What is 904L Stainless Steel Plate?
904L stainless steel is a high alloy austenitic stainless steel known for its excellent corrosion resistance, especially in acidic environments. It is commonly used in industries such as chemical processing, oil and gas, and pharmaceuticals due to its superior performance in harsh conditions.
Chemical Composition
The chemical composition of 904L stainless steel is carefully balanced to provide optimal performance. The key elements include:
| Element | Weight Percentage (%) |
|---|---|
| Carbon (C) | ≤ 0.02 |
| Manganese (Mn) | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 19.0-23.0 |
| Nickel (Ni) | 23.0-28.0 |
| Molybdenum (Mo) | 4.0-5.0 |
| Copper (Cu) | 1.0-2.0 |
| Nitrogen (N) | ≤ 0.10 |
| Iron (Fe) | Balance |
Mechanical Properties
904L stainless steel exhibits impressive mechanical properties, making it suitable for demanding applications. Here’s a summary of its key mechanical properties:
| Property | Value |
|---|---|
| Tensile Strength | 490 MPa (71 ksi) |
| Yield Strength | 220 MPa (31 ksi) |
| Elongation | 35% min |
| Hardness | 90 HRB |
| Modulus of Elasticity | 193 GPa (28 x 10^6 psi) |
| Density | 7.98 g/cm³ |
| Poisson’s Ratio | 0.3 |
Key Features and Benefits
High Corrosion Resistance: 904L stainless steel offers excellent resistance to pitting and crevice corrosion, especially in chloride-rich environments. Its high molybdenum and copper content enhances its ability to resist reducing acids, such as sulfuric acid.
Superior Weldability: Despite its high alloy content, 904L stainless steel maintains good weldability. It can be welded using standard techniques, and its low carbon content minimizes the risk of sensitization and intergranular corrosion.
High Temperature Performance: 904L stainless steel performs well at elevated temperatures, maintaining its strength and corrosion resistance up to 400°C (752°F). However, it is not ideal for long-term use at higher temperatures.
Applications
904L stainless steel is used in a variety of industries due to its exceptional properties. Some common applications include:
- Chemical Processing: Used in heat exchangers, tanks, piping systems, and valves where resistance to corrosive chemicals is essential.
- Oil and Gas: Employed in offshore platforms, pipelines, pumps, and wellhead equipment due to its high strength and corrosion resistance.
- Pharmaceuticals: Utilized in mixing tanks, sterilizers, process reactors, and storage vessels for its non-reactive nature and cleanliness.
- Power Generation: Used in flue gas scrubbers, nuclear waste containers, turbine blades, and cooling systems for its durability and resistance to harsh environments.
- Watchmaking: Rolex and other watch manufacturers use 904L stainless steel for its superior polishability and corrosion resistance.
Fabrication and Welding
Fabrication of 904L stainless steel involves standard methods such as cutting, drilling, and bending. Special care must be taken during welding to avoid hydrogen-induced cracking. The steel can be welded using techniques like TIG, MIG, and MMA welding. Post-weld heat treatment is usually not necessary but following recommended procedures ensures optimal performance.
Heat Treatment
The mechanical properties of 904L stainless steel are achieved through a quenching and tempering process. This involves heating the steel to a high temperature, followed by rapid cooling (quenching) and reheating to a lower temperature (tempering). This process enhances the steel’s strength, toughness, and ductility.
Conclusion
904L stainless steel is a versatile and high-performance material that offers numerous benefits for various industrial applications. Its combination of high strength, excellent corrosion resistance, and good weldability makes it an ideal choice for demanding projects. By understanding its properties and applications, industries can maximize the potential of 904L stainless steel and ensure the longevity and reliability of their projects.