Optimization of High Frequency Welding Procedure and Pipe Joint Properties of Heavy Wall 16Cr Stainless Steel Pipe

The microstructure and formability of weld for 16Cr stainless steel plate with 3.4 mm thickness by high frequency welding method in different welding parameters were studied, and the welding process was optimized. Then the properties of 16Cr stainless steel welded pipe joint under optimized process were studied by tensile test, flattening test and flaring test. The results show that welded joint with excellent formability was obtained when welding speed was 10 m·min^-1 and welding heat input was 3.0 kJ·cm^-1. The microstructure of weld was composed of austenite and δ-ferrite. Although the welded pipe had high strength, the toughness got worse due to the presence of oxide inclusions in the weld. The oxide inclusion in the weld could be effectively reduced by application of appropriate gas protection and avoiding high temperature weld contacted with water.