Tensile strength and mechanical properties of 904L super austenitic stainless steel pipe

Chemical composition of 904L stainless steel pipe (%)

 

C ≤ 0.0200

 

Mn ≤ 2.0000

 

P ≤ 0.0400

 

S ≤ 0.0300

 

Si ≤ 1.0000

 

Cr 19.0000-230000

 

Ni 23.0000-28.0000

 

Mo 4.0000-5.0000

 

Cu 1.0000-2.0000

 

 

904L super austenitic stainless steel is a low-carbon, high nickel, molybdenum austenitic stainless acid resistant steel, which was introduced from France by H? S Company's proprietary materials. It has excellent activation passivation transformation ability, excellent corrosion resistance, good corrosion resistance in non oxidizing acids such as sulfuric acid, acetic acid, formic acid, and phosphoric acid, good resistance to pitting corrosion in neutral chloride ion containing media, and good resistance to crevice corrosion and stress corrosion. Suitable for various concentrations of sulfuric acid below 70 ℃, it has excellent corrosion resistance under atmospheric pressure to any concentration and temperature of acetic acid and a mixture of formic acid and acetic acid.

 

 

Main ingredients: 20Cr-24Ni-4.3Mo-1.5Cu

 

 

Brand and standard: UNS N08904, DIN1.4539, ASTM A240 (new standard classified as stainless steel series, original standard ASME SB-625 classified as nickel based alloy series), SUS890L.

 

 

The metallographic structure of 904L super austenitic stainless steel pipe: 904L is a completely austenitic structure, which is different from austenitic stainless steel with high molybdenum content in general α The precipitation of phases is not sensitive.

 

 

Physical and mechanical properties: Density: 8.24g/cm3. Tensile strength: σ B ≥ 520Mpa. Elongation: δ≥ 35%.

 

 

Corrosion resistance of 904L super austenitic stainless steel pipe: Due to its low carbon content (maximum 0.020%), there will be no carbide precipitation under general heat treatment and welding conditions. This eliminates the risk of intergranular corrosion that occurs after general heat treatment and welding. Due to its high chromium nickel 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 results in a lower corrosion rate in the active state. In pure sulfuric acid at a concentration range of 0-98%, the service temperature of 904L super austenitic stainless steel pipe can reach up to 40 degrees Celsius. In pure phosphoric acid with a concentration range of 0-85%, its corrosion resistance is very good. In industrial phosphoric acid produced by wet process, impurities have a strong impact on corrosion resistance. Among all types of phosphoric acid, 904L has better corrosion resistance than ordinary stainless steel. In strong oxidizing nitric acid, 904L super austenitic stainless steel pipes have lower corrosion resistance compared to high alloyed steel grades without molybdenum. In hydrochloric acid, the use of 904L super austenitic stainless steel pipes 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. The 904L super austenitic stainless steel pipe has high resistance to spot corrosion. In chloride solution, its resistance to crevice corrosion is also very good. The high nickel content of 904L super austenitic stainless steel pipe reduces the corrosion rate at 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 super austenitic stainless steel pipes have high resistance to stress corrosion cracking in chloride solutions, concentrated hydroxide solutions, and environments rich in hydrogen sulfide.