Questions about pipeline welding
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I would like to ask: which type of pipeline should be welded using which welding method? Such as stainless steel, carbon steel, chromium-molybdenum steel, etc. What are the regulations regarding things like TIG welding as a preheating process? What are the advantages, disadvantages, and differences of various welding methods? Are there any relevant materials? Thank you
Stainless steel is always welded using TIG welding; for some thick pipes, TIG welding is used for the root pass, while MIG welding is used for the cover pass. Welding of duplex steel requires special protective agents. There is a lot of specific information available online
Generally, for materials with a diameter of ≥DN50, TIG welding is used for the root pass and shielded metal arc welding for the cover pass, while for those with a diameter of <DN50, pure TIG welding is employed. Large-diameter carbon steel pipes can also be welded using a root pass by electric welding, followed by double-sided welding with carbon rods to clean the back side. For large-diameter stainless steel pipes with thick wall thicknesses, double-sided welding by two welders can also be employed in accordance with the process requirements; if conditions permit, TIG welding can be used for the root pass, followed by submerged arc automatic welding for the cover pass. Wait.