) and High-N (ASTM F1586) medical grade austenitic stainless steels by plasma surface alloying with nitrogen (at 430°C), carbon (at 500°C) and both carbon and nitrogen (at 430°C) has been investigated. The corrosion behaviour of the S-phase layers in Ringer's solutions was evaluated using potentiodynamic and immersion corrosion tests. The corrosion damage was evaluated using microscopy, hardness testing, inductive coupled plasma mass spectroscopy and X-ray diffraction. The experimental results have demonstrated that low-temperature nitriding, carburising and carbonitriding can improve the localised corrosion resistance of both industrial and medical grade austenitic stainless steels as long as the threshold sensitisation temperature is not reached. Carburising at 500°C has proved to be the best hardening treatment with the least effect on the corrosion resistance of the parent alloy.

  2. 75 FR 55769 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2010-09-14

    ... company's investment activities. See Memorandum from Sheikh M. Hannan, Senior Accountant to Neal M. Halper... Determination of Sales at Less Than Fair Value: Certain Cut-to-Length Carbon Steel Plate from South Africa,...

  3. Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Duffó, G.S. [Departamento de Materiales, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Universidad Nacional de San Martín, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Tecnológicas – CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Farina, S.B., E-mail: farina@cnea.gov.ar [Departamento de Materiales, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Universidad Nacional de San Martín, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Tecnológicas – CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Schulz, F.M. [Consejo Nacional de Investigaciones Científicas y Tecnológicas – CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)

    2013-07-15

    Highlights: • There are no works related to the corrosion of drums containing radioactive waste. • Chloride induces high corrosion rate and after 1 year it drops abruptly. • Decrease in the corrosion rate is due to the lack of water to sustain the process. • Cementated ion-exchange resins do not pose risks of corrosion of the steel drums. -- Abstract: Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums.

  4. Deformation induced martensite in an AISI 301LN stainless steel: characterization and influence on pitting corrosion resistance

    OpenAIRE

    Hamilton Ferreira Gomes de Abreu; Sheyla Santana de Carvalho; Pedro de Lima Neto; Ricardo Pires dos Santos; Válder Nogueira Freire; Paulo Maria de Oliveira Silva; Sérgio Souto Maior Tavares

    2007-01-01

    In austenitic stainless steels, plastic deformation can induce martensite formation. The induced martensite is related to the austenite (gamma) instability at temperatures close or below room temperature. The metastability of austenite stainless steels increases with the decreasing of stacking fault energy (SFE). In this work, the deformation induced martensite was analyzed by X ray diffraction, electron back scatter diffraction (EBSD), magnetic methods and atomic force microscope (AFM) in sa...

  5. Corrosion resistance of AISI 304 and 444 stainless steel pipes in sanitizing solutions of clean-in-place process

    OpenAIRE

    Lins,Vanessa de Freitas Cunha; Gonçalves,Giselle Aline dos Santos; Leão,Tiago Paschoalin; Soares,Renata Braga; Costa,Cíntia Gonçalves Fonseca; Viana,Adolfo Kalergis do Nascimento

    2016-01-01

    Stainless steel (SS) is successfully used in food industries due to the characteristics of its surface, which is essential for the maintenance of the properties of food. Tanks and stainless steel pipes, which come into direct contact with food and drink, undergo a process of cleaning and disinfecting called CIP (Clean-in-Place). This method consists of automatic recirculation of a detergent solution for a controlled time followed by a rinsing with water, and finally a cleaning and sanitizing ...

  6. Simulation of a long term atmospheric corrosion process on plain and weathering steels

    OpenAIRE

    Bolivar, F.; Morales, A.; Arroyave, C.

    2003-01-01

    Information on weathering steel behaviour and its rust products characteristics after decades of atmospheric exposure are scarce. On the other side, generally accepted laboratory tests for the assessment of its corrosion resistance have not been developed yet. Consequently, simulating corrosion in the laboratory during long periods of time is attractive for the interesting and complete information obtainable from them. In the present work, AISI-SAE 1008 and ASTM-588 B steel samples have been ...

  7. Corrosion of Steel in Concrete, Part I – Mechanisms

    DEFF Research Database (Denmark)

    Küter, André; Møller, Per; Geiker, Mette Rica

    2006-01-01

    prematurely. Reinforcement corrosion is identified to be the foremost cause of deterioration. Steel in concrete is normally protected by a passive layer due the high alkalinity of the concrete pore solution; corrosion is initiated by neutralization through atmospheric carbon dioxide and by ingress...... of depassivation ions, especially chloride ions. The background and consequences of deterioration of reinforced concrete structures caused by steel corrosion are summarized. Selected corrosion mechanisms postulated in the literature are briefly discussed and related to observations. The key factors controlling...... initiation and propagation of corrosion of steel in concrete are outlined....

  8. Study on Structure and Corrosion Resistance Analysis of Carburizing Organization of Austenitic Stainless Steel%奥氏体不锈钢渗碳层的组织及耐蚀强化性能研究

    Institute of Scientific and Technical Information of China (English)

    李朋; 潘邻; 张良界; 杨闽红; 朱云峰; 马飞; 王成虎

    2013-01-01

    针对常规渗碳工艺会削弱奥氏体不锈钢耐蚀性的问题,通过对现有气体渗碳技术进行改进,采用前处理活化、降低渗碳温度的方法,实现了奥氏体不锈钢渗碳兼顾表面强度与耐蚀性能的目标.采用该工艺对AISI304和AISI316奥氏体不锈钢进行渗碳处理,并分析渗层组织和性能,结果表明,在470℃条件下,AISI316不锈钢经气体渗碳处理后,渗碳层具有优异的耐蚀强化性能.%In view of the conventional carburization weakening austenitic stainless steel corrosion resistance problem,based on the existing gas carburizing technology was improved,using pretreatment activation,carburizing temperature reduction methods,realized the austenitic stainless steel carburized surface strength and corrosion resistant properties of the target.Using this process on AISI304,AISI316 austenitic stainless steel carburizing processing,and get the austenitic stainless steel for low temperature carburizing organization performance carries on the analysis and research,research shows that under the condition of 470 ℃,AISI316 stainless steel carburization treated by low temperature gas carburizing layer has excellent corrosion resistance improved performance.

  9. Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

    Directory of Open Access Journals (Sweden)

    Marko Chigondo

    2016-01-01

    Full Text Available Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.

  10. [Corrosion of stainless steel 201, 304 and 316L in the simulated sewage pipes reactor].

    Science.gov (United States)

    Bao, Guo-Dong; Zuo, Jian-E; Wang, Ya-Jiao; Gan, Li-Li

    2014-08-01

    The corrosion behavior of stainless steel 201, 304 and 316L which would be used as sewer in-situ rehabilitation materials was studied in the simulated sewage pipes reactor. The corrosion potential and corrosion rate of these three materials were studied by potentiodynamic method on the 7th, 14th, 21st, 56th day under two different conditions which were full immersion condition or batch immersion condition with a 2-day cycle. The electrode process was studied by Electrochemical Impedance Spectroscopy (EIS) on the 56th day. The microstructure and composition of the corrosion pitting were analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) on the 56th day. The results showed that 304 and 316L had much better corrosion resistance than 201 under both conditions. 304 and 316L had much smaller corrosion rate than 201 under both conditions. The corrosion resistance of all three kinds of stainless steel under the batch immersion condition was much better than those under the full immersion condition. The corrosion rate of all three kinds of stainless steel under the batch immersion condition was much smaller than those under the full immersion condition. Point pitting corrosion was formed on the surfaces of 304 and 316L. In comparison, a large area of corrosion was formed in the surface of 201.

  11. Corrosion behavior of niobium coated 304 stainless steel in acid solution

    Science.gov (United States)

    Pan, T. J.; Chen, Y.; Zhang, B.; Hu, J.; Li, C.

    2016-04-01

    The niobium coating is fabricated on the surface of AISI Type 304 stainless steel (304SS) by using a high energy micro arc alloying technique in order to improvecorrosion resistance of the steel against acidic environments. The electrochemical corrosion resistance of the niobium coating in 0.7 M sulfuric acid solutions is evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and the open circuit potential versus time. Electrochemical measurements indicate that the niobium coating increases the free corrosion potential of the substrate by 110 mV and a reduction in the corrosion rate by two orders of magnitude compared to the substrate alone. The niobium coating maintains large impedance and effectively offers good protection for the substrate during the long-term exposure tests, which is mainly ascribed to the niobium coating acting inhibiting permeation of corrosive species. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion resistance behavior of the niobium coating in acid solutions.

  12. Manufacture of high-nitrogen corrosion-resistant steel by an aluminothermic method in a high-pressure nitrogen atmosphere

    Science.gov (United States)

    Dorofeev, G. A.; Karev, V. A.; Kuzminykh, E. V.; Lad'yanov, V. I.; Lubnin, A. N.; Vaulin, A. S.; Mokrushina, M. I.

    2013-01-01

    The conditions of aluminothermic synthesis of high-nitrogen Cr-N and Cr-Mn-N steels in a high-pressure nitrogen atmosphere are studied by thermodynamic simulation and metallurgical experiments. Thermodynamic analysis shows that the aluminothermic reduction reactions are incomplete. The most important synthesis parameter is the ratio of the aluminum to the oxygen content in a charge, and its optimum value ensures a compromise between the degree of oxide reduction, the aluminum and oxygen contents in steel (degree of deoxidation), and steel contamination by aluminum nitride. An analysis of experimental heats demonstrates good agreement between the experimental results and the data calculated by a thermodynamic model. As-cast ingots have the structure of nitrogen pearlite, and quenched ingots have an austenitic structure.

  13. General and Localized corrosion of Austenitic and Borated Stainless Steels in Simulated Concentrated Ground Waters

    Energy Technology Data Exchange (ETDEWEB)

    D. Fix; J. Estill; L. Wong; R. Rebak

    2004-05-28

    Boron containing stainless steels are used in the nuclear industry for applications such as spent fuel storage, control rods and shielding. It was of interest to compare the corrosion resistance of three borated stainless steels with standard austenitic alloy materials such as type 304 and 316 stainless steels. Tests were conducted in three simulated concentrated ground waters at 90 C. Results show that the borated stainless were less resistant to corrosion than the witness austenitic materials. An acidic concentrated ground water was more aggressive than an alkaline concentrated ground water.

  14. General and Localized Corrosion of Austenitic And Borated Stainless Steels in Simulated Concentrated Ground Waters

    Energy Technology Data Exchange (ETDEWEB)

    Estill, J C; Rebak, R B; Fix, D V; Wong, L L

    2004-03-11

    Boron containing stainless steels are used in the nuclear industry for applications such as spent fuel storage, control rods and shielding. It was of interest to compare the corrosion resistance of three borated stainless steels with standard austenitic alloy materials such as type 304 and 316 stainless steels. Tests were conducted in three simulated concentrated ground waters at 90 C. Results show that the borated stainless were less resistant to corrosion than the witness austenitic materials. An acidic concentrated ground water was more aggressive than an alkaline concentrated ground water.

  15. Improvement of the corrosion resistance by using enamel coating applied to the carbon steel fin tubes of the HRSG

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won Seok; Lee, Jong Wook [BHI, Haman (Korea, Republic of)

    2014-07-15

    Gas side corrosion affects all heat recovery steam generators (HRSGs). Consequences range from unsightliness and reduced performance to reliability problems and potential safety hazards. The enamel coating used for the HRSG fin tubes was visually and microscopically inspected, analyzed and compared with original one. From the results of the analysis, there was not much different between the coating and the original in the comparison of the strength, SEM (scanning electron microscope), and thermal expansion. For the overall heat transfer due to the coating, it was found that the coating fin tubes have about 2% degradation in comparison with the original ones. However, the use of enamel coating can help strongly to delay the corrosion problem by flue gases in the HRSG.

  16. The resistance of high frequency inductive welded pipe to grooving corrosion in salt water

    Energy Technology Data Exchange (ETDEWEB)

    Duran, C.; Triess, E.; Herbsleb, G.

    1986-09-01

    When exposed to neutral, salt-containing waters, electric resistant welded pipe in carbon and low alloy steels with increased sulfur contents may suffer preferential corrosion attack in the weld area. Because of its appearance, this type of corrosion is called grooving corrosion. The susceptibility to grooving corrosion may be determined and quantitatively described by means of an accelerated potentiostatic exposure test. The importance of type, concentration, and temperature of the electrolytic solution; potential; test duration; and the sulfur content of the steel in the accelerated corrosion test and the susceptibility of steels to grooving corrosion are described. Line pipe in high frequency inductive (HFI) welded carbon and low alloy steels are resistant to grooving corrosion particularly because of their low sulfur content.

  17. Marine corrosion of mild steel at Lumut, Perak

    Science.gov (United States)

    Ting, Ong Shiou; Potty, Narayanan Sambu; Liew, Mohd. Shahir

    2012-09-01

    The corrosion rate of structural steels in the adverse marine and offshore environments affects the economic interest of offshore structures since the loss of steel may have significant impact on structural safety and performance. With more emphasis to maintain existing structures in service for longer time and hence to defer replacement costs, there is increasing interest in predicting corrosion rate at a given location for a given period of exposure once the protection coating or cathodic protection is lost. The immersion depth, salinity, steel composition and water pollution will be taken into account. Various corrosion allowances are prescribed for structural members by different standards. There are no studies to determine the appropriate corrosion allowance for steel structures in marine environment in Malaysia. The objectives of the research are to determine the nature and rate of corrosion in mm/year for steel structures in marine environment. It also tries to identify whether the corrosion rate is affected by differences in the chemical composition of the steels, and microalgae. Two sets of corrosion coupons of Type 3 Steel consisting of mild steel were fabricated and immersed in seawater using steel frames. The corrosion rate of the coupon in mm/ per year is estimated based on the material weight loss with time in service. The results are compared with recommendations of the code.

  18. Assessing the effect of cement-steel interface on well casing corrosion in aqueous CO2 environments

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jiabin [Los Alamos National Laboratory; Carey, James W [Los Alamos National Laboratory; Zhang, Jinsuo [Los Alamos National Laboratory

    2010-01-01

    CO{sub 2} leakage is a critical safety concern for geologic storage. In wellbore environments, important leakage paths include the rock-cement and cement-casing interfaces. If the cement-casing interface is filled with escaping CO{sub 2}, the well casing directly contacts the CO{sub 2}. This can cause severe corrosion in the presence of water. This paper studies the effect of steel-cement interface gaps, ranging from 1 mm to 0 um, on casing corrosion. Corrosion kinetics were measured employing electrochemical techniques including linear polarization resistance, open circuit potential and electrochemical impedance spectroscopy. The experimental results showed that the corrosion of steel is not significant where the gap between steel and cement is small ({le} 100 {micro}m). Corrosion rates are controlled by the diffusion of corrosive species (H{sub 2}CO{sub 3} and H{sup +}) along the interface. In contrast, steel corrosion is severe in a broad gap where the corrosion process is limited only by the reaction kinetics of steel and corrosive species. The threshold leading to severe corrosion in terms of the cement-steel interface size (100 {micro}m) was determined. Our research clarifies a corrosion scenario at the cement-steel interface. Casing steel corrosion is initiated when attacked by corrosive species at the cement-steel interface. For relatively tight interfaces, this results in a slow thinning of the casing and expansion of the interface width. If the gap increases beyond the critical threshold size, the corrosion rate increases significantly, and a potentially damaging cycle of corrosion and interface expansion is developed.

  19. Corrosion Behavior of Carbon Steel in Synthetically Produced Oil Field Seawater

    Directory of Open Access Journals (Sweden)

    Subir Paul

    2014-01-01

    Full Text Available The life of offshore steel structure in the oil production units is decided by the huge corrosive degradation due to SO42-, S2−, and Cl−, which normally present in the oil field seawater. Variation in pH and temperature further adds to the rate of degradation on steel. Corrosion behavior of mild steel is investigated through polarization, EIS, XRD, and optical and SEM microscopy. The effect of all 3 species is huge material degradation with FeSx and FeCl3 and their complex as corrosion products. EIS data match the model of Randle circuit with Warburg resistance. Addition of more corrosion species decreases impedance and increases capacitance values of the Randle circuit at the interface. The attack is found to be at the grain boundary as well as grain body with very prominent sulphide corrosion crack.

  20. The influence of molybdenum on stress corrosion in Ultra Low Carbon Steels with copper addition

    Directory of Open Access Journals (Sweden)

    M. Mazur

    2010-07-01

    Full Text Available The influence of molybdenum content on the process of stress corrosion of ultra-low carbon structural steels with the addition of copper HSLA (High Strength Low Alloy was analyzed. The study was conducted for steels after heat treatment consisting of quenching andfollowing tempering at 600°C and it was obtained microstructure of the tempered martensite laths with copper precipitates and the phaseLaves Fe2Mo type. It was found strong influence of Laves phase precipitate on the grain boundaries of retained austenite on rate anddevelopment of stress corrosion processes. The lowest corrosion resistance was obtained for W3 steel characterized by high contents ofmolybdenum (2.94% Mo which should be connected with the intensity precipitate processes of Fe2Mo phase. For steels W1 and W2which contents molybdenum equals 1.02% and 1.88%, respectively were obtained similar courses of corrosive cracking.

  1. Unexpected corrosion of stainless steel in low chloride waters – microbial aspects

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Carpén, Leena; Møller, Per

    2009-01-01

    Abstract Stainless steels EN 1.4301 and 1.4401/1.4404 are normally considered corrosion resistant in low chloride natural waters like drinking water. However, a number of corrosion failures have been observed in e.g. fire extinguisher systems and drinking water installations, where stagnant...... stains on the outside of the installation. Corrosion may occur in water qualities with rather low chloride contents and fairly low conductivity, which would usually not be considered especially corrosive towards stainless steel. One key parameter is the ennoblement documented on stainless steel...... of iron facilitates the growth of iron oxidising bacteria. A number of failure cases from Danish and Finnish stainless steel installations are discussed with the objective to identify key parameters, suggest possible mechanisms and discuss whether prediction is possible. The paper includes a short...

  2. 电梯用439不锈钢耐腐蚀性的影响因素%Influencing Factors on Corrosion Resistance of 439 Stainless Steel Used in Elevators

    Institute of Scientific and Technical Information of China (English)

    袁龙; 张波; 徐勇军

    2011-01-01

    The influencing factors were studied that relate to the corrosion resistance of 439 stainless steel used in elevators, through surface morphology evaluation and corrosion resistance test for the samples whose alloy element contents, production process and grinding technology were adjusted. The results showed that the corrosion resistance of 439 stainless steel can be improved by improving Cr content, adopting the technology of first grinding and then annealing and pickling, controlling the particle size of abrasive belt and S content of abrasive materials.%通过调整合金元素含量、生产工艺流程和研磨工艺,并对制备的产品试样进行了表面形态评定和耐腐蚀性试验,研究了影响电梯用439不锈钢耐腐蚀性的因素.结果表明:适当提高铬元素含量,采用先研磨后退火酸洗的工艺以及控制研磨过程中研磨砂带粒度和研磨介质中硫元素的含量,可提高439不锈钢的耐腐蚀性.

  3. Surface modification for corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-06-01

    The raw gas environments that arise from coal gasification have chemical compositions that are low in pO{sub 2} and moderate-to-high in pS{sub 2}. Metallic materials for service in such an environment undergo predominantly sulfidation attack at temperatures of 400 to 700{degree}C. Modification of alloy compositions in bulk can alter the scaling processes and lead to improvements in corrosion resistance, but the benefits can only be attained at temperatures much higher than the service temperatures of the components. Modification of surfaces of structural components by several of the coating techniques examined in this study showed substantial benefit in corrosion resistance when tested in simulated coal gasification environments. The paper presents several examples of surface modification and their corrosion performance.

