There are two classification methods for
stainless steel pipe: one is classified into chromium stainless steel and chrome-nickel stainless steel according to the characteristics of alloying elements; the other is classified into M stainless steel, F stainless steel, and A stainless steel according to the state of steel in the normalized state. , A-F duplex stainless steel.
1, martensitic stainless steel
Typical martensitic stainless steels include 1Cr13~4Cr13 and 9Cr18.
1Cr13 steel processing performance is good. Deep drawing, bending, crimping and welding without preheating. 2Crl3 does not require preheating before cold deformation, but preheating before welding, 1Crl3, 2Cr13 is mainly used to make corrosion resistant structural parts such as steam turbine blades, etc., while 3Cr13, 4Cr13 are mainly used to make medical surgical scalpels and wear parts; 9Crl8 can be used as corrosion resistant bearings and tools.
2, ferritic stainless steel
The content of Cr in ferritic stainless steel is generally 13% to 30% and the carbon content is less than 0.25%. Sometimes other alloying elements are added. The metallographic structure is mainly ferrite, and there is no α<=> γ transformation during heating and cooling, and it cannot be strengthened by heat treatment. Strong anti-oxidation. At the same time, it also has good hot workability and certain cold workability. Ferritic stainless steel is mainly used to make components that require high corrosion resistance and low strength requirements. It is widely used in the manufacture of equipment for the production of nitric acid, nitrogen fertilizer and chemicals.
Typical ferritic stainless steels are Crl7, Cr25 and Cr28.
3, austenitic stainless steel
Austenitic stainless steel is developed to overcome the lack of corrosion resistance and excessive brittleness of Martensitic stainless steel. The basic composition is Crl8%, Ni8% is referred to as 18-8 steel. It is characterized in that the carbon content is less than 0.1%, and a single-phase austenite structure is obtained by using Cr and Ni.
