Q345E钢板折弯开裂原因分析  

Causes Analysis of Bending Rupture in Q345E Steel Plate

作　　者：胡宏伟[1] 赵晓辉 付冬阳 刘丹 李肖 师帅 Hu Hongwei;Zhao Xiaohui;Fu Dongyang;Liu Dan;Li Xiao;Shi Shuai(China Classification Society Wuhan Branch;HBIS Group Wusteel Company)

机构地区：[1]中国船级社武汉分社 [2]河钢集团舞钢公司

出　　处：《宽厚板》2022年第4期46-48,共3页Wide and Heavy Plate

摘　　要：25 mm厚度Q345E钢板在折弯加工过程中出现开裂。从开裂区取样,通过低倍检验、高倍金相显微镜和扫描电子显微镜对钢板表面裂纹产生原因进行分析。结果表明:钢板厚度1/4处存在严重偏析以及大量的硫化物、氮化物夹杂;严重偏析导致钢板厚度1/4处存在较宽的马氏体带,夹杂物的聚集破坏了钢板基体连贯性,钢板受力后缺陷处易发生应力集中,继而萌生微裂纹,同时硬相组织与正常组织晶界粘合力弱,裂纹扩展造成钢板开裂。根据分析结果制定提高出钢温度、强化精炼渣控制、保证真空脱气效果等改进措施,使钢板内部质量得到明显改善。The Q345 E steel plate of 25 mm thickness ruptures during the bending process.Samples are taken from the fracture,the formation causes of plate surface cracks are analysed by macro-examination,high magnification metallographic microscope and scanning electron microscope.The results show that severe segregation and a large number of sulfide and nitride inclusions exist at 1/4 plate thickness position.The severe segregation leads to wide martensite band at 1/4 plate thickness,the aggregation of inclusions destroys the matrix consistency of steel plate,the stress is easily concentrated at the defect when the plate is under stress,and microcracks are produced,the weak grain boundary bonding force of hard phase microstructure and normal microstructure enables crack propagation,resulting in the rupture of steel plate.The improvement measures such as increasing tapping temperature,strengthening refining slag control,ensuring vacuum degassing effect are taken,the internal quality of the steel plate is significantly improved.

关 键 词：折弯开裂 偏析 夹杂聚集 微裂纹 内部质量 

分 类 号：TG142.1[一般工业技术—材料科学与工程]