摘要
针对微合金钢连铸坯角部横裂纹缺陷,通过实验室试验研究角部横裂纹微观组织、微观形貌和裂纹附近成分等,初步确定了角部横裂纹的形成机理。连铸坯内弧侧和外弧侧均存在角部横裂纹,90%以上的裂纹发生在振痕波谷处。角部横裂纹沿原始奥氏体晶界向钢基体扩展,裂纹处被氧化,未检测到结晶器保护渣的成分,因此推断裂纹并非在结晶器内开裂,而是在二冷区产生。通过高温力学性能测试,获得连铸坯的脆性温度区间为751~861℃。利用连铸坯凝固传热模型优化二冷配水,使得弯曲段连铸坯外弧的角部温度和矫直段连铸坯内弧的角部温度均高于861℃,完全避开第Ⅲ脆性温度区间。按照优化水量进行工业试验,连铸坯角部横裂纹完全消失。
Aiming at the transverse corner crack defects of microalloyed steel continuous casting slabs,the microstructure,micromorphology and components near the cracks through laboratory experiments were investigated,and the formation mechanism of the transverse corner cracks was preliminarily determined.There are transverse corner cracks on both the loose and fixed sides of the continuous casting slabs,and more than 90%of the cracks occurred at the valley of oscillation marks.The transverse corner cracks extended along the original austenite grain boundary to the steel matrix,and the cracks were oxidized.The composition of the mold powder was not detected.Therefore,it was inferred that the cracks were not generated in the mold,and formed in the secondary cooling zones.Through high-temperature mechanical properties testing,the brittle temperature range of the continuous casting slab was obtained to be 751-861℃.The solidification and heat transfer model of the continuous casting slab was used to optimize the distribution of the secondary cooling water,so that the corner temperature of the fixed side of the continuous casting slab in the bending zone,and the corner temperature of the loose side of the continuous casting slab in the straightening zone were both higher than 861℃,completely avoiding the brittle temperature range.Industrial trials were carried out according to the optimized water strategy,and the transverse corner cracks of the continuous casting slab completely disappeared.
作者
万永健
郭朝军
王亚栋
赵德利
张立峰
WAN Yongjian;GUO Chaojun;WANG Yadong;ZHAO Deli;ZHANG Lifeng(Han Steel Company,HBIS Group,Handan 056015,China;School of Mechanical and Materials Engineering,North China University of Technology,Beijing 100144,China;China First Heavy Industries Co.,Ltd.,Qiqihar 161041,China)
出处
《炼钢》
北大核心
2026年第1期80-87,共8页
Steelmaking
基金
国家重点研发计划项目(2023YFB3709900)
国家自然科学基金资助项目(U22A20171,52204333)
北京市自然科学基金资助项目(2242034)
河钢集团重点科技项目(HG2025108)。
关键词
角部横裂纹
连铸板坯
微合金钢
高温力学性能
模拟
transverse corner cracks
continuous casting slab
microalloyed steel
high temperature mechanical properties
simulation
