Enhancement of fatigue resistance for 316L welds produced by magnetic field assisted laser-MIG hybrid welding

摘要

Crack growth rate (CGR) in air for welds produced by 24 mT magnetic field assisted laser-MIG hybrid welding was decreased by 33%. CGR in 3.5% NaCl solution for welds produced by 16 mT magnetic field assisted welding was reduced by 20%. Texture variation in welds was investigated through electron backscattered diffraction (EBSD). External magnetic field lowered thermal gradient and changed orientations of maximum thermal gradient (del T-max), resulting in weaker texture intensity and less ferrite. Reduced intensity of {100} planes and 100 orientations improved resistance to cyclic plastic deformation. Reduced ferrite increased the volume of strain induced martensite at crack tip, improving fatigue cracking resistance.