Q355B钢板坯延迟断裂原因与控制措施  

Reasons for belayed fracture of Q355B slab and its control measures

作　　者：王慧峰 Wang Huifeng(Hebei Yan Mountains Iron and Steel Group Co.,Ltd.,Qian'an 064403,China)

机构地区：[1]河北燕山钢铁集团有限公司,河北迁安064403

出　　处：《冶金标准化与质量》2023年第2期27-30,共4页Metallurgical Standardization & Quality

摘　　要：对出现横向断裂的Q355B钢连铸板坯的断口进行宏观形貌分析、横向及纵向低倍分析、微观形貌分析,研究了板坯横向断裂的原因。结果表明:Q355B钢连铸板坯中存在严重的中间裂纹;断口整体表现为脆性解理形貌,断口处存在大量白点和氢致裂纹,断口的自由晶面存在碳氮析出物和含P化合物的析出物。在钢液凝固过程中钢液中氢原子及析出物在铸坯的中间裂纹处富集析出并产生体积变化导致铸坯横向断裂。通过降低钢液中H、N、O、P、S的含量和加强连铸机设备维护和检修,保持良好的对弧精度等措施可以防止铸坯断裂。The macroscopic morphology analysis,lateral and longitudinal low-magnification analysis and micro-morphology analysis of the fracture of the Q355B steel continuous casting slab with transverse fracture were carried out to study the causes of the transverse rupture of the slab.The results show that there are severe intermediate cracks in the continuously cast slab of Q355B steel;the fractures show a brittle cleavage morphology,and there are a lot of white spots and hydrogeninduced cracks at the fracture surface.The free crystal faces of the fractures are precipitated with carbon and nitrogen and contain P.Precipitation of compounds.During the solidification process of molten steel,hydrogen atoms and precipitates in the molten steel concentrate at the middle crack of the slab and cause volume change to cause the transverse rupture of the slab.By reducing the content of H,N,O,P,S in the molten steel and strengthening the maintenance and overhaul of the caster equipment,and maintaining good arc-precision precision,the strand can be prevented from breaking.

关 键 词：铸坯断裂 氢致裂纹 中间裂纹 断口形貌 

分 类 号：O3[理学—力学] TG111.91[金属学及工艺—物理冶金]