1, different performance
Corrosion resistance: 430 stainless steel contains 16.00- 18.00% chromium and basically contains no nickel metal, while 304 stainless steel contains more chromium and nickel metal, so the corrosion resistance of 430 stainless steel is not as good as that of 304 stainless steel.
Stability: 430 stainless steel is ferrite, 304 stainless steel is austenite and 304 stainless steel is more stable than 430 stainless steel.
Toughness: 304 stainless steel has strong toughness, stronger than 430 stainless steel.
Thermal conductivity: Ferrite of 430 stainless steel has better thermal conductivity than austenite of 304 stainless steel.
Mechanical properties: 430 stainless steel is added with stable chemical element titanium, and the mechanical properties of weld are better than 304 stainless steel.
2. Different fields of use
430 stainless steel is mainly used in building decoration, fuel burner parts, household appliances and household appliances. 430F steel with free cutting performance is added to 430 steel, which is mainly used for automatic lathes, bolts and nuts. Adding Ti or Nb to 430 steel reduces the C content to 430LX, which improves the machinability and weldability. Mainly used in hot water tank, hot water supply system, sanitary ware, household durable appliances, bicycle flywheel, etc.
304 stainless steel has the characteristics of high temperature resistance, good processability and high toughness, and is widely used in industry, furniture decoration industry and food and medical industry. 304 stainless steel has strong corrosion resistance and is widely used to manufacture equipment and parts that require good comprehensive performance (corrosion resistance and formability).
3, the applicable environment is different
The original intention of 304 stainless steel research and development is obviously inclined to be used in harsh environments, such as coastal areas, cold and humid places or places with high pH in the air. , but also more people-oriented, more consideration of consumer health and use feelings.
The excellent heat resistance of 430 stainless steel tends to be used in places with high environmental requirements, such as boilers, hot water tanks and hot water supply systems. It can not only prevent rust and corrosion, but also resist heat and high temperature. This is the real use of 430 ferritic stainless steel.
Extended data:
The reasons why 304 stainless steel rusts are as follows:
1, chloride ion
Chloride ion exists widely, such as salt/sweat/seawater/sea breeze/soil and so on. In the presence of chloride ion, stainless steel corrodes quickly, even exceeding ordinary low carbon steel. Therefore, there is a requirement for the use environment of stainless steel, which needs to be wiped frequently to remove dust and keep it clean and dry.
2, solid solution treatment
The alloy elements are not dissolved in the matrix, which leads to low alloy content and poor corrosion resistance in the matrix.
3, intergranular corrosion
This material without titanium and niobium has a tendency of intergranular corrosion. Adding titanium and niobium and stabilizing treatment can reduce intergranular corrosion. A high alloy steel resistant to air or chemical corrosive medium. Stainless steel is a kind of steel with beautiful surface and good corrosion resistance. It does not need surface treatment, such as color electroplating, but exerts its inherent surface properties. It is widely used and is usually called stainless steel.
High alloy steels such as 13 Cr steel and 18-8 Cr-Ni steel are its representative properties. From the metallographic point of view, because stainless steel contains chromium, a very thin chromium film is formed on the surface, which isolates the oxygen invading the steel and plays a role in corrosion resistance. In order to maintain the inherent corrosion resistance of stainless steel, welding steel must contain more than 12% chromium.
The low carbon content minimizes carbide precipitation in the heat affected zone near the weld, which may lead to intergranular corrosion (welding corrosion) of stainless steel in some environments.
Material characteristics of 430 stainless steel;
430 stainless steel has the ability of anti-oxidation corrosion, but it has the tendency of intergranular corrosion.
430 stainless steel wire rods is widely used in axle center.
Because it is safe and non-toxic, it is widely used in food tableware.
References:
Baidu Baike -304 Stainless Steel
Baidu encyclopedia -430 stainless steel