不同晶粒尺寸的铸态12%Cr铁素体耐热钢热变形行为  

Hot Deformation Behavior of As-cast 12%Cr Ferritic Heat-resistant Steel with Different Grain Sizes

作　　者：余健 

机构地区：[1]上海交通大学材料科学与工程学院,上海200240

出　　处：《热加工工艺》2017年第19期102-106,共5页Hot Working Technology

基　　金：国家重点基础研究发展计划(973计划)项目(2011CB012900)

摘　　要：利用Gleeble-3500热模拟试验机对铸态柱状晶12%Cr铁素体耐热钢在变形温度为950~1250℃与应变速率为0.001~1 s-1下进行了等温热压缩实验,研究了不同柱状晶晶粒尺寸下钢的流变应力、本构方程与微观组织。结果表明:铸态12%Cr钢的流变应力随变形温度的提高与应变速率的降低而减小,原始晶粒尺寸越小,峰值应力越大。利用Arrhenius双曲正弦本构方程对不同变形下的流变应力进行了描述,计算出不同晶粒下的热变形激活能(Q(小柱状晶)>Q(大柱状晶)),且小柱状晶下的预测结果更为准确。原始晶粒尺寸越小,动态再结晶晶粒越多且尺寸越小。The isothermal hot compression tests of 12% Cr ferrite heat-resistant steel with as-cast columnar-grain were conducted at the deformation temperature of 950-1250℃ and the strain rate of 0.001 -1 s-1 by using Gleeble-3500 thermal-mechanical simulator. The flow stress, constitutive equation and microstructure of the steel with different columnar-grain sizes were studied. The results show that the flow stress of as-cast 12% Cr steel decreases with the deformation temperature increasing and the strain rate decreasing. The smaller the original grain size is, the higher the peak stress is. The flow stress under different deformation conditions was described by using the Arrhenius hyperbolic sine constitutive equation. The activation energy of thermal deformation under different grains was calculated （Q （small columnar grain）〉Q （large columnar grain））, and the prediction result of small columnar grain size is more accurate. The smaller the original grain size is, the more the amount of dynamic recrystallization is, and the smaller the size is.

关 键 词：12%Cr铁素体耐热钢 热压缩变形 流变应力 本构方程 动态再结晶 

分 类 号：TG316[金属学及工艺—金属压力加工]