材料期刊网

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。

During production of pipeline steel L245 by No.3 wide billet casting machine in TISCO No.2 steel making plant, transverse cracks often appear in the corner of billet which cause edge crack defects after hot rolled. High temperature thermoplastic rate and high temperature strength tests of pipeline steel L245 have been done using Gleeble-3800 type thermal/mechanical simulation testing machine, and observation of test sample fracture morphology by scanning electron microscopy (SEM). Analysis of experimental results: chemical composition of pipeline steel L245 is a crucial factor to the sensitivity of crack, as high temperature thermoplastic rate is low in the third brittle temperature range zone, leading to surface crack on the billet in the case of uneven cooling and pressure in casting process. To avoid billet corner crack, during straightening of continuous casting billet, its corner temperature should avoid the third brittle temperature range zone.