Stainless Steel 304H Seamless Pipes & Tubes Manufacturer & Supplier
SS 304H (UNS S30409) is the high-carbon version of 304, with carbon controlled to 0.04-0.10%. This higher carbon content provides significantly improved creep strength and rupture properties at temperatures between 425-816C, making it the preferred grade for boiler, superheater, and heat exchanger applications in power generation and petrochemical industries.
UNS: S30409 | Category: Austenitic Stainless Steel | Werkstoff Nr: 1.4948 | EN Name: X6CrNi18-10
SS 304H — Also Known As
SS 304H is also commonly known as SS 304H, 304H SS, Stainless Steel 304H Seamless Pipes & Tubes, S30409, UNS S30409, 1.4948, Werkstoff 1.4948, W.Nr 1.4948, X6CrNi18-10, 304h, aisi 304h.
SS 304H — Applicable Standards & Specifications
SS 304H is commonly supplied to ASTM A312, ASME SA312, ASTM A213, ASME SA213, ASME SA269, ASTM A376, ASME SA376, EN 10216-5.
Size Range
Outer Diameter: 1/4" NPS to 10" NPS (6.35mm to 273.1mm OD)
Wall Thickness: SCH 5S to SCH 160, XXS
Chemical Composition (%)
| C | Mn | Si | Cr | Ni | P | S |
|---|---|---|---|---|---|---|
| 0.04-0.10 | 2.00 max | 0.75 max | 18.0-20.0 | 8.0-10.5 | 0.045 max | 0.030 max |
Mechanical Properties
- Tensile Strength
- 515 MPa min
- Yield Strength
- 205 MPa min
- Elongation
- 35% min
- Hardness
- 92 HRB max
Physical Properties
- Density
- 7.93 g/cm3
- Melting Range
- 1400-1450 C
- Thermal Conductivity
- 16.2 W/m-K
- Electrical Resistivity
- 720 nOhm-m
- Specific Heat
- 500 J/kg-K
- Coeff. of Thermal Expansion
- 17.2 um/m-C
Corrosion Resistance
- Pitting Resistance (PREN)
- ~18
- Max Service Temp (Oxidizing)
- 870 C (continuous)
- Intergranular Corrosion
- Susceptible if sensitized (higher carbon)
- Stress Corrosion Cracking
- Susceptible in chlorides >60C
- General Corrosion Rate
- <0.1 mm/yr in mild acids
- Seawater Resistance
- Limited - pitting risk
Applicable Standards
- ASTM A312 / ASME SA312
- ASTM A213 / ASME SA213
- ASTM A269
- DIN EN 10216-5
Applications
- High-temperature service (425-816C)
- Power plant superheater and reheater tubes
- Refinery heater tubes and furnace components
- Boiler and pressure vessel components
- Heat treatment equipment
- Petrochemical cracking furnaces
Industries Served
- Power Generation
- Petrochemical
- Refineries
- Heat Treatment
- Boiler & Pressure Vessels
Key Advantages
- Superior creep strength at elevated temperatures (425-816C)
- Higher carbon ensures better high-temperature rupture properties
- Same base corrosion resistance as 304
- Excellent for prolonged high-temperature service
- ASME approved for pressure vessel and boiler applications
- Cost-effective alternative to stabilized grades (321, 347) for some high-temp uses
Equivalent Grades
- ASTM
- TP304H
- JIS
- SUS 304HTB
- BS
- 304S51
- GOST
- 08Kh18N10