Taking austenitic stainless steel Z2CND18-12（AC） used in nuclear power instrument tanks as the test object

the difference between automatic pulse TIG welding and GTAW welding is studied

including weld appearance in welding process and after welding

girth welding shrinkage

weld reinforcement and surface flatness

and the macroscopic metallography

microstructure and mechanical properties of welded joints. The results show that pulsed TIG welding has smaller welding shrinkage

better weld surface smoothness

more uniform weld microstructure distribution

smaller grain size

and better weld strength

plastic toughness and deformation resistance.