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利用Gleeble-3180热模拟机对铸态12%wtCr马氏体不锈钢进行了高温热压缩实验,研究了该钢在900~1200℃和0.001~10 s-1条件下的热变形行为,建立了热加工图。分析了工艺参数对铸态12%Cr钢微观组织的影响。结果表明:铸态12%Cr钢的流变应力随变形温度的提高和应变速率的降低而增大。动态再结晶晶粒尺寸与Z参数成反比关系。依据动态材料模型,建立了热加工图,流变失稳区集中在900~1050℃、应变速率大于1 s-1的区域,其微观组织表现为变形带和M/δ相界处的微孔、微裂纹。最佳的热加工工艺参数范围为:1050~1200℃和0.001~0.01 s-1,在稳定变形区,粗大的毫米级的柱状晶会被细化到10~40μm。
Hot compression tests were carried out on the as-cast 12% wtCr martensitic stainless steel using the Gleeble-3180 thermal simulator. The hot deformation behavior of the as-cast steel at 900-1200 ℃ and 0.001-10 s-1 was studied. Processing diagram. The influence of technological parameters on the microstructure of as-cast 12% Cr steel was analyzed. The results show that the flow stress of as-cast 12% Cr steel increases with the increase of deformation temperature and the decrease of strain rate. Dynamic recrystallization grain size is inversely proportional to the Z parameter. According to the dynamic material model, the hot working diagram is established. The rheological instability zone is concentrated in the range of 900-1050 ℃ and the strain rate is greater than 1 s-1. The microstructure is characterized by micropores at the deformation zone and M / δ phase boundary , Micro-cracks. The optimal thermal processing parameters range from 1050 to 1200 ℃ and from 0.001 to 0.01 s-1. In the stable deformation zone, the coarse, millimeter-sized columnar crystals are refined to 10-40 μm.