Effect of Aging on σ Phase Precipitation and Properties of 4A Duplex Stainless Steel
LU Panpan1, WANG Aiqin1, XIE Jingpei2, WANG Wenyan1
1 College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023; 2 Collaborative Innovation Center of Nonferrous Metals of Henan Province, School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023
Abstract: The effect of aging treatment on precipitation behavior of σ phase of 4A duplex stainless steel after solution treatment was observed by OM, and the precipitation process of σ phase at 850 ℃ for different time was analyzed. In order to investigate the precipitation characteristics and the mechanisms of σ phase, the morphology of the sample by aging for 4 hours was analyzed by SEM, EDS and TEM. Finally, the mechanical properties and corrosion resistance of 4A duplex stainless steel were also studied. The results show that σ phase is rich in Cr, Mo but Ni-depleted, its crystal structure is tetragonal and it is formed by the decomposition of δ; σ phase precipitation increased first and then decreased with the increase of aging temperature, and it reaches a peak at 850 ℃. The σ phase precipitation is more, when the aging time is longer under the same temperature; σ phase causes higher hardness of the material, but generally declining tensile strength, impact toughness and corrosion resistance, among which the impact toughness is particularly sensitive to the σ phase precipitation.
1 吴玖. 双相不锈钢[M]. 北京: 冶金工业出版社,2000. 2 Feng H, Zhou X Y, Liu H, et al. Development and trend of hyper duplex stainless steels[J]. J Iron Steel Res, 2015,27(4):1(in Chinese). 丰涵, 周晓玉, 刘虎,等. 特超级双相不锈钢的发展现状及趋势[J]. 钢铁研究学报,2015,27(4):1. 3 Jimenez J A, Carsi M, Ruano O A, et al. Characterization of a delta/gamma duplex stainless steel[J]. J Mater Sci,2000,35(4):907. 4 Hussain E A M, Robinson M J. Erosion-corrosion of 2205 duplex stainless steel in flowing seawater containing sand particles[J]. Corros Sci,2007,49(4):1737. 5 Ghosh S K, Mondal S. High temperature ageing behaviour of a duplex stainless steel[J]. Mater Character, 2008, 59(12):1776. 6 Huang C S, Shih C C. Effects of nitrogen and high temperature aging on σ phase precipitation of duplex stainless steel[J]. Mater Sci Eng A,2005,402(1-2):66. 7 Chen T H, Yang J R. Effects of solution treatment and continuous cooling on σ-phase precipitation in a 2205 duplex stainless steel[J]. Mater Sci Eng A, 2001,311(1-2):28. 8 Wei Bin, Bai Zhenquan, Yin Chengxian, et al. Effects of solid solution treatment on pitting corrosion behavior of 2205 duplex stainless steel[J].Trans Mater Heat Treatment,2009,30(4):73(in Chinese). 魏斌, 白真权, 尹成先,等. 固溶处理对2205双相不锈钢点蚀性能的影响[J]. 材料热处理学报,2009,30(4):73. 9 Sato Y S, Kokawa H. Preferential precipitation site of sigma phase in duplex stainless steel weld metal[J]. Scr Mater,1999,40(6):659. 10 Bin Yuanhong, Li Peifen, Li Zhizheng, et al. Precipitation of σ-phase and its effect on impact toughness of a duplex stainless steel solution-treated at different temperatures[J]. Trans Mater Heat Treatment,2013,34(8):136(in Chinese). 宾远红, 李培芬, 李志铮,等. 不同固溶温度对双相不锈钢σ相析出及冲击韧性的影响[J]. 材料热处理学报,2013,34(8):136. 11 Ding X P, Liu X, He Y L, et al. Study of precipitation evolution in 2205 DSS during aging treatment and its effect on impact toughness[J]. Iron Steel,2010,45(6):84(in Chinese). 丁秀平, 刘雄, 何燕霖,等. 时效条件下2205双相不锈钢中的析出相分析及其对冲击性能的影响[J]. 钢铁,2010,45(6):84. 12 Luo Z Y, Li J Y. Precipitation behavior of σ phase in UNS S32760 super duplex stainless steel[J]. Trans Mater Heat Treatment,2015,36(4):110(in Chinese). 罗照银, 李静媛. S32760超级双相不锈钢中σ相的析出规律[J]. 材料热处理学报,2015,36(4):110. 13 Liu X, He Y L, Ding X P, et al. Effect of high temperature aging on σ-phase precipitation in a 2205 duplex stainless steel[J]. Trans Mater Heat Treatment,2010,31(3):48(in Chinese). 刘雄, 何燕霖, 丁秀平,等. 高温时效对2205双相不锈钢中σ相析出行为的影响[J]. 材料热处理学报,2010,31(3):48. 14 Maehara Y, Koike M, Fujino N, et al. Precipitation of σ phase in a 25Cr-7Ni-3Mo duplex phase stainless steel[J]. Trans Iron Steel Institute Jpn,1983,23(3):240. 15 Zhao Z Y, Xu L, Li G P, et al. Precipitation behavior of σ-phase and its effect on microstructure and properties of a super duplex stainless steel[J].Trans Mater Heat Treatment,2010,31(10):75(in Chinese). 赵志毅, 徐林, 李国平,等. 超级双相不锈钢σ相析出及对组织性能的影响[J]. 材料热处理学报,2010,31(10):75. 16 Xiang H L, Liu D, Ruan F R, et al. Effects of precipitation for aging on mechanical and corrosion resistance properties of cast 2507 super duplex stainless steel [J]. Acta Metall Sin,2010,46(8):941(in Chinese). 向红亮, 刘东, 阮方如,等. 时效析出相对铸造2507超级双相不锈钢力学及耐蚀性能的影响[J]. 金属学报,2010,46(8):941. 17 Pohl M, Storz O, Glogowski T. Effect of intermetallic precipitations on the properties of duplex stainless steel[J]. Mater Character,2007,58(1):65. 18 Liu X, Ding X P, He Y L, et al. Effect of aging treatment on σ phase precipiation and toughness property in a 2205 duplex stainless steel [J]. Shanghai Metals,2010,32(1):39(in Chinese). 刘雄, 丁秀平, 何燕霖,等. 高温时效对2205双相不锈钢冲击韧性的影响[J]. 上海金属,2010,32(1):39.