30CrMo精冲钢连铸板坯高温力学性能研究

Study on High Temperature Mechanical Properties of Fine Blanking 30CrMo Steel Continuous Casting Slab

利用Gleeble-3800热模拟机测试了30CrMo精冲钢连铸坯从1350℃以5℃/s和15℃/s冷却至600~900℃拉伸的高温力学性能,通过扫描电镜对拉伸试样的断口形貌和显微组织进行了观察分析,讨论了各温度区域变形断裂的机理。结果表明,冷却速度增大,铸坯整体的断面收缩率减小,铸坯的热塑性降低。30CrMo精冲钢的第Ⅲ脆性温度区间在650-750℃。将二冷区矫直点入口处的铸坯角部温度提升至800℃以上可以有效避免角部裂纹发生。

The high temperature mechanical properties of 30 CrMo fine blanking steel continuous casting slab cooling from 1 350℃with 5 ℃/s and 15 ℃/s to 600~900℃ and tensioning are tested using Gleeble-3800 thermal simulator.The fracture morphology and microstructure of the tensile specimens are observed and analyzed by scanning electron microscopy,and the mechanism of deformation fracture in each temperature region is discussed.Results demonstrate that with the increase of cooling rate,the overall reduction of area of the slab decreases and the thermo-plasticity of the slab also decreases.The Ⅲ brittleness temperature range of 30 CrMo fine blanking steel is 650 ~750 ℃,and raising the corner temperature of the slab in the straightening section of secondary cooling zone to above 800℃ can effectively avoid the corner cracking.