It is understood that the range of nitrogen content in different matrix structures is different: in the ferrite matrix, the mass fraction of nitrogen t>0.08%; in the austenite matrix, the mass fraction of nitrogen is 1>0.4%.
Depending on the amount of nitrogen added, the structure and composition of the stainless wire steel are also different. The following classifications are roughly carried out, namely, ultra-high nitrogen steel with a nitrogen mass fraction> 1%, and high nitrogen steel with a nitrogen mass fraction of 0.3% to 0.5%, Below this range is nitrogen-containing steel.
Stainless Steel Wire Stock
The Role of Nitrogen in Stainless Wire
The role of nitrogen in the stainless wire is mainly reflected in the three aspects of the stainless steel matrix structure, mechanical properties, and corrosion resistance. Nitrogen is an element that strongly forms and stabilizes austenite and expands the austenite phase region. It can replace part of nickel in stainless steel, reduce the ferrite content in steel, make austenite more stable, and prevent harmful metals. The precipitation of interphase can avoid martensite transformation even under cold working conditions.
Enhance Corrosion Resistance:
Nitrogen can combine with chromium to form chromium nitride, which can further improve the corrosion resistance of stainless steel. Chromium nitride can form a dense oxide layer on the surface of stainless steel to effectively prevent the erosion of oxygen, water, and other corrosive media.
Improve Strength and Hardness:
By introducing an appropriate amount of nitrogen into stainless steel, its strength, and hardness can be significantly improved. Nitrogen forms strong bonds with the iron atoms, strengthening the crystal structure, and resulting in better mechanical properties of stainless steel.
Improve Welding Performance:
Adding appropriate nitrogen to stainless steel can improve its welding performance. Nitrogen can combine with elements such as titanium and niobium to form stable nitrides, preventing precipitation at grain boundaries, and thereby reducing the brittleness of the welding heat-affected zone.
Improve Heat Treatment Responsiveness:
Nitrogen can improve the heat treatment responsiveness of stainless steel. During the heating process, nitrogen will form a solid solution with other alloying elements, changing the crystal structure, so that stainless steel can perform better after heat treatment.
The effect of nitrogen on the mechanical properties of stainless steel is mainly manifested in nitrogen, which can significantly increase the strength of stainless steel without reducing the plastic toughness of the material; nitrogen can improve the creep, fatigue, wear resistance, and yield strength of stainless steel.
Nitrogen, as an element to improve corrosion resistance, can form NH4+ in the corrosion pores, eliminate the generated H+, and inhibit the decrease of pH value, thereby inhibiting the occurrence of pitting corrosion and the dissolution rate of metal in the corrosion pores, which reduces the local corrosion performance.