ASTM A213 TP304H 1.4948 UNS S30409 Stainless Steel Seamless Tube Heat Exchanger Tube
ASTM A213 TP304H 1.4948 Stainless Steel Seamless Tube Pickled and An Heat Exchanger Tube
ASTM A213 TP304H stainless steel seamless tube is the workhorse alloy for high-temperature, high-pressure heat exchange applications. Its defining feature is the elevated carbon content ("H"), which is a deliberate formulation to ensure superior creep resistance and tensile strength at elevated temperatures, making it an essential material in the power generation and process industries. It is selected not for its room-temperature properties, but for its reliable performance in extreme thermal environments.
Direct Comparison & Selection Guide for Different Condition of Stainless Steel 304H
| Feature | Bright Annealed (BA) | Pickled & Annealed (P&A) |
|---|---|---|
| Surface | Reflective, shiny, smooth. | Matte, uniform grey-white, etched. |
| Corrosion Resistance | Theoretically superior. Pristine passive layer. | Excellent and fully code-compliant. Slightly more active surface. |
| Cost | Higher premium. | Standard, more economical. |
| Primary Applications | Hygienic/High-Purity: Food, Pharma, Biotech, Semiconductor, Instrumentation, Decorative. | General Industrial: Pressure tubes, heat exchangers, boilers, structural, mechanical, welded fabrications. |
| Ideal for Welding? | Yes, but the clean surface requires careful preparation to avoid contamination. | Yes, the industry standard. Etched surface is very weld-friendly. |
| Scale/Oxide | Never formed. | Chemically removed. |
| Environmental Impact | Clean process (hydrogen can be recycled). | Involves hazardous acid use and disposal. |
Summary: Choose Bright Annealed when you need the best corrosion resistance, a hygienic cleanable surface, or a decorative finish.
Choose Pickled & Annealed for general industrial, high-temperature, and pressure applications where cost-effectiveness and proven weldability are key. For your A213 TP304H tubes, unless otherwise specified, they will almost certainly be supplied in the Pickled & Annealed condition.
| Grade | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
| BS | En | No | Name | ||||
| 304H | S30409 | 304S51 | - | 1.4948 | X6CrNi18-11 | - | - |
ASTM A213 TP304H Stainless Steel Seamless Tube Chemical Composition
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
| 304H | min. | 0.04 | - | - | -0.045 | - | 18.0 | - | 8.0 | - |
| max. | 0.10 | 2.0 | 0.75 | 0.030 | 20.0 | 10.5 | ||||
ASTM A213 TP304H Stainless Steel Seamless Tube Mechanical Properties
| Grade |
Tensile Strength (MPa) min |
Yield Strength 0.2% Proof (MPa) min |
Elongation (% in 50mm) min |
Hardness | |
| Rockwell B (HR B) max | Brinell (HB) max | ||||
| 304H | 515 | 205 | 40 | 92 | 201 |
| 304H also has a requirement for a grain size of ASTM No 7 or coarser. | |||||
ASTM A213 TP304H Stainless Steel Seamless Tube (annealed condition) Physical Properties
Grade |
Density (kg/m3) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion (μm/m/°C) | Thermal Conductivity (W/m.K) | Specific Heat 0-100°C (J/kg.K) | Electrical Resistivity (nΩ.m) | |||
| 0-100°C | 0-315°C | 0-538°C | at 100°C | at 500°C | |||||
| 304/L/H | 8000 | 193 | 17.2 | 17.8 | 18.4 | 16.2 | 21.5 | 500 | 720 |
Application
Its sole purpose is for high-temperature, high-pressure service:
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Superheater & Reheater Tubes in fossil fuel power plants.
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Heat Exchanger Tubes in refining, petrochemical, and chemical processing.
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Boiler Tubes in high-efficiency industrial boilers.
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Steam Lines & Piping for high-temperature steam conveyance.
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