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针对管线钢L245钢在太钢炼钢二厂北区3号宽板坯铸机生产时铸坯角部经常出现横裂纹,造成其热轧后卷板边部存在裂纹缺陷,利用Gleeble-3800型热/力学模拟试验机对管线钢L245钢进行了高温面塑率及高温强度的测试,并用扫描电镜对测试试样断口形貌进行观察。从试验结果分析认为:管线钢L245钢的化学成分设计决定其对裂纹的敏感性,由于第Ⅲ区脆性温度区间的高温面塑率低导致其在连铸过程铸坯冷却或受力不均衡情况下铸坯角部裂纹的发生。为要避免铸坯角部横裂纹的产生,在连铸坯矫直时,其角部温度应避开第Ⅲ区脆性温度区间。
For the pipeline steel L245 steel at the Tisco Steel Plant No.3 North wide slab caster at the production of slab corner often appear horizontal cracks, resulting in the hot rolling after the existence of the flaw edge of the plate, the use of Gleeble-3800 type Thermal / mechanical simulation testing machine for pipeline steel L245 high temperature plasticity and high temperature strength of the test, and the use of scanning electron microscopy fracture morphology of the test specimen were observed. From the analysis of the test results, it is considered that the chemical composition of L245 steel determines the sensitivity to crack. Due to the high surface area plasticity ratio in the brittle temperature zone III, Occurrence of corner crack in slab. In order to avoid the occurrence of transverse cracks in the corner of the slab, the corner temperature of the slab should be kept away from the zone III brittleness temperature zone during straightening of the slab.