904L stainless steel plate is a type of super austenitic stainless steel

2025-09-01 23:26:28

　　904L, also known as N08904 or 1.4539, is a super austenitic stainless steel renowned for its exceptional corrosion resistance and high strength. This steel contains a high proportion of chromium, nickel, molybdenum, and copper, which enables it to maintain excellent performance in various corrosive environments.

　　1. Chemical composition

　　The chemical composition of 904L forms the basis of its excellent properties. Its main components include:

　　· Carbon (C): ≤0.020%

　　· Silicon (Si): ≤1.00%

　　· Manganese (Mn): ≤2.00%

　　· Phosphorus (P): ≤0.045%

　　· Sulfur (S): ≤0.035%

　　· Chromium (Cr): 19.0% - 23.0%

　　Nickel (Ni): 23.0% - 28.0%

　　· Molybdenum (Mo): 4.00% - 5.00%

　　· Copper (Cu): 1.00% - 2.00%

　　2. Performance parameters

　　The performance parameters of 904L are as follows:

　　Density: approximately 8.0 g/cm³

　　· Tensile strength: σb ≥ 520 MPa

　　· Elongation: δ ≥ 35%

　　· Melting point range: 2372 – 2520°C

　　The high chromium and nickel content of 904L, as well as the addition of copper, enhance its resistance to chloride intergranular corrosion and stress corrosion cracking. This stainless steel is almost free from pitting and cracking, and its resistance to pitting corrosion is even superior to other steel grades.

　　3. Heat treatment system

　　904L is typically supplied in a solution-treated state, which helps ensure the material's corrosion resistance and mechanical properties. The heating temperature range for solution treatment is 1080-1130°C.

　　4. Processing performance

　　904L has good processability and can be formed and processed through conventional metalworking techniques. However, due to its high alloy content, the rate of cold work hardening may be faster than that of ordinary stainless steel, so special measures may need to be taken during processing.

　　5. Welding performance

　　904L can be welded using most standard welding processes. During welding, it is necessary to use compatible welding materials, such as welding electrodes (E385-16/17) and welding wires (ER385), to ensure the corrosion resistance of the weld area.

　　6. Application fields

　　The application fields of 904L are very extensive, mainly including:

　　· Chemical industry: equipment used for manufacturing and processing corrosive media such as sulfuric acid, acetic acid, formic acid, and phosphoric acid.

　　· Marine engineering: Due to its excellent seawater corrosion resistance, it is suitable for ships, offshore platforms, etc.

　　· Paper industry: Used in pulp and paper-making equipment, which typically contain corrosive chemicals.

　　· Food processing: used for manufacturing equipment that comes into contact with food, due to its corrosion resistance and hygienic properties.

　　· Environmental protection equipment: Such as flue gas desulfurization devices, 904L can withstand corrosion in acidic environments.

　　7. Corrosion resistance

　　904L exhibits excellent corrosion resistance in various corrosive media, including non-oxidizing acids and media containing chloride ions. It has superior corrosion resistance in dilute sulfuric acid and can withstand any concentration and temperature of acetic acid under normal pressure.