Khả năng chống ăn mòn của thép không gỉ 904L

Thuộc tính chung

904L stainless steel does not produce carbide precipitation during heat treatment or welding. This eliminates the risk of intergranular corrosion. Crôm cao của nó, niken, and molybdenum content, combined with added copper, allows for effective passivation even in reducing environments such as sulfuric and formic acid.

Performance in Specific Acids

Sulfuric Acid: In concentrations of 0-98%, 904L can be used at temperatures up to 40°C.
Phosphoric Acid: It offers excellent resistance in pure phosphoric acid within the 0-85% concentration range. Tuy nhiên, in industrial phosphoric acid (wet process), impurities may impact its corrosion resistance. Mặc dù vậy, 904L performs better than ordinary stainless steels in all types of phosphoric acid.
Axit Nitric: Resistance to corrosion is lower compared to high-alloy steels without molybdenum.
Hydrochloric Acid: Its use is restricted to low concentrations (1-2%), where it outperforms conventional stainless steel.

Pitting and Crevice Corrosion Resistance

904L demonstrates strong resistance to pitting corrosion and crevice corrosion in chloride solutions. Its high nickel content minimizes the corrosion rate in pits and crevices.

Stress Corrosion Cracking

Ordinary austenitic stainless steels are prone to stress corrosion cracking in chloride-rich environments above 60°C. This sensitivity is reduced by increasing nickel content. The high nickel content in 904L provides excellent resistance to stress corrosion cracking in chloride solutions, concentrated hydroxide solutions, and hydrogen sulfide-rich environments.

Bản tóm tắt

904L stainless steel is highly resistant to a range of corrosive environments. Its superior properties make it a reliable choice for applications in industries dealing with harsh chemical and acidic conditions.