  4. Microbially induced corrosion of carbon steel in deep groundwater environment

    Directory of Open Access Journals (Sweden)

    Pauliina eRajala

    2015-07-01

    Full Text Available The metallic low and intermediate level radioactive waste generally consists of carbon steel and stainless steels. The corrosion rate of carbon steel in deep groundwater is typically low, unless the water is very acidic or microbial activity in the environment is high. Therefore, the assessment of microbially induced corrosion of carbon steel in deep bedrock environment has become important for evaluating the safety of disposal of radioactive waste. Here we studied the corrosion inducing ability of indigenous microbial community from a deep bedrock aquifer. Carbon steel coupons were exposed to anoxic groundwater from repository site 100 m depth (Olkiluoto, Finland for periods of three and eight months. The experiments were conducted at both in situ temperature and room temperature to investigate the response of microbial population to elevated temperature. Our results demonstrate that microorganisms from the deep bedrock aquifer benefit from carbon steel introduced to the nutrient poor anoxic deep groundwater environment. In the groundwater incubated with carbon steel the planktonic microbial community was more diverse and 100-fold more abundant compared to the environment without carbon steel. The betaproteobacteria were the most dominant bacterial class in all samples where carbon steel was present, whereas in groundwater incubated without carbon steel the microbial community had clearly less diversity. Microorganisms induced pitting corrosion and were found to cluster inside the corrosion pits. Temperature had an effect on the species composition of microbial community and also affected the corrosion deposits layer formed on the surface of carbon steel.

  5. Erosion and Corrosion of Mild Steel and Stainless Steel in Sodium Carbonate/Bicarbonate Solution Bearing Alumina Particle

    Institute of Scientific and Technical Information of China (English)

    YUAN Qing-long; LIANG Hong-da

    2004-01-01

    With a rotating cylinder electrode apparatus, the polarization behaviors of the mild steel and the stainless steel 0Cr18Ni9 in NaHCO3 (0.5 M)+Na2CO3 (0.5 M) solution with and without erodent particles were investigated and compared. The results show that the rotation speed of cylinder hardly affects the polarization behavior of sample in solution without particles but exerts a great influence on that with particles. Increasing rotation speed, the free corrosion potential shifts to positive direction and the oxygen limiting current density increases. Both the mild steel and stainless steel 0Cr18Ni9 experience a significant increase of the mass loss by increasing erosion, and erosive wear was dominated by severe micro-plowing. The insufficient mechanical strength of both materials leads to a low resistance to particle removal. Increasing peripheral velocities of the rotating cylinder enhances the corrosion rate of the mild steel. The stainless steel 0Cr18Ni9, due to a high erosive wear, also suffers from similar erosion-corrosion damage, despite that its corrosion resistance is much higher than that of the mild steel.

  6. Application of Self Assembled 6-aminohexanol layers for corrosion protection of 304 stainless steel surface

    Energy Technology Data Exchange (ETDEWEB)

    Yu Fei [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Chen Shougang, E-mail: sgchen2000@yahoo.com.cn [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Li Houmin; Yang Lejiao [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Yin Yansheng [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 200135 (China)

    2012-05-31

    Grafting of 6-aminohexanol onto a 304 stainless steel substrate was performed with the assistance of polydopamine self assembly. The surface structure of the films was characterized using optical and scanning electron microscopy and X-ray energy dispersive spectroscopy confirmed the establishment of organic films. The corrosion resistance properties were characterized using the electrochemical impedance spectroscopy and potentiodynamic polarization curve measurements. Enhanced corrosion resistance performance was mainly ascribed to the compact film structure and the blocking characteristics against electron transfer of the modified 304 stainless steel substrate. - Highlights: Black-Right-Pointing-Pointer Organic layers for corrosion protection of 304 stainless steel (SS) surface. Black-Right-Pointing-Pointer Bio-inspired self assembly of polydopamine/composite films. Black-Right-Pointing-Pointer 6-aminohexanol membrane synthesized on polydopamine modified SS surface. Black-Right-Pointing-Pointer An efficiency route for improving corrosion protection.

  7. Influence of Heat Treatment on the Corrosion of Microalloyed Steel in Sodium Chloride Solution

    Directory of Open Access Journals (Sweden)

    Asiful Hossain Seikh

    2013-01-01

    Full Text Available Microalloyed Steels find wide application in car bodies and other engineering parts because of its high strength as well as high ductility. Very fine grained microstructure is the reason behind the combination of strength and ductility. It has been reported that repeated quenching leads to further refining of microstructure. In the present investigation, corrosion resistance property of E34 microalloy steel has been studied in 3.5% NaCl solution in different microstructural conditions such as the as rolled one and three repeated quenched conditions. Weight loss, potentiodynamic polarization method, and electrochemical impedance spectroscopy (EIS techniques have been used. To reveal the corrosion resistance of different treated steels, some significant characterization parameters such as Ecorr, Icorr, Rp, and Rct in linear polarization and EIS curves were analyzed and compared. It is found that with repeated recrystallization grains become finer, and corrosion rate increases suggesting that a compromise has to strike between high mechanical property and corrosion rate.

  8. Significance of coplanar macrocells to corrosion in concrete-embedded steel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, P. [Univ. Autonoma de Nuevo Leon (Mexico); Ramirez, E. [Inst. de Investigacion Tecnologica Industrial y de Normas Tecnicas, Lima (Peru); Feliu, S.; Gonzalez, J.A. [Centro Nacional de Investigaciones Metalurgicas, Madrid (Spain); Lopez, W. [CEMEX, S.A. Monterrey (Mexico)

    1999-03-01

    The influence of microcells and galvanic macrocells on the corrosion kinetics of concrete-embedded steel was investigated experimentally. Nine stainless steel/carbon steel coplanar macrocouples in cathodic-to-anodic ratios of 0.02 to 50 were cast in concrete slabs made from cement, sand, and water in a 1:3:0:5 proportion plus 2% calcium chloride (CaCl{sub 2}) per cement weight. Corrosion potential (E{sub corr}), galvanic current (i{sub g}), polarization resistance (R{sub p}), and impedance measurements from 100 kHz to 0.01 Hz were made for the two metals, coupled and uncoupled. i{sub g} data provided by a zero resistance ammeter led to potentially underestimated corrosion rates for anodic areas, whereas R{sub p} measurements provided fairly reliable corrosion rates. Macrocells polarized anodic areas very slightly at points where an anodic and a cathodic process took place simultaneously.

  9. Corrosion protection of steel in ammonia/water heat pumps

    Science.gov (United States)

    Mansfeld, Florian B.; Sun, Zhaoli

    2003-10-14

    Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

  10. Corrosion resistant metallic bipolar plate

    Science.gov (United States)

    Brady, Michael P.; Schneibel, Joachim H.; Pint, Bruce A.; Maziasz, Philip J.

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  11. CORROSION RESISTANT JACKETED METAL BODY

    Science.gov (United States)

    Brugmann, E.W.

    1958-08-26

    Reactor faul elements of the elongated cylindrical type which are jacketed in a corrosion resistant material are described. Each feel element is comprised of a plurality of jacketed cylinders of fissionable material in end to end abutting relationship, the jackets being welded together at their adjoining ends to retain the individual segments together and seat the interior of the jackets.

  12. Improvement in corrosion resistance of magnesium coating with cerium treatment

    Institute of Scientific and Technical Information of China (English)

    Samia Ben Hassen; Latifa Bousselmi; Patricc Bercot; El Mustafa Rezrazi; Ezzeddine Triki

    2009-01-01

    Corrosion protection afforded by a magnesium coating treated in cerium salt solution on steel substrate was investigated using open circuit potential, polarization curves, and electrochemical impedance spectroscopy (EIS) in 0.005 M sodium chloride solution (NaCl). The morphology of the surface was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The cerium treated coating was obtained by immersion in CeCl3 solution. The results showed that the corrosion resistance of the treated magnesium coating was improved. The corrosion potential of the treated coating was found to be nobler than that of the untreated magnesium coating and the corrosion current decreased significantly. Impedance results showed that the cerium treatment increased corrosion protection. The improvement of anti-corrosion properties was ataibuted to the formation of cerium oxides and hydroxides that gave to a physical barrier effect.

  13. Corrosion of stainless steels in lead-bismuth eutectic up to 600 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Soler, L. [Dpto. Fision Nuclear, CIEMAT, Edificio 30, Avda. Complutense 22, Madrid 28040 (Spain)]. E-mail: laura.soler@ciemat.es; Martin, F.J. [Dpto. Fision Nuclear, CIEMAT, Edificio 30, Avda. Complutense 22, Madrid 28040 (Spain); Hernandez, F. [Dpto. Fision Nuclear, CIEMAT, Edificio 30, Avda. Complutense 22, Madrid 28040 (Spain); Gomez-Briceno, D. [Dpto. Fision Nuclear, CIEMAT, Edificio 30, Avda. Complutense 22, Madrid 28040 (Spain)

    2004-11-01

    An experimental program has been carried out to understand the differences in the corrosion behaviour between different stainless steels: the austenitic steels 304L and 316L, the martensitic steels F82Hmod, T91 and EM10, and the low alloy steel P22. The influence of oxygen level in Pb-Bi, temperature and exposure time is studied. At 600 deg. C, the martensitic steels and the P22 steel exhibit thick oxide scales that grow with time, following a linear law for the wet environment and a parabolic law for the dry one. The austenitic stainless steels show a better corrosion behaviour, especially AISI 304L. Under reducing conditions, the steels exhibit dissolution, more severe for the austenitic stainless steels. At 450 deg. C, all the materials show an acceptable behaviour provided a sufficient oxygen level in the Pb-Bi. At reducing conditions, the martensitic steels and the P22 steel have a good corrosion resistance, while the austenitic steels exhibit already dissolution at the longer exposures.

  14. Microbiological Corrosion in Low Carbon Steels

    Directory of Open Access Journals (Sweden)

    O. Medina–Custodio

    2009-01-01

    Full Text Available The Microbiologically Induced Corrosion affects several industries, such as oil industry where it is estimated that 20% to 30% pipes failures are related with microorganism . The chemical reactions generate ions transfer, this validate the use of electrochemical techniques for its analysis. Coupons submerged in a nutritional medium with presence and absence of three different microorganisms during two periods, 48 hours and 28 days we restudied. Polarization resistance (Rp and Electrochemical Impedance Spectroscopy (EIS techniques we re applied to determine the corrosivity of the systems. The results show a greater corrosive effect of abiotic system, this indicates a microorganisms protection effect to the metal, opposite to the first hypothesis. This result was ratified observing surfaces coupons by using Scanning Electron Microscopy (SEM technique. A possible mechanism based on Evans – Tafel graph is proposed to explain inhibitor microorganism effect.

  15. SECM Study of Effect of Chromium Content on the Localized Corrosion Behavior of Low-Alloy Steels in Chloride Environment

    Science.gov (United States)

    Indira, K.; Nishimura, T.

    2016-10-01

    This paper investigates the effect of chromium (Cr) content (0, 1, 3 and 5% Cr) in epoxy-coated alloy steel against corrosion using in situ electrochemical techniques such as EIS and SECM in a 3% NaCl solution. The EIS results revealed that the epoxy-coated Cr steel exhibited higher impedance values than carbon steel, which is attributed to the greater resistance of Cr steel toward corrosion. Based on the cyclic voltammogram results, the tip potentials were set at -0.7, 0.04 and 0.60 V for determining the concentration of dissolved oxygen at cathodic region, and oxidation of Cr2+ and Fe2+ at anodic region, respectively. The SECM measurements showed that, the tip current in the anodic region has decreased with increase in Cr content of the sample, which indicates that the oxidation of Fe2+ and Cr2+ decreases (corrosion is reduced) with the increase in Cr content of the steel. Besides, 5% Cr steel can maintain the highest corrosion resistance, and 1 and 3% Cr steels have higher corrosion resistance than the 0% Cr steel. This higher corrosion resistance of Cr steel samples could be due to the formation of Cr-rich hydro-oxide layers [Cr(OH)3 as a corrosion product] on the surface of the samples. Thus, the epoxy-coated Cr alloy steel has greater corrosion resistance in a chloride-containing environment than the carbon steel. Hence, epoxy-coated Cr alloy steel can be successfully used as a construction material in structures.

  16. Corrosion of Steel in Concrete – Thermodynamical Aspects

    DEFF Research Database (Denmark)

    Küter, Andre; Møller, Per; Geiker, Mette Rica

    2004-01-01

    The present understanding of selected corrosion phenomena in reinforced concrete is reviewed. Special emphasis is given to chloride induced corrosion. There is a general acceptance of the basic corrosion mechanism for steel in concrete. However different anodic reactions governing the subsequent...

  17. Marine atmospheric corrosion of carbon steels

    Directory of Open Access Journals (Sweden)

    Morcillo, Manuel

    2015-06-01

    Full Text Available Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a environmental conditions necessary for akaganeite formation; (b characterisation of akaganeite in the corrosion products formed; (c corrosion mechanisms of carbon steel in marine atmospheres; (d exfoliation of rust layers formed in highly aggressive marine atmospheres; (e long-term corrosion rate prediction; and (f behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camariñas, Galicia in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM/energy dispersive spectrometry (EDS, X-ray diffraction (XRD, Mössbauer spectroscopy and SEM/μRaman spectroscopy.La investigación fundamental en corrosión atmosférica marina de aceros al carbono es un campo científico relativamente joven que presenta grandes lagunas de conocimiento. La formación de akaganeíta en los productos de corrosión que se forman sobre el acero cuando se expone a atmósferas marinas conduce a un incremento notable de la velocidad de corrosión. En el trabajo se abordan las siguientes cuestiones: (a condiciones ambientales necesarias para la formación de akaganeíta, (b caracterización de la akaganeíta en los productos de corrosión formados, (c mecanismos de corrosión del acero al carbono en atmósferas marinas, (d exfoliación de las capas de herrumbre formadas en atmósferas marinas muy agresivas, (e predicción de la velocidad de corrosión a largo plazo, y (f comportamiento de aceros patinables. La

  18. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC of carbon steel must be monitored on-line in order to provide an efficient protection...... corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS...... and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic techniques even though localised corrosion rate cannot be measured. FSM measures general...

  19. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic techniques even though localised corrosion rate cannot be measured. FSM measures general......Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC of carbon steel must be monitored on-line in order to provide an efficient protection...... corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS...

  20. Effect of Nitrite Inhibitor on the Macrocell Corrosion Behavior of Reinforcing Steel

    Directory of Open Access Journals (Sweden)

    Zhonglu Cao

    2015-01-01

    Full Text Available The effect of nitrite ions on the macrocell corrosion behavior of reinforcing steel embedded in cement mortar was investigated by comparing and analyzing the macrocell corrosion current, macrocell polarization ratios, and slopes of anodic and cathodic steels. Based on the experimental results, the relationship between macrocell potential difference and macrocell current density was analyzed, and the mechanism of macrocell corrosion affected by nitrite ions was proposed. The results indicated that nitrite ions had significant impact on the macrocell polarization ratios of cathode and anode. The presence of nitrite could reduce the macrocell current by decreasing the macrocell potential difference and increasing the macrocell polarization resistance of the anode.

  1. Electrochemical corrosion behavior of X52 and X60 steels in carbon dioxide containing saltwater solution

    Directory of Open Access Journals (Sweden)

    Rihan Omar Rihan

    2013-02-01

    Full Text Available X52 and X60 high strength low alloy (HSLA steels are widely used in the construction of petroleum pipelines. This paper discusses the corrosion resistance of X52 and X60 steels in CO2 containing saltwater at pH 4.4 and 50 ºC. A circulating flow loop system inside an autoclave was used for conducting the experimental work. The rotating impeller speed was 2000 rpm. The corrosion rate was monitored using in situ electrochemical methods such as potentiodynamic sweep, linear polarization resistance, and electrochemical impedance spectroscopy (EIS methods. Results indicated that the corrosion rate of X60 steel is relatively higher than that of X52 steel.

  2. Electrochemical corrosion behavior of X52 and X60 steels in carbon dioxide containing saltwater solution

    Directory of Open Access Journals (Sweden)

    Rihan Omar Rihan

    2012-01-01

    Full Text Available X52 and X60 high strength low alloy (HSLA steels are widely used in the construction of petroleum pipelines. This paper discusses the corrosion resistance of X52 and X60 steels in CO2 containing saltwater at pH 4.4 and 50 ºC. A circulating flow loop system inside an autoclave was used for conducting the experimental work. The rotating impeller speed was 2000 rpm. The corrosion rate was monitored using in situ electrochemical methods such as potentiodynamic sweep, linear polarization resistance, and electrochemical impedance spectroscopy (EIS methods. Results indicated that the corrosion rate of X60 steel is relatively higher than that of X52 steel.

  3. X65钢和3Cr钢作为海底管道用钢抗CO2腐蚀性能研究%Research on the CO2 corrosion resistance of X65 and 3Cr steels applied to subsea pipeline

    Institute of Scientific and Technical Information of China (English)

    胡丽华; 常炜; 张雷; 李忠涛; 于湉; 许立宁; 路民旭

    2011-01-01

    The high-pressure high temperature au toclave was used to simulate the typical corrosion environment for oil and gas pipeline, and the CO2 corrosion resistance of X65 and 3Cr steels applied to subsca pipeline was researched.The corrosion rates of both X65 and 3Cr steels were low in mild corrosion environment, so we could choose X65 steel in this environment.With temperature and CO2 par tial pressure increasing, the CO2 corrosion resistance of 3Cr was superior to X65 steel; the average corro sion rate of 3Cr steel was obviously lower than X65 in the middling corrosion environment and 3Cr steel can avoid local corrosion in the middling and severe corrosion environments, so the 3Cr steel was more appropriate than X65 steel in such corrosion environ ment.The corrosion product scale enriched with Cr element was formed on the surface of the steel to protect the matrix from corrosion, which was the main reason that the CO2 corrosion resistance of 3Cr steel was superior to that of X65.%用高温高压反应釜模拟油气输送管道典型腐蚀环境,研究X65钢和3Cr钢作为海底管道用钢的抗CO2腐蚀性能.在温和腐蚀环境,X65钢与3Cr钢的平均腐蚀速率均较低,使用X65钢是安全的.随着温度和CO2分压提高,与X65钢相比3Cr钢表现出更优越的抗CO2腐蚀性能:在中等腐蚀环境3Cr钢平均腐蚀速率较X65钢大幅降低,在中等和苛刻腐蚀环境3Cr钢可有效抑制局部腐蚀的发生;在这样的腐蚀条件下,3Cr钢作为海底管道用钢较X65钢安全.3Cr钢较X65钢抗CO2腐蚀性能提高的主要原因是表面形成了富Cr的腐蚀产物膜,结构致密,对基体起到了有效的保护作用.

  4. Coatings for improved corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1992-05-01

    Several coating approaches are being developed to resist attack in coal-fired environments and thereby minimize corrosion of underlying substrate alloys and extend the time for onset of breakaway corrosion. In general, coating systems can be classified as either diffusion or overlay type, which are distinguished principally by the method of deposition and the structure of the resultant coating-substrate bond. The coating techniques examined are pack cementation, electrospark deposition, physical and chemical vapor deposition, plasma spray, and ion implantation. In addition, ceramic coatings are used in some applications.

  5. Environmental Cracking of Corrosion Resistant Alloys in the Chemical Process Industry - A Review

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2006-12-04

    A large variety of corrosion resistant alloys are used regularly in the chemical process industry (CPI). The most common family of alloys include the iron (Fe)-based stainless steels, nickel (Ni) alloys and titanium (Ti) alloys. There also other corrosion resistant alloys but their family of alloys is not as large as for the three groups mentioned above. All ranges of corrosive environments can be found in the CPI, from caustic solutions to hot acidic environments, from highly reducing to highly oxidizing. Stainless steels are ubiquitous since numerous types of stainless steels exist, each type tailored for specific applications. In general, stainless steels suffer stress corrosion cracking (SCC) in hot chloride environments while high Ni alloys are practically immune to this type of attack. High nickel alloys are also resistant to caustic cracking. Ti alloys find application in highly oxidizing solutions. Solutions containing fluoride ions, especially acid, seem to be aggressive to almost all corrosion resistant alloys.

