Nickel is an important component of 304 stainless steel plates and the main alloying element in austenitic stainless steel. Its main function is to stabilize the austenitic structure, so that the steel has good strength, plasticity and toughness, and has excellent hot and cold processing properties, cold formability and weldability, while improving the thermodynamic stability of austenitic stainless steel. Let us introduce in detail the great role of nickel on 304 stainless steel plates.

   Effect of nickel on the structure: Nickel element can stabilize austenite and expand the austenite phase area. In order to obtain a single austenite structure, the minimum nickel content required when the steel contains 0.1% carbon and 18% chromium is about 8%, which is the basic composition of the most famous 304 chromium-nickel austenitic stainless steel. In austenitic stainless steel, as the nickel content increases, the residual ferrite can be completely eliminated and the tendency of σ phase formation is significantly reduced. At the same time, the martensite hydrocarbon transition temperature decreases, and the λ→M phase transformation may not even occur. However, the increase in nickel content will reduce the solubility of carbon in austenitic stainless steel, thereby increasing the tendency of carbide precipitation.

   Effect of nickel on properties: The effect of nickel on the mechanical properties of austenitic stainless steel is mainly determined by the effect of nickel on the stability of austenite. Within the nickel content range where martensite transformation may occur in the steel, as the nickel As the content increases, the strength of the steel decreases and the plasticity increases. The toughness (including extremely low temperature toughness) of chromium-nickel austenitic stainless steel with stable austenite structure is very excellent, so it can be used as low-temperature steel. For chromium-manganese austenitic stainless steel with stable austenite structure, the addition of nickel can further improve its toughness. Nickel can also significantly reduce the cold work hardening tendency of austenitic stainless steel. This is mainly due to the increased stability of austenite, reducing or even eliminating the martensite transformation during cold working. At the same time, it has no effect on the cold work hardening of austenite itself. Too obvious.