ASTM A403 WP304
Key Properties:
- High-Temperature Performance: Excellent resistance to heat and thermal stress.
- Superior Strength: High tensile and yield strength.
- Corrosion Resistance: Improved resistance to oxidation and corrosion in high-temperature environments.
- Versatility: Suitable for a range of fitting types and custom designs.
ASTM A403 WP304 Chemical Composition
| Element | Percentage (%) |
|---|---|
| Carbon (C) | 0.15 max |
| Manganese (Mn) | 0.30–0.60 |
| Phosphorus (P) | 0.03 max |
| Sulfur (S) | 0.03 max |
| Silicon (Si) | 0.50 max |
| Chromium (Cr) | 4.00–6.00 |
| Molybdenum (Mo) | 0.45–0.65 |
ASTM A403 WP304 Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 415 MPa min |
| Yield Strength | 205 MPa min |
| Elongation | 20% min |
ASTM A403 WP304 Physical Properties
| Property | Value |
|---|---|
| Density | ~7.85 g/cm³ |
| Melting Point | ~1425–1500°C |
| Thermal Conductivity | ~35 W/m·K at 500°C |
| Specific Heat Capacity | ~460 J/kg·K |
| Electrical Resistivity | ~1.2 μΩ·m at 20°C |
| Thermal Expansion Coefficient | ~11.7 µm/m·K (20–100°C) |
Applications
ASTM A403 WP304 alloy steel pipe fittings are extensively used in:
- Power Plants: Boiler piping systems, reheaters, and superheaters.
- Petrochemical Industry: High-temperature pipelines for refineries and chemical plants.
- Oil & Gas: Offshore platforms, pipelines, and processing facilities.
- Industrial Processing: Equipment and piping in thermal plants and furnaces.
Grade Specification Comparison
ASTM A403 WP304 is often compared with other grades like WP11 and WP9. While WP5 is optimized for moderate to high temperatures and pressures, WP11 offers enhanced high-temperature performance, and WP9 has higher chromium content for superior oxidation resistance.
Possible Alternative Grades
When ASTM A403 WP304 is not the ideal fit, the following grades can serve as alternatives:
- ASTM A403 WP304: For higher temperature applications.
- ASTM A335 P5: A seamless pipe grade with similar properties.
- ASTM A403 WP304: For more demanding high-pressure and temperature environments.
Corrosion Resistance
The chromium content in WP5 provides excellent resistance to oxidation and scaling in high-temperature environments. However, in highly corrosive environments, protective coatings or inhibitors may be required for optimal performance.
Heat Resistance
ASTM A403 WP304 exhibits exceptional heat resistance, maintaining structural integrity and performance at operating temperatures up to 600°C (1112°F). This makes it ideal for boiler components, superheaters, and reheaters.
Heat Treatment
To enhance its mechanical properties and stress resistance, WP5 fittings undergo heat treatments like normalizing, tempering, or annealing. The choice of heat treatment depends on the intended application and required properties.
Welding
ASTM A403 WP304 is weldable using conventional methods like TIG, MIG, or SMAW. Preheating is generally required to prevent cracking, especially for thick sections. Post-weld heat treatment (PWHT) ensures the removal of residual stresses and improves toughness.
Fabrication
The alloy's machinability and formability allow for precise fabrication of pipe fittings. Special care must be taken during machining to account for its high strength and hardness.
Types Of Buttweld Fittings