  6. Electrochemical Evaluation of Corrosion Inhibitors to Austenistic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Yosmari Adames Montero

    2014-03-01

    Full Text Available The use of corrosion inhibitors is one of the most universal methods, and diffused for the protection ofmetals, because they reduce substantially the corrosion losses when they are added in smallconcentrations. At the present work it was carried out the electrochemical tests evaluation of twoinhibitors, A and B, to be used in the chemical cleanings for trays of heat interchanger, which aresuffering thickness losses until its perforation. By the chemical composition analysis, it wasdemonstrated that the metal is an austenistic stainless steel and by electrochemical tests of linearpolarization resistance, electrochemical noise and cyclic sweep, were demonstrated the localizedcorrosion. The best efficiency of the inhibitor A was obtained with one and two percent concentration,while the inhibitor B shows values efficiency near 95% with two percent concentration.

  7. Corrosion susceptibility of steel drums to be used as containers for intermediate level nuclear waste

    Directory of Open Access Journals (Sweden)

    Duffó G.

    2013-07-01

    Full Text Available The present work is a study of the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins contaminated with different types and concentrations of aggressive species. A special type of specimen was manufactured to simulate the cemented ion-exchange resins in the drum. The evolution of the corrosion potential and the corrosion rate of the steel, as well as the electrical resistivity of the matrix were monitored over a time period of 900 days. The aggressive species studied were chloride ions (the main ionic species of concern and sulphate ions (produced during radiolysis of the cationic exchange-resins after cementation. The work was complemented with an analysis of the corrosion products formed on the steel in each condition, as well as the morphology of the corrosion products. When applying the results obtained in the present work to estimate the corrosion depth of the steel drumscontaining the cemented radioactive waste after a period of 300 years (foreseen durability of the Intermediate Level Radioactive Waste facility in Argentina , it is found that in the most unfavourable case (high chloride contamination, the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums.

  8. Corrosion behavior of oxide dispersion strengthened ferritic steels in supercritical water

    Science.gov (United States)

    Gao, Wenhua; Guo, Xianglong; Shen, Zhao; Zhang, Lefu

    2017-04-01

    The corrosion resistance of three different Cr content oxide dispersion strengthened (ODS) ferritic steels in supercritical water (SCW) and their passive films formed on the surface have been investigated. The results show that the dissolved oxygen (DO) and chemical composition have significant influence on the corrosion behavior of the ODS ferritic steels. In 2000 ppb DO SCW at 650 °C, the 14Cr-4Al ODS steel forms a tri-layer oxide film and the surface morphologies have experienced four structures. For the tri-layer oxide film, the middle layer is mainly Fe-Cr spinel and the Al is gradually enriched in the inner layer.

  9. Stress corrosion cracking for 316 stainless steel clips in a condensate stabilizer

    Energy Technology Data Exchange (ETDEWEB)

    Al-Awar, A.; Aldajah, S.; Harhara, A. [Department of Mechanical Engineering, United Arab Emirates University, P. O. Box 17555 Al-AIn 17555 (United Arab Emirates)

    2011-09-15

    In one of the gas processing facilities in Abu Dhabi, UAE; a case of 316L stainless steel material failure occurred in the fractionating column due to stress cracking corrosion twice in a cycle of less than 2 years. This paper studies the stress corrosion cracking behavior of the 316L stainless steel in an accelerated corrosion environment and compares it with a higher corrosion resistant nickel alloy (Inconel 625). The experimental work was designed according to ASTM G36 standard, the samples were immersed in a boiling magnesium chloride medium which provided the accelerated corrosion environment and the tested samples were shaped into U-bend specimens as they underwent both plastic and elastic stresses. The specimens were then tested to determine the time required for cracks to initiate. The results of the experimental work showed that the main mode of failure was stress corrosion cracking initiated by the proven presence of chlorides, hydrogen sulfide, and water at elevated temperatures. Inconel 625 samples placed in the controlled environment showed better corrosion resistance as it took them an average of 56 days to initiate cracks, whereas it took an average of 24 days to initiate cracks in the stainless steel 316L samples. The scanning electron microscopy (SEM) micrographs showed that the cracks in the stainless steel 316L samples were longer, wider, and deeper compared to the cracks of Inconel 625. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Salt bath nitriding of 304 austenitic stainless steel at low temperature and corrosion resistance of nitriding layer%304奥氏体不锈钢低温盐浴氮化处理及其耐蚀性

    Institute of Scientific and Technical Information of China (English)

    黄润波; 闫静; 曾德志; 张太平; 胡泽晶; 罗伟; 王均

    2012-01-01

    采用低温(430℃)盐浴对304奥氏体不锈钢进行氮化处理,研究了氮化时间对渗氮层组织,显微硬度及耐蚀性的影响.分别用X射线衍射仪(XRD)、表面显微硬度计、光学显微镜分析了渗氮层的相组成、显微硬度、截面形貌和厚度.结果表明,304不锈钢表面的渗氮层厚度和显微硬度都随处理时间的延长而增大.氮化处理1h得到的渗氮层由单一的S相组成.经盐浴渗氮处理的304不锈钢,其耐Cl-点蚀性能得到改善,430℃下氮化4h得到的渗氮层耐蚀性能最好.%304 austenitic stainless steel was nitrided in a salt bath at low temperature (430 °C). The effects of nitriding time on microstructure, microhardness, and corrosion resistance of nitriding layer were studied. The phase composition, microhardness, cross-sectional morphology, and thickness of nitriding layer were examined by X-ray diffraction (XRD), microhardness tester, and optical microscopy. The results showed that the thickness and microhardness of nitriding layer on 304 stainless steel substrate are increased with the increasing of nitriding time. The layer obtained by nitriding for 1 h is composed of a single S phase. The 304 stainless steel shows improved corrosion resistance by nitriding and exhibits optimal corrosion resistance after nitriding for 4 h.

  11. Electrochemical Study of Welded AISI 304 and 904L Stainless Steel in Seawater in View of Corrosion

    Directory of Open Access Journals (Sweden)

    Richárd Székely

    2010-10-01

    Full Text Available This is a comparative study of the corrosion behaviour of welds in AISI 304 and AISI 904L stainless steels carried out in seawater model solution in the temperature range 5-35°C and the standard of corrosion testing of welds was followed. The corrosion rate and corrosion attack characteristics were determined for welds of the examined steels with several type of treatment. The aim of this work was to compare the steels based on their resistance against the corrosion in terms of pitting potential (Epit and repassivation potential (Erepass. Seawater is an electrochemically aggressive medium, which can initiate localised corrosion in welded stainless steels. Different electrochemical and testing methods were used, including cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy (EIS, pH measuring and penetration tests.

  12. Effect of environment on corrosion characteristics of newly developed DMR-1700 structural steel

    Directory of Open Access Journals (Sweden)

    Injeti Gurrappa and Guntupalli Malakondaiah

    2008-01-01

    Full Text Available The corrosion resistance of any metallic material depends on the environment to which it is exposed. DMR-1700 steel is a material for structural applications that has been recently developed at Defence Metallurgical Research Laboratory by changing the chemistry of alloying elements. Therefore, a detailed understanding of its corrosion characteristics under different environmental conditions is essential. In the present paper, we report the results of a systematic corrosion study that was carried out on the new steel to determine the effect of the environment on the protective nature of the oxide scale that forms on its surface under different environmental conditions. Furthermore, the oxide scale as well as the resistance to pitting and crevice corrosion were studied in various environments. The surface morphologies of the corroded steels were observed under a scanning electron microscope (SEM to determine the nature of the corrosion. On the basis of studies by different techniques, DMR-1700 steel is recommended for the manufacture of components used in various systems in conjunction with the application of an appropriate protective coating to improve its resistivity to corrosion.

  13. Systematic Study of Nanocrystalline Plasma Electrolytic Nitrocarburising of 316L Austenitic Stainless Steel for Corrosion Protection

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A number of studies have been reported on the use of nanocrystalline plasma electrolytic nitrocarburising technology for surface hardening of stainless steels for higher corrosion resistance resulted from this technique. However, very few studies have focused on the optimization of the nanocrystalline plasma electrolytic nitrocarburising process parameters. In this study, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the nanocrystalline plasma electrolytic nitrocarburising not only for surface hardening but also for the corrosion protection of 316L austenitic stainless steel by controlling the coating process's factors. The experimental design consisted of four factors (Urea concentration, electrical conductivity of electrolyte, voltage and duration of process), each containing three levels. Potentiodynamic polarization measurements were carried out to determine the corrosion resistance of the coated samples. The results were analyzed with related software. An analysis of the mean of signal-to-noise (S/N) ratio indicated that the corrosion resistance of nanocrystalline plasma electrolytic nitrocarburised 316L stainless steel was influenced significantly by the levels in the Taguchi orthogonal array. The optimized coating parameters for corrosion resistance are 1150 g/L for urea concentration, 360 mS/cm for electrical conductivity of electrolyte, 260 V for applied voltage, 6 min for treatment time. The percentage of contribution for each factor was determined by the analysis of variance (ANOVA). The results showed that the applied voltage is the most significant factor affecting the corrosion resistance of the coatings.

  14. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    Abstract Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC...... of carbon steel must be monitored on-line in order to provide an efficient protection and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic...... techniques even though localised corrosion rate cannot be measured. FSM measures general corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable...

  15. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    of carbon steel must be monitored on-line in order to provide an efficient protection and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic......Abstract Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC...... techniques even though localised corrosion rate cannot be measured. FSM measures general corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable...

  16. Corrosion monitoring of reinforcing steel in concrete by electrochemical sensors

    Science.gov (United States)

    Qiao, Guofu; Hong, Yi; Ou, Jinping

    2010-04-01

    Health degradation by corrosion of steel in civil engineering, especially in rough environment, is a persistent problem. Structural health monitoring (SHM) techniques can lead to improved estimates of structural safety and serviceability. A novel all solid state-current confined corrosion sensor has been developed to provide the platform for corrosion monitoring of the steel bar in concrete beam by electrochemical method. Finite element method has been used to certify the current confined effect of the sensor. The sensors have been used in concrete beams to monitor the corrosion of the steel bar. Also, half-cell potential of the beam has obtained. The results shows that the corrosion sensor can effectively confine the current in the fixed area which is 45mm×π×Dsteel bar and the monitoring results of the corrosion sensor are accurate.

  17. Peptide-based biocoatings for corrosion protection of stainless steel biomaterial in a chloride solution.

    Science.gov (United States)

    Muruve, Noah G G; Cheng, Y Frank; Feng, Yuanchao; Liu, Tao; Muruve, Daniel A; Hassett, Daniel J; Irvin, Randall T

    2016-11-01

    In this work, PEGylated D-amino acid K122-4 peptide (D-K122-4-PEG), derived from the type IV pilin of Pseudomonas aeruginosa, coated on 304 stainless steel was investigated for its corrosion resistant properties in a sodium chloride solution by various electrochemical measurements, surface characterization and molecular dynamics simulation. As a comparison, stainless steel electrodes coated with non-PEGylated D-amino acid retroinverso peptide (RI-K122-4) and D-amino acid K122-4 peptide (D-K122-4) were used as control variables during electrochemical tests. It was found that the D-K122-4-PEG coating is able to protect the stainless steel from corrosion in the solution. The RI-K122-4 coating shows corrosion resistant property and should be investigated further, while the D-K122-4 peptide coating, in contrast, shows little to no effect on corrosion. The morphological characterizations support the corrosion resistance of D-K122-4-PEG on stainless steel. The adsorption of D-K122-4 molecules occurs preferentially on Fe2O3, rather than Cr2O3, present on the stainless steel surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. 冻融环境下引气混凝土的抗钢筋锈蚀能力研究%Study on Ability of Resistance to Steel Corrosion of Air Entraining Concrete Under Freeze-thaw Environment

    Institute of Scientific and Technical Information of China (English)

    马志鸣; 赵铁军; 巴光忠; 管庭

    2014-01-01

    对带钢筋的普通混凝土及引气混凝土试件进行抗冻融循环试验,在不同冻融损伤程度下对试件进行氯离子侵蚀试验。利用半电池电位法和线性极化法分别测定经过不同冻融循环次数下混凝土试件内部钢筋的电位和腐蚀电流密度,从而定量地确定混凝土内部钢筋的锈蚀情况。研究结果表明:向混凝土内部掺入一定比例引气剂,可以提高混凝土的抗冻性能,从而增强其在腐蚀环境下抗钢筋锈蚀能力,提高了混凝土的耐久性能;对试件进行劈裂试验后,钢筋的实际锈蚀情况与利用由化学方法测定结果一致。%The freeze-thaw cycle tests of the ordinary concrete specimen and the air entraining concrete specimen with steel were carried out ,and the chloride corrosion tests under different freeze-thaw damage degrees were done . The potential values and corrosion current density of steel in concrete specimens were determined under different freeze-thaw cycle times by using half-cell potential method and linear polarization method ,then the steel corrosion condition in concrete was qualitatively determined . The study results show that adding air entraining agent can improve the anti-freeze property of concrete ,promote the ability of resistance to steel corrosion , and prolong the durability of concrete structure .After specimen splitting test ,the actual steel corrosion condition has the same result with the result by chemical approach .

  19. Corrosion resistance of 15Mo3 in steam boiler pipe surfaced with Inconel 625 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Aracic, S.; Samardzic, I.; Krumes, D. [Mechanical Engineering Faculty, Trg Ivane Brlic Mazuranic 18, HR-35000 Slavonski Brod (Croatia)

    2004-07-01

    This paper presents accelerated laboratory corrosion resistant investigation results made on steam boiler 15Mo3 steel pipes surfaced with alloy Inconel 625. Surfacing of 15Mo3 pipes was made due to pipes corrosion resistance increase in exploitation conditions which are present in fire box of trash burning plant. Corrosion resistance investigations were made in fire box simulated atmosphere and in salt spray chamber. (authors)

  20. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo

    2005-01-01

    Effects of film formation on carbon steel in hydrogen sulfide media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from hydrogen sulfide solutions, biological sulfide media and natural sulfide containing geothermal water have been collected and the process...... corrosion rates, but this effect may not be detected if rates are already overestimated. It is concluded that electrochemical techniques can be used for corrosion rate monitoring in som hydrogen sulfide media, but care must be taken when choosing the scan rates, and it is important to realize when direct...... in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Oxygen entering the system accelerates...

  1. Acoustic emission detection of 316L stainless steel welded joints during intergranular corrosion

    Institute of Scientific and Technical Information of China (English)

    Meng-yu Chai; Quan Duan; Wen-jie Bai; Zao-xiao Zhang; Xu-meng Xie

    2015-01-01

    This study analyzes acoustic emission (AE) signals during the intergranular corrosion (IGC) process of 316L stainless steel welded joints under different welding currents in boiling nitric acid. IGC generates several AE signals with high AE activity. The AE tech-nique could hardly distinguish IGC in stainless steel welded joints with different welding heat inputs. However, AE signals can effectively distinguish IGC characteristics in different corrosion stages. The IGC resistance of a heat-affected zone is lower than that of a weld zone. The initiation and rapid corrosion stages can be distinguished using AE results and microstructural analysis. Moreover, energy count rate and am-plitude are considered to be ideal parameters for characterizing different IGC processes. Two types of signals are detected in the rapid corro-sion stage. It can be concluded that grain boundary corrosion and grain separation are the AE sources of type 1 and type 2, respectively.

  2. Cathodic corrosion protection of steel pipes; Kathodischer Korrosionsschutz von Rohrleitungsstaehlen

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Markus [SGK Schweizerische Gesellschaft fuer Korrosionsschutz, Zuerich (Switzerland); Schoeneich, Hanns-Georg [Open Grid Europe, Essen (Germany)

    2011-07-01

    The cathodic corrosion protection has been proven excellently in the practical use for buried steel pipelines. This is evidenced statistically by a significantly less frequency of loss compared to non-cathodically protected pipelines. Based on thermodynamic considerations, the authors of the contribution under consideration describe the operation of the cathodic corrosion protection and regular adjustment of the electrochemical potential at the interface steel / soil in practical use. Subsequently, the corrosion scenarios are discussed that may occur when an incorrect setting of the potential results from an operation over several decades. This incorrect setting also can be caused by the failure of individual components of the corrosion protection.

  3. Modeling Corrosion Reactions of Steel in a Dilute Carbonate Solution

    Science.gov (United States)

    Eliyan, Faysal Fayez; Alfantazi, Akram

    2016-02-01

    This research models the corrosion reactions of a high-strength steel in an aerated, dilute, carbonate solution during a single-cycle voltammetry. Based on a previous study (Eliyan et al. in J Mater Eng Perform 24(6):1-8, 2015) and a literature survey, the corrosion reactions of the cathodic reduction, anodic dissolution, and passivation, as well as the interfacial interactions and the chemistry of the corrosion products are illustrated in schematics. The paper provides a visual guide on the corrosion reactions for steel in carbonate solutions based on the available mechanistic details that were reported and are still being investigated in literature.

  4. Effect of Pharmaceutically Active Compound Nitroxoline on the Corrosion of Mild Steel in an Acidic Environment

    Directory of Open Access Journals (Sweden)

    R. Ganapathi Sundaram

    2016-01-01

    Full Text Available The effect of Nitroxoline, antibiotic drug, was tested as a corrosion inhibitor for mild steel (MS in an acidic environment by chemical method (mass loss measurement and electrochemical methods such as electrochemical impedance spectroscopy and potentiodynamic polarization. The surface morphology of mild steel was investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, and atomic force microscopy techniques. From the chemical and electrochemical methods, the resistance of corrosion was increased with the addition of Nitroxoline concentration. Tafel curves indicate that the pharmaceutically active compound is a cathodic type inhibitor. An adsorption of Nitroxoline on the surface of mild steel was obeyed by Langmuir isotherm. SEM, EDX, and AFM techniques prove the adsorption process. All the obtained results confirmed that the investigated compound Nitroxoline acts as a good inhibitor for the corrosion of mild steel in an acidic environment.

  5. Effect of piperidones on hydrogen permeation and corrosion inhibition of mild steel in acidic solutions

    Indian Academy of Sciences (India)

    S Muralidharan; R Chandrasekar; S V K Iyer

    2000-04-01

    The influence of 3-methyl-2,6-diphenyl piperidin-4-one (MDPO) and 2-phenyl decahydroquinoline-4-one (PDQO) synthesised in the laboratory on hydrogen permeation and corrosion inhibition of mild steel in 1N H2SO4 has been studied using weight loss and various electrochemical AC and DC corrosion-monitoring techniques. Both the compounds inhibit the corrosion of mild steel in H2SO4 Potentiodynamic polarisation studies clearly reveal that they behave predominantly as cathodic inhibitors. The extent of decrease in hydrogen permeation current through steel surfaces has been studied by the hydrogen electropermeation technique. Double layer capacitance () and charge transfer resistance () values are derived from Nyquist plots obtained from AC impedance studies. The adsorption of these compounds on mild steel surfaces from H2SO4 obeys Temkin’s adsorption isotherm.

  6. Passivation and Corrosion Behavior of Modified Ferritic-Pearlitic Railway Axle Steels

    Science.gov (United States)

    Moon, A. P.; Sangal, S.; Srivastav, Simant; Gajbhiye, N. S.; Mondal, K.

