42CrMo钢法兰开裂原因分析  

Cause Analysis on Cracking of 42CrMo Steel Flanges

作　　者：王亚楠 李亚波[1] 李忠华[1] 赵文涛 WANG Ya'nan;LI Yabo;LI Zhonghua;ZHAO Wentao(School of Material Science and Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013

出　　处：《热加工工艺》2022年第21期156-158,共3页Hot Working Technology

摘　　要：42CrMo钢经辗环、调质处理后有沿轧制方向扩展的裂纹,最大宽度可达到90μm。采用金相显微镜、扫描电镜(带能谱仪)对裂纹附近组织进行检测,发现在裂纹附近存在明显的脱碳层且裂纹内部有铁氧化物,在钢的基体内发现大量大尺寸夹杂物,主要有Al、Mg、Si、Ca、O等元素。由此确定裂纹是在辗制过程中产生的,由于夹杂物尺寸过大且形状不规则,在钢变形时夹杂物附近会产生严重的应力集中,而导致开裂。原材料钢水未经二次精炼,洁净度不足,不适合作为辗环原材料使用。42CrMo steel has a crack extending along the rolling direction after ring rolling and quenching and tempering,and the maximum width can reach 90 μm. The microstructure near the crack was detected by metallographic microscope and scanning electron microscope with energy dispersive spectrometer. It is found that there are obvious decarburization layers near the crack and iron oxides inside the crack. A large number of large size inclusions are found in the steel matrix, mainly containing Al, Mg, Si, Ca and O. It is determined that the crack is produced during rolling. Due to the large size of inclusions and irregular shape, serious stress concentration will occur near the inclusions in steel deformation, which will lead to cracking. the cleanliness of raw material molten steel without secondary refining is insufficient, and it not suitable for use as ring rolling raw materials.

关 键 词：42CRMO钢 裂纹 夹杂物 钢洁净度 辗环 

分 类 号：TG304[金属学及工艺—金属压力加工] TG316.192