The chromium content in 20 1 stainless steel is about 15%, and that in 304 stainless steel is 18%. Similarly, the nickel content in 20 1 stainless steel is 5%, while the nickel content in 304 stainless steel is more, accounting for about 9%. So from the appearance, the two colors are different. 20 1 stainless steel has a bright surface, while 304 stainless steel has a matte surface.
304 stainless steel has good corrosion resistance and is not easy to rust, but its material will be softer. 20 1 stainless steel will have greater hardness, but it will be inferior to 304 stainless steel in corrosion resistance. Although the surface is bright, it is easy to rust during use.
20 1 stainless steel has low corrosion resistance, but high density and no pinhole inside. It is generally suitable for dry environment, such as decoration site and industrial products, and can meet the demand well. 304 stainless steel has good corrosion resistance, so it can be used in industry, home decoration, medical treatment and other industries, and is also very suitable for some coastal or humid areas.
Manufacturing method of stainless steel
1, melting raw materials
Put different stainless steel materials into a furnace and heat them to their melting points. This process may take 8 to 12 hours.
Step 2 remove excess carbon
The molten material is put into a vacuum oxygen decarbonization (VOD) or argon oxygen decarbonization (AOD) system to remove excess carbon.
Step 3 Tune or stir
To help fine-tune the quality of the final product, molten steel can be stirred to help remove specific stainless steel components from the mixture.
4. Molded metal
When stainless steel begins to cool, it will go through various forming processes-starting from hot rolling, when the steel is still above its crystallization temperature. Hot rolling helps to make steel into rough shapes, and is usually used to make metal billets or ingots.
5. Heat treatment
In order to reduce the internal stress and change the mechanical properties of stainless steel, it can be annealed.
6, cutting and forming
After the annealing process, stainless steel goes through various cutting and forming processes to produce an ideal final product suitable for the application.
7, the application of surface treatment
Stainless steel manufacturers can carry out different surface treatments on stainless steel billets, billets or wires before transporting them to other manufacturers.