热轧10B21钢盘条冷镦开裂的原因及预防措施  

Cause for Cracking of Hot- Rolled 10B21 Steel Wire Rod during Cold- Heading and Precautions

作　　者：苏振伟 周淼 赵赟 屠兴圹 林俊 万文华 SU Zhenwei;ZHOU Miao;ZHAO Yun;TU Xingkuang;LIN Jun;WAN Wenhua(Technology Center,Zenith Steel Group Co.,Ltd.,Changzhou Jiangsu 213011,China)

机构地区：[1]中天钢铁集团有限公司技术中心,江苏常州213011

出　　处：《上海金属》2022年第5期38-41,共4页Shanghai Metals

摘　　要：采用未退火的热轧10B21钢盘条制造的法兰螺栓冷镦时法兰边缘常常开裂。检验了开裂螺栓的化学成分、宏观形貌、显微组织及热轧盘条的冷镦成形性能。结果表明:裂纹部位严重变形,裂纹为穿晶裂纹;盘条无明显缺陷,显微组织为铁素体和珠光体,铁素体晶粒大小不均匀;盘条试样仅能冷镦至1/3高度而不开裂。通过适当降低钢坯加热温度、终轧速率和吐丝温度,及提高轧后冷却速率,使铁素体晶粒细化至10~11级,消除混晶,盘条试样能冷镦至1/5高度而不开裂,冷镦时法兰螺栓再未开裂。When made from hot-rolled 10 B21 steel wire rod not annealed, flange edge of flange bolt cracked frequently during cold-heading. The cracked bolt was tested for chemical composition, macroscopic appearance and microstructure, and the hot-rolled wire rod was tested for cold-heading formability. The results showed that(a) the crack portion deformed severely, and was transrystalline cracking;(b) the wire rod had no evident defect, exhibited microstructure consisting of ferrite and pearlite, and the ferrite varied in grain size;and(c) the wire rod specimen only was able to be cold-headed to 1/3 height without cracking. By the appropriate decrease in heating temperature, finish rolling speed and spinning temperature of the billet, and the increase in cooling rate after rolling, the refinement of grain size of ferrite to grades 10 to 11, and the elimination of mixed crystal, the wire rod specimen was likely to be cold-headed to 1/5 height without cracking, and the flange bolt did not crack again during cold-heading.

关 键 词：10B21钢 冷镦 法兰螺栓 晶粒度 

分 类 号：TG335.6[金属学及工艺—金属压力加工]