    2015-01-01

    Electrochemical polarization behavior of two newly developed ferritic-pearlitic railway axle steels (MS3 and MS6) and the standard Indian conventional axle steel has been studied in sodium borate buffer solution of pH 8.4 with and without the presence of NaCl. The polarization behavior of both the new axle steels shows close resemblance, whereas, different polarization behavior has been observed for the conventional axle steel. Electrochemical impedance spectroscopy measurements have clearly reflected significantly improved passivation behavior for the newly developed steels compared to that of the conventional axle steel. NaCl salt fog exposure tests have also shown superior corrosion resistance of the newly developed axle steels as compared to the conventional axle steel. Higher surface roughness on the corroded conventional axle steel has also been observed compared to the smoother surface in case of the new axle steels. Higher corrosion resistance of the new axle steels has been attributed to their finer microstructure and strongly adherent protective rusts.

  7. Corrosion inhibitors in concrete. Part II: Effect on chloride threshold values for corrosion of steel in synthetic pore solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mammoliti, L.; Hansson, C.M.; Hope, B.B.

    1999-10-01

    The effectiveness of four commercially available corrosion inhibitors for use in cement-based materials was assessed in synthetic concrete pore solution containing chlorides. The effect of the surface topography of the sample and the composition of the pore solution was also assessed. Although in a parallel study the inhibitors were observed to delay the onset of corrosion, in these tests in pore solution they were found to be ineffective in increasing the chloride threshold value of reinforcing steel exposed to chlorides and had little influence on the progression of corrosion once initiated. This suggests that chemical reactions within the cement phase are responsible for the observed results. Metallographically polished samples proved the most resistant to corrosion regardless of electrolyte composition and samples with all surface finishes exhibited lower resistance in solutions containing only calcium hydroxide than in the higher pH synthetic concrete pore solutions.

  8. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Prabhu Paulraj

    2015-08-01

    Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

  9. Accelerating Effect of Wetting-Drying Cycles on Steel Bar Corrosion in Concrete

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Raining and sun-shining processes in natural climate were simulated by water spraying and infrared light shining alternately as wetting-drying cycles in accelerated durability test. The accelerating effects of the wetting-drying cycles and the variation of corrosion current density and corrosion potential of steel bar in concrete under such conditions were studied. The result shows that the main reason leading to accelerating corrosion of steel bar in concrete is the wetting-drying cycles, which can cause the increase of corrosion potential difference between the anode and cathode of steel bar corrosion cell and the decrease of concrete resistance. Corrosion rate of the steel bar in concrete under four typical conditions, including wetting-drying cycle, long time submerging in water, long time exposure to indoor and outdoor environment were measured and compared. The test results indicate that the corrosion rates under the four typical conditions are in the order of spraying and infrared light shining cycles, outdoor environment, indoor environment, and submerging in water, respectively.

  10. The corrosion behavior of nano-meter embedded phase in Ti implanted H13 steel

    Institute of Scientific and Technical Information of China (English)

    张通和; 吴瑜光; 邓志威; 马芙蓉; 王晓妍; 梁宏; 周固; 赵渭江; 薛建明

    1999-01-01

    On the SEM micrographs of Ti implanted H13 steel, a tree-branch-like structure can be observed. Further investigation with TEM shows that the newly tormed composition is a formation of nann-meter FeTi2 phase in Ti implanted layer. The layer with a relatively high corrosion resistance has been formed in Ti implanted H13 steel with this structure.The results of electrochemical measurement show that the corrosion current density decreases obviously with an increase of ion dose. The corrosion current density in Ti implanted steel with a dose of 1.3×1018/cm2 is 8-20 times less than that of Ti implanted steel with a dose of 6×1017/cm2. The corrosion behavior of Ti implanted steel with a dose of 6×1017/cm2 could be further improved as the sample was annealed at 500℃ for 20 min and the corrosion current density decreases by 48-80 times compared to that of non-implanted samples. The corrosion trace was not observed on the annealing sample by SEM, after multi-sweep cyclic voltammetry of 40 cycles

  11. Structure and Corrosion Resistance of a Composite γ-Amino Propyl Triethoxy Silane and γ-Glycidoxy Propyl Trimethoxy Silane Conversion Coating on Galvanized Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; LIU Chang-sheng; YU Hai-yun; AN Cheng-qiang

    2012-01-01

    In an aqueous solution of the mixtures of γ-amino propyl triethoxy silane and γ-glycidoxy propyl trimethoxy silane, a composite silane conversion coating was developed on galvanized steel. FESEM (field emission scanning electron microscope), XPS (X-ray photoelectron spectroscopy), ATR FTIR (attenuated total reflection Flourier transform infrared spectroscopy) and SST (salt spray test) were used to characterize the obtained composite silane conversion coating and also the coating formation process was studied. The result showed that the surface of the composite silane conversion coating was complete, consecutive and compact. The coating could endure a neutral salt spray test for 72 h without corrosion. The result of salt spray test indicated that the composite silane conversion coating can provide a better corrosion inhibition than the coating which was composed of the single silane. Based on observation and analysis, it was proposed that the formation process of the silane coating on zinc should consist of three steps: the hydrolysis of the silane molecules, silane chemical adsorption and silane crosslinking condensation. The crosslinking reactions took place between ~'-amino propyl triethoxy and "/-glycidoxy propyl trimethoxy silane during the forming process of the coating, and a high crosslinked density interpenetrating structure network was obtained, so the composite silane conversion coating could keep the corrosive substances from the zinc more effectively.

  12. Hot Corrosion Behavior of HVOF Sprayed Coatings on ASTM SA213-T11 Steel

    Science.gov (United States)

    Sidhu, H. S.; Sidhu, B. S.; Prakash, S.

    2007-09-01

    Cr3C2-NiCr, NiCr, WC-Co and Stellite-6 alloy coatings were sprayed on ASTM SA213-T11 steel using the HVOF process. Liquid petroleum gas was used as the fuel gas. Hot corrosion studies were conducted on the uncoated as well as HVOF sprayed specimens after exposure to molten salt at 900 °C under cyclic conditions. The thermo-gravimetric technique was used to establish the kinetics of corrosion. XRD, SEM/EDAX and EPMA techniques were used to analyze the corrosion products. All these overlay coatings showed a better resistance to hot corrosion as compared to that of uncoated steel. NiCr Coating was found to be most protective followed by the Cr3C2-NiCr coating. WC-Co coating was least effective to protect the substrate steel. It is concluded that the formation of Cr2O3, NiO, NiCr2O4, and CoO in the coatings may contribute to the development of a better hot-corrosion resistance. The uncoated steel suffered corrosion in the form of intense spalling and peeling of the scale, which may be due to the formation of unprotective Fe2O3 oxide scale.

  13. Spectral Analysis of CO{sub 2} Corrosion Product Scales on 13Cr Tubing Steel

    Energy Technology Data Exchange (ETDEWEB)

    Guan-fa, Lin; Zhen-quan, Bai; Yao-rong, Feng [The Key Laboratory for Mechanical and Environmental Behavior of Tubular Goods, Xi' an (China); Xun-yuan, Xu [PetroChina Tarim Oilfeld Compamy, Korla (China)

    2008-08-15

    CO{sub 2} corrosion product scales formed on 13 Cr tubing steel in autoclave and in the simulated corrosion environment of oil field are investigated in the paper. The surface and cross-section profiles of the scales were observed by scanning electron microscopy (SEM), the chemical compositions of the scales were analyzed using energy dispersion analyzer of X-ray (EDAX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to confirm the corrosion mechanism of the 13 Cr steel in the simulated CO{sub 2} corrosion environment. The results show that the corrosion scales are formed by the way of fashion corrosion, consist mainly of four elements, i.e. Fe, Cr, C and O, and with a double-layer structure, in which the surface layer is constituted of bulky and incompact crystals of FeCO{sub 3}, and the inner layer is composed of compact fine FeCO{sub 3} crystals and amorphous Cr(OH){sub 3}. Because of the characteristics of compactness and ionic permeating selectivity of the inner layer of the corrosion product scales, 13 Cr steel is more resistant in CO{sub 2} corrosion environment.

  14. A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-08-21

    The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.

  15. Monitoring Corrosion of Steel Bars in Reinforced Concrete Structures

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar Verma

    2014-01-01

    Full Text Available Corrosion of steel bars embedded in reinforced concrete (RC structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP method. This paper also presents few techniques to protect concrete from corrosion.

  16. Corrosion of Steel in Concrete – Thermodynamical Aspects

    DEFF Research Database (Denmark)

    Küter, Andre; Møller, Per; Geiker, Mette Rica

    2004-01-01

    The present understanding of selected corrosion phenomena in reinforced concrete is reviewed. Special emphasis is given to chloride induced corrosion. There is a general acceptance of the basic corrosion mechanism for steel in concrete. However different anodic reactions governing the subsequent...... formation and composition of corrosion products have been proposed. Suggested reactions, except half-cell reactions, are verified or rejected based on their Gibbs free energy, while the electrode potential is calculated for half-cell reactions. Corrosion products postulated to form are related...

  17. Monitoring corrosion of steel bars in reinforced concrete structures.

    Science.gov (United States)

    Verma, Sanjeev Kumar; Bhadauria, Sudhir Singh; Akhtar, Saleem

    2014-01-01

    Corrosion of steel bars embedded in reinforced concrete (RC) structures reduces the service life and durability of structures causing early failure of structure, which costs significantly for inspection and maintenance of deteriorating structures. Hence, monitoring of reinforcement corrosion is of significant importance for preventing premature failure of structures. This paper attempts to present the importance of monitoring reinforcement corrosion and describes the different methods for evaluating the corrosion state of RC structures, especially hal-cell potential (HCP) method. This paper also presents few techniques to protect concrete from corrosion.

  18. Corrosion behaviour of steels and refractory metals and tensile features of steels exposed to flowing PbBi in the LECOR loop

    Energy Technology Data Exchange (ETDEWEB)

    Fazio, C. E-mail: concetta.fazio@psf.fzk.de; Ricapito, I.; Scaddozzo, G.; Benamati, G

    2003-05-15

    An experimental activity has been started using the LECOR loop at the ENEA Brasimone centre to investigate the corrosion behaviour of steels and refractory metals as well as the tensile properties of steels exposed to flowing liquid lead bismuth with low oxygen activity. The oxygen content in the liquid metal was controlled and monitored by a dedicated system. The compatibility test was performed at 673 K and the corrosion and tensile results herein reported concern the first 1500-h run of the loop operation. All the materials tested suffered from liquid metal attack exhibiting a weight loss. The consequent evaluation of the corrosion rate showed that, under the given test conditions, the refractory metals are more resistant than the steels. The tensile properties of austenitic steel are not affected by the liquid metal corrosion, while the martensitic steel exhibited a mixed brittle-ductile fracture surface.

  19. INHIBITION OF THE CORROSION OF MILD STEEL IN ...

    African Journals Online (AJOL)

    explained in terms of the difference in their molecular structures and solubility rather than .... Kinetic and thermodynamic data for the corrosion of mild steel in 0.1 M HCl solution containing ... transition state theory for ING and IN, respectively.

  20. ELECTROCHEMICAL STUDIES ON THE CORROSION OF CARBON STEEL IN OXALIC ACID CLEANING SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B; John Mickalonis, J

    2007-10-08

    The Savannah River Site (SRS) will disperse or dissolve precipitated metal oxides as part of radioactive waste tank closure operations. Previously SRS has utilized oxalic acid to accomplish this task. Since the waste tanks are constructed of carbon steel, a significant amount of corrosion may occur. Although the total amount of corrosion may be insignificant for a short contact time, a significant amount of hydrogen may be generated due to the corrosion reaction. Linear polarization resistance and anodic/cathodic polarization tests were performed to investigate the corrosion behavior during the process. The effect of process variables such as temperature, agitation, aeration, sample orientation, light as well as surface finish on the corrosion behavior were evaluated. The results of the tests provided insight into the corrosion mechanism for the iron-oxalic acid system.

  1. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    Directory of Open Access Journals (Sweden)

    Shih-Chen Shi

    2016-07-01

    Full Text Available The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC, hydroxypropyl methylcellulose phthalate (HPMCP, and hydroxypropyl methylcellulose acetate succinate (HPMCAS film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate promising anti-corrosion performance of HPMC and HPMCP. With increasing film thickness, both materials reveal improvement in corrosion inhibition. Moreover, because of a hydrophobic surface and lower moisture content, HPMCP shows better anti-corrosion performance than HPMCAS. The study is of certain importance for designing green corrosion inhibitors of high speed steel surfaces by the use of biopolymer derivatives.

  2. Corrosion of ferritic-martensitic steels and nickel-based alloys in supercritical water

    Science.gov (United States)

    Ren, Xiaowei

    The corrosion behavior of ferritic/martensitic (F/M) steels and Ni-based alloys in supercritical water (SCW) has been studied due to their potential applications in future nuclear reactor systems, fossil fuel power plants and waste treatment processes. 9˜12% chromium ferritic/martensitic steels exhibit good radiation resistance and stress corrosion cracking resistance. Ni-based alloys with an austenitic face-centered cubic (FCC) structure are designed to retain good mechanical strength and corrosion/oxidation resistance at elevated temperatures. Corrosion tests were carried out at three temperatures, 360°C, 500°C and 600°C, with two dissolved oxygen contents, 25 ppb and 2 ppm for up to 3000 hours. Alloys modified by grain refinement and reactive element addition were also investigated to determine their ability to improve the corrosion resistance in SCW. A duplex oxide structure was observed in the F/M steels after exposure to 25 ppb oxygen SCW, including an outer oxide layer with columnar magnetite grains and an inner oxide layer constituted of a mixture of spinel and ferrite phases in an equiaxed grain structure. An additional outermost hematite layer formed in the SCW-exposed samples when the oxygen content was increased to 2 ppm. Weight gain in the F/M steels increased with exposure temperatures and times, and followed parabolic growth kinetics in most of the samples. In Ni-based alloys after exposure to SCW, general corrosion and pitting corrosion were observed, and intergranular corrosion was found when exposed at 600°C due to formation of a local healing layer. The general oxide structure on the Ni-based alloys was characterized as NiO/Spinel/(CrxFe 1-x)2O3/(Fe,Ni). No change in oxidation mechanism was observed in crossing the critical point despite the large change in water properties. Corrosion resistance of the F/M steels was significantly improved by plasma-based yttrium surface treatment because of restrained outward diffusion of iron by the

  3. Welding and corrosion resistance of the new nitrogen alloyed steel X2 CrNiMnMoN241764. Caracteristicas de soldadura y resistencia a la corrosion de nuevo acero X2 CrNiMnMoN 241764 aleado con nitrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Arit, N.; Henser, H.; GroB, V.

    1994-01-01

    Remanit 4565 S is a new developed nitrogen alloyed austenitic stainless steel. Characteristic features are: improved strength and toughness, delayed precipitation of carbides and intermetallic phases, improved corrosion resistance. Welding fabrication is possible without the risk of pore formation. TIG-welded joints are as resistant as the base metal, using filler metal SG-NiCr 20 Mo 15 (Thermanit Nimo C) respectively SG-NiCr 28 Mo(Thermanit 30/40 E) according to the area of application. (Author) 8 refs.

  4. Corrosion of aluminium, stainless steels and AISI 680 nickel alloy in nitrogen-based fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kap, I.; Starostin, M.; Shter, G.E.; Grader, G.S. [Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa (Israel)

    2012-07-15

    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. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. [Measurement of low corrosion rate of coronary stents-made of 316L and 317L stainless steel].

    Science.gov (United States)

    Liang, Chenghao; Guo, Liang; Chen, Wan

    2006-08-01

    Electrochemical constant current linear polarization and atomic absorption spectroscopy were used to measure the corrosion rate of coronary stents made of 316L and 317L stainless steel in 30 degrees C Tyrode's solution. The results indicated that the corrosion rate of 316L and 317L stainless steel was 21 X 10(-3) microm/a, 9.8 X 10(-3) microm/a and 0.8 X 10(-3) m/a, 0.6 X 10(-3) microm/a, respectively. All corrosion rates were lower than the medical materials corrosion rate criteria, i.e. 0.25 microm/a. Moreover the corrosion resistance of 317L stainless steel was much higher than that of 316L stainless steel. The results from atomic absorption spectroscopy may correctly reflect the quantity of releasing metal ions in the solution.

  6. Effect of Aging Temperature on Corrosion Behavior of Sintered 17-4 PH Stainless Steel in Dilute Sulfuric Acid Solution

    Science.gov (United States)

    Szewczyk-Nykiel, Aneta; Kazior, Jan

    2017-07-01

    The general corrosion behavior of sintered 17-4 PH stainless steel processed under different processing conditions in dilute sulfuric acid solution at 25 °C was studied by open-circuit potential measurement and potentiodynamic polarization technique. The corrosion resistance was evaluated based on electrochemical parameters, such as polarization resistance, corrosion potential, corrosion current density as well as corrosion rate. The results showed that the precipitation-hardening treatment could significantly improve the corrosion resistance of the sintered 17-4 PH stainless steel in studied environment. As far as the influence of aging temperature on corrosion behavior of the sintered 17-4 PH stainless steel is concerned, polarization resistance and corrosion rate are reduced with increasing aging temperature from 480 up to 500 °C regardless of the temperature of solution treatment. It can be concluded that the highest corrosion resistance in 0.5 M H2SO4 solution exhibits 17-4 PH after solution treatment at 1040 °C followed by aging at 480 °C.

  7. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    OpenAIRE

    Shih-Chen Shi; Chieh-Chang Su

    2016-01-01

    The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS) film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate prom...

  8. Corrosion Protection of Steels by Conducting Polymer Coating

    Directory of Open Access Journals (Sweden)

    Toshiaki Ohtsuka

    2012-01-01

    Full Text Available The corrosion protection of steels by conducting polymer coating is reviewed. The conducting polymer such as polyaniline, polypyrrole, and polythiophen works as a strong oxidant to the steel, inducing the potential shift to the noble direction. The strongly oxidative conducting polymer facilitates the steel to be passivated. A bilayered PPy film was designed for the effective corrosion protection. It consisted of the inner layer in which phosphomolybdate ion, PMo12O3−40 (PMo, was doped and the outer layer in which dodecylsulfate ion (DoS was doped. The inner layer stabilized the passive oxide and the outer possessed anionic perm-selectivity to inhibit the aggressive anions such as chloride from penetrating through the PPy film to the substrate steel. By the bilayered PPy film, the steel was kept passive for about 200 h in 3.5% sodium chloride solution without formation of corrosion products.

  9. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    KAUST Repository

    Serdar, Marijana

    2015-05-01

    © 2015 Elsevier Ltd All rights reserved. The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide-hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel.

  10. Effects of Sodium Thiosulfate and Sodium Sulfide on the Corrosion Behavior of Carbon Steel in an MDEA-Based CO2 Capture Process

    Science.gov (United States)

    Emori, W.; Jiang, S. L.; Duan, D. L.; Zheng, Y. G.

    2017-01-01

    The corrosion behavior of carbon steel has been tested in the presence of sodium thiosulfate and sodium sulfide in an MDEA-based CO2 capture system using electrochemical methods, weight loss measurements and surface analysis. The results of electrochemical measurements revealed that both thiosulfate and sulfide showed corrosion resistance properties to carbon steel corrosion. The corrosion resistance for the system with thiosulfate increased with concentration, while the system with sulfide yielded better corrosion resistance to carbon steel at lower concentrations as increase in sulfide concentration decreased the corrosion resistance. The corrosion inhibition behaviors for both systems at 0.05 M salt concentrations were confirmed by weight loss measurement, and the solution with sodium sulfide exhibited a better inhibition with time.

  11. Effects of Sodium Thiosulfate and Sodium Sulfide on the Corrosion Behavior of Carbon Steel in an MDEA-Based CO2 Capture Process

    Science.gov (United States)

    Emori, W.; Jiang, S. L.; Duan, D. L.; Zheng, Y. G.

