Q235C冷变形加工及焊接开裂缺陷分析

Analysis of Q235C Cold Deformation Processing and Welding Cracking Defect

本文对Q235C焊管缺陷材料的断口形貌观察,开裂缺陷钢管基体成分进行研究,对开裂缺陷材料进行金相组织、焊缝边缘钢材硬度、非金属夹杂分析。研究了Q235C高频集肤焊钢管开裂的原因与机理。分析发现焊缝断裂面上没有发现非金属夹杂,焊缝边缘钢板中存在离散分布的魏氏体组织,通过对焊缝宽度测量和焊缝溢出物分析,发现焊接过程过热是产生该案组织的主要原因,焊缝材料中的魏氏体组织是导致焊缝脆化、开裂的诱因,微裂纹受到外部应力作用产生开裂,建议优化焊接工艺。对于冷加工开裂的材料,分析原因发现钢板组织不均匀,偏析带中存在魏氏体组织和非金属夹杂,解决这类开裂的有效措施是降低材料偏析和提高钢制纯净度。

In this paper,the fracture morphology of Q235C welded pipe defect material was observed,the matrix composition of cracking defect steel pipe was analyzed,and the metallographic structure,weld edge steel hardness and non-metallic inclusions of cracking defect material were analyzed.The cracking reason and mechanism of Q235C high frequency skin welded steel pipe were studied.No non-metallic inclusions were found on the fracture surface of the weld.There is discrete Widmanstatten structure in the edge of weld,through the weld width measurement and weld overflow analysis,the welding process overheating is the main reason for this structure,Widmanstatten structure in the weld material is the inducement of weld embrittlement and cracking,micro-cracks crack under the action of external stress,it is suggested to optimize the welding process.For the cold working cracking material,the reason is that the structure of the steel plate is not uniform,and there are Widmanstatten structure and non-metallic inclusions in the segregation band.The effective measures to solve this kind of cracking are to reduce the material segregation and improve the purity of steel.