Fracture path deviation (FPD) often occurs in standard V-notch Charpy (STD-Cv) test for laser welds because plastic deformation takes place preferably in the soft heat affected zone adjacent to the very narrow and hard weld metal. It is very important to measure the toughness of the laser welds by the test method without FPD. Among several methods, which have been developed to avoid the FPD, the side grooved Charpy (SG-Cv) test is considered to be the most simple and effective way. A decrease in the absorbed energy and an upward shift of the energy transition curve are observed in the SG-Cv test, compared with the STD-Cv test. In the previous paper, the difference between these two Charpy tests was discussed by analyzing fracture appearance. In this study, the lateral contraction of the Charpy specimen is used as a more simple measure to clarify such difference in Charpy test results. The method of evaluating the STD-Cv toughness from the SG-Cv test results is proposed based on the correlation between the lateral contraction and the Charpy energy. It is demonstrated that the proposed method gives a good estimation of STD-Cv energy.
