Duplex stainless steel 2205 Duplex stainless steel pipe welding process points are as follows:
1. Selection of duplex stainless steel pipe and welding materials
Duplex stainless steel has good pitting and stress corrosion resistance, and good mechanical properties and welding performance. In the design and manufacture of railway salt open cars, in order to prevent chloride corrosion on the car body, the car body and salt contact part use duplex stainless steel 2205 hot-rolled steel plate. Duplex stainless steel pipe is austenite + ferrite, and the ferrite content is 45% (volume fraction). ER2209 welding wire is selected, and the wire diameter is 1.2mm.

2. Duplex stainless steel pipe welding process
1) Considering the characteristics of locomotive vehicle manufacturing, the melting electrode gas shielded welding is adopted, ER2209 welding wire is selected, the shielding gas is Ar+2%O2 (volume fraction), and the shielding gas flow rate is 18L/min.
2) The selection of welding parameters is particularly important for the welding of duplex stainless steel pipes, which directly affects the proportion of ferrite in the weld metal. If the welding heat input is too small, excessive ferrite structure may be generated; if the heat input is too large, although sufficient austenite can be obtained, it will also cause the ferrite grains in the heat-affected zone to grow, causing the mechanical properties of the welded joint to deteriorate.