Transactions of Materials and Heat Treatment

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

Authors： Li Ruobing Yang Zheng

Unit： Langfang Yanjing Vocational Technical College

KeyWords： Q195 low-carbon steel cold heading densely arranged peeling cracking scratch-folding cracking casting billet crack rolling groove wear

ClassificationCode：TG335.6

year,vol(issue):pagenumber：2023,48(2):36-43

Abstract：

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.

Funds：

作者简介：李若冰（1984-），女，硕士，副教授，E-mail：yjciteme@163.com；通信作者：杨正（1991-），男，硕士，讲师，E-mail：ncsth9r@163.com

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