高频微振辅助工艺对激光焊接接头组织性能的影响

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

关键词:  高频微振|激光焊接|晶粒细化|显微硬度

Key words:  high-frequency micro-vibration|laser welding|grain refinement|microhardness

摘要:

基于自主搭建的高频微振平台，进行316L不锈钢振动辅助激光焊接试验，探究高频微振激光焊接工艺对接头组织性能的影响. 结果表明，施加振动后，焊缝表面无飞溅，成形良好. 截面未出现塌陷、堆高，背部熔宽均匀. 振动的施加，能够明显细化焊缝区的晶粒，在共振频率1 467.5 Hz的高频微振激光焊条件下，晶粒尺寸最小. 点状颗粒物分布在奥氏体晶粒间，趋于弥散，新相及大颗粒物减少. 随着振动频率增加，焊缝区显微硬度值跟着增加，在较高共振频率显微硬度值增加显著，在共振频率1 467.5 Hz、加速度160 m/s²条件下，焊缝区平均硬度206 HV，与无振动相比，硬度值增加5.6%.

Abstract:

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.