摘要
分析了单向压缩热模拟条件下碳素钢应变诱导铁素体相变过程中的σ－ε曲线特征结果表明，应变诱导相变过程有自己特定的σ－ε曲线，与典型的奥氏体动态再结晶σ－ε曲线有明显差异．随形变温度的降低σ－ε曲线由典型的奥氏体动态再结晶型过渡到铁素体应变诱导相变型在９００℃奥氏体稳定状态应变时，随应变速率的提高，奥氏体动态再结晶被推迟，铁素体应变诱导相交提前奥氏体的动态再结晶并不能完全抑止铁素体的诱导相变．在７７０℃奥氏体亚稳态应变时，奥氏体不能动态再结晶．应变速率的变化主要与铁素体析出速率相关．这时表现为过冷与应变对转变的相对贡献上．粗晶奥氏体的σ－ε曲线与细晶不同，两者的差异主要表现在铁素体转变的后期应变诱导相变过程中，铁素体析出的临界应变量σ－ε与应变峰值εｐ的关系受应变温度和应变速率的影响．在奥氏体不能动态再结晶的条件下，εｃ＜０．３εｐ．降温单道次形变过程中，Ｑ２３５碳素钢中会相继发生奥氏体的动态再结晶，铁素体应变诱导相变及铁素体的动态再结晶并反映在σ－ε曲线上．
The σ-ε curves of strain induced transformation in Q235 plain carbon steel are ana- lyzed at large temperature range by thermal simulating tests. Results indicate that the characteristics of σ-ε curves are distinguished to those of austenite dynamic recrystallization and a transition between them was observed as deforming temperature decreased. At the temperature where austenite was stable the dynamic recrystallization of austenite was delayed and ferrite transformation was accelerated as strain rate increased, whereas on straining at 770 ℃ of austenite substable state no austenite dynamic recrystallization took place and the change of strain rate was simply reflected in transformation rate which can be interpreted as the result of the relative contribution of supercooling and straining. During strain induced transformation the relationship of critical strain of ferrite formation and peak strain was influenced by strain rate and deforming temperature. At the non-recrystallization temperature of austenite, εc <0.3εp. During single pass compression at declining temperature the austenite dynamic recrystallization, strain induced transformation and ferrite dynamic recrystallization can take place successively.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2001年第6期609-616,共8页
Acta Metallurgica Sinica
基金
国家科技部973资助项目 G1998061506
关键词
碳素钢
应变诱导相变
应力-应变曲线
plain carbon steel, strain induced transformation, σ-ε curve
