ML40Cr冷镦螺栓法兰外圈表面开裂原因分析  

Cause analysis of surface cracking of ML40Cr bolt flange during cold heading

作　　者：王小忠 朱文凯 安鹏达 王涛 WANG Xiaozhong;ZHU Wenkai;AN Pengda;WANG Tao(Zenith Steel Group Company Limited,Changzhou 213011,Jiangsu,China)

机构地区：[1]中天钢铁集团有限公司,江苏常州213011

出　　处：《四川冶金》2022年第2期44-47,共4页Sichuan Metallurgy

摘　　要：ML40Cr钢Φ10mm盘条生产10.9级螺栓,经冷镦六角螺栓的法兰外圈表面出现大量密集性、斜向、“X”字型交叉裂纹现象。经对开裂螺栓解剖分析,主要与盘条退火拉拔后表层存在片状珠光体组织有关,该类组织因塑性较低、冷变形能力差等因素,在冷镦六角螺栓时,其法兰面因变形量较大容易出现开裂现象,而拉拔材表层片状珠光体与原始盘条经球化退火加热时温度过快、过高产生的冲温现象有关。In the production of grade 10.9 bolts withΦ10mm wire rod of ML40CR steel,a large number of dense,oblique and“X”shaped cross cracks appeared on the surface of Flange outer ring of cold heading hexagon bolts.After dissecting and analyzing the cracking bolt,it is mainly related to the existence of Lamellar pearlite structure on the surface of the wire rod after annealing and drawing,the surface of the Flange is easy to crack because of large deformation,and the flake pearlite on the surface of the drawing material is related to the charging phenomenon of the original wire rod heated by spheroidizing annealing.

关 键 词：ML40Cr钢 螺栓 片状珠光体 球化退火 

分 类 号：TG142.1[一般工业技术—材料科学与工程]