    2016-12-01

    The corrosion behavior of carbon steel has been tested in the presence of sodium thiosulfate and sodium sulfide in an MDEA-based CO2 capture system using electrochemical methods, weight loss measurements and surface analysis. The results of electrochemical measurements revealed that both thiosulfate and sulfide showed corrosion resistance properties to carbon steel corrosion. The corrosion resistance for the system with thiosulfate increased with concentration, while the system with sulfide yielded better corrosion resistance to carbon steel at lower concentrations as increase in sulfide concentration decreased the corrosion resistance. The corrosion inhibition behaviors for both systems at 0.05 M salt concentrations were confirmed by weight loss measurement, and the solution with sodium sulfide exhibited a better inhibition with time.

  12. Selection of Corrosion Resistant Materials for Nuclear Waste Repositories

    Energy Technology Data Exchange (ETDEWEB)

    R.B. Rebak

    2006-08-28

    Several countries are considering geological repositories to dispose of nuclear waste. The environment of most of the currently considered repositories will be reducing in nature, except for the repository in the US, which is going to be oxidizing. For the reducing repositories, alloys such as carbon steel, stainless steels and titanium are being evaluated. For the repository in the US, some of the most corrosion resistant commercially available alloys are being investigated. This paper presents a summary of the behavior of the different materials under consideration for the repositories and the current understanding of the degradation modes of the proposed alloys in ground water environments from the point of view of general corrosion, localized corrosion and environmentally assisted cracking.

  13. Selection of Corrosion Resistant Materials for Nuclear Waste Repositories

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B

    2006-06-01

    Several countries are considering geological repositories to dispose of nuclear waste. The environment of most of the currently considered repositories will be reducing in nature, except for the repository in the US, which is going to be oxidizing. For the reducing repositories alloys such as carbon steel, stainless steels and titanium are being evaluated. For the repository in the US, some of the most corrosion resistant commercially available alloys are being investigated. This paper presents a summary of the behavior of the different materials under consideration for the repositories and the current understanding of the degradation modes of the proposed alloys in ground water environments from the point of view of general corrosion, localized corrosion and environmentally assisted cracking.

  14. Corrosion behavior of steel in concrete made with slag-blended cement

    Energy Technology Data Exchange (ETDEWEB)

    Dehghanian, C. [Univ. of Technology, Isfahan (Iran, Islamic Republic of). Dept. of Chemical Engineering

    1999-03-01

    Concretes formulated with slag as a partial replacement for cement were used to evaluate the corrosion behavior of steel embedded in concrete, resistivity, and the compressive strength of the concrete. Corrosion rates and pitting corrosion of steel in concrete with up to 30% slag and exposed to sodium chloride (NaCl) solutions decreased. Slag-blended cement concrete increased concrete resistivity. A water-to-cement ratio <0.55 and submersion in water for a period of 18 days gave the best chloride (Cl{sup {minus}}) diffusion resistance from the external salt solutions. Compressive strength of the concrete decreased with addition of slag in the early ages of the concrete. After 5 months of age, compressive strength of the concrete increased with addition of slag. This trend continued with up to 30% slag addition.

  15. Wear resistance and hot corrosion behaviour of laser cladding Co-based alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    2Cr13 stainless steel was surface cladded with Co-based alloy using a high power carbon dioxide laser. The microstructure, wear resistance and corrosion properties of the clad layer were investigated. It is found that the high temperature corrosion behavior and wearing resistant property of the clad layer are 3 and 2.5 times higher than those of the parent metal. Under the high temperature molten lead sulphate salt corrosion condition, the clad layer fails by spalling which is caused by intergrannular corrosion within the clad layer. The fine dendritic structure and the oxide help to retard the penetration of the sulphur ion that induces the intergrannular corrosion.

  16. Comparison of electrochemical techniques during the corrosion of X52 pipeline steel in the presence of sulfate reducing bacteria (SRB)

    Energy Technology Data Exchange (ETDEWEB)

    Galvan-Martinez, R.; Genesca, J. [Universidad Nacional Autonoma de Mexico (UNAM), Facultad de Quimica, Depto. de Ingenieria Metalurgica, Ciudad Universitaria. Mexico DF, CP 04510 (Mexico); Garcia-Caloca, G.; Duran-Romero, R.; Mendoza-Flores, J. [Instituto Mexicano del Petroleo, Direccion Ejecutiva de Exploracion y Produccion, Corrosion, Eje Central Lazaro Cardenas 152, Mexico D.F., 07730 (Mexico); Torres-Sanchez, R. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigaciones, Metalurgicas. Edificio ' ' U' ' , C.U. Morelia, Michoacan (Mexico)

    2005-10-01

    This work compares three electrochemical techniques, linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN), used in the study of corrosion of X52 steel samples in an environment containing a culture of sulfate reducing bacteria (SRB). The study emphasizes the different electrochemical information obtained when using these techniques in microbiologically influenced corrosion (MIC) studies. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  17. The corrosion and stress corrosion cracking behavior of a novel alumina-forming austenitic stainless steel in supercritical water

    Science.gov (United States)

    Sun, Hongying; Yang, Haijie; Wang, Man; Giron-Palomares, Benjamin; Zhou, Zhangjian; Zhang, Lefu; Zhang, Guangming

    2017-02-01

    The general corrosion and stress corrosion behavior of Fe-27Ni-15Cr-5Al-2Mo-0.4Nb alumina-forming austenitic (AFA) steel were investigated in supercritical water under different conditions. A double layer oxide structure was formed: a Fe-rich outer layer (Fe2O3 and Fe3O4) and an Al-Cr-rich inner layer. And the inner layer has a low growth rate with exposing time, which is good for improvement of corrosion resistance. Additionally, some internal nodular Al-Cr-rich oxides were also observed, which resulted in a local absence of inner layer. Stress corrosion specimens exhibited a combination of high strength, good ductility and low susceptibility. The stress strength and elongation was reduced by increasing temperature and amount of dissolved oxygen. In addition, the corresponding susceptibility was increased with decreased temperatures and increased oxygen contents.

  18. Tropical Weather Resistant Galvanized Steel Coated and Uncoated

    Directory of Open Access Journals (Sweden)

    Suárez-Corrales Xenia Isbel

    2014-01-01

    Full Text Available The corrosion behavior of coated and uncoated galvanized steel products is determined by exposing them to accelerated and natural climatic test. Accelerated tests were carried out in climatic chambers and natural atmospheric test in a marine-coastal station (Cojimar. The influence of tropical humid climate on these products is determined. Adhesion is an important property for a good performance, from the decorative point of view or as an additional protection. The evaluation indicates that 95% of the galvanized steel products show a good corrosion resistance; although 71% of coated galvanized products and 100% of painted galvanized products do not cover the requirements with respect to the mechanical and corrosion protection aspects. For a good efficiency and economic performance of metal mechanical industry, a correct surface treatment and coating application is required. A key point is to increase the quality by improving a better corrosion protective performance respecting uncoated galvanized steel.

  19. Relationship Between pH and Electrochemical Corrosion Behavior of Thermal-Sprayed Ni-Al-Coated Q235 Steel in Simulated Soil Solutions

    Science.gov (United States)

    Wei, Wei; Wu, Xin-qiang; Ke, Wei; Xu, Song; Feng, Bing; Hu, Bo-tao

    2017-09-01

    Electrochemical corrosion behavior of a thermal-sprayed Ni-Al-coated Q235 steel was investigated in the simulated soil solutions at different pH values using measurements of potentiodynamic polarization curves and electrochemical impedance spectroscopy as well as surface analyses including x-ray diffraction analysis, scanning electron microscope equipped with an energy-dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The results showed that the corrosion resistance of the Ni-Al-coated Q235 steel was dependent on the pH of the test solution. From pH = 3.53 to pH = 4.79, the corrosion resistance of the coated steel increased rapidly. In the pH range from 4.79 to 12.26, the corrosion resistance exhibited no significant change. At pH 13.25, the corrosion resistance of the sample was found to decrease. The calculated corrosion rate of Ni-Al-coated Q235 steel was lower than that of the uncoated Q235 steel and galvanized steel in all the test solutions. Over a wide range of pH values, the Ni-Al-coated Q235 steel exhibited extremely good corrosion resistance. The experimental data together with the potential-pH diagrams provided a basis for a detailed discussion of the related corrosion mechanisms of the coated steel.

  20. Electrochemical corrosion behavior of X52 and X60 steels in carbon dioxide containing saltwater solution

    OpenAIRE

    Rihan Omar Rihan

    2013-01-01

    X52 and X60 high strength low alloy (HSLA) steels are widely used in the construction of petroleum pipelines. This paper discusses the corrosion resistance of X52 and X60 steels in CO2 containing saltwater at pH 4.4 and 50 ºC. A circulating flow loop system inside an autoclave was used for conducting the experimental work. The rotating impeller speed was 2000 rpm. The corrosion rate was monitored using in situ electrochemical methods such as potentiodynamic sweep, linear polarization resistan...

  1. Improvement of stress corrosion cracking (SCC) resistance by cyclic pre-straining of 316L austenitic stainless steel in an aqueous boiling MgCl{sub 2} solution; Amelioration de la tenue a la corrosion sous contrainte (CSC) de l'acier inoxydable austenitique 316L en solution bouillante de MgCl{sub 2} par application d'une predeformation cyclique

    Energy Technology Data Exchange (ETDEWEB)

    Curiere, I. de; Bayle, B.; Magnin, Th. [Ecole Nationale Superieure des Mines, URA CNRS 1884, 42 - Saint-Etienne (France)

    2000-07-01

    Improving the materials resistance to stress corrosion cracking (SCC) has become a topic of wide interest for theoretical, engineering and financial reasons. The aim of this paper is to propose a process to delay the SCC damage. Recent studies of 316L austenitic stainless steel in boiling MgCl{sub 2} solutions show an improvement in SCC resistance by cyclic pre-straining in low cycle fatigue. This improvement consists of an increase in both strain to failure and crack initiation strain, during Slow Rate Tensile (SSRT) tests in aqueous solution. This paper analyses the effect of pre-fatigue in 316L on its mechanical and electrochemical responses to better understand the delay of SCC damage in boiling MgCl{sub 2}. The explanation for this beneficial effect is related to a modification of both surface electrochemical reactions kinetics and corrosion/plasticity interactions at the crack tip, due to the particular dislocation structure. (authors)

  2. An Evaluation of the Corrosion and Mechanical Performance of Interstitially Surface Hardened Stainless Steel

    Science.gov (United States)

    2013-05-10

    metallography and microhardness profiling. The corrosion performance of the hardened surface is assessed using electrochemical potentiodynamic testing to...cracking resistance, and galling performance. Metallurgical Evaluation: Microhardness testing was conducted for Processes B1 and B2, which represent...incorporated experimental testing conducted on 316L stainless steel that has been surface hardened using available commercial techniques, using both

  3. Research on Improving Corrosion Resistance Property of Welded Joints of 13XΦA Steel Oil Pipeline%13XΦA钢石油管道焊接接头耐蚀性能改善的研究

    Institute of Scientific and Technical Information of China (English)

    许贵芝

    2013-01-01

    In this article, it introduced a kind of method to produce 13XΦA steel oil pipeline by high frequency welding and tempering treatment after 720 ℃. The results showed that welded joint possess ferrite-pearlite structure, the met allograph ic structure and mechanical performance are close to base metal, and is with high anti-corrosion stability. Based on a lot of tests, combined with the highest corrosion resistance property and the metallographic structure of mechanical performance specimen, the structure standard sample of 13XΦA steel pipeline welded joint was developed, which can quickly assess whether the corrosion resistance is reliable, and this kind of assessment method is quick and simple.%介绍了一种采用高频焊接、焊后720℃回火热处理工艺生产13XΦA钢石油管道的方法.研究结果表明,焊接接头具有铁素体-珠光体组织,其金相组织、力学性能与母材接近,并具有较高的耐蚀稳定性.在大量试验研究的基础上,综合最高耐蚀性能和力学性能试样的金相组织,研制出能迅速评估焊接接头耐蚀性是否可靠的13XΦA钢管道焊接接头组织标样,为石油管道的安全使用提供了一种快速简便的对照评估方法.

  4. In situ 3D monitoring of corrosion on carbon steel and ferritic stainless steel embedded in cement paste

    KAUST Repository

    Itty, Pierre-Adrien

    2014-06-01

    In a X-ray microcomputed tomography study, active corrosion was induced by galvanostatically corroding steel embedded in cement paste. The results give insight into corrosion product build up, crack formation, leaching of products into the cracks and voids, and differences in morphology of corrosion attack in the case of carbon steel or stainless steel reinforcement. Carbon steel was homogeneously etched away with a homogeneous layer of corrosion products forming at the steel/cement paste interface. For ferritic stainless steel, pits were forming, concentrating the corrosion products locally, which led to more extensive damage on the cement paste cover. © 2014 Elsevier Ltd.

  5. Properties, weldability and corrosion behavior of supermartensitic stainless steels for on- and offshore applications

    Energy Technology Data Exchange (ETDEWEB)

    Taban, Emel; Kaluc, Erdinc; Ojo, Olatunji Oladimeji [Kocaeli Univ. (Turkey). Welding Research, Education and Training Center

    2016-08-01

    Stimulated material-environment interactions inside and around flowlines of deep or ultra deep wells during oil and gas exploration, and fabrication economy of pipelines have been the major challenges facing the oil and gas industries. Presumably, an extensive focus on high integrity, performance and material economy of flowlines have realistically made supermartensitic stainless steels (SMSS) efficient and effective material choices for fabricating onshore and offshore pipelines. Supermartensitic stainless steels exhibit high strength, good low temperature toughness, sufficient corrosion resistance in sweet and mildly sour environments, and good quality weldability with both conventional welding processes and modern welding methods such as laser beam welding, electron beam welding and hybrid welding approaches. In terms of economy, supermartensitic stainless steels are cheaper and they are major replacements for more expensive duplex stainless steels required for tubing applications in the oil and gas industry. However, weld areas of SMSS pipes are exposed to sulphide stress cracking (SSC), so intergranular stress corrosion cracking (IGSCC) or stress corrosion cracking can occur. In order to circumvent this risk of cracking, a post-weld heat treatment (PWHT) for 5 minutes at about 650 C is recommended. This paper provides detailed literature perusal on supermartensitic stainless steels, their weldability and corrosion behaviors. It also highlights a major research area that has not been thoroughly expounded in literature; fatigue loading behaviors of welded SMSS under different corrosive environments have not been thoroughly detailed in literature.

  6. Grey interrelation analysis of alloy elements and steel corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jinglei; Hou Baorong; Huang Yanliang; Guo Gongyu [Chinese Academy of Sciences, Qingdao (China). Dept. of Oceanology

    2000-07-01

    Mathematical grey interrelation analysis method was used to study the correlation of alloy elements and low steel corrosion in the splash zone. Eighteen kinds of low alloy steels were selected for 350-day experiments in a large marine corrosion environment simulating apparatus. The analysis results showed that the correlation of alloy elements and alloy corrosion rate is in the order: Mn>Si>P>V>Cu>Al>Cr>Mo. The correlation degree was 0.92, 0.89, 0.86, 0.83, 0.82, 0.82, 0.81, 0.77. (orig.)

  7. Effects of laser heat treatment on the fracture morphologies of X80 pipeline steel welded joints by stress corrosion

    Institute of Scientific and Technical Information of China (English)

    De-jun Kong; Cun-dong Ye

    2014-01-01

    The surfaces of X80 pipeline steel welded joints were processed with a CO2 laser, and the effects of laser heat treatment (LHT) on H2S stress corrosion in the National Association of Corrosion Engineers (NACE) solution were analyzed by a slow strain rate test. The frac-ture morphologies and chemical components of corrosive products before and after LHT were analyzed by scanning electron microscopy and energy-dispersive spectroscopy, respectively, and the mechanism of LHT on stress corrosion cracking was discussed. Results showed that the fracture for welded joints was brittle in its original state, while it was transformed to a ductile fracture after LHT. The tendencies of hydro-gen-induced corrosion were reduced, and the stress corrosion sensitivity index decreased from 35.2%to 25.3%, indicating that the stress corrosion resistance of X80 pipeline steel welded joints has been improved by LHT.

  8. Corrosion Behavior of MIG Brazed and MIG Welded Joints of Automotive DP600-GI Steel Sheet

    Science.gov (United States)

    Basak, Sushovan; Das, Hrishikesh; Pal, Tapan Kumar; Shome, Mahadev

    2016-12-01

    Galvanized dual-phase steel sheets are extensively used by the auto industry for their corrosion resistance property. Welding by the metal inert gas (MIG) process causes degradation of the steel in the vicinity of the joint due to excessive zinc evaporation. In order to minimize Zn loss, the MIG brazing process has been tried out in lap joint configuration over a heat input range of 136-204 J mm-1. The amount of zinc loss, intermetallic formation and corrosion properties in the joint area has been evaluated for both MIG brazing and MIG welding. Corrosion rate of 21 mm year-1 has been reduced to 2 mm year-1 by adopting MIGB in place MIGW. Impedance study has shown that the corrosion mechanism in base metal, MIG brazed and MIG welded joints is dominated by charge transfer, diffusion and mixed mode control processes, respectively.

  9. High-Temperature Performance of Ferritic Steels in Fireside Corrosion Regimes: Temperature and Deposits

    Science.gov (United States)

    Dudziak, T.; Hussain, T.; Simms, N. J.

    2016-11-01

    The paper reports high temperature resistance of ferritic steels in fireside corrosion regime in terms of temperature and deposits aggressiveness. Four candidate power plant steels: 15Mo3, T22, T23 and T91 were exposed under simulated air-fired combustion environment for 1000 h. The tests were conducted at 600, 650 and 700 °C according to deposit-recoat test method. Post-exposed samples were examined via dimensional metrology (the main route to quantify metal loss), and mass change data were recorded to perform the study of kinetic behavior at elevated temperatures. Microstructural investigations using ESEM-EDX were performed in order to investigate corrosion degradation and thickness of the scales. The ranking of the steels from most to the least damage was 15Mo3 > T22 > T23 > T91 in all three temperatures. The highest rate of corrosion in all temperatures occurred under the screening deposit.

  10. Stress Corrosion Cracking Behavior of X80 Pipeline Steel in Acid Soil Environment with SRB

    Science.gov (United States)

    Wang, Dan; Xie, Fei; Wu, Ming; Liu, Guangxin; Zong, Yue; Li, Xue

    2017-06-01

    Self-designed experimental device was adopted to ensure the normal growth of sulphate-reducing bacteria (SRB) in sterile simulated Yingtan soil solution. Stress corrosion cracking (SCC) behavior of X80 pipeline steel in simulated acid soil environment was investigated by electrochemical impedance spectroscopy, slow strain rate test, and scanning electron microscope. Results show that the presence of SRB could promote stress corrosion cracking susceptibility. In a growth cycle, polarization resistance first presents a decrease and subsequently an increase, which is inversely proportional to the quantities of SRB. At 8 days of growth, SRB reach their largest quantity of 1.42 × 103 cells/g. The corrosion behavior is most serious at this time point, and the SCC mechanism is hydrogen embrittlement. In other SRB growth stages, the SCC mechanism of X80 steel is anodic dissolution. With the increasing SRB quantities, X80 steel is largely prone to SCC behavior, and the effect of hydrogen is considerably obvious.

  11. Corrosion behavior of a 14Cr-ODS steel in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Hu, H.L. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhou, Z.J., E-mail: zhouzhangjianustb@163.com [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Liao, L. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, L.F. [School of Nuclear Science and Engineering, Shanghai Jiaotong University, Shanghai 200240 (China); Wang, M.; Li, S.F.; Ge, C.C. [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2013-06-15

    The corrosion behavior of a 14Cr-ODS steel in the supercritical water was investigated using a variety of characterization techniques. Compared with 316L austenitic steel, the 14Cr-ODS steel had better corrosion resistant property. As the increasing of the exposure time, the weight gain increased, but the corrosion rates decreased. The curve of weight gain as a function of time followed a parabolic law. The general weight gain was 0.3476 mg/(dm{sup 2} h). A triple layer was observed which consisted of an outer layer, an inner layer and a diffusion layer. The outer layer was iron rich and contained Fe{sub 3}O{sub 4}, on which pores were observed. The inner layer and diffusion layer contained mainly (Fe,Cr{sub 2})O{sub 4}. The oxidation mechanism was also discussed.

