ASME SA403 / ASTM A403 WP304H End Cap ASME B16.9 Stainless Steel Buttweld Pipe Fittings
ASTM A403 WP304H End Cap ANSI/ASME B16.9 Stainless Steel Buttweld Pipe Fitting
YUHONG GROUP is a specialized manufacturer of stainless steel buttweld pipe fittings, and our ASME SA403 / ASTM A403 WP304H End Cap (manufactured in compliance with ASME B16.9) is one of our most demanded products. WP304H is a high‑carbon version of 304 stainless steel (C content 0.04–0.10%), offering superior creep strength and oxidation resistance at elevated temperatures – ideal for sealing pipe ends in high‑temperature service (e.g., superheater headers, boiler manifolds, petrochemical reactors).
Our end caps and full range of buttweld fittings (elbows, tees, reducers, caps) are produced from premium seamless or welded pipe, then solution annealed, pickled, and 100% inspected.
Equivalent Grades of ASTM A403 WP304H End Cap ASME B16.9 Stainless Steel Buttweld Pipe Fittings
| EN | SS/ UNS | JIS | AFNOR | GOST | ISO |
| X6CrNi18-10 (1.4948) | 304H/ UNS S30409 | SUS304H | Z6CN18-09 | 08KH18N10 | X7CrNi18-9 |
Chemical Compositions% of ASTM A403 WP304H End Cap ASME B16.9 Stainless Steel Buttweld Pipe Fittings
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N |
| SS 304H | 0.10 max | 2.0 max | 0.75 max | 0.045 max | 0.03 max | 18 – 20 | - | 8 – 10.5 | - |
Mechanical Properties of ASTM A403 WP304H End Cap ASME B16.9 Stainless Steel Buttweld Pipe Fittings
| Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 8.0 g/cm3 | 1400 °C (2550 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 40% |
Why WP304H for End Caps?
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High‑temperature strength – retains good creep rupture strength up to ~800°C. Used in superheater outlet headers, reheater piping, furnace coils.
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Oxidation resistance – forms stable Cr₂O₃ scale.
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Not susceptible to embrittlement – austenitic structure remains tough.
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Carbon content (0.04–0.10%) – improves creep strength compared to standard 304, but may lead to sensitization if welded improperly. Therefore, welding must use low heat input and filler metal like AWS E/ER308H.
Applications
- Oil & gas (refineries, petrochemical)
- Chemical processing
- Food / pharmaceutical
- Onshore & offshore
- Pig launcher / receiver barrels
- Manifolds & headers
- Corrosion / erosion protection
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