904L Acid Alkali / High Temperature Resistant Round Steel 1.4529 Stainless Steel Rod

904L Acid Alkali And High Temperature Resistant Round Steel 1.4529 Stainless Steel Rod

Introduction to 904L Stainless Steel:

904L (N08904, 14539) super austenitic stainless steel contains 14.0-18.0% chromium, 24.0-26.0% nickel, and 4.5% molybdenum. 904L Super Austenitic Stainless Steel is a low-carbon, high nickel, molybdenum austenitic stainless steel with excellent activation passivation transformation ability and corrosion resistance. It has good corrosion resistance in non oxidizing acids such as sulfuric acid, acetic acid, formic acid, and phosphoric acid, as well as good resistance to pitting corrosion in neutral chloride ion media. It also has good resistance to crevice corrosion and stress corrosion. Suitable for various concentrations of sulfuric acid below 70 ℃, it is resistant to any concentration and temperature of acetic acid under normal pressure, and has good corrosion resistance in mixed acids of formic acid and acetic acid.

Carbon (C): ≤ 0.02%
Silicon (Si): ≤ 1.00%
Manganese (Mn): ≤ 2.00%
Phosphorus (P): ≤ 0.045%
Sulfur (S): ≤ 0.035%
Chromium (Cr): 19.00% -23.00%
Nickel (Ni): 23.00% -28.00%
Molybdenum (Mo): 4.00% -5.00%
Copper (Cu): 1.00% -2.00%

These chemical components give 904L stainless steel the following special properties:

Corrosion resistance: 904L stainless steel exhibits excellent corrosion resistance in non oxidizing acids such as sulfuric acid, acetic acid, formic acid, and phosphoric acid, making it suitable for various concentrations and temperatures of these acidic media.
Pitting corrosion resistance: 904L stainless steel has good pitting corrosion resistance in neutral chloride ion media.
Resistance to crevice corrosion and stress corrosion: 904L stainless steel also performs well in these areas and is suitable for various harsh corrosive environments.

Metallographic structure of 904L stainless steel:

904L has a completely austenitic structure and is less sensitive to the precipitation of ferrite and alpha phase compared to typical austenitic stainless steels with high molybdenum content.

Physical and mechanical properties:

Density: 8.0g/cm3.

Tensile strength: σ b ≥ 520Mpa.

Elongation rate: δ ≥ 35%.

Corrosion resistance of 904L stainless steel:

Due to the low carbon content of 904L (up to 0.020%), there will be no carbide precipitation during general heat treatment and welding.

This eliminates the risk of intergranular corrosion that typically occurs after heat treatment and welding.

Due to its high chromium nickel molybdenum content and the addition of copper element, 904L can be passivated even in reducing environments such as sulfuric acid and formic acid.

The high nickel content also results in a lower corrosion rate in its active state.

In the concentration range of 0-98% pure sulfuric acid, the operating temperature of 904L can reach up to 40 degrees Celsius. In the concentration range of 0-85% pure phosphoric acid, its corrosion resistance is very good. Impurities have a strong impact on the corrosion resistance of industrial phosphoric acid produced by wet process technology. Among all types of phosphoric acid, 904L has better corrosion resistance than ordinary stainless steel. In highly oxidizing nitric acid, 904L has lower corrosion resistance compared to high alloyed steel grades without molybdenum. In hydrochloric acid, the use of 904L is limited to lower concentrations of 1-2%. Within this concentration range. The corrosion resistance of 904L is better than that of conventional stainless steel. 904L steel has high resistance to pitting corrosion. Its resistance to crevice corrosion is also very good 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. By increasing the nickel content of the stainless steel, this sensitization can be reduced. Due to its high nickel content, 904L has high resistance to stress corrosion cracking in chloride solutions, concentrated hydroxide solutions, and environments rich in hydrogen sulfide.

904L has the following applications:
*Petroleum and petrochemical equipment, such as reactors in petrochemical equipment.

*Storage and transportation equipment for sulfuric acid, such as heat exchangers.

*The flue gas desulfurization device in power plants is mainly used in the tower body, flue, baffle plate, internal components, spray system, etc. of the absorption tower.

*Scrubbers and fans in organic acid treatment systems.

*Seawater treatment equipment, seawater heat exchangers, papermaking industry equipment, sulfuric acid and nitric acid equipment, acid and pharmaceutical industry and other chemical equipment, pressure vessels, food equipment.

*Pharmaceutical factories: centrifuges, reactors, etc.

*Plant based foods: soy sauce jars, cooking wine, salt jars, equipment, and dressings.

*904L is a suitable steel grade for the strong corrosive medium of dilute sulfuric acid.