What is the difference between 304 and 904L?

1. Chemical composition and properties
304 stainless steel:
The main components include chromium (Cr) content of about 18%-20%, and nickel (Ni) content of about 8%-10.5%. It is an austenitic stainless steel with good comprehensive properties such as corrosion resistance and toughness. The corrosion resistance mainly depends on the chromium and nickel elements it contains, and is usually used for equipment and parts that require good corrosion resistance and formability.
904L stainless steel:
It is a martensitic stainless steel, but its structure is completely austenitic. It contains higher alloy elements such as nickel, chromium, molybdenum and copper, such as nickel content may be higher than 10%, chromium content may be higher than 18%, and contains a certain amount of molybdenum. It has excellent corrosion resistance and wear resistance, especially for strong acids and alkalis such as chlorine and chlorine.

2. Corrosion resistance and high temperature resistance
304 stainless steel: Good corrosion resistance, but in certain specific media or high temperature conditions, the corrosion resistance may decrease. It can withstand a certain high temperature environment, but the high temperature resistance is relatively limited.
904L stainless steel: It has extremely strong corrosion resistance and is particularly suitable for piping systems in corrosive environments. It has excellent high temperature resistance and can maintain stable performance in high temperature environments.

3. Mechanical properties
304 stainless steel: It has excellent mechanical properties, with tensile strength ≥520MPa, yield strength ≥205MPa, and elongation ≥40%. It is easy to process and form, and is widely used in a variety of industrial applications.
904L stainless steel: It also has good mechanical properties, with high strength and ductility. It has high hardness and good wear resistance after quenching, and is suitable for applications that require high wear resistance.

4. Application areas
304 stainless steel: It is widely used in food, medical, chemical, construction, household goods and other fields.
904L stainless steel: It is mainly used in chemical, petroleum, marine engineering and other fields, especially in environments that require high corrosion resistance and high temperature resistance.

5. Price
904L stainless steel: Due to its special composition and excellent performance, the price is usually higher than 304 stainless steel.