Abstract
This study was performed to obtain the optimum condition of TIG treatment, to confirm how there is improving effect on fatigue test based on maximum stress, and to analyze the improving factors quantitatively, in improving the fatigue strength of fillet welded joint by TIG arc remelting of weld toe region.
Fourteen S-N fatigue tests (JSME-5002: Standard Method of Statistical Fatigue Testing) based on maximum stress fixed to yield stress (S=σmax-σmin, σmax=σY) were performed on non-load-carrying cruciform fillet welded joints of 569 MPa tensile strength class high strength steel (SM58Q). The joints were made by shielded metal arc welding, and the toe region of fillet weld was treated by TIG arc remelting.
It was found that the fatigue limit of TIG arc treated test specimen obtained by staircase method judged at 2×106 cycles was about 2.7 times as high as one of as welded test specimen, and that weaving TIG arc treatment executed with relatively high heat input was more effective than other treatments, judging from various statistical analyses of fatigue strength on fatigue test based on maximum stress.
