微合金非调质钢30Mn2V奥氏体未再结晶区形变σ-ε曲线与相变特征分析

Analysis of σ-ε Curves and Transformation Characteristics of Non-tempered and Quenched Steel 30Mn2V During the Deformation of Austenite at Non-recrystallization Zone

研究了奥氏体未再结晶区 ,形变温度与形变速率对其 σ- ε曲线以及相变特征的影响。结果表明 :随着形变温度的降低 ,峰值应力逐渐增加 ,形变抗力在很大的应变范围内开始下降或保持不变 ,曲线由奥氏体再结晶型转变为动态回复型 ;在低温奥氏体区 ,当形变温度为 70 0℃时 ,奥氏体是非稳态的 ,压下率达到 6 5 %左右时 ,则有可能引起形变诱导铁素体析出 ,导致形变抗力下降 ,反映在曲线上 ,为第二个弱峰值应力的出现 ;室温组织中观察到的类似于形变铁素体的组织 ,并非真正的形变铁素体 ,实际上是在冷却的过程中 。

The effect of deformation temperature and strain rate on σ ε curves and transformation characteristics of non tempered and quenched steel 30Mn2V during the deformation of austenite at non recrystallization zone had been studied.The results indicate that the peak stress gradually increased and then keep balance or decrease slowly as the deformation temperature decreased,the transitions of the characteristics of σ ε curves from austenite recrystallization to dynamic recovery has been observed; while on straining at 700℃, austenite is in substable state and a transition of deformation induced ferrite will be occurred while deformation amount is above 65%;And the second peak stress will be appeared on the σ ε curves;In fact,the ferrite grains just like deformed is the result of ferrite nucleation and the grow of ferrite grains along the deformation bands and grain boundaries.