METHOD FOR IMPROVING FATIGUE LIFE OF WELDED JOINS BY A WELDING TOOL OF FRICTION STIR PROCESS

摘要

PURPOSE: A method for modifying a weld part using a welding tool for a FSP(Friction Stir Process) is provided to prevent residual stress weld, solidification cracking, and voids by modifying the microstructure of the weld part into fine crystal grains. CONSTITUTION: A method for modifying a weld part using a welding tool(50) for a FSP is as follows. A weld toe(30) and base metals are prepared by welding metal materials of ships or offshore structures. A welding tool equipped with a tool pin(53) is inserted into a contact portion between the base metals and the weld toe. A solid-phase modified portion(40) is formed in the part, in which the welding tool for FSP passes by a plastic flow generated by the combination of friction heat and mechanical processing.