预应变对Nb微合金化09MnNiDR低温钢高温塑性的影响  

Effect of Pre-strain on Hot Ductility of Nb-microalloyed 09MnNiDR Cryogenic Steel

作　　者：李建华[1,2] 吴开明[1] 邱金鳌[1] 

机构地区：[1]武汉科技大学,武汉430081 [2]武钢研究院,武汉430080

出　　处：《材料工程》2012年第11期82-85,91,共5页Journal of Materials Engineering

基　　金：国家自然科学基金重点项目(50734004)

摘　　要：利用光学和电子显微镜观察断口组织,并测定断面收缩率来研究预拉伸应变对Nb微合金化低温钢09MnNiDR高温塑性的影响。当试样进行5%变形量预拉伸,800℃时断口组织主要为铁素体,晶界处有网状先共析晶界铁素体,断面收缩率为63%;900℃时断口组织主要为贝氏体和针状铁素体以及大量碳氮化物,断面收缩率降至35%;1000℃时断口组织主要为板条马氏体,断面收缩率升至95%。与未进行预应变试样相比,在800～920℃的温度区间,断面收缩率显著降低,预应变明显恶化了Nb微合金化09MnNiDR钢的高温塑性,这主要与预应变促进了尺寸为十几纳米至几十纳米Nb碳氮化物的沿晶界析出有关。The effect of tensile pre-strain on the hot ductility of the Nb-microalloyed 09MnNiDR cryogenic steel was investigated by examining microstructures of the tensile fracture using optical microscopy and electron microscopy,and by measuring the reduction of area.When 5% tensile pre-strain was applied at 800℃,the microstructure was composed of ferrite grains and lots of grain boundary ferrite allotriomorphs along grain boundaries,the reduction of area being 63%.When it was applied at 900℃,the microstructure was composed of bainite,acicular ferrite and lots of massive grain boundary carbonitrides,the reduction of area falling to 35%.When it was applied at 1000℃ the microstructure mainly consisted of lath-like martensite,the reduction of area climbing up to 95%.Comparing with the specimens without applying pre-strain,the reduction of area of the specimens applied with pre-strain between 800℃ and 920℃ dropped remarkably.Results indicate that pre-strain severely deteriorated the hot ductility of the Nb-microalloyed 09MnNiDR cryogenic steel,which was mainly attributed to precipitation of grain boundary niobium carbonitride（10-100nm）.

关 键 词：NB微合金钢 预应变 碳氮化物 高温塑性 

分 类 号：TG111[金属学及工艺—物理冶金] TG142[金属学及工艺—金属学]