200, 300, 400 Series Stainless Steel

    Stainless steel is the abbreviation for stainless acid-resistant steel that are resistant to weak corrosive media such as steam, water, air or other has rust resistance. And steel types that are resistant to chemical corrosive media like acids, alkali, salts and beyond are called acid-resistant steel.

Due to the difference in chemical composition between the stainless steel and acid-resistant steel, the former is not necesssarily resistant to chemical corrosion, while the latter generally have rust resistance.

    The corrosive resistance of stainless steel depends on the alloy elments contained in steel. Usually, stainless steel is divided into 3 categories according to the metallographic structure: austenitic stainless steel, ferritic stainless steel and martensitic stainless steel. In specific demands and purpose, it continuously derives duplex steel, precipitation hardening stainless steel and high alloy steel.

1. Austenitic stainless steel 奥氏体型不锈钢

The matrix is mainly an austenite structure (CY phase) with a face-centered cubic structure. It's non-magnetic and will cause magnetic after cold treatment. The AISI labels it as 200 and 300 series stainless steel.

2. Ferritic stainless steel 铁素体型不锈钢

The matrix is mainly a ferrite structure (a phase) with body-centered cubic crystal structure. It's magnetic and cannot be hardened by heat treatment but the cold treatment. The AISI labels it as 400 series stainless steel such as 430, 446 etc.

3. Martensitic stainless steel 马氏体型不锈钢

The matrix is a martensiitic structure with body-centered cubic . It has magnetic and its mechanical properties can be adjusted through heat treatment. The AISI marks with 410, 420, 440 etc.

4. Austenitic-ferritic duplex steel奥氏体-铁素体(双相)型不锈钢

329 is a typical duplex stainless steel, which is magnetic and can be strengthened by cold processing. With the high strength of duplex steel, its resistance to intergranular corrosion, chloride stress and pitting corrosion has been significantly improved.

5. Precipitation hardening stainless steel 沉淀硬化型不锈钢

In mildly corrosive environments if the material is required high strength and hardness, we can utilize the martensitic stainless steel and PH stainless steel. The AISI marks it as 630.

Feature Table about 200 & 300 & 400 Series Stainless Steel