Polished Round Stainless Steel Rod 904l N08904 10-300mm Corrosion Resistant

Polished Round Stainless Steel Rod 904l N08904 10-300mm Corrosion Resistant

‌904L stainless steel is a super austenitic stainless steel with excellent corrosion resistance and other excellent properties‌. It belongs to the category of high alloy stainless steel and contains a large amount of alloying elements. The combination of these elements makes it perform well in various corrosive environments.

Since the carbon content of 904L is very low (maximum 0.020%), no carbide will precipitate under normal heat treatment and welding. This eliminates the risk of intergranular corrosion after general heat treatment and welding. Due to the high chromium, nickel, and molybdenum content and the addition of copper, 904L can be passivated even in reducing environments such as sulfuric acid and formic acid. The high nickel content also makes it have a low corrosion rate in the active state. In pure sulfuric acid in the concentration range of 0~98%, the use temperature of 904L can be as high as 40 degrees Celsius. In pure phosphoric acid in the concentration range of 0~85%, its corrosion resistance is very good. In industrial phosphoric acid produced by wet process, impurities have a strong influence on corrosion resistance. Among all kinds of phosphoric acid, 904L has better corrosion resistance than ordinary stainless steel. In strongly oxidizing nitric acid, 904L has lower corrosion resistance than high-alloyed steels without molybdenum. In hydrochloric acid, the use of 904L is limited to a lower concentration of 1-2%. In this concentration range. 904L has better corrosion resistance than conventional stainless steel. 904L steel has high resistance to pitting corrosion. It also has good resistance to crevice corrosion in chloride solutions. The high nickel content of 904L reduces the corrosion rate in pits and crevices. Ordinary austenitic stainless steel may be sensitive to stress corrosion in a chloride-rich environment at temperatures above 60 degrees Celsius. This sensitization can be reduced by increasing the nickel content of the stainless steel. Due to the high nickel content, 904L has high resistance to stress corrosion cracking in chloride solutions, concentrated hydroxide solutions and hydrogen sulfide-rich environments.

Chemical composition and physical properties

The main chemical components of 904L stainless steel include:

Alloy (C): ≤0.02%
Manganese (Mn): ≤2.00%
Silicon (Si): ≤1.00%
Chromium (Cr): 19.0~23.0%
Nickel (Ni): 23.0~28.0%
Molybdenum (Mo): 4.0~5.0%
Copper (Cu): 1.0~2.0%
Phosphorus (P): ≤0.045%
Sulfur (S): ≤0.035%

Its physical properties include:

Density: 8.0g/cm³
Tensile strength: σb≥520MPa
Elongation: δ≥35%

Corrosion resistance

904L stainless steel performs well in various corrosive environments, especially in acidic environments:

‌Non-oxidizing acids‌: It has good corrosion resistance in sulfuric acid, acetic acid, formic acid, and phosphoric acid.
‌Chloride ion media‌: It has good resistance to pitting and crevice corrosion in seawater and chloride solutions.
‌Other acids‌: In industrial phosphoric acid produced by wet process, its corrosion resistance is better than that of ordinary stainless steel. In strongly oxidizing nitric acid, its corrosion resistance is low, but it performs better than conventional stainless steel in hydrochloric acid‌

Application areas
904L stainless steel is widely used in various occasions that require high corrosion resistance, including:

Petroleum and petrochemical equipment: such as reactors, heat exchangers, etc.
Power plants: flue gas desulfurization devices, absorption towers, flues, etc.
Chemical equipment: seawater treatment devices, papermaking industry equipment, acid production, pharmaceutical industry, etc.
Food equipment: such as soy sauce tanks, cooking wine, salt tanks, etc.