The grain size and precipitate amount which are affected by heat treatment have significant impact on the properties of high nitrogen austenitic stainless steel.In this study,Cr18Mn18 high nitrogen steel sheet is empl...The grain size and precipitate amount which are affected by heat treatment have significant impact on the properties of high nitrogen austenitic stainless steel.In this study,Cr18Mn18 high nitrogen steel sheet is employed to investigate the effects of precipitate on austenitic grain size.It can be seen that the lamella precipitates which are rich in nitrogen and chromium nucleate in the austenite grain boundary and grow inward into grain when aged at 800℃through electron probe micro-analyzer.The transmission electron microscopy results demonstrate that the precipitate is Cr2N and its morphology are detected as ellipsoid-like with major axis of 100-300 nm and minor axis of 50-100 nm roughly.The experiment show that coarsen of the austenite grain is quite critical at 1000-1100℃.However,the samples which pre-precipitated at 800℃for 240 min to obtain the most nitride precipitate exhibits much smaller grain size than the as-rolled samples after solid solution treated at 1000,1050 and 1100℃for 240 min.The results show that the nitride precipitates in the grain boundary can effectively pin the austenite grain boundary and inhibit the grain growth.展开更多
基金National Nature Science Foundation of China(50974014)
文摘The grain size and precipitate amount which are affected by heat treatment have significant impact on the properties of high nitrogen austenitic stainless steel.In this study,Cr18Mn18 high nitrogen steel sheet is employed to investigate the effects of precipitate on austenitic grain size.It can be seen that the lamella precipitates which are rich in nitrogen and chromium nucleate in the austenite grain boundary and grow inward into grain when aged at 800℃through electron probe micro-analyzer.The transmission electron microscopy results demonstrate that the precipitate is Cr2N and its morphology are detected as ellipsoid-like with major axis of 100-300 nm and minor axis of 50-100 nm roughly.The experiment show that coarsen of the austenite grain is quite critical at 1000-1100℃.However,the samples which pre-precipitated at 800℃for 240 min to obtain the most nitride precipitate exhibits much smaller grain size than the as-rolled samples after solid solution treated at 1000,1050 and 1100℃for 240 min.The results show that the nitride precipitates in the grain boundary can effectively pin the austenite grain boundary and inhibit the grain growth.
