Microstructure Analysis of 316L Welds under Different Ultrasonic Frequency Arc

The microstructure of 316L stainless steel weld by using different ultrasonic frequency arc assisted TIG welding was studied by means of stereomicroscope and EBSD. The results show that by using a certain ultrasonic frequency arc, the columnar grains of the weld can be reduced and the equiaxed grains can be increased.When the pulse frequency is 60 kHz, compared with that of the common TIG welding, the width of the weld columnar grains decreases by 58.6%, and the grain size of the weld decreases by 35.6%, and the grain boundary orientation difference of the weld metal is increased, and the grain boundary stability is higher.It effectively improves the weld performance.