Prediction method of fracture strain of welded portion, forecasting system, and method of manufacturing member provided with welded portion

摘要

PROBLEM TO BE SOLVED: To provide a prediction method of a fracture strain of a weld capable of accurately predicting the fracture strain without limiting a welding method such as spot welding or laser welding and without performing a local fracture strain deviation process on a metal material of which the fracture strain has not been derived yet.SOLUTION: The prediction method of the fracture strain of the weld includes the steps of: collecting the fracture strains, regarding a plurality of metal materials of which the fracture strains are calculated beforehand, for each material parameter specified by a chemical component and welding metal hardness of the metal material and determining an approximation master curve of the fracture strains from resultant distribution of the fracture strains; calculating the material parameter of the metal material subjected to evaluation in accordance with the chemical component and the welding metal hardness of the metal material subjected to the evaluation; and calculating the fracture strain of the metal material subjected to the evaluation while using the determined approximation master curve and the calculated material parameter of the metal material subjected to the evaluation.