Fast transform ultra-sonic pulse TIG welding

A current fast transform ultra-sonic pulse TIG power source based on new type IGBT topology was developed. The supremest output pulse current frequency is 30 kHz. The pulse current change rate is up to 50 A per microsecond. 0Cr18Ni9Ti austenitic stainless steel was welded by this fast transform ultra-sonic pulse TIG welding and conventional DC TIG welding respectively. These joints were analyzed by X-radial check-up, tensile strength and specific elongation detection, optical-microscope and scanning electron microscope to study the difference between joints welded by different welding technologies. The result shows that fast transform ultra-sonic pulse TIG welding can refine grain and narrow the width of the coarse grain zone. These indicate that welding quality is improved by introducing fast transform ultra-sonic pulse TIG welding technology.