【摘要】 以304L奥氏体不锈钢为基础,熔炼了4种添加不同微量元素的实验钢·实验钢热轧板冷轧后进行不同温度的再结晶退火处理以使晶粒尺寸在一定范围内变化,然后进行不同温度的均一化热处理以消除前面热处理带来晶界偏聚量的差异,最后进行力学性能测试、显微组织观察和晶粒尺寸统计,将所得数据处理成Hall-Petch关系式·通过对不同成分和不同热处理制度的对比,研究了微量元素Nb,B,C,N对304L不锈钢Hall-Petch的影响规律·结果表明:微量C,N和B对奥氏体不锈钢的Hall-Petch关系式中的σ0影响不大,N和B可以提高细晶强化系数ky·微量Nb可以与部分C,N结合形成Nb(C,N),在700℃均一化热处理时,对σ0影响不大,但能够提高细晶强化系数ky值;在500℃均一化热处理时,使σ0降低,而ky值提高更加显著·更多还原

【Abstract】 Four experimental specimens were prepared from molten 304L austenitic stainless steel, with different trace elements added in it. After cold rolling and recrystallization annealing at different temperatures to cause grain size distribution change to a certain extent, those specimens were annealed again for homogeneity at different temperatures to eliminate the different grain boundary segregation resulting from different annealing temperatures. Then, their mechanical properties were tested with their microstructures observed for grain size statistics, thus getting the Hall-Petch relation through data processing. The effects of such microalloying elements as Nb, B, C and N on Hall-Petch relation were investigated by comparing the results of different specimens and heat-treatments. Conclusions are therefore drawn that: without Nb addition, the trace elements C,N and B have little influence on σ₀ in Hall-Petch relation, but N or B can increase grain refinement strengthening coefficient k_y. Once Nb is added in the austenitic stainless steel, it compounds with the elements C and N to form the carbonitride of Nb, which has no obvious influence on σ₀ but increases k_y when reannealing the specimens for homogeneity at 700℃. However, it decreases σ₀ but increases k_y at 500℃.更多还原