ASTM A312 TP304H / 1.4948 Stainless Steel Seamless Pipe Pickled Annealed Round Pipe
ASTM A312 / ASME SA312 TP304H Stainless Steel Seamless Pipe 1.4948 Steel Pipe
A high-temperature-resistant stainless steel pipe, made without a weld seam, that has been heat-treated to soften it and acid-cleaned to make it clean and corrosion-resistant, specifically designed for long-term service above 550°C (1022°F) where normal stainless steel would creep and fail.
The single biggest reason to choose TP304H is superior creep rupture strength at elevated temperatures (> 550°C / 1022°F), combined with good oxidation resistance and lower cost than stabilized or high-alloy grades.
Equivalent Grade of ASTM A312 TP304H / 1.4948 Stainless Steel Seamless Pipe
| EU/EN | UNS | JIS | AFNOR | GOST | ISO |
| X6CrNi18-10 (1.4948) |
304H S30409 |
SUS304H | Z6CN18-09 | 08KH18N10 | X7CrNi18-9 |
European equivalent grade for Austenitic creep resisting steel 304H ( AISI, ASTM, UNS): X6CrNi18-10 (1.4948)
Chemical composition and properties of european equivalents (EN) for 304H (USA, AISI, ASTM, UNS): X6CrNi18-10 (1.4948)
| Grade | UNS Designation | Composition, % | ||||||
| Carbon | Manganese | Phosphorus, max | Sulfur, max | Silicon | Chromium | Nickel | ||
| 304H | S30409 | 0.04-0.10 | 2.00 | 0.045 | 0.03 | 0.75 | 18-20 | 8-10.5 |
Summary Table – Stainless Steel TP304H vs. Other Stainless Steels
| Grade | Best Application | Why Choose 304H Over It? | Why Choose Other Over TP304H? |
| 304/304L | General purpose, low temperature, wet service | For high T > 550°C: TP304H has far better creep life. | Below 450°C or welded corrosive service: 304L avoids sensitization. |
| 316/316L | Chloride and acid resistance | TP304H is cheaper and has higher creep strength above 550°C. | Need pitting resistance or service below 500°C with chlorides. |
| 321H | High temperature + welded corrosive service | TP304H is 20–30% cheaper, similar oxidation, adequate creep for many boilers. | Your welded assembly will see aqueous corrosion during shutdowns. |
| 347H | Highest creep among austenitics | TP304H is 30–40% cheaper, available off-the-shelf, easier to machine. | You need maximum creep strength and resistance to intergranular corrosion. |
| 310H | Extreme oxidation up to 1150°C | TP304H is far cheaper and sufficient below 925°C. | Operating temperature regularly > 950°C. |
Applications
Because of its high-temperature mechanical strength, you will find TP304H seamless pipe in:
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Power Generation: Superheater and reheater tubes in coal/gas-fired boilers.
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Petrochemical: Furnace tubes, heat exchangers, and high-temperature hydrocarbon service piping.
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Refineries: Catalytic reformers and high-temperature flue gas systems.
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Industrial Heating: Radiant tubes, burner parts, and kilns.
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