两相区热处理对工程结构用高强钢低周疲劳性能的影响  

Effect of heat treatment in two-phase region on low-cycle fatigue properties of high strength steel for engineering structures

作　　者：吕卫东[1] 

机构地区：[1]宝山钢铁股份有限公司,上海201900

出　　处：《材料与冶金学报》2016年第2期132-136,146,共6页Journal of Materials and Metallurgy

基　　金：国家科技支撑计划项目(2011BAE13B03)

摘　　要：为提高工程结构用高强钢的低周疲劳性能,通过光学显微镜、扫描电子显微镜、X射线衍射仪、疲劳试验等方法,研究了两相区热处理工艺条件下工程结构用钢的显微组织演变及低周疲劳断裂行为.结果表明：两相区热处理组织由细小且形状不规则的回火态马氏体与条带状铁素体组成,马氏体体积分数约为61.7%,残余奥氏体体积分数为2%～5%。试样具有优良的综合性能,与传统调质工艺相比,具有较低的屈强比及较高的低温冲击韧性.同时,两相区热处理后呈现出较高的抗低周疲劳性能,因为塑性变形能力提高,降低了过早形成疲劳裂纹的概率并减小裂纹扩展速率,使高应变低周疲劳性能提高.Optical microscopy,scanning electron microscopy,X- ray diffraction and fatigue tests were used to study the microstructure evolution and low- cycle fatigue fracture behavior of the engineering structure steel treated by heat treatment in two- phase region. The results showed that the microstructure consists of fine and irregularly tempered martensite and stripped ferrite,where the martensite is about 61. 7 % and the residual austenite is about 2% ~ 5%.The samples possess excellent comprehensive properties. Compared with the conventional quenched and tempered steels,our samples have a lower yield ratio and a higher low- temperature impact toughness. Meanwhile,the tested samples present a relatively higher low- cycle fatigue resistance. The high plasticity deformation capacity can reduce the probability of early formation of fatigue crack and decrease the crack propagation rate,which ensure that the samples have good high- strain low- cycle fatigue properties.

关 键 词：两相区热处理 高强钢 高应变低周疲劳 循环特性 

分 类 号：TG155.1[金属学及工艺—热处理]