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采用高速摄影技术并辅以计算机数据采集系统，通过横向变拘束热裂纹试验方法，改变试件加载过程中的变形速度，较系统地研究了金属在凝固过程中的塑性变化规律。成功地建立了高强钢焊接熔池三维凝固塑性模型，并就变形速度对金属凝固塑性的影响机理进行了讨论。结果表明，变形速度是导致焊缝金属热裂的重要因素，它是通过金属凝固过程中不同的变形方式影响金属在脆性温度区间内的变形能力，从而影响到焊缝金属在脆性温度区内热裂纹的启裂时间、启裂温度、临界应变量以及脆性温度区范围
Using high-speed photographic technique and computer data acquisition system, the transverse deformation restrained hot crack test method was used to change the deformation rate during the specimen loading process. The plastic variation regularity of the metal in the solidification process was systematically studied. The three-dimensional solidification plasticity model of high-strength steel welding pool was successfully established and the influence mechanism of deformation speed on solidification plasticity was discussed. The results show that the deformation rate is an important factor leading to the thermal cracking of the weld metal. It affects the deformation ability of the metal in the brittle temperature range through different deformation modes in the process of metal solidification, thus affecting the thermal cracking of the weld metal in the brittle temperature region Crack initiation time, cracking temperature, critical strain and brittle temperature range