Q195低碳钢冷顶锻开裂类型原因分析及改进措施  

Cause analysis and improvement measures of cold heading cracking types for Q195 low-carbon steel

作　　者：李若冰 杨正 Li Ruobing;Yang Zheng(Department of Mechanical and Electrical Engineering,Langfang Yanjing Vocational Technical College,Langfang 065200,China)

机构地区：[1]廊坊燕京职业技术学院机电工程系,河北廊坊065200

出　　处：《锻压技术》2023年第2期36-43,共8页Forging & Stamping Technology

摘　　要：针对Q195低碳钢盘条在冷顶锻时产生的开裂问题,进行了6组试验,并根据裂纹特征对开裂类型进行了分类和研究。使用扫描电镜等设备对开裂试样的成分、铸坯、母材和微观形貌进行了观察,阐明了密集排列起皮开裂和划伤折叠开裂的主要原因,并提出了相应的改进措施。结果表明:密集排列起皮开裂主要是由于铸坯表面或近表面存在微裂纹,在加热过程中该处生成了氧化铁并存留在盘条表面,在冷顶锻过程中受径向压应力而导致开裂,可通过稳定钢水过热度、及时更换磨损严重的铜管和被堵喷嘴来改善;划伤折叠开裂主要是由于精轧区域轧槽的不均匀磨损划伤和盘条在减定区进口导卫内发生扭转的共同作用导致的,可通过减轻轧槽的不均匀磨损、控制减定区域的导卫开口度和扭转角的精度来改善。Aiming at the cracking problem of Q195 low-carbon steel wire rod during cold heading,six sets of industrial tests were conducted,and according to the crack characteristics and cracking types were classified and studied.Then,the composition,casting billet,parent metal and microstructure morphology of cracked specimens were observed by scanning electron microscopy and other equipments.Furthermore,the main reasons for densely arranged peeling cracking and scratch-folding cracking were elucidated,and the corresponding improvement measures were proposed.The results show that the densely arranged peeling cracking is mainly due to the fact that the micro-cracks on the surface or near the surface of billet generate iron oxide during the heating process which remains on the surface of the wire rod,and then carcking is caused by radial compressive stress during the cold heading process,which can be improved by stabilizing the superheat of molten steel,timely replacing the severely worn copper tubes and blocked nozzles.The scratch-folding cracking is mainly caused by the combined action of uneven wear and scratches of the rolling grooves in the finishing rolling area and the twisting of the wire rod in the inlet guide of the reducing area,which can be improved by reducing the uneven wear of the rolling groove and controlling the opening of the guide and the accuracy of the torsion angle for the reducing area.

关 键 词：Q195低碳钢 冷顶锻 密集排列起皮开裂 划伤折叠开裂 铸坯裂纹 轧槽磨损 

分 类 号：TG335.6[金属学及工艺—金属压力加工]