  12. PITTING CORROSION OF AISI 316Ti STAINLESS STEEL WITH POLISHED SURFACE

    Directory of Open Access Journals (Sweden)

    Viera Zatkalíková

    2010-05-01

    Full Text Available AISI 316Ti is Cr–Ni–Mo austenitic stainless steel with the high Pitting Resistance Equivalent Number (PREN. The effect of the surface finishing by polishing on the pitting corrosion resistance was tested in aggressive 5% FeCl3 solution. The immersion tests were curried out at the temperature 30, 50, 80 °C. The electrochemical cyclic potentiodynamic tests were carried out in the same solution at temperature 30 and 50 °C. The evaluation of the corrosion resistance arose from the comparison of the results of the immersion and the cyclic potentiodynamic tests.

  13. Effect of Fe ion concentration on corrosion of carbon steel in CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    In this work, the corrosion behaviour of steel wires in solutions containing different concentrations of Fe2+ was investigated by the linear polarisation resistance method, while the evolution of pH was monitored in situ and changes of the Fe2+ concentration were monitored ex situ. Characterisation...... of the corrosion scales was performed using microscopic and diffraction techniques. Scale analysis revealed that the passivation of samples, exposed to initially highly Fe2+ supersaturated solution, occurred when a formation of a double layer took place, resulting in 30 times lower corrosion rate compared...

  14. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo

    2007-01-01

    accelerates corrosion rates, but this effect may not be detected if rates are already overestimated. It is concluded that electrochemical techniques can be used for corrosion reate monitoring in some H2S media, but care must be taken in the choice of scan ratre; it is important to realize when direct......Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biological sulfide media, and natural sulfide containing geothermal water have been collected, and the process...... techniques like electrical resistance or mass loss should be used instead....

  15. Enhanced corrosion resistance of mild steel in molar hydrochloric acid solution by 1,4-bis(2-pyridyl)-5H-pyridazino[4,5-b]indole: Electrochemical, theoretical and XPS studies

    Energy Technology Data Exchange (ETDEWEB)

    Bentiss, F. [Laboratoire de Cristallochimie et Physicochimie du Solide, CNRS UMR 8012 ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France); Laboratoire de Chimie de Coordination et d' Analytique, Universite Chouaib Doukkali, Faculte des Sciences, B.P. 20, El Jadida (Morocco); Gassama, F. [Laboratoire de Chimie Organique EA 2692, Bat. C4, USTL, F-59652 Villeneuve d' Ascq Cedex (France); Barbry, D. [Laboratoire de Chimie Organique EA 2692, Bat. C4, USTL, F-59652 Villeneuve d' Ascq Cedex (France); Gengembre, L. [Laboratoire de Catalyse, CNRS UMR 80100, Bat. C3, USTL, F-59652 Villeneuve dAscq Cedex (France); Vezin, H. [Laboratoire de Chimie Organique et Macromoleculaire, CNRS UMR 8009, USTL Bat C3, F-59655 Villeneuve d' Ascq Cedex (France); Lagrenee, M. [Laboratoire de Cristallochimie et Physicochimie du Solide, CNRS UMR 8012 ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France); Traisnel, M. [Laboratoire des Procedes d' Elaboration des Revetements Fonctionnels, UPRES EA 1040 ENSCL, BP 90108, F-59652 Villeneuve d' Ascq Cedex (France)]. E-mail: Michel.Traisnel@ensc-lille.fr

    2006-02-15

    The inhibition effect of the new pyridazine derivative, namely 1,4-bis(2-pyridyl)-5H-pyridazino[4,5-b]indole (PPI) against mild steel corrosion in 1 M HCl solutions was evaluated using weigh loss and electrochemical techniques (potentiodynamic polarisation curves and impedance spectroscopy). The experimental results suggest that PPI is a good corrosion inhibitor and the inhibition efficiency increased with the increase of PPI concentration, while the adsorption followed the Langmuir isotherm. X-ray photoelectron spectroscopy (XPS) and theoretical calculation of electronic density were carried out to establish the mechanism of corrosion inhibition of mild steel with PPI in 1 M HCl medium. The inhibition action of this compound was, assumed to occur via adsorption on the steel surface through the active centres contained of the molecule. The corrosion inhibition is due to the formation of a chemisorbed film on the steel surface.

  16. 热镀锌钢板表面硅烷膜的制备工艺与耐蚀性能%Preparation and Corrosion Resistance of Silane Film on Hot-dip Galvanized Steel

    Institute of Scientific and Technical Information of China (English)

    吴海江; 卢锦堂

    2009-01-01

    采用正交试验结合中性盐雾试验和极化曲线测定等方法,研究了热镀锌钢板表面的硅烷膜在制备过程中的硅烷体积分数、水解溶剂中甲醇体积分数、水解时间、水解温度、溶液PH值、浸涂时间等因素对硅烷膜耐蚀性能的影响,并确定了最佳成膜工艺,讨论了硅烷膜作用机理.结果表明:最佳成膜工艺为硅烷体积分数7%、溶液pH值4、水解溶剂中甲醇体积分数10%、水解温度40℃、水解时间6 h、浸涂时间120 s,采用该工艺制备硅烷膜可明显推迟热镀锌钢板出现白锈的时间;硅烷膜同时也抑制了热镀锌钢板在腐蚀过程中阳极和阴极的反应,显著改善了热镀锌钢板的耐蚀性能.%A nontoxic silanized treatment process for hot-dip galvanized steel was investigated by the orthogonal experiment. The protection of silane films on galvanized steel surface was evaluated by neutral salt spray test and polarization test. The factors affecting the corrosion resistance of silane films were discussed, including concentration of silane solution, concentration of methanol, hydrolysis time, hydrolysis temperature, pH of silane solution and immersion time. The optimum technological parameters were obtained, and the mechanism was analyzed. The results show that the silane films had the optimum anti-corrosion properties under the conditions of concentration of the silane solution 7%, concentration of methanol in hydrolysis solvents 10%, hydrolysis time 6 h, hydrolysis temperature 40 ℃, pH of the silane solution 4 and immersion time 120 s acted as a physical barrier of galvanized steel and suppressed both cathodic and anodic reactions of corrosion simultaneously. The time of white rust occurence on galvanized coating was delayed. The silane films obtained excellent corrosion resistance under the optimum technological conditions.

  17. Corrosion behavior induced by LiCl-KCl in type 304 and 316 stainless steel and copper at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Jee Hyung; Kim, Yong Soo; Cho, Il Je [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

    2017-06-15

    The corrosion behavior of stainless steel (304 and 316 type) and copper induced by LiCl-KCl at low temperatures in the presence of sufficient oxygen and moisture was investigated through a series of experiments (at 30°C, 40°C, 60°C, and 80°C for 24 hours, 48 hours, 72 hours, and 96 hours). The specimens not coated on one side with an aqueous solution saturated with LiCl-KCl experienced no corrosion at any temperature, not even when the test duration exceeded 96 hours. Stainless steel exposed to LiCl-KCl experienced almost no corrosion below 40°C, but pitting corrosion was observed at temperatures above 60°C. As the duration of the experiment was increased, the rate of corrosion accelerated in proportion to the temperature. The 316 type stainless steel exhibited better corrosion resistance than did the 304 type. In the case of copper, the rate of corrosion accelerated in proportion to the duration and temperature but, unlike the case of stainless steel, the corrosion was more general. As a result, the extent of copper corrosion was about three times that of stainless steel.

  18. Atmospheric corrosion of carbon steel resulting from short term exposures

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, R.; Cook, D.C.; Perez, T.; Reyes, J. [Department of Physics, Old Dominion University, Norfolk, VA 23529 (United States)

    1998-12-31

    The study of corrosion products from short term atmospheric exposures of carbon steel, is very important to understand the processes that lead to corrosion of steels, and ultimately improve the performance of such steel in highly corrosive environments. Many regions along the Gulf of Mexico have extremely corrosive environments due to high mean annual temperature, humidity, time-of-wetness and every high atmospheric pollutants. The process the formation of corrosion products resulting from short term exposure of carbon steel, both as a function of environmental conditions and exposure time, has been investigated. Two sets of coupons were exposed at marine and marine locations, in Campeche, Mexico. Each set was exposed between 1 and 12 months to study the corrosion as a function of time. During the exposure periods, the relative humidity, rainfall, mean temperature, wind speed and wind direction were monitored along with the chloride and sulfur dioxide concentrations in the air. The corroded coupons were analyzed by Moessbauer, Raman, Infrared spectroscopies and X-ray diffraction in order to completely identify the oxides and map their location in the corrosion coating. Scattering and transmission Moessbauer analysis showed some layering of the oxides with lepidocrocite and akaganeite closer to the surface. The fraction of akaganeite phase increased at sites with higher chloride concentrations. A detailed analysis on the development of the oxide phases as a function of exposure time and environmental conditions will be presented. (Author)

  19. Internal corrosion of carbon steel piping in hot aquifers service

    Directory of Open Access Journals (Sweden)

    Simičić Miloš V.

    2011-01-01

    Full Text Available Internal corrosion of carbon steel pipelines is a major problem encountered in water service. In terms of prediction of the remaining lifetime for water pipelines based on the corrosion allowance, the three main approaches are corrosion modelling, corrosion inhibitor availability, and corrosion monitoring. In this study we used two theoretical corrosion models, CASSANDRA and NORSOK M-506 of quite different origin in order to predict uniform corrosivity of hot aquifers in eight different pipelines. Because of the varying calculation criteria for the different models, these can give very different corrosion rate predictions for the same data input. This is especially true under conditions where the formation of protective films may occur, such as at elevated temperatures. The evaluation of models was conducted by comparison using weight-loss coupons and three corrosion inhibitors were obtained from commercial suppliers. The tests were performed during the 60-day period. Even though inhibitors’ efficiencies of 98% had been achieved in laboratory testing, inhibitors’ availabilities of 85% have been used due to logistics problems and other issues. The results, given in mmpy, i.e. millimeter per year, are very consistent with NORSOK M-506 prediction. This is presumably because the model considers the effect of the formation of a passive iron carbonate film at temperatures above 80 °C and significant reduction in corrosion rate. Corrosion inhibitor A showed a better performance than inhibitors B and C in all cases but the target corrosion rates of less than 0.1 mmpy were achieved for all inhibitors. The chemical type of corrosion inhibitor A is based on quaternary amines mixed with methanol, isopropyl alcohol, xylene and ethylbenzene. Based on the obtained results the carbon steel lifetime of 30 years, provided proper inhibitors are present and 3mm corrosion allowance, can be achieved for hot aquifers service with presented water compositions.

  20. Corrosion of reinforcement bars in steel ibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe

    Steel fibres have been known as an alternative to traditional reinforcement bars for special applications of structural concrete for decades and the use of steel fibre reinforced concrete (SFRC) has gradually increased in recent years. Steel fibres lead to reduced crack widths in concrete formed......, among other reasons, due to shrinkage and/or mechanical loading. Steel fibres are nowadays also used in combination with traditional reinforcement for structural concrete, where the role of the fibres is to minimize the crack widths whereas the traditional reinforcement bars are used for structural....... The aim of the work presented in this Ph.D. thesis was to quantify the influence of steel fibres on corrosion of traditional reinforcement bars embedded in uncracked concrete as well as cracked concrete. Focus of the work was set on the impact of steel fibres on corrosion propagation in uncracked concrete...

  1. Antibacterial and corrosive properties of copper implanted austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    Juan Xiong; Bo-fan Xu; Hong-wei Ni

    2009-01-01

    Copper ions were implanted into austenitic stainless steel (SS) by metal vapor vacuum arc with a energy of 100 keV and an ions dose range of (0.5-8.0)x 1017 cm-2. The Cu-implanted SS was annealed in an Ar atmosphere furnace. Glancing X-ray diffraction (GXRD), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES) were used to reveal the phase com-positions, microstructures, and concentration profiles of copper ions in the implanted layer. The results show that the antibacterialproperty of Cu-implanted SS is attributed to Cu9.9Fe0.1 which precipitated as needles. The depth of copper in Cu-implanted SS with annealing treatment is greater than that in Cu-implanted SS without annealing treatment, which improves the antibacterial property against S. Aureus. The salt wetting-drying combined cyclic test was used to evaluate the corrosion-resistance of antibacterial SS, and the results reveal that the antibacterial SS has a level of corrosion-resistance equivalent to that of un-implanted SS.

  2. Adhesion and corrosion behaviour of Zn-Co electrodeposits on mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Panagopoulos, C.N., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Lagaris, D.A.; Vatista, P.C. [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece)

    2011-03-15

    Research highlights: {yields} The Zn-Co alloy coatings consisted of zinc solid solution and {gamma}{sub 2} Zn-Co intermetallic phase (CoZn{sub 13}). {yields} The adhesive load (LA) of the Zn-Co coatings to the mild steel was observed to decrease slightly with increasing alloy coating thickness. {yields} The Zn-Co alloy coatings act as sacrificial anodes to the mild steel substrates. - Abstract: Zn-Co alloy coatings of various thicknesses were electrodeposited on mild steel substrate, using a sulphate bath. SEM, EDS and XRD were used to study surface morphology, chemical composition and phase structure of the produced coatings. The microhardness of the produced coatings and the adhesive strength between the Zn-Co alloy coatings and the mild steel substrate were examined. The corrosion behaviour of the coated mild steel specimens in 0.1 M NaCl solutions, having different pH values, was also investigated by means of potentiodynamic corrosion experiments. The results showed that the corrosion resistance of the Zn-Co coated mild steel specimen was lower in acidic and alkaline than in neutral solutions. The corrosion products formed on the surface of the alloy coatings were analysed with the aid of a Scanning Electron Microscope (SEM) and an X-ray Diffractometer (XRD).

  3. Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.

    Science.gov (United States)

    Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Séverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves

    2012-11-01

    A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films.

  4. Influence of Freeze-Thaw Damage on the Steel Corrosion and Bond-Slip Behavior in the Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Fangzhi Zhu

    2016-01-01

    Full Text Available This paper mainly studies the behavior of steel corrosion in various reinforced concrete under freeze-thaw environment. The influence of thickness of concrete cover is also discussed. Additionally, the bond-slip behavior of the reinforced concrete after suffering the freeze-thaw damage and steel corrosion has also be presented. The results show that the freeze-thaw damage aggravates the steel corrosion in concrete, and the results become more obvious in the concrete after suffering serious freeze-thaw damage. Compared with the ordinary concrete, both air entrained concrete and waterproofing concrete possess better resistance to steel corrosion under the same freeze-thaw environment. Moreover, increasing the thicknesses of concrete cover is also an effective method of improving the resistance to steel corrosion. The bond-slip behavior of reinforced concrete with corroded steel decreases with the increase of freeze-thaw damage, especially for the concrete that suffered high freeze-thaw cycles. Moreover, there exists a good correlation between the parameters of bond-slip and freeze-thaw cycles. The steel corrosion and bond-slip behavior of reinforced concrete should be considered serious under freeze-thaw cycles environment, which significantly impact the durability and safety of concrete structure.

  5. Study on corrosion simulation device for marine structural steel

    Indian Academy of Sciences (India)

    Hou Baorong; Xiang Bin

    2003-04-01

    A corrosion simulation device was studied using offshore long scale hanging specimens. An Ni–Cu–P steel specimen was studied by analysing its corrosion products and corrosion types. The appearance of the samples and the surface of the metallic substrate after the removal of the rust layer produced by these two methods were observed and compared after 470 days of exposure. The phase structure of the corrosion products under different marine environments were analysed and compared. It further indicated good correlation between the electrically connected hanging specimen method and the long scale hanging specimen method.

  6. Spatial distribution of crystalline corrosion products formed during corrosion of stainless steel in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Serdar, Marijana [Department of Materials, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb (Croatia); Meral, Cagla [Middle East Technical University, Department of Civil Engineering, Ankara (Turkey); Kunz, Martin [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Bjegovic, Dubravka [Department of Materials, Faculty of Civil Engineering, University of Zagreb, 10000 Zagreb (Croatia); Wenk, Hans-Rudolf [Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 (United States); Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-05-15

    The mineralogy and spatial distribution of nano-crystalline corrosion products that form in the steel/concrete interface were characterized using synchrotron X-ray micro-diffraction (μ-XRD). Two types of low-nickel high-chromium reinforcing steels embedded into mortar and exposed to NaCl solution were investigated. Corrosion in the samples was confirmed by electrochemical impedance spectroscopy (EIS). μ-XRD revealed that goethite (α-FeOOH) and akaganeite (β-FeOOH) are the main iron oxide–hydroxides formed during the chloride-induced corrosion of stainless steel in concrete. Goethite is formed closer to the surface of the steel due to the presence of chromium in the steel, while akaganeite is formed further away from the surface due to the presence of chloride ions. Detailed microstructural analysis is shown and discussed on one sample of each type of steel. - Highlights: • Synchrotron micro-diffraction used to map the distribution of crystalline phases. • Goethite and akaganeite are the main corrosion products during chloride induced corrosion in mortar. • Layers of goethite and akaganeite are negatively correlated. • EDS showed Cr present in corrosion products identified by SEM.

  7. Effects of Welding Processes on Microstructure and Corrosion Resistance of Weld Metal of Corrosion Resistant Ship Plate Steel DH36%焊接工艺对 DH36耐蚀船板钢焊缝金属组织与耐蚀性能的影响

    Institute of Scientific and Technical Information of China (English)

    隋志强; 齐彦昌; 王军丽; 马成勇

    2016-01-01

    Corrosion resistant ship plate steels DH36 were welded by using submerged-arc welding,flux cored wire CO 2 gas shielded welding and shielded metal arc welding processes,and then corrosion experiments were carried out in the simulated environment around bottom plates of cargo oil tanks,the effects of welding processes on microstructure and corrosion resistance of weld metals were studied.The results show that under three welding processes,microstructure of the weld metals consisted predominantly of acicular ferrite,ferrite side-plate and proeutectoid ferrite.Compared with shielded metal arc welding and gas shielded welding,the weld metal prepared by submerged-arc welding had the best corrosion resistance,this due to the decrease of proeutectoid ferrite caused by higher heat input.Under three welding processes,the size and distribution of inclusion in weld metal were similar,and there was no obvious difference in the effects of inclusion on corrosion property of weld metal.%分别采用埋弧焊、药芯焊丝 CO 2气体保护焊和焊条电弧焊工艺对 DH36耐蚀船板钢进行对接焊,然后在模拟油船货油舱下底板的腐蚀环境中进行腐蚀试验,研究了焊接工艺对焊缝金属组织和耐蚀性能的影响。结果表明:在3种焊接工艺下,焊缝金属的组织均主要由先共析铁素体、侧板条铁素体和针状铁素体组成;与焊条电弧焊和气体保护焊相比,采用埋弧焊得到的焊缝金属的耐蚀性能最优,这源于埋弧焊较高的热输入导致针状体素体数量减少;在三种焊接工艺下,焊缝金属中夹杂物的尺寸、分布均相似,它们对焊缝金属耐蚀性能的影响基本相同。

  8. Corrosion and wear properties of Ni-Sn-P ternary deposits on mild steel via electroless method

    Directory of Open Access Journals (Sweden)

    A.P.I. Popoola

    2016-09-01

    Full Text Available The rising necessity to improve corrosion and wear resistance of metals for engineering applications cannot be over emphasized. This has led to employing diverse models, method and techniques to obtain better corrosion and wear resistances for metallic materials and components which will otherwise fail during service. This work investigated the effect of Ni-P binary and Ni-Sn-P ternary electroless depositions on the corrosion and wear behavior of mild steel. Micro-structural examination using scanning electron microscopy (SEM analysis shows finer and more evenly distributed particle orientation across the substrate surface. The Ni-Sn-P ternary deposits on the mild steel displayed from the linear polarization analysis a better corrosion resistance with corrosion rate values of 0.000246 mm/yr as compared with that of the Ni-P binary deposits with 0.016672 mm/yr. Also the coefficient of friction of the unplated sample varies between 0 and 0.08 while for the plated samples the coefficient of friction was relatively lesser and ranged from 0 to 0.02. Significant improvement in corrosion resistance was also indicated by a positive shift in potential. Sliding wear analysis demonstrates consistently enhanced wear resistance of the ternary deposits as well as the binary deposits, with the ternary Sn addition showing better resistance to wear. This work has established that Ni-Sn-P electroless coating of mild steel can be used to improve the corrosion and wear resistance for engineering applications.

