40Mn钢链片断裂原因分析及改进措施  

Fracture reason of 40Mn steel chain and improvement measure

作　　者：陈连生[1] 沈永革[1] 宋进英[1] 卢珺玮[1] 

机构地区：[1]河北联合大学河北省现代冶金技术重点实验室,河北唐山063009

出　　处：《金属热处理》2013年第4期115-119,共5页Heat Treatment of Metals

基　　金：河北省自然科学基金(E2009000791)

摘　　要：采用硬度计、光学显微镜、扫描电镜及能谱仪等试验手段,研究分析了40Mn钢链片热处理装配后产生裂纹的原因。结果表明,断口形貌主要为冰块状沿晶断裂,是沿原始奥氏体扩展的马氏体相变局部应力集中所造成;断裂试样硬度严重不均且显微组织中存在大量带状组织;C-Mn元素成分偏析引起带状组织,从而导致晶界间结合力大大降低;改进炼钢及连铸工艺可消除铸坯中心偏析和带状组织,经930℃正火亦可使钢板中带状组织消失。Fraeturc reason of 40Mn steel chain afler heal lreatment during the assembly were analysed by means of hardness tester, optical microscopy, SEM and EDS. The results show that the stress concentrates at the time of martensite phase transfiwmation, whieh causes the ice-iike intergranuiar fracture and expansion along the original austenitie grain boundary. The hardness nun-uniformity and a lot of banded structure in mierostructure arc caused by the segregation of C-Mn that reduces the grain boundary bonding. The center segregation can be eliminated by improving steel making and continuous casting process, thus the banded structure can aiso be eliminated. The banded structure Can be eliminated by normalizing at about 930℃.

关 键 词：40Mn钢链片 沿晶断裂 带状组织 

分 类 号：TG157[金属学及工艺—热处理]