时效温度对AM 355不锈钢组织和力学性能的影响

Effects of Aging Temperatures on Microstructure and Mechanical Properties of AM 355 Stainless Steel

对AM 355不锈钢进行了1 070℃固溶处理、-73℃冷处理,随后分别在200℃、240℃、300℃、340℃、400℃和480℃时效处理3 h。检测了钢的力学性能和显微组织。结果表明:AM 355不锈钢在低于300℃的温度时效后,其组织为回火马氏体和碳化物;随着时效温度的升高,有析出相出现,在480℃时效后析出相与基体仍保持共格关系。此外,随着时效温度的升高,钢的强度和硬度先降后升,塑性则先升后降。

AM 355 stainless steel was solution treated at 1 070 ℃, cold treated at-73 ℃, and aged at 200, 240,300, 340, 400, and 480 ℃ for 3 h, respectively. Subsequently, the steel was subjected to microstructure survey and mechanical property measurements. The results showed that the steel exhibited tempered martensite and carbides after aging at temperatures lower than 300 ℃, and a precipitated phase after aging at temperatures higher than 300 ℃, with the precipitated phase having still coherent relation to the matrix after aging at 480 ℃.Furthermore, as the aging temperature became higher, the steel showed strength and hardness which first lowered and then rose, and plasticity which first rose and then lowered.