Stainless Steel 304H (UNS S30409 / EN 1.4948)
Stainless Steel 304H (UNS S30409 / EN 1.4948) – Specifications, Properties and Applications
Stainless Steel 304H (UNS S30409 / EN 1.4948) is a high-carbon version of the standard 304 austenitic stainless steel. The increased carbon content enhances its strength and creep resistance at elevated temperatures, making it particularly suitable for high-temperature pressure-containing applications.
Grade 304H offers excellent oxidation resistance, good corrosion resistance, outstanding weldability, and reliable mechanical properties under prolonged exposure to high temperatures. It is widely used in power generation, petrochemical plants, refineries, heat exchangers, pressure vessels, and process piping systems.
Emirerri Steel supplies Stainless Steel 304H in plates, sheets, pipes, tubes, bars, flanges, and fittings for customers across Tunisia, Algeria, Morocco, Libya, and international markets.
Stainless Steel 304H Specifications
- Excellent high-temperature strength
- Superior creep resistance
- Excellent oxidation resistance
- Good corrosion resistance
- Outstanding weldability
- Good formability
- Suitable for pressure equipment
- Long service life
- Excellent structural stability
- Low maintenance requirements
Stainless Steel 304H Specifications
| Specification | Details |
|---|
| Grade | Stainless Steel 304H |
| UNS Number | S30409 |
| Werkstoff Number | 1.4948 |
| EN Designation | X6CrNi18-10 |
| Stainless Steel Family | Austenitic Stainless Steel |
| Standards | ASTM A240, ASTM A312, ASTM A213, ASTM A182, EN 10088 |
| Product Forms | Plate, Sheet, Coil, Pipe, Tube, Round Bar, Flanges, Pipe Fittings |
| Surface Finish | No.1, 2B, BA, No.4, Mirror Finish |
| Supply Condition | Solution Annealed |
Equivalent Grades of Stainless Steel 304H
| Standard | Equivalent Grade |
| ASTM | 304H |
| UNS | S30409 |
| EN | 1.4948 |
| DIN | X6CrNi18-10 |
| JIS | SUS304H |
| ISO | X6CrNi18-10 |
Available Sizes
Plates
- Thickness: 5 mm to 100 mm
- Width: 1000 mm to 2500 mm
- Length: Up to 12000 mm
Sheets
- Thickness: 0.5 mm to 6 mm
- Width: Up to 2000 mm
Pipes & Tubes
- Outside Diameter: 6 mm to 610 mm
- Wall Thickness: 0.5 mm to 40 mm
Round Bars
- Diameter: 6 mm to 500 mm
Chemical Composition of Stainless Steel 304H
| Element | Composition (%) |
| Chromium (Cr) | 18.0 – 20.0 |
| Nickel (Ni) | 8.0 – 10.5 |
| Carbon (C) | 0.04 – 0.10 |
| Manganese (Mn) | ≤ 2.00 |
| Silicon (Si) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Nitrogen (N) | ≤ 0.10 |
| Iron (Fe) | Balance |
Mechanical Properties of Stainless Steel 304H
| Property | Value |
| Tensile Strength | ≥ 515 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 201 HB |
| Modulus of Elasticity | 193 GPa |
Physical Properties of Stainless Steel 304H
| Property | Value |
| Density | 7.90 g/cm³ |
| Melting Range | 1400 – 1450°C |
| Thermal Conductivity | 16.2 W/m·K |
| Electrical Resistivity | 0.72 µΩ·m |
| Specific Heat Capacity | 500 J/kg·K |
| Magnetic Permeability | Essentially Non-Magnetic (Annealed Condition) |
Types of Stainless Steel 304H Products
Stainless Steel 304H Plates
Ideal for pressure vessels, boilers, and industrial heat exchangers.
Stainless Steel 304H Sheets
Suitable for furnace components, industrial equipment, and fabrication.
Stainless Steel 304H Pipes
Used in process piping, refineries, and power plants.
Stainless Steel 304H Tubes
Commonly used in superheaters, heat exchangers, and condensers.
Stainless Steel 304H Round Bars
Suitable for machined components, shafts, and high-temperature fasteners.
Stainless Steel 304H Flanges & Pipe Fittings
Designed for high-temperature piping systems in chemical and power industries.
Heat Resistance
Stainless Steel 304H is specifically engineered for elevated-temperature service.
Service Temperature
- Continuous Service: Up to approximately 925°C
- Intermittent Service: Up to approximately 870°C
Benefits
- Excellent oxidation resistance
- High creep strength
- Good structural stability
- Resistance to scaling
- Reliable performance during long-term high-temperature exposure
Résistance à la Chaleur
Le 304H est spécialement conçu pour les applications à température élevée.
Températures de Service
- Service continu : jusqu’à 925°C
- Service intermittent : jusqu’à 870°C
Avantages
- Excellente résistance à l’oxydation
- Très bonne résistance au fluage
- Bonne stabilité métallurgique
- Résistance à la déformation thermique
Heat Treatment
Solution Annealing
- Temperature: 1010°C – 1120°C
- Cooling: Rapid air or water quenching
Benefits
- Restores corrosion resistance
- Dissolves chromium carbides
- Improves ductility
- Relieves internal stresses
Stainless Steel 304H cannot be hardened by heat treatment but can be strengthened through cold working.
Welding of Stainless Steel 304H
Grade 304H offers excellent weldability using conventional welding processes.
Recommended Welding Methods
- GTAW (TIG)
- GMAW (MIG)
- SMAW (Shielded Metal Arc Welding)
- SAW (Submerged Arc Welding)
- Resistance Welding
Welding Advantages
- Excellent weld integrity
- No preheating required
- Good post-weld mechanical properties
- Suitable for pressure-retaining equipment
Post-weld cleaning and passivation are recommended to restore optimum corrosion resistance. For critical high-temperature service, post-weld heat treatment may be specified depending on design codes.
Fabrication of Stainless Steel 304H
Machining
- Turning
- Milling
- Drilling
- Threading
Forming
- Cold bending
- Roll forming
- Press forming
- Deep drawing
Cutting
- Laser cutting
- Plasma cutting
- Waterjet cutting
- Mechanical sawing
Surface Finishing
- Pickling
- Passivation
- Mechanical polishing
- Electropolishing
Applications
Power Generation
- Boilers
- Superheaters
- Steam piping
- Heat recovery systems
Petrochemical Industry
- Process piping
- Reactors
- Heat exchangers
- Refinery equipment
Chemical Processing
- Pressure vessels
- Storage tanks
- High-temperature process equipment
Oil & Gas Industry
- Process plants
- Furnace components
- Refinery piping systems
Industrial Manufacturing
- High-temperature machinery
- Industrial furnaces
- Thermal processing equipment
Pressure Equipment
- ASME pressure vessels
- High-temperature pipelines
- Steam distribution systems
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