Ferritic stainless steel
Contains 15% ~ 30% chromium.The corrosion resistance, toughness and weldability of Crl7, Cr17Mo2Ti, Cr25, Cr25Mo3Ti and Cr28 are improved with the increase of chromium content.Ferritic stainless steel, due to its high chromium content, has good corrosion resistance and oxidation resistance, but its mechanical and technological properties are poor.This kind of steel can resist the corrosion of atmosphere, nitric acid and brine solution, and has the characteristics of high temperature oxidation resistance, small thermal expansion coefficient, etc.
Austenitic stainless steel
Contains more than 18% chromium, also contains about 8% nickel and a small amount of molybdenum, titanium, nitrogen and other elements.The comprehensive performance is good, can resist various medium corrosion.The common brands of austenitic stainless steel are 1Cr18Ni9, 0Cr19Ni9, etc.Wc of 0Cr19Ni9 steel <0.08%, marked "0" in steel number.This kind of steel contains a lot of Ni and Cr, making the steel present the austenite state at room temperature.This kind of steel has good plasticity and toughness, weldability and corrosion resistance and non-magnetic or weak magnetic, the corrosion resistance in oxidizing and reducing medium are good, used to make acid equipment, such as corrosion resistant containers and equipment lining, pipelines, nitric acid resistant equipment parts, etc., also can be used as the main body of watches and clocks jewelry stainless steel material.Austenitic stainless steel with solid solution treatment, the steel heating to 1050 ~ 1150 ℃, then water-cooled or air-cooled, for single-phase austenitic organization.
Austenite - ferritic duplex - phase stainless steel
It has the advantages of both austenite and ferritic stainless steel and superplasticity.Austenitic and ferritic tissues each account for about half of stainless steel.In the case of low C content, Cr content was 18%~28% and Ni content was 3%~10%.Some steels also contain Mo, Cu, Si, Nb, Ti, N and other alloy elements.This kind of steel both austenite and ferrite stainless steel, the characteristics of compared with ferrite, plasticity and toughness is higher, no room temperature brittleness, intergranular corrosion resistance and welding performance were significantly increased, while maintaining a ferritic stainless steel of 475 ℃ brittleness and high thermal conductivity, has the characteristics of superplasticity.Compared with austenitic stainless steels, high strength, intercrystalline corrosion resistance and chloride stress corrosion resistance are obviously improved.Two-phase stainless steel has excellent corrosion resistance and is also a kind of ni-saving stainless steel.
martensitic stainless steel
High strength, but poor plasticity and weldability.Martensitic stainless steel is commonly used as 1Cr13, 3Cr13, etc. Due to its high carbon content, martensitic stainless steel has high strength, hardness and abrasion resistance, but slightly poor corrosion resistance.This kind of steel is used after quenching and tempering.Annealing is required after forging and stamping.