Overview of AISI 904L Stainless Steel Seamless Pipes:
904L super austenitic stainless steel is a low-carbon, high-nickel, molybdenum austenitic stainless and acid-resistant steel, which is a proprietary material imported from France H·S. It has good 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, and good corrosion resistance in neutral chloride-containing media It has good pitting corrosion resistance and good resistance to crevice corrosion and stress corrosion. It is suitable for sulfuric acid of various concentrations below 70°C, and has good corrosion resistance in acetic acid at any concentration and at any temperature and the mixed acid of formic acid and acetic acid under normal pressure.
Super austenitic stainless steel 904L (00Cr20Ni25Mo4.5Cu; UNS: N08904; EN: 1.4539) is a high-alloy austenitic stainless steel with low carbon content. It has good corrosion resistance in dilute sulfuric acid and is specially designed for corrosion conditions. Designed for harsh environments. It has a high chromium content and sufficient nickel content. The addition of copper makes it highly resistant to acid, especially to chloride crevice corrosion and stress corrosion cracking. It is not easy to appear corrosion spots and cracks, and is resistant to spots. Corrosion ability is slightly better than other steel grades, has good workability and weldability, and can be used in pressure vessels.
Chemical Composition of ASTM A312 UNS N08904 Seamless Pipe:
| alloy | % | nickel | chromium | molybdenum | copper | iron | carbon | manganese | silicon | phosphorus | sulfur |
| 904L | min | 23 | 19 | 4 | 1 | margin | | | | | |
| | max | 28 | twenty three | 5 | 2 | | 0.02 | 2 | 1 | 0.045 | 0.035 |
Physical Properties of ASME SA312 SS 904L Seamless Pipes:
Density: 8.24g/cm3
Melting point: 1300-1390 ℃
Magnetism: None
Heat treatment: heat preservation between 1100-1150℃ for 1-2 hours, rapid air cooling or water cooling.
Mechanical Properties of Stainless Steel 904L Seamless Pipes:
| Alloy state | tensile strength Rm N/mm2 | Yield Strength RP0.2N/mm2 | Elongation A5% |
| 904L | 490 | 216 | 35 |
Application of ASTM A312 904L Stainless Steel Seamless Pipe:
* Petroleum and petrochemical equipment, such as reactors in petrochemical equipment, etc.
* Sulfuric acid storage and transportation equipment, such as heat exchangers, etc.
* Power plant flue gas desulfurization device, the main use parts are: the tower body of the absorption tower, flue, gate plate, internal parts, spray system, etc.
* Scrubber and fan in the organic acid treatment system.
*Sea water treatment equipment, sea water heat exchanger, paper industry equipment, sulfuric acid, nitric acid equipment, acid making, pharmaceutical industry and other chemical equipment, pressure vessels, food equipment.
*Pharmaceutical factories: centrifuges, reactors, etc.
*Plant food: soy sauce cans, cooking wine, salt cans, equipment and dressings.
* 904L is a matched steel grade for the strong corrosive medium of dilute sulfuric acid.
