热变形条件对P92钢动态再结晶组织及机制的影响

采用Gleeble-1500D热力模拟压缩试验机,研究P92锻态料在温度900℃～1300℃、应变速率0.5s-1～25s-1、变形程度50%条件下的热变形行为,分析热变形参数对应力-应变曲线、动态再结晶组织演变规律和机制的影响,获得了动态再结晶分数和动态再结晶晶粒尺寸。结果表明,P92钢动态软化机制有动态回复、不连续动态再结晶和几何动态再结晶3种方式。动态再结晶分数随温度的升高而增大,且随着应变速率的增大,发生不连续动态再结晶的温度范围扩大。采用提高热变形温度和高应变速率的改进工艺,可获得P92钢优良的组织和性能。

Effect of hot deformation condition on the dynamic recrystallization microstructure and mechanism of P92 steel

The hot deformation behavior of P92 forging billet has been investigated at 900℃～1300℃,strain rate 0.5s-1～25s-1 and maximum deformation to 50% by means of hot compression tests on the Gleeble-1500D thermal simulator.Effects of hot deformation parameters on the stress strain curve,dynamic recrystallization microstructure and mechanism have been analyzed.And dynamic recrystallization fraction and dynamic recrystallization grain size of P92 steel under different softening ways have been acquired.The results indicate that P92 steel has three types of dynamic recrystallization softening mechanism,that is,dynamic recovery,discontinous dynamic recrystallization and geometric dynamic recrystallization.Dynamic recrystallization fraction increases with rising temperature and the temperature range generating discontinuous dynamic recrystallization increases with increase of strain rate.The P92 steel pipe of better microstructure and property could be acquired by the improved technology with increasing hot deformation temperature and strain rate.