The Performance and Application of 300 Series Stainless Steel
According to the American AISI standard, stainless steel is represented by three Arabic numerals. The first digit indicates the category, and the second and third digits indicate the sequence number. The 300 series stainless steel whose first digit starts with 3 is austenitic stainless steel with a Cr-Ni structure. Common grades are:
1, 304
Low-carbon austenitic stainless steel
Performance: General anti-intergranular corrosion performance and excellent corrosion resistance. It has a certain anti-corrosion ability to alkali and most organic and inorganic acids. Uses: Widely used in acid pipelines and chemical equipment, etc.
2, 304L
Low-carbon austenitic stainless steel
Performance: It has good resistance to crystal and corrosion, and has good corrosion resistance to various strong corrosive media. Uses: Suitable for petrochemical corrosion-resistant equipment parts, especially welded pipe fittings that cannot be heat treated after welding.
3, 304H
Austenitic stainless heat-resistant steel
Performance: Good corrosion resistance and welding performance, good heat strength performance. Uses: Mainly used in large-scale boiler superheaters, reheaters, steam pipes, and petrochemical heat exchangers.
4, 316
Austenitic stainless hot-strength steel
Performance: Good corrosion resistance and pitting resistance to a variety of inorganic acids, organic acids, alkalis, and salts, and good variable strength at high temperatures. Uses: Suitable for large-scale boiler superheaters, reheaters, steam pipes, petrochemical heat exchanger pipe fittings, and can be used as pitting-resistant materials.
5, 316L
Ultra-low carbon austenitic stainless acid-resistant steel
Performance: It has good resistance to crystal and corrosion, and has good corrosion resistance to organic acids, alkalis and salts. Uses: Widely used in acid pipelines and chemical equipment, etc.
6, 321
Austenitic stainless acid-resistant steel
Performance: It has high resistance to intergranular corrosion, and has good corrosion resistance to some organic and inorganic acids. Uses: Used to manufacture acid-resistant transportation pipelines, large boiler superheaters, reheaters, steam pipelines, petrochemical heat exchangers, etc.
7, 317L
Austenitic stainless acid-resistant steel
Performance: Excellent corrosion resistance, better pitting resistance in chloride-containing solutions. Uses: To manufacture main resistant pipes for industrial equipment such as synthetic fiber, petrochemical, textile, papermaking, and atomic energy post-processing.
8, 310S
Austenitic heat-resistant stainless steel
Performance: good resistance to intergranular corrosion, excellent resistance to chloride stress corrosion, and good resistance to high-temperature oxidation. Uses: used to make furnace tubes, boiler superheaters, heat exchanger pipe fittings.
9, 347H
Austenitic stainless hot-strength steel
performance: has good corrosion resistance, welding performance, and thermal strength. Uses: used in large boiler superheaters, reheaters, steam pipes, and petrochemical heat exchanger pipe fittings.