大规格AISI 4130连铸圆坯端面裂纹分析及改进措施

针对ø600 mm规格AISI 4130连铸圆坯锯切后端面发现裂纹缺陷问题,系统研究了端面裂纹形成机理和铸坯缓冷工艺。研究结果表明,铸坯缓冷后仍存在较大的组织应力和热应力,随着锯切的深入产生应力集中,在最薄弱的地方开裂并延伸,形成应力裂纹。通过对缓冷坑进行改造、入坑铸坯两端加盖保温帽和调整连铸圆坯缓冷工艺,极大减少了铸坯内部应力,显著提高了产品合格率。

Analysis of endface cracks and improvement measures for large size AISI 4130 continuous casting billets

Crack formation mechanism and the slow cooling process of the cast billet were systematically studied for the problem of crack defects found on the end face of ø600 mm specifications AISI 4130 continuous cast billet after sawing. The research results show that after slow cooling, there are still large tissue and thermal stresses in the cast billet, and as the sawing progresses, stresses are concentrated, cracking and extending at the weakest point, thus forming stress cracks. By modifying the slow cooling pit, adding insulation caps at both ends of the pit and adjusting the slow cooling process of the continuous casting round billet, the internal stress of the billet was greatly reduced and the product qualification rate was significantly improved.