摘要
针对轧机牌坊铸造过程中产生的大深度和大尺寸(最大尺寸达500mm×300mm×200mm)缺陷,提出了一种基于CO_(2)气体保护焊的焊接修复方法。通过分析牌坊材质(GS240+N铸钢)的化学成分与力学性能,结合缺陷类型(裂纹、气孔等)评估,确定了以预热控制、U形坡口制备、多层多道平焊及层间应力消除为核心的全流程修复工艺。采用“进二退一”运条法、阶段性退火处理(650℃)及超声波/渗透探伤等质量控制措施,显著降低了焊接残余应力和裂纹倾向。实际修复案例表明,该方法可将首次探伤合格率提升至98.5%,修复后牌坊的承载性能与使用寿命完全恢复。为同类大型铸钢结构件的缺陷修复提供了高效可靠的技术方案。
In view of the large-depth and large-size(maximum size of 500 mm×300 mm×200 mm)defects generated during the casting process of the mill housing,this paper proposes a welding repair method based on CO_(2) shielded welding.By analyzing the chemical composition and mechanical properties of the mill housing material(GS240+N cast steel),combined with the evaluation of defect types(cracks,pores,etc.),the whole process repair process with preheating control,U-shaped groove preparation,multi-layer multi-pass flat welding and interlayer stress relief as the core was determined.The welding residual stress and crack tendency are significantly reduced by using quality control measures such as“two-step advance,one-step retreat manipulation method”,stepped annealing treatment(650℃)and ultrasonic/penetration flaw detection.As a result,the actual repair cases show that this method can increase the qualified rate of the first flaw detection to 98.5%,and the bearing performance and service life of the mill housing are completely restored after repair.It provides an efficient and reliable technical scheme for defect repair of similar large cast steel structural parts.
作者
苏盛毅
王淇申
倪雅琪
申智
魏勇
Su Shengyi;Wang Qishen;Ni Yaqi;Shen Zhi;Wei Yong(Metal Structure Plant of Ansteel Heavy Machinery Co.,Ltd.,Anshan 114042,Liaoning,China;Ansteel Group Iron and Steel Research Institute,Anshan 114009,Liaoning,China)
出处
《冶金设备管理与维修》
2025年第3期36-38,41,共4页
Metallurgical Equipment Management and Maintenance
关键词
轧机牌坊
大深度缺陷
CO_(2)气体保护焊
应力消除
多层多道焊接
探伤合格率
mill housing
large-depth defects
CO_(2) shielded welding
stress relief
multi-layer multi-pass welding
qualified rate of flaw detection
