High nitrogen steel is one kind of stainless steel whose nitrogen content exceeds the limit nitrogen content that can be achieved in steel under conventional conditions. According to the different amount of nitrogen added, the following classification is roughly made, that is, the steel with nitrogen content >1% is ultra-high [SCALE STEEL]nitrogen, the steel with nitrogen content 0.3 ~ 0.5% is high nitrogen, and the steel with nitrogen content below this range is nitrogen. The effect of nitrogen in stainless steel is mainly reflected in three aspects: the microstructure, mechanical properties and corrosion resistance of stainless steel. The results show that nitrogen is a very strong element that forms and stabilizes austenite and enlarges the austenite phase region. It can replace part of nickel in stainless steel, reduce the ferrite content in steel, make austenite more stable, prevent the precipitation of harmful intermetallic phases, and even avoid the occurrence of martensite transformation under cold working conditions.
Used to think that nitrogen in steel will be brittle and must be processed to remove elements as, but during the period of 1910 ~ 1930 in nitrogen in steel can improve the strength of the research, and use it to improve the toughness, fatigue strength and corrosion resistance, such as performance, found that the addition of[SCALE STEEL] nitrogen quantity the more the more the performance improving trend, so as to carry out the related research of the amount of the expanded to join.
The biggest reason for interest in nitrogen is that it can substitute nickel. In the 1930s and 1940s, in order to save nickel from wartime supplies in Japan, nitrogen as a substitute for nickel to form austenite phase was paid [SCALE STEEL]attention to. However, until now, how to improve the properties of steel by nitrogen solution and its mechanism are still unknown, which need to be solved urgently.
Mechanical Properties of High Nitrogen Content Stainless Steel:
With the increase of nitrogen element in stainless steel, the hardness, yield strength, tensile strength and fatigue resistance of stainless steel have been significantly improved. The introduction of nitrogen can effectively improve the strength of stainless steel and stabilize the austenite phase, which can be said to kill two birds with one stone. Especially the introduction of nitrogen can significantly improve the yield strength and tensile strength of alloy materials.
Local Area Corrosion Resistance:
There is no doubt that the introduction of nitrogen greatly improves the corrosion resistance of the material. This can be clearly [SCALE STEEL]seen from The calculation formula of The Pitting resistance Equivalent number:
Formula 1: PREN=%Cr+3.3%Mo+16%N
According to the above formula, the pitting corrosion equivalent of stainless steel is mainly determined by the nitrogen content in stainless steel. Its calculation factor reaches 16. Nitrogen content also significantly[SCALE STEEL] changed PREN values. This is just a calculation formula for the PREN value of nitrogenous stainless steel materials. In the high nitrogen stainless steel materials composed of different formulas, the calculation factor of nitrogen element even reaches more than 25.