The role of nitrogen in stainless steel welded pipes is mainly reflected in the structure, mechanical properties and corrosion resistance of stainless steel. Nitrogen is a very strong element that forms and stabilizes austenite and causes the austenite phase to expand. It can replace part of the nickel in stainless steel, reduce the ferritic content, and make austenite more stable. Even under cold conditions, the precipitation of harmful intermetallic phases and martensitic transformation can be prevented.
The effect of nitrogen on the mechanical properties of stainless steel: nitrogen significantly improves the strength without reducing the ductility and toughness of stainless steel materials; Nitrogen stainless steel can improve creep resistance, fatigue resistance, wear resistance and yield strength. As an element to improve corrosion resistance, nitrogen can also be formed in the hole NH 4 +, the elimination of H + production, the suppression of pH, thus inhibiting the pitting and dissolution rate in the metal hole, and improving local corrosion.
