904L is a super austenitic stainless steel. It belongs to the category of high alloy stainless steel and contains a large amount of alloying elements. The combination of these alloying elements gives it excellent corrosion resistance and other excellent properties.

Corrosion Resistance

904L has excellent corrosion resistance, especially in acidic and chloride containing environments. For example, in a sulfuric acid environment, it can withstand higher concentrations of sulfuric acid solution, and its corrosion resistance is much stronger than ordinary stainless steel (such as 304 stainless steel). In media containing chloride ions such as seawater, it can also effectively resist pitting and crevice corrosion, because the synergistic effect of elements such as chromium, nickel, molybdenum, and copper makes the passivation film on its surface more stable and dense. It also has good tolerance to organic acids, inorganic acids (except for a few strong acids such as hydrofluoric acid), alkaline solutions, etc., and can maintain good performance in complex industrial environments with various chemical media.

Mechanical Performance

The tensile strength is generally between 490-790MPa, and the yield strength is ≥ 215MPa. Its strength can meet the manufacturing requirements of many industrial equipment, while also having good toughness, with an elongation rate of ≥ 35%, which makes it less likely to break when subjected to certain external deformation.

Processing Performance

● Hot processing: The hot processing performance is good, and when forging, rolling, and other operations are carried out within a suitable temperature range (such as 1100-1150 ℃), the shape can be smoothly changed. However, it is important to control the heating speed and processing temperature during the hot working process to avoid defects such as overheating or overburning.

● Cold processing: It is also relatively easy to form during cold processing, such as cold bending, cold rolling, and other processing. However, due to its relatively high strength, a large processing force may be required during cold working, and appropriate annealing treatment may be necessary after processing to eliminate cold working stress.

● Welding performance: The welding performance is good, and various welding methods can be used, such as manual arc welding, tungsten inert gas arc welding, etc. Suitable welding materials and welding processes need to be selected during welding to ensure that the quality and performance of the welded joint are similar to that of the base material.

Application Area 

● Chemical industry: widely used in the manufacturing of chemical equipment, such as reaction vessels, heat exchangers, pipelines, etc. In the production and processing of strong acids such as sulfuric acid and nitric acid, 904L stainless steel can resist the corrosion of chemical media, ensuring the long-term stable operation of equipment.

● Ocean engineering: It has a wide range of applications in seawater desalination devices, structural components of ocean platforms, and pipeline systems of ships. Due to its excellent resistance to seawater corrosion, it can effectively extend the service life of equipment in marine environments.

● Pharmaceutical industry: used in the manufacturing of pharmaceutical equipment, as the pharmaceutical process often involves various chemical reagents and complex acid-base environments, 904L stainless steel can meet the strict requirements of equipment for corrosion resistance.