Influence of chemical composition and cold deformation on aging precipitation behavior of high nitrogen austenitic stainless steels
来源期刊:中南大学学报(英文版)2013年第12期
论文作者:LI Hua-bing(李花兵) JIANG Zhou-hua(姜周华) FENG Hao(冯浩) ZHU Hong-chun(朱红春) ZHANG Zu-rui(张祖瑞)
文章页码:3354 - 3362
Key words:high nitrogen austenitic stainless steel; aging precipitation; time-temperature-precipitation curve; chemical composition; cold deformation
Abstract: The influence of chemical composition and cold deformation on aging precipitation behavior of 18Cr-16Mn-2Mo-1.1N (HNS-A), 18Cr-16Mn-1.3N (HNS-B), 18Cr-18Mn-2Mo-0.96N (HNS-C) and 18Cr-18Mn-2Mo-0.77N (HNS-D) high nitrogen austenitic stainless steels was investigated. The results show that the “nose” temperatures and incubation periods of the initial time-temperature-precipitation (TTP) curves of aged HNSs are found to be 850 °C, 60 s; 850 °C, 45 s; 850 °C, 60 s and 900 °C, 90 s, respectively. Based on the analysis of SAD patterns, the coarse cellular Cr2N precipitate which presents a lamellar structure has a hexagonal structure of a=0.478 nm and c=0.444 nm. The χ phase corresponding to a composition of Fe36Cr12Mo10, is determined to be a body-centered cubic structure of a=0.892 nm. The precipitating sensitivity presents no more difference with the nitrogen content increasing from 0.77% to 0.96%, but exhibits so obviously that the cellular precipitates nearly overspread the whole field. The addition of Mo element can restrain the TTP curves moving left and down, which means decreasing the sensitivity of aging precipitation. With increasing the cold deformation, the sensitivity of precipitation increases obviously.
LI Hua-bing(李花兵), JIANG Zhou-hua(姜周华), FENG Hao(冯浩), ZHU Hong-chun(朱红春), ZHANG Zu-rui(张祖瑞)
(School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China)
Abstract:The influence of chemical composition and cold deformation on aging precipitation behavior of 18Cr-16Mn-2Mo-1.1N (HNS-A), 18Cr-16Mn-1.3N (HNS-B), 18Cr-18Mn-2Mo-0.96N (HNS-C) and 18Cr-18Mn-2Mo-0.77N (HNS-D) high nitrogen austenitic stainless steels was investigated. The results show that the “nose” temperatures and incubation periods of the initial time-temperature-precipitation (TTP) curves of aged HNSs are found to be 850 °C, 60 s; 850 °C, 45 s; 850 °C, 60 s and 900 °C, 90 s, respectively. Based on the analysis of SAD patterns, the coarse cellular Cr2N precipitate which presents a lamellar structure has a hexagonal structure of a=0.478 nm and c=0.444 nm. The χ phase corresponding to a composition of Fe36Cr12Mo10, is determined to be a body-centered cubic structure of a=0.892 nm. The precipitating sensitivity presents no more difference with the nitrogen content increasing from 0.77% to 0.96%, but exhibits so obviously that the cellular precipitates nearly overspread the whole field. The addition of Mo element can restrain the TTP curves moving left and down, which means decreasing the sensitivity of aging precipitation. With increasing the cold deformation, the sensitivity of precipitation increases obviously.
Key words:high nitrogen austenitic stainless steel; aging precipitation; time-temperature-precipitation curve; chemical composition; cold deformation