Open AccessStudy on Microstructure and Mechanical Properties of TP321 Thick-Walled Stainless Steel Tube by CMT Welding
Author(s) -
Hailong Lu
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/774/1/012099
Subject(s) - welding , materials science , microstructure , metallurgy , ferrite (magnet) , ultimate tensile strength , composite material , flash welding , heat affected zone , base metal , brittleness , carbide , elongation , gas metal arc welding
The CMT welding process of TP321 thick-walled stainless steel pipe was analyzed. The tensile properties, microstructures and phase composition of the welded joint were tested, and the effect of welding current on the microstructures and properties was studied. The results show that for the CMT welding of TP321 thick-walled stainless steel pipe, when the optimum welding current is 110A, the maximum tensile strength of welded joints reaches 643 MPa, 92.7% of base metal, and the elongation reaches 58.7%. The fracture location of welded joints is heat-affected zone, basically ductile fracture. With the increase of welding heat input, the precipitation of ferrite and carbide gradually increases in the weld structure of TP321 stainless steel. When the current is too high, the brittle σ phase of ferrite transformation will decrease, resulting in the decrease of strength and plasticity of welded joints.