Microstructure and property of laser welded joint with high frequency micro-vibration process

Based on high frequency micro-vibration platform, the 316L stainless steel was welded by laser welding with vibration. The microstructure and property of laser welded joint with high frequency micro-vibration process had been investigated. The results indicate that good welding surface could be got under vibration. No spatters could be found. No collapse and excess weld metal existed. Weld width form uniformly in the back weld. Grain refinement is related to resonant vibration frequency during solidification in the weld. The smallest grain size and the most conspicuous grain refinement were obtained at the resonant frequency of 1 467.5 Hz. In addition, the particles spreaded and dispersed between the austenite grains. The new phase and the large particles were reduced with vibration. With the increase of the vibration frequency, weld microhardness increased, especially with the higher resonance frequency. At the resonant frequency of 1 467.5 Hz, vibration acceleration of 160 m/s², the average microhardness value of weld is 206 HV, which was increased by 5.6% compared with that with no vibration condition.