Common stainless steel models are commonly represented by digital symbols, including 200 series, 300 series and 400 series. They are the representation methods of the United States, such as 201, 202, 302, 303, 304, 316, 410, 420, 430, etc. The American Iron and Steel Society uses three digits to mark various standard grades of malleable stainless steel. Among them:

 

Austenitic stainless steel is numerically marked by series 200 and 300, ferrite and martensitic stainless steel by series 400. For example, some common austenitic stainless steels are marked 201, 304, 316 and 310, and ferritic stainless steels are marked 430 and 446, martensitic stainless steels are marked 410, 420 and 440C, duplex (austenite-ferrite). Fourthly, stainless steels, precipitation hardening stainless steels and high alloys with iron content less than 50% are usually named by *** or trademark.

 

Functional differences:

 

304 is a versatile and widely used stainless steel material, which is widely used in the manufacture of equipment and components requiring good comprehensive properties (corrosion resistance and formability). It can withstand general corrosion in buildings, resist the erosion of food processing media (but corrosion may occur at high temperatures containing concentrated acids and chlorides), and resist organic compounds, dyes and a wide range of inorganic compounds. Type 304L (low carbon), good nitric acid resistance, and durable to medium temperature and concentration of sulfuric acid, is widely used as liquid gas storage tank, low temperature equipment (304N), other consumer products, kitchen equipment, hospital equipment, transportation tools, wastewater treatment equipment.

 

Type 430 has lower content than type 304 alloy. It can be used for high polishing and decoration in mild atmosphere. It can also be used as nitric acid and food processing equipment.

 

The difference between stainless steel 201 and 304

1, specifications: commonly used stainless steel plates are divided into 201 and 304 models, the actual composition is different, 304 quality is better, but the price is expensive, 201 is worse. 304 is imported stainless steel plate, 201 is domestic stainless steel plate.

 

2. 201 is composed of 17Cr-4.5Ni-6Mn-N, which is a substitute steel for saving Ni and 301 steel. It has magnetism after cold processing and is used for railway vehicles.

 

3. 304 is composed of 18Cr-9Ni, which is a stainless steel and heat-resistant steel widely used. Used in food production equipment, chemical equipment, nuclear energy and so on.

 

4. 201 has a high manganese content, a bright surface with dark and bright, and a high manganese content is easy to rust. 304 contains more chromium and its surface is matte and rust-free. The two are compared when put together. More importantly, the corrosion resistance of 201 is very poor, so the price is much cheaper. Because 201 contains low nickel, so the price is lower than 304, so the corrosion resistance is not as good as 304.

 

5. The difference between 201 and 304 is the problem of nickel. And the price of 304 is now relatively expensive, generally close to 50,000 tons, but 304 can at least ensure that the process of use will not rust. (Can be tested with liquid medicine)

 

6. Stainless steel is not easy to rust because the formation of chromium-rich oxides on the surface of steel can protect the steel body. 201 belongs to high manganese stainless steel with higher hardness, high carbon and low nickel than 304.

 

 

 Component control

 

304, C < 0.08 Ni8.00-10.00 Cr18.00-20.00, Mn <=2.0Si<=1.0S<=0.030 P<=0.035

 

430, C < 0.12 Cr16.00--18.00, Mn <=1.0, Ni <=0.75Si <=1.0S <=0.030 P <=0.040201,

 

1Cr17Mn6Ni5N, C < 0.15, P < 0.06, S < 0.03202,

 

1Cr18Mn8Ni5N, C<0.15, P<0.06, S<0.03

 

Stainless steels 201 and 304 are distinguished from each other in carbon, manganese, nickel and chromium.