NM450钢板折弯开裂原因分析  

Analysis of cracking in bending process of NM450 steel

作　　者：谢世正[1] 刘宁 梁亮[1] 周剑丰[1] 张波 王勃 XIE Shi-zheng;LIU Ning;LIANG Liang;ZHOU Jian-feng;ZHANG Bo;WANG Bo(Lianyuan Iron and Steel Corporation of Hunan Hualing,Loudi 417009,Hunan,China;School of Metallurgical and Material Engineering,Hunan University of Technology,Zhuzhou 412007,Hunan,China)

机构地区：[1]湖南华菱涟源钢铁有限公司,湖南娄底417009 [2]湖南工业大学冶金与材料工程学院,湖南株洲412007

出　　处：《中国冶金》2021年第7期46-49,共4页China Metallurgy

基　　金：湖南省科技创新计划资助项目(2018XK2301);湖南省自然科学基金资助项目(2019JJ60062)。

摘　　要：NM450钢在使用过程中的折弯开裂是影响其使用效率的主要因素之一。通过对开裂处取样,结合金相组织检验、扫描电镜、能谱分析和硬度检测结果,对开裂原因进行分析研究。研究结果表明,Mn、P等元素的偏析导致其组织结构上存在差异,从而在不同组织结合处产生裂纹源引起开裂;在裂纹处存在TiN和MnS夹杂聚集。MnS夹杂的聚集导致材料受机械应力影响沿夹杂物聚集的方向开裂,而TiN夹杂的聚集造成在折弯过程中应力微裂纹出现,进一步促进折弯开裂的出现。The bending cracking of NM450steel is one of the main factors affecting its service efficiency.The crack-ing causes were analyzed and studied by taking samples from the cracking place,and combining with the results of the metallographic examination,scanning electron microscope,energy spectrum analysis and hardness test.The re-sults showed that the segregation of Mn,P and other elements led to the difference of microstructure,which resul-ted in the generation of crack sources at the joint of different structures.Meanwhile,TiN and MnS inclusions were accumulated at the crack.The aggregation of MnS inclusions caused the material to crack along the direction of in-clusion aggregation under the influence of mechanical stress.The accumulation of TiN inclusions resulted in the ap-pearance of stress microcracks in the bending process,which further promoted the occurrence of bending cracks.

关 键 词：NM450 折弯开裂 夹杂物 偏析 硬度 

分 类 号：TG142.15[一般工业技术—材料科学与工程]