The similar and dissimilar TIG welding of 316L and 321 austenitic stainless steels

Abstract

Beingone the modern high quality industrial welding process especially for stainlesssteels and titanium alloys. TIG welding process has been has been researchedfor decades in order to define its parameters such as welding speed, currentand arc length to improve the weld penetration. Hence it is a popular techniquefor joining thin materials - the thickness of the work piece is in generalrestricted to less than 6 mm- inmanufacturing industries. In this study, AISI 321 and 316L stainless steelsheets of 4 mm of thickness were used as welding metals. Thus, AISI 321 weldingmetal couples, AISI 316L welding metal couples and AISI 321 and 316L weldingmetal couples were selected to ensure a combination of similar and dissimilarmetals. The filler metal rod was made of 316L SS. The specimens were cut indimensions of 150 x 30 x 4 mm as using an abrasive cutter, then the V weld buttjoint configuration with single groove of 37.5o ± 2.5o groove angle by a lathemachine. The welding current was 200 A and TIG welding process was performedmanually in single under argon shielding gas atmosphere. After TIG weldingprocess, the separate metallographic preparations, then microscopic andmacroscopic examinations of the specimens, also hardness measurements ofspecimens were made. The rest of them was shaped for tensile strengthmeasurement using Instron Universal Testing Machine. The hardness of thespecimens were observed being altered in the range of 145-151 HRV(average) andtheir tensile strength values in the scale of 345-400 MPa (average).