  9. Influence of the surface finishing on electrochemical corrosion characteristics of AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Sylvia Dundeková

    2015-05-01

    Full Text Available Stainless steels from 316 group are very often and successfully uses for medical applications where the good mechanical and chemical properties in combination with non-toxicity of the material assure its safe and long term usage. Corrosion properties of AISI 361L stainless steel are strongly influenced by surface roughness and treatment of the engineering parts (specimens and testing temperature. Electrochemical characteristics of ground, mechanically polished and passivated AISI 316L stainless steel specimens were examined with the aim to identify the polarization resistance evolution due to the surface roughness decrease. Results obtained on mechanically prepared specimens where only natural oxide layer created due to the exposure of the material to the corrosion environment was protecting the materials were compared to the passivated specimens with artificial oxide layer. Also the influence of temperature and stabilization time before measurement were taken into account when discussing the obtained results. Positive influence of decreasing surface roughness was obtained as well as increase of polarization resistance due to the chemical passivation of the surface. Increase of the testing temperature and short stabilization time of the specimen in the corrosion environment were observed negatively influencing corrosion resistance of AISI 316L stainless steel.

  10. Electrochemical Corrosion Behavior of Spray-Formed Boron-Modified Supermartensitic Stainless Steel

    Science.gov (United States)

    Zepon, Guilherme; Nogueira, Ricardo P.; Kiminami, Claudio S.; Botta, Walter J.; Bolfarini, Claudemiro

    2017-04-01

    Spray-formed boron-modified supermartensitic stainless steel (SMSS) grades are alloys developed to withstand severe wear conditions. The addition of boron to the conventional chemical composition of SMSS, combined with the solidification features promoted by the spray forming process, leads to a microstructure composed of low carbon martensitic matrix reinforced by an eutectic network of M2B-type borides, which considerably increases the wear resistance of the stainless steel. Although the presence of borides in the microstructure has a very beneficial effect on the wear properties of the alloy, their effect on the corrosion resistance of the stainless steel was not comprehensively evaluated. The present work presents a study of the effect of boron addition on the corrosion resistance of the spray-formed boron-modified SMSS grades by means of electrochemical techniques. The borides fraction seems to have some influence on the repassivation kinetics of the spray-formed boron-modified SMSS. It was shown that the Cr content of the martensitic matrix is the microstructural feature deciding the corrosion resistance of this sort of alloys. Therefore, if the Cr content in the alloy is increased to around 14 wt pct to compensate for the boron consumed by the borides formation, the corrosion resistance of the alloy is kept at the same level of the alloy without boron addition.

  11. Electrochemical Corrosion Behavior of Spray-Formed Boron-Modified Supermartensitic Stainless Steel

    Science.gov (United States)

    Zepon, Guilherme; Nogueira, Ricardo P.; Kiminami, Claudio S.; Botta, Walter J.; Bolfarini, Claudemiro

    2017-01-01

    Spray-formed boron-modified supermartensitic stainless steel (SMSS) grades are alloys developed to withstand severe wear conditions. The addition of boron to the conventional chemical composition of SMSS, combined with the solidification features promoted by the spray forming process, leads to a microstructure composed of low carbon martensitic matrix reinforced by an eutectic network of M2B-type borides, which considerably increases the wear resistance of the stainless steel. Although the presence of borides in the microstructure has a very beneficial effect on the wear properties of the alloy, their effect on the corrosion resistance of the stainless steel was not comprehensively evaluated. The present work presents a study of the effect of boron addition on the corrosion resistance of the spray-formed boron-modified SMSS grades by means of electrochemical techniques. The borides fraction seems to have some influence on the repassivation kinetics of the spray-formed boron-modified SMSS. It was shown that the Cr content of the martensitic matrix is the microstructural feature deciding the corrosion resistance of this sort of alloys. Therefore, if the Cr content in the alloy is increased to around 14 wt pct to compensate for the boron consumed by the borides formation, the corrosion resistance of the alloy is kept at the same level of the alloy without boron addition.

  12. Analysis of features of stainless steels in dissimilar welded joints in chloride inducted corrosion

    Science.gov (United States)

    Topolska, S.; Łabanowski, J.

    2017-08-01

    Stainless steels of femtic-austenitic microstructure that means the duplex Cr-Ni-Mo steels, in comparison with austenitic steel includes less expensive nickel and has much better mechanical properties with good formability and corrosion resistance, even in environments containing chloride ions. Similar share of high chromium ferrite and austenite, which is characterized by high ductility, determines that the duplex steels have good crack resistance at temperatures up to approximately -40°C. The steels containing approximately 22% Cr, 5% Ni, 3% Mo and 0.2% N crystallizes as a solid solution δ, partially transforming from the temperature of about 1200°C to 850°C into the phase α. The stable structure of considered steels, at temperatures above 850°C, is ferrite, and at lower temperatures the mixture of phase γ+α +σ. The two-phase structure α+γ the duplex steel obtains after hyperquenching at the temperature of stability of the mixture of α+γ phases, and the share of the phases depends on the hyper quenching attributes. Hyperquenching in water, with a temperature close to 1200°C, ensures the instance in the microstructure of the steel a large share of ferrite and a small share of the high chromium austenite. This causes the increase of strength properties and reducing the plasticity of the steel and its resistance ability to cracking and corrosion. Slower cooling from the mentioned temperature, for example in the air, enables the partial transformation of the a phase into the γ one (α → γ) and increasing the share of austenite in the steel structure. It leads to improvement of plasticity properties. In the paper are presented the results of investigations of heteronymous welded joints of duplex steel and austenitic one. The results include the relation between the chemical composition of steels and their weldability.

  13. Corrosion of an austenite and ferrite stainless steel weld

    Directory of Open Access Journals (Sweden)

    BRANIMIR N. GRGUR

    2011-07-01

    Full Text Available Dissimilar metal connections are prone to frequent failures. These failures are attributed to the difference in the mechanical properties across the weld, the coefficients of thermal expansion of the two types of steels and the resulting creep at the interface. For the weld analyzed in this research, it was shown that corrosion measurements can be used for a proper evaluation of the quality of weld material and for the prediction of whether or not the material, after the applied welding process, can be in service without failures. It was found that the corrosion of the weld analyzed in this research resulted from the simultaneous activity of different types of corrosion. In this study, electrochemical techniques including polarization and metallographic analysis were used to analyze the corrosion of a weld material of ferrite and austenitic stainless steels. Based on surface, chemical and electrochemical analyses, it was concluded that corrosion occurrence was the result of the simultaneous activity of contact corrosion (ferrite and austenitic material conjuction, stress corrosion (originating from deformed ferrite structure and inter-granular corrosion (due to chromium carbide precipitation. The value of corrosion potential of –0.53 V shows that this weld, after the thermal treatment, is not able to repassivate a protective oxide film.

  14. 低碳-低锰系油井套管用钢抗硫化氢应力腐蚀开裂性能%Hydrogen Sulfide Resistant Stress Corrosion Cracking of Low C-Mn Steels for Oil Well Casing

    Institute of Scientific and Technical Information of China (English)

    贺飞; 尚成嘉; 张峰; 毕宗岳

    2013-01-01

    对621 MPa(90ksi)级抗硫化氢腐蚀油井套管用钢的合金设计、热处理工艺以及组织和性能关系进行了研究,分别设计了0.08C-0.8Mn和0.20C-0.8Mn 2种低碳-低锰试验钢,并重点研究了经调质处理后试验钢的位错、析出物和碳化物对SSCC性能的影响.研究结果表明,采用低碳-低锰,结合Nb、V、Ti和B的微合金设计,通过适当的调质热处理工艺可以获得优良的力学性能、韧性和抗硫化氢应力腐蚀开裂性能,满足相关标准的要求.研究结果还表明,不共平面的位错群、细小的析出物以及弥散的高球化率碳化物,可以使钢具有很好的抗硫化氢应力腐蚀开裂性能.%Alloy design, heat treatment process and microstructure and properties relationship of 621 MPa(90ksi) grade oil well casing steels of H2S resistant corrosion were studied. Such two kinds as 0. 08C-0. 8Mn and 0. 20C-0. 8Mn of low C-Mn tested steels were designed, respectively. And the effect of dislocation, precipitation and carbide of tested steels after heat treatment on SSCC performance was investigated. The results show that the low C-Mn and Nb-V-Ti-B micro-alloy design has excellent mechanical properties, toughness and resistance to H2S stress corrosion cracking performance through proper quenching and tempering heat treatment process, to meet the requirements of the relevant standards. The results also show that the un-coplanar dislocation group, fine precipitates and dispersive high sphericity carbide would be beneficial to excellent hydrogen sulfide stress corrosion cracking resistance.

  15. Unexpected corrosion of stainless steel in low chloride waters – microbial aspects

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Carpén, Leena; Møller, Per

    2009-01-01

    Abstract Stainless steels EN 1.4301 and 1.4401/1.4404 are normally considered corrosion resistant in low chloride natural waters like drinking water. However, a number of corrosion failures have been observed in e.g. fire extinguisher systems and drinking water installations, where stagnant...... in drinking water qualities, due to the formation of a biofilm. In itself, this is not enough to initiate pitting in these water qualities, but combined with a geometrically or metallurgically vulnerable area, corrosion may accelerate. The mechanism is linked to the naturally occurring microbial activity...... conditions or periods of low water consumption have occurred prior to the failure. Typically the corrosion attacks appear within 2-3 years in weld nuggets, heat affected zones or in crevices like e.g. press fitting pipe connections. The failure mode is pitting and crevice corrosion leading to leaks and rust...

  16. Forecasting of Corrosion Properties of Steel Wires for Production of Guide Wires for Cardiological Treatment

    Directory of Open Access Journals (Sweden)

    J. Przondziono

    2013-01-01

    Full Text Available The study presents evaluation of the influence of strain in drawing process and of surface modification on resistance to electrochemical corrosion of wires made of stainless steel for production of guide wires used in invasive cardiology. The results of static tensile test enabled us to determine the course of flow curve of wires made of X10CrNi 18-8 steel as well as mathematical form of flow stress function. Resistance to electrochemical corrosion was evaluated on the ground of registered anodic polarisation curves by means of potentiodynamic method. The tests were performed in solution simulating human blood on samples that were electrolytically polished and samples that were polished and then chemically passivated. Exemplary anodic polarisation curves were given. It was proved that with the applied strain, corrosion properties decrease. It was found that chemical passivation improves wire corrosion characteristics. Statistical analysis showed that there is a significant dependence between corrosion properties (polarisation resistance Rp and strain ε applied in drawing process. Functions that present the change Rp=f(ε were selected. The issue is of importance to guide wire manufacturers because application of the suggested methodology will enable us to forecast corrosion characteristics of wire with the required strength drawn with the applied strain.

  17. The maraging steel corrosion properties with hardening of different kinds after double aging

    Directory of Open Access Journals (Sweden)

    L. V. Tarasenko

    2014-01-01

    Full Text Available The paper proposes to use high-strength corrosion-resistant maraging steels, which were developed for aircraft industry instead of carbon steel with coating to improve operation properties of the forcemeasuring resilient member in electronic strain-gauge balance.It examines the possibility to apply the martensitic-aging steels of Fe-Cr-Ni-Mo-Ti (ЭП678 and Fe-Cr-Ni-Mo-Cu-Nb (ЭП817 alloying systems. It was shown, that a traditional heat strain-hardening treatment including hardening and overageing of this steels provides combination of durability viscosity and corrosion- resistance, but at the same time it increases nonelastic effects and lowers the limit of elasticity because of reversing austenite formation. In this connection, it was proposed to use hardening with double aging i.e. main and low-temperature aging with no austenite formation as heat strainhardening treatment of steels for force-measuring resilient member. The goal of this work was to study the influence of double aging on the structure and properties of ЭП678 (06Х14Н6Д2МБТ and ЭП817 (03Х111Н10М2Т steels.The modes of double aging for ЭП817 steel were conformed to 4500С + 400 0С and 475 0С+ 400 0С, for ЭП678 steel – 530 0С + 500 0С. The structure and properties of hardened steels after main and double aging were compared.Metallographic analysis of samples after electrolytic etching was conducted with Leitz Metallovert microscope while the CamScan 4DV raster electronic microscope was used for Microroentgen-spectral analysis. The quantity of austenite was controlled with computerized setting DRON-4, the hardness was measured with ТК-2М instrument, corrosion-resistance was estimated with polarized curves, which were taken using a П-5848 potentiostat.The conducted research has shown, that double aging causes the additional hardening of steels due to disintegration of martensite and formation of dispersed Cu – corpuscles in ЭП817 steel and of Ni3Ti

  18. Corrosion Products and Formation Mechanism During Initial Stage of Atmospheric Corrosion of Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    XIAO Kui; DONG Chao-fang; LI Xiao-gang; WANG Fu-ming

    2008-01-01

    The formation and development of corrosion products on carbon steel surface during the initial stage of atmospheric corrosion in a laboratory simulated environment have been studied by scanning electron microscopy (SEM)and Raman spectroscopy.The results showed that two different shapes of corrosion products,that is,ring and chain,were formed in the initial stage of corrosion.MnS clusters were found in the nuclei of corrosion products at the active local corrosion sites.The ring-shaped products were composed of lepidocrocite (γ-FeOOH) and maghemite(γ-Fe2 O3) transformed from lepidocrocite.The chain-type products were goethite (α-FeOOH).A formation mechanism of the corrosion products is proposed.

  19. Corrosivity of paper mill effluent and corrosion performance of stainless steel.

    Science.gov (United States)

    Ram, Chhotu; Sharma, Chhaya; Singh, A K

    2015-01-01

    Present study relates to the corrosivity of paper mill effluent and corrosion performance of stainless steel (SS) as a construction material for the effluent treatment plant (ETP). Accordingly, immersion test and electrochemical polarization tests were performed on SS 304 L, 316 L and duplex 2205 in paper mill effluent and synthetic effluent. This paper presents electrochemical polarization measurements, performed for the first time to the best of the authors' information, to see the influence of chlorophenols on the corrosivity of effluents. The corrosivity of the effluent was observed to increase with the decrease in pH and increase in Cl- content while the addition of SO4- tends to inhibit corrosion. Mill effluent was found to be more corrosive as compared to synthetic effluent and has been attributed to the presence of various chlorophenols. Corrosion performance of SS was observed to govern by the presence of Cr, Mo and N contents.

  20. Corrosion resistance of silane/silicate composite films on hot-dip galvanized steel%热镀锌钢表面硅烷/硅酸盐复合膜的耐蚀性能研究

    Institute of Scientific and Technical Information of China (English)

    吴海江; 卢锦堂

    2009-01-01

    To improve the corrosion resistance of silane films further, the silane/silicate composite films were prepared by immersion hot-dip galvanized (HDG) steel samples in silane solution firstly and then in sodium silicate solution. The corrosion resistance of the composite films were investigated by neutral salt spray (NSS)test, humid thermic test, salt water test and electrochemical impedance spectroscopy (EIS). The results revealed that the corrosion resistance of the composite films was significantly enhanced, which was superior to the single silane film, even better than some chromate passivation film. Furthermore, the low frequency inductive loop in EIS was disappeared and the low frequency impedance values for the composite films in 5% NaCl solution were firstly increased then decreased with the increasing of the immersion time, which demonstrated the self-healing activity of the composite films.%为了改善硅烷膜的耐蚀性,将硅烷化热镀锌钢板用硅酸钠溶液封闭后处理,获得了硅烷/硅酸盐复合膜.采用中性盐雾试验(NSS)、湿热试验、盐水全浸试验和电化学交流阻抗谱(EIS)评价了膜层的耐蚀性能.结果表明,与单一硅烷膜相比,复合膜的耐蚀性能明显提高,超过了常规铬酸盐钝化膜.尤其是在5%NaCl溶液中,复合膜的低频阻抗数值随浸泡时间的增加先增大后减小,表明其具有一定的"自修复"能力.

  1. Corrosion Behaviors of Steel A3 Exposed to Thiobacillus Ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    Jianhua LIU; Xin LIANG; Songmei LI

    2008-01-01

    The corrosion behaviors of steel A3 in synergistic action of Thiobacillus ferrooxidans (T.f) and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential (Eocp) and electrochemical impedance spectroscopy (EIS) of the steel A3 electrodes were measured in leathen culture medium without and with T.f (simply called T.f solution in the following paper)in immersion electrode way at the time of the 2nd, 5th, 10th, 20th and 30th days, respectively. It was found that Eocp of the electrode for immersion in leathen culture medium shifted negatively with the immersion time while that for immersion in T.f solutions shifted negatively, then positively and finally negatively. On the 20th day, the corrosion of steel A3 for immersion in culture medium was in pitting initiation stage while that for immersion in T.f solutions was in pitting growth stage. It was found that the corrosion of steel A3 was accelerated by T.f. The morphology of corrosion product of steel A3 immersion in T.f solutions observed through scanning electron microscopy (SEM) transformed from solid globules to tabular plates and to spongy globules and plates.

  2. Effect of Chromium on Corrosion Behavior of P110 Steels in CO2-H2S Environment with High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Jianbo Sun

    2016-03-01

    Full Text Available The novel Cr-containing low alloy steels have exhibited good corrosion resistance in CO2 environment, mainly owing to the formation of Cr-enriched corrosion film. In order to evaluate whether it is applicable to the CO2 and H2S coexistence conditions, the corrosion behavior of low-chromium steels in CO2-H2S environment with high pressure and high temperature was investigated using weight loss measurement and surface characterization. The results showed that P110 steel suffered localized corrosion and both 3Cr-P110 and 5Cr-P110 steels exhibited general corrosion. However, the corrosion rate of 5Cr-P110 was the highest among them. The corrosion process of the steels was simultaneously governed by CO2 and H2S. The outer scales on the three steels mainly consisted of FeS1−x crystals, whereas the inner scales on Cr-containing steels comprised of amorphous FeS1−x, Cr(OH3 and FeCO3, in contrast with the amorphous FeS1−x and FeCO3 mixture film of P110 steel. The more chromium the steel contains, the more chromium compounds the corrosion products contain. The addition of chromium in steels increases the uniformity of the Cr-enriched corrosion scales, eliminates the localized corrosion, but cannot decrease the general corrosion rates. The formation of FeS1−x may interfere with Cr-enriched corrosion scales and lowering the corrosion performance of 3Cr-P110 and 5Cr-P110 steels.

  3. Investigation of Corrosion and Cathodic Protection in Reinforced Concrete. II: Properties of Steel Surface Layers

    NARCIS (Netherlands)

    Koleva, D.A.; De Wit, J.H.W.; Van Breugel, K.; Lodhi, Z.F.; Ye, G.

    2007-01-01

    The present study explores the formation of corrosion products on the steel surface (using as-received low carbon construction steel) in reinforced concrete in conditions of corrosion and subsequent transformation of these layers in conditions of cathodic protection (CP).

