The hot cracking susceptibility in the Trans-Varestraint test was evaluated using the nominal strain calculated using the curvature radius of a bending block and the thickness of a specimen based on the theory of material mechanics. The nominal strain was calculated using the material properties at room temperature. Thus, in the Trans-Varestraint test, the non-uniformity of the strain around the weld part due to the temperature distribution is not considered. Therefore, the strain in the Trans-Varestraint test cannot be evaluated correctly. The aim of this study is to reveal the loaded strain at the weld metal to understand the evaluation of hot cracking susceptibility in the Trans-Varestraint test. The loaded strain around the trailing edge of the weld pool of pure iron was measured in-situ using a high-speed camera and high-resolution optical lens. The results of strains measured using image analysis and the finite-element method at the center of the weld bead were compared. Accordingly, it was clarified that the strain was concentrated on the weld part owing to the bending occurring along the weld line, and the strain exceeding the nominal strain was loaded to the trailing edge of the weld pool.

Trans-Varestraint 试验中的热裂纹敏感性是使用基于材料力学理论的弯曲块的曲率半径和试样的厚度计算的名义应变来评估的。使用室温下的材料特性计算标称应变。因此，在 Trans-Varestraint 测试中，没有考虑由于温度分布导致的焊缝部分周围应变的不均匀性。因此，无法正确评估 Trans-Varestraint 测试中的应变。本研究的目的是揭示焊缝金属处的加载应变，以了解 Trans-Varestraint 试验中热裂纹敏感性的评估。使用高速相机和高分辨率光学镜头原位测量纯铁熔池后缘周围的加载应变。比较了使用图像分析和有限元方法在焊道中心测量的应变结果。因此，明确了由于沿熔接线发生弯曲，应变集中在焊接部分，并且超过标称应变的应变被加载到熔池的后缘。