高温锻造中ASME SA508-3钢的动态软化

Dynamic softening mechanism on steel of ASME SA508 3 during hot working

大型锻件高温锻造是核反应堆压力容器中重要的热加工工艺，优化的锻造工艺不仅可以满足合格的产品外形尺寸，而且可以获得优良的微观组织性能。采用热力模拟手段研究了核电用钢ＡＳＭＥＳＡ５０８－３的动态软化微观机制与高温锻造热力参数之间的关系，得到了该钢种在不同变形条件下的真应力应变关系、动态再结晶临界应变值、动态再结晶晶粒尺寸与Ｚｅｎｅｒ－Ｈｏｌｏｍｏｎ参数之间的关系。探讨了Ｚ参数的唯一性及在锻造过程中动态再结晶的应用范围，为核电锻件微观组织性能控制锻造提供了必要的力学、物理、材料关系。

Heavy forging is a very important hot working process for pressure vessels in nuclear reactors. The need of outer shape, size, and inner microstructure in heavy forgings can be met by optimum forging processing parameters. The dynamic softening mechanism on the steel of ASME SA508 3 during hot working was researched with Thermal Mechanical method. The relationships of true stress strain were obtained under different deformation conditions. The critical strains for dynamic recrystallization and the relationship between grain size and parameter Z were studied. The unique of parameter Z and the range of application for dynamic recrystallization were analysised. The relationships among mechanics, physical, and materials play very significant role theoretically and practically in microstructure control forging.