  4. Corrosion of mild steel, copper and brass in crude oil / seawater mixture

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi, S.; Sawant, S.S.; Wagh, A.B.

    Mild steel, copper and brass coupons were introduced in natural seawater containing varying amount of crude oil. Mild steel showed higher rate of corrosion in seawater containing oil and lower corrosion rate in natural as well as artificial seawater...

  5. 高强度耐候H型钢和普通C-Mn低合金H型钢耐大气腐蚀性能比较%Comparison of Atmospheric Corrosion Resistance between High Strength Weathering H Section Steel and Common C-Mn Steel

    Institute of Scientific and Technical Information of China (English)

    米丰毅; 王向东; 陈小平; 彭云; 陶东平

    2011-01-01

    通过周浸加速腐蚀试验,对比了高强度耐候H型钢与普通C-Mn低合金H型钢的耐蚀性能,采用扫描电镜(SEM)、X射线衍射(XRD)及电化学阻抗谱(EIS)等方法研究了两种钢腐蚀产物的形貌、组成以及电化学性质的差异.结果表明,在模拟工业大气环境下,高强耐候H型钢的耐蚀性显著优于普通C-Mn钢,腐蚀产物性质的差别是导致两种钢腐蚀率差异的主要原因.普通C-Mn钢腐蚀后表面粗糙,锈层疏松且存在大量贯穿性裂纹;耐候H型钢锈层连续致密,且腐蚀产物主要由保护性较好的α-FeOOH和非晶态锈组成,能有效减缓电化学腐蚀反应的进行.%The differences of corrosion resistance between high strength weathering H section steel (HSWS-H) and common C-Mn steel (CMS) were investigated by cyclic immersion corrosion test, scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (ELS). The results showed that HSWS-H exhibited much higher corrosion resistance than CMS in the simulated industrial atmospheric environment.The difference between two corrosion products of the experimental steels was the main cause of the corrosion rate difference. The corrosion surface of CMS was rough, the rust layer was loose and had lots of perfoliate crack The rust layer of HSWS-H was continuous, dense and mainly consisted of α-FeOOH and amorphous phase, which can inhibit the electrochemical corrosion reaction effectively.

  6. An experimental study on cavitation erosion-corrosion performance of ANSI 1020 and ANSI 4135 steel

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Leqin; Qiu, Ning [Institute of Process Equipment, Zhejiang University, Hangzhou (China); Hellmann, Dieter-Heinz [KSB Aktiengesellschaft, Frankenthal (Germany); Zhu, Xiaowen [Zhejiang Keer Pump Stock Co., Ltd, Whenzhou (China)

    2016-02-15

    Cavitation erosion is quite complex, containing corrosion-erosion interaction effect. High temperature oxidization may be aroused after bubble collapse, accompanied by hot gas contacting with the pump component surface. The analysis of the erosion pits can be an effective way to know the mechanism of cavitation erosion. In present paper, the cavitation erosion resistance of carbon steel (ANSI 1020) and alloy steel (ANSI 4135) were tested in an ultrasonic vibration apparatus. By using energy dispersive X-ray spectroscope and three dimensional laser microscope, the chemical composition around erosion pits and the oxidation film structure were analyzed. By using metallographic microscope and scanning electronic microscope, the metallographic structure of specimens (e.g., carbon steel and alloy steel), the nano structured iron oxide and corresponding influence on specimen's anti-erosion performance were discussed. Based on the comparison between the different tests performed in distilled water and tap water respectively, results can be obtained that erosion rate of carbon steel and alloy steel varies with the component of water which had close correlation to the oxidation effect. Erosion rate of alloy steel 4135 was much lower in distilled water compared to tap water while the difference of carbon steel 1020 was not that large. The remarkable different responses of these two materials had close relationship with oxidation effect. The oxidation effect transferred the original structure of alloy steel surface which had high anti-erosion capability, into newly generated iron oxide structure, which was preferentially to be attacked. The pumping of slightly corrosive fluids frequently leads to erosion-corrosion damage on impellers, and corrosion can further amplify the erosion process.

  7. Corrosion behaviour of steels and CRA in sour gas environments

    Energy Technology Data Exchange (ETDEWEB)

    Lara, M. Alvarez de; Lancha, A.M.; Hernandez, F.; Gomez-Briceno, D. [CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain); Coca, P. [ELCOGAS, S.A., C.T. GICC Puertollano, Carretera de Calzada de Calatrava a Puertollano, km 27, 13500 Puertollano, Ciudad Real (Spain)

    2004-07-01

    the resistance of these materials to generalised and localised corrosion, in simulated sour environments (containing chlorides, fluorides, sulphides, formates, etc. and acid gas formed by H{sub 2}S and CO{sub 2}) and reproducing power plant conditions have been carried out at CIEMAT. Alloys tested were the in-service alloys and other materials considered as alternative to the existing ones: duplex stainless steel UR52N{sup +}, and nickel-based alloys A59 and 625. Tests were performed at 140 deg. C using non-welded and welded flat specimens exposed to gas phase, interface and liquid phase. In addition, stress corrosion cracking tests using AISI 316Ti C-ring specimens were performed. Nickel based alloys had the lowest corrosion rates and in all materials the corrosion resistance was better in the specimens located at the gaseous phase, the interface specimens having the poorest behavior. (authors)

  8. Corrosive Effect of Formation Water in Petroleum with High Contents of CO2 on Steel Pipelines

    Directory of Open Access Journals (Sweden)

    Alexander Cueli Corugedo

    2013-11-01

    Full Text Available The corrosion of the carbon steel pipelines of petroleum, is a serious problem, because big economic and material losses take place and in some cases damages to productive lands. The purpose of this work is to determine the aggressiveness of the formation water of the petroleum contaminated with CO2 (g, on the construction steel of the pipelines, keeping in mind the variations of temperature that happens during the course of petroleum. The Linear Polarization Resistance (LPR was used to determine the corrosion rate of the steel. It was demonstrated that the increase of the temperature and the saturation condition of CO2 in the formation water of the petroleum, increase the corrosion in the steel. The spectra of electrochemical noise results and the localization index calculated demonstrate the presence of corrosion located in the API 5L X - 52 steel surface. This result was complemented by the Optic Microscopy technique that allowed corroborating the poor adherence of the layers that were deposited on the metal and the appearance of located events increases in the environment that was investigated with the increment of the temperature and CO2 concentration.

  9. Corrosion inhibitor mechanisms on reinforcing steel in Portland cement pastes

    Science.gov (United States)

    Martin, Farrel James

    2001-07-01

    The mechanisms of corrosion inhibitor interaction with reinforcing steel are investigated in the present work, with particular emphasis on effects associated with corrosion inhibitors admixed into Portland cement paste. The principal objective in reinforcing steel corrosion inhibition for Portland cement concrete is observed to be preservation of the naturally passive steel surface condition established by the alkaline environment. Introduction of chloride ions to the steel surface accelerates damage to the passive film. Excessive damage to the passive film leads to loss of passivity and a destabilization of conditions that facilitate repair of the passive film. Passive film preservation in presence of chloride ions is achieved either through stabilization of the passive film or by modification of the chemical environment near the steel surface. Availability of inhibitors to the steel surface and their tendency to stabilize passive film defects are observed to be of critical importance. Availability of admixed corrosion inhibitors to the passive film is affected by binding of inhibitors during cement paste hydration. It is determined that pore solution concentrations of inorganic admixed inhibitors tend to be lower than the admixed concentration, while pore solution concentrations of organic admixed inhibitors tend to be higher than the admixed concentration. A fundamental difference of inhibitor function is observed between film-forming and defect stabilizing corrosion inhibitors. Experiments are conducted using coupons of reinforcing steel that are exposed to environments simulating chloride-contaminated Portland cement concrete. A study of the steel/cement paste interface is also performed, and compounds forming at this interface are identified using X-Ray diffraction.

  10. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Science.gov (United States)

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  11. The study of corrosion behavior of laser induced surface improvement (LISI) on steel and aluminum substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, N.; Vasanth, K.L.

    1999-07-01

    Laser Induced Surface Improvement (LISI) is a new process developed by University of Tennessee Space Institute (UTSI) which employs lasers to melt precursor coatings and portions of the substrate to form a durable corrosion resistant surface. The LISI surface can be tailored to yield a composition that provides minimum impact to the base substrate material while giving good corrosion characteristics. The LISI surface treatment of tungsten carbide was applied on 7075 and 6061 aluminum alloys. The LISI treatment uses a chromium/nickel mixture and a stainless steel type mixture (pseudo stainless steel of 18 wt% chromium, 8 wt% nickel and a trace amount of manganese and silicon) on steel alloy 1010. The corrosion characteristics of these samples were determined in 3.5 wt% NaCl aqueous solution using linear polarization resistance technique. Potentiodynamic scans were run to determine the corrosion rates and optical microscopy was used to examine pitting characteristics of the different surface coatings. The effectiveness of the LISI modified surfaces to protect both steel and aluminum substrates is discussed.

  12. Corrosion Behavior of the Stressed Sensitized Austenitic Stainless Steels of High Nitrogen Content in Seawater

    Directory of Open Access Journals (Sweden)

    A. Almubarak

    2013-01-01

    Full Text Available The purpose of this paper is to study the effect of high nitrogen content on corrosion behavior of austenitic stainless steels in seawater under severe conditions such as tensile stresses and existence of sensitization in the structure. A constant tensile stress has been applied to sensitized specimens types 304, 316L, 304LN, 304NH, and 316NH stainless steels. Microstructure investigation revealed various degrees of stress corrosion cracking. SCC was severe in type 304, moderate in types 316L and 304LN, and very slight in types 304NH and 316NH. The electrochemical polarization curves showed an obvious second current peak for the sensitized alloys which indicated the existence of second phase in the structure and the presence of intergranular stress corrosion cracking. EPR test provided a rapid and efficient nondestructive testing method for showing passivity, degree of sensitization and determining IGSCC for stainless steels in seawater. A significant conclusion was obtained that austenitic stainless steels of high nitrogen content corrode at a much slower rate increase pitting resistance and offer an excellent resistance to stress corrosion cracking in seawater.

  13. Erosion and Corrosion Behavior of Laser Cladded Stainless Steels with Tungsten Carbide

    Science.gov (United States)

    Singh, Raghuvir; Kumar, Mukesh; Kumar, Deepak; Mishra, Suman K.

    2012-11-01

    Laser cladding of tungsten carbide (WC) on stainless steels 13Cr-4Ni and AISI 304 substrates has been performed using high power diode laser. The cladded stainless steels were characterized for microstructural changes, hardness, solid particle erosion resistance and corrosion behavior. Resistance of the clad to solid particle erosion was evaluated using alumina particles according to ASTM G76 and corrosion behavior was studied by employing the anodic polarization and open circuit potential measurement in 3.5% NaCl solution and tap water. The hardness of laser cladded AISI 304 and 13Cr-4Ni stainless steel was increased up to 815 and 725Hv100 g, respectively. The erosion resistance of the modified surface was improved significantly such that the erosion rate of cladded AISI 304 (at 114 W/mm2) was observed ~0.74 mg/cm2/h as compared to ~1.16 and 0.97 mg/cm2/h for untreated AISI 304 and 13Cr-4Ni, respectively. Laser cladding of both the stainless steels, however, reduced the corrosion resistance in both NaCl and tap water.

  14. Corrosion resistant storage container for radioactive material

    Science.gov (United States)

    Schweitzer, Donald G.; Davis, Mary S.

    1990-01-01

    A corrosion resistant long-term storage container for isolating radioactive waste material in a repository. The container is formed of a plurality of sealed corrosion resistant canisters of different relative sizes, with the smaller canisters housed within the larger canisters, and with spacer means disposed between judxtaposed pairs of canisters to maintain a predetermined spacing between each of the canisters. The combination of the plural surfaces of the canisters and the associated spacer means is effective to make the container capable of resisting corrosion, and thereby of preventing waste material from leaking from the innermost canister into the ambient atmosphere.

  15. Corrosion inhibition of mild steel by aerobic biofilm

    Energy Technology Data Exchange (ETDEWEB)

    Chongdar, Shobhana [Naval Materials Research Laboratory, Addl. Ambarnath 421506 (India); Gunasekaran, G. [Naval Materials Research Laboratory, Addl. Ambarnath 421506 (India)]. E-mail: gunanmrl@rediffmail.com; Kumar, Pradeep [Naval Materials Research Laboratory, Addl. Ambarnath 421506 (India)

    2005-08-30

    Mild steel electrodes were incubated in phosphate-buffered basal salt solution (BSS) having two different aerobic bacteria, viz. Pseudomonas alcaligenes and Pseudomonas cichorii. In the medium containing P. cichorii, significant reduction in the corrosion rate was observed due to the surface reaction leading to the formation of corrosion inhibiting bacterial biofilm. With a view to understand the mechanism of microbially influenced corrosion/corrosion inhibition, electrochemical and biological experiments such as electrochemical impedance spectroscopy (EIS) measurements and biochemical analysis were made. The exposed surfaces were examined using scanning electron micrographs (SEM), energy dispersive spectroscopy (EDS) and electron spectroscopy for chemical analysis (ESCA). The scraped surface film was also examined using FT-IR spectroscopy. The results suggested that mild steel surface contained iron oxide-phosphate layer covered with bacteria and exo polymeric substance (EPS)/iron-EPS complex for P. cichorii and iron oxides and iron phosphate for P. alcaligenes.

  16. AFM study of steel corrosion in aqueous solutions in concrete

    Directory of Open Access Journals (Sweden)

    Díaz-Benito, B.

    2011-03-01

    Full Text Available Early corrosion stages are studied in carbon steel by means of a solution simulating that contained in concrete pores. Non-carbonated solution contains 5% NaCl. The atomic force microscopy (AFM technique is used to study material performance after different immersion times (up to 48 h. Obtained data are compared to electrochemical ones (corrosion potential and polarization resistance. Analysis of images and roughness evolution along time shows that steel initially tends to reach passivity, although the passive layer rapidly loses its protective character due to chloride attack.

    Este trabajo estudia los primeros estados de la corrosión de un acero al carbono en una disolución que simula la existente en los poros del hormigón, sin carbonatar, con un 5% de NaCl. Para ello, se ha empleado la técnica de microscopía de fuerza atómica (AFM, estudiando el comportamiento del material tras diferentes tiempos de inmersión, hasta 48 h, en la disolución. Estos datos se comparan con datos electroquímicos (potencial de corrosión y resistencia de polarización. El análisis de las imágenes y la evolución de la rugosidad con el tiempo muestran que el acero tiende inicialmente a pasivarse, pero la capa pasiva pierde rápidamente su carácter protector debido al ataque de los cloruros.

  17. Erosion and corrosion of ceramic-metallic coatings and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Bjordal, M.

    1995-04-01

    Simultaneous corrosion and erosion is a well-known problem in many environments, for instance in hydroelectric power plants and in oil production systems. This thesis presents a study of the combined effect of corrosion and erosion for some thermal spray ceramic-metallic coatings (cemented carbides) and a duplex stainless steel. By measuring the two effects separately and comparing them to the total material loss obtained when they occur simultaneously, it has been possible to reveal the relative contribution from the two deterioration mechanisms and how they interact. The materials were exposed to flowing aerated synthetic sea water containing silica particles. Specimens of various shapes were moved in the slurry. It is generally found that the corrosion percentage decreases when the erosivity of the environment is increased, for instance by increased flow velocity, and at the same time erosion plays a more important role. For all the materials tested the corrosion rate is increased by addition of particles to the flow. Differences are found between the thermal spray coatings. Small additions of Cr to the actively corroding Co matrix of the 83WC 17Co sample improve the corrosion resistance. Even if the amount of corrosion relative to the total weight loss rate is small, the corrosion can lead to a synergism of up to 90 %. Stainless steel does not exhibit a clear synergism. The computer code FLUENT was used for modelling the flow conditions. 79 refs., 67 figs., 29 tabs.

  18. 45钢表面激光相变硬化改性组织及耐蚀性能%Microstructure and Corrosion Resistance of Laser Transformation Hardening Modified on 45 Steel Surface

    Institute of Scientific and Technical Information of China (English)

    邱星武

    2015-01-01

    目的:为了改善45钢表面状态,提高其表面性能,采用CO2激光器对其表面进行激光相变硬化处理。方法利用带有能谱的扫描电子显微镜( SEM/EDS )、盐雾试验机等,对激光相变硬化层组织及耐蚀性能进行了观察和分析。结果激光相变硬化层由熔化区、相变硬化区和热影响区三部分组成,其组织依次为:混合马氏体+未溶碳化物、针状马氏体、残余奥氏体。随扫描速度增加,耐蚀性先变好而后变差。结论激光相变硬化处理可改善45钢的表面性能,显著提高其耐蚀性能。%In order to improve the surface properties of 45 steel, the laser transformation hardening treatment was car-ried out by CO2 laser on its surface. The microstructure and properties of alloying layer were analyzed by scanning electron microscope with energy spectrum ( SEM/EDS) , salt spray tester, etc. The laser transformation hardening layer was consti-tuted by melting zone, transformation hardened zone and heat affected zone. The microstructure included the mixed mar-tensite plus undissolved carbides, acicular martensite, and retained austenite. With the increase of the scanning speed, the corrosion resistance increased first and then decreased. After laser transformation hardening treatment, the surface proper-ties of 45 steel were improved, which significantly increased the corrosion resistance.

  19. Corrosion of API XL 52 steel in presence of Clostridium celerecrescens

    Energy Technology Data Exchange (ETDEWEB)

    Monroy, O.A. Ramos; Ordaz, N. Ruiz; Ramirez, C. Juarez [Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Prolongacion de Carpio y Plan de Ayala, Mexico D. F., C. P. 11340 (Mexico); Gayosso, M.J. Hernandez; Olivares, G. Zavala [Instituto Mexicano del Petroleo, Grupo Corrosion, Eje Central Lazaro Cardenas 152, Col. San Bartolo Atepehuacan, Mexico D. F., C. P. 07730 (Mexico)

    2011-09-15

    During the characterization of sediments formed in pipelines transporting hydrocarbons, the knowledge of the microbiological diversity becomes very interesting, especially when it is related to microbiologically influenced corrosion (MIC). The presence of microorganisms is considered as one of the factors that affect the corrosion processes occurring at the pipeline; therefore, their corrosiveness must be determined. In this way, the identification of new species affecting the MIC processes is still considered relevant. In this work, the effect of Clostridium celerecrescens upon the corrosion of API KL 52 steel was evaluated. This microorganism was isolated and identified from the sediments collected during the inner cleaning procedures of a gas pipeline. The polarization resistance (PR) and electrochemical impedance spectroscopy (EIS) techniques were considered to estimate the microorganism behavior during the corrosion process. The results were complemented with a metal surface analysis, using a scanning electron microscope (SEM). The resistance values induced by the presence of the microorganisms clearly indicated that C. celerecrescens has an effect on the corrosion process occurring at the API XL 52 steel surface. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Corrosion of bare and galvanized steel in gypsum

    Directory of Open Access Journals (Sweden)

    Gómez, Mercedes

    1988-12-01

    Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.

    El yeso es un material de construcción de relativo bajo coste y que, además, es muy abundante en nuestro país. Debido a su pH cercano a la neutralidad, cuando entra en contacto con el acero, este puede corroerse a elevadas velocidades. En esta comunicación se presentan los resultados de un estudio sobre la velocidad de corrosión del acero desnudo y galvanizado en contacto con yeso y escayola y la influencia que tienen: el tratamiento térmico del curado del yeso, la humedad relativa ambiental y la adición de aditivos de diversa naturaleza y finalidad. Como técnicas de medida se han utilizado la medida de la Resistencia de Polarización y de la pérdida de peso, así como observaciones visuales. De los resultados se puede deducir que en