Effect of Thermal Processing on the "Gold Dust" Defect of 430 Ferritic Stainless Steel
SHAO Ze-bin1,2, CHEN Hai-tao2, LANG Yu-ping2, ZHU Xin-kun1
1. Faculty of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. Institute of Structure Materials, Central Iron and Steel Research Institute, Beijing 100081, China
Abstract：The relationship between the intergranular corrosion and "gold dust" defects on surfaces of 430 ferritic stainless steel was investigated. On the basis of the different hot rolling tests performed on Gleeble 3800 thermal mechanical simulation and simulated coiling test after deformation, a study was conducted in order to determine the effect of thermal processing on the intergranular corrosion of 430 ferritic stainless steel. The DL-EPR was introduced to measure the susceptibility to intergranular corrosion.The results showed that the 430 ferritic stainless steel sensitization happened in the process of hot rolling, then conduce intergranular corrosion during the pickling, eventually produced the "gold dust" defects after cold rolling. It is found that the intergranular corrosion sensitization could be effectively prevented with a combination of final rapid cooling (water cooling) at the final deformation temperature of 900-950℃.By the analysis of simulated coiling test results, the intergranular corrosion susceptibility of 430 ferritic stainless steel can be further avoided and eliminated by a treatment of 650-800℃.
余海峰,毛惠刚,崔培耀,等.410S不锈钢带表面"砂金"缺陷成因及机理分析[J].宝钢技术,2006,(1):35-39,71.YU H F,MAO H G,CUI P Y,et al. Formation causes and mechanism of "Punctuate" defect on surface of 410S stainless steel strip[J].Baosteel Technology,2006,(1):35-39,71.
UEDA M. Process for production of stainless steel thin strip and sheet having superior surface gloss and high rusting resistance.USA Patent:5181970,1993.
KIM D K, LEE D G, LEE S. Correlation of microstructure and surface roughness of disc drums fabricated by hot forging of an AISI 430F stainless steel[J]. Metallurgical and Materials Transactions,2001, 32A(5): 1111-1118.
查小琴,邵军.不锈钢晶间腐蚀测试方法[J].材料开发与应用,2009,24(3):60-65.ZHA X Q,SHAO J.Review on intergranular corrosion testing methods of stainless steels [J].Development and Application of Materials,2009,24(3):60-65.
AMADOU T, SIDHOM H, BRAHAM C. Double loop electrochemical potentiokinetic reactivation test optimization in checking of duplex stainless steel intergranular corrosion susceptibility[J]. Metallurgical and Materials Transactions, 2004, 35A(11): 3499-3513.
SIDHOM H, AMADOU T, SAHLAOUI H, et al. Quantitative evaluation of aged AISI 316L stainless steel sensitization to intergranular corrosion: comparison between microstructural electrochemical and analytical methods[J]. Metallurgical and Materials Transactions, 2007, 38A(6): 1269-1280.
金维松,郎宇平,荣凡.EPR法评价奥氏体不锈钢晶间腐蚀敏感性的研究[J].中国腐蚀与防护学报,2007,27(1):54-59.JIN W S,LANG Y P,RONG F.Research of EPR on the susceptibility to intergranular attack of austenitic stainless steel [J].Journal of Chinese Society for Corrosion and Protection,2007,27(1):54-59.
ASTM G108—94(1999),standard test method for electrochemical reactivation (epr) for detecting sensitization of AISI type 304 and 304L stainless steels[S].
高中平,陈范才,赵常就.动电位再活化法评价晶间腐蚀敏感性的各种判据[J].四川化工与腐蚀控制,1999,(3):40-44. GAO Z P,CHEN F C,ZHAO C J.Different criteria of electrochemical potentiokinetic reactivation method to evaluate the susceptibility to intergranular corrosion[J].Sichuan Chemical and Corrosion Control,1999,(3):40-44.
BOWEN A W, LEAK G M. Solute diffusion in alpha- and gamma-iron[J]. Metallurgical and Materials Transactions B, 1970, 1(6): 1695-1700.