ASTM A234 WP11 / WP22
A234 WP11 / WP22: Specifications | Grades & Standards | Product Types | Equivalent Grades | Chemical Composition | Mechanical Properties | BW Fittings
ASTM A234 WP11 / WP22 Alloy Steel Fittings – Comprehensive range of WP11 and WP22 buttweld elbows, tees, reducers, caps, crosses, stub ends, and pipe bends. Engineered for high-pressure, high-temperature Cr-Mo piping systems in power plants, chemical plants, and refineries.
Best Export Prices: sales@midlandforgefittings.com
Midland Forge and Fittings Pvt. Ltd. is a premier manufacturer and global supplier of SA234 WP11 and WP22 buttweld fittings. With a strong emphasis on quality and precision, our company specializes in producing high-performance elbows, tees, reducers, caps, crosses, stub ends, and pipe bends tailored for high-temperature and high-pressure Cr-Mo applications. Backed by state-of-the-art forging facilities and stringent quality control processes, the company ensures that every fitting meets international standards and client specifications.
Serving critical sectors such as power generation, refineries, petrochemicals, and industrial boilers, we combine technical expertise with reliable delivery, making it a trusted partner for complex piping solutions worldwide.
ASTM A234 WP11 and WP22 are high-strength chromium-molybdenum alloy steel grades specified for the fabrication of buttweld fittings such as elbows, tees, reducers, caps, crosses, stub ends, and bends. WP11 is a Cr-Mo alloy steel suitable for moderate to high-temperature applications, while WP22 has a higher chromium content, providing enhanced creep and oxidation resistance for elevated temperature services. Both grades conform to stringent chemical composition limits to ensure toughness, weldability, and dimensional stability under high-pressure and high-temperature conditions.
Mechanically, WP11 and WP22 fittings offer excellent tensile strength, yield strength, and elongation, making them ideal for use in power plants, refineries, petrochemical plants, and industrial boilers. The materials support various welding processes, including SMAW, GMAW, and GTAW, and are often supplied in seamless or welded configurations to meet ASME B16.9 and ASME B31.1 piping system requirements.
ASTM A234 WP11 Buttweld Fittings Specifications
Alloy Steel A234 WP22 Fittings– Grades & Standards
| Grade | ASTM Standard | Material Type | Application / Notes |
|---|---|---|---|
| WP11 | ASTM A234 | Cr-Mo Alloy Steel Buttweld Fitting | Moderate to high-temperature service, power plant piping, petrochemical and refinery lines |
| WP22 | ASTM A234 | Cr-Mo Alloy Steel Buttweld Fitting | High-temperature and high-pressure service, boiler, superheater, and industrial process piping |
ASTM A234 Alloy Steel Fittings : WP11, WP22
Cr-Mo Alloy Steel WP11 Seamless & Welded Fittings - Equivalent Grades
| Standard | WP11 Equivalent | WP22 Equivalent |
|---|---|---|
| ASME / ASTM | WP11 | WP22 |
| EN / DIN | 13CrMo4-5 | 15CrMo4-5 |
| JIS | SCM 2 | SCM 4 |
| GOST / Russian | 12KhM | 15KhM |
| UNS | K11511 | K11522 |
| BS | 8112-11 | 8112-22 |
ASME SA234 WP22 Pipe Fittings - Chemical Composition
| Element | WP11 | WP22 |
|---|---|---|
| Carbon (C) | 0.05 – 0.15 | 0.05 – 0.15 |
| Manganese (Mn) | 0.30 – 0.60 | 0.30 – 0.60 |
| Phosphorus (P) | ≤ 0.035 | ≤ 0.035 |
| Sulfur (S) | ≤ 0.035 | ≤ 0.035 |
| Silicon (Si) | 0.10 – 0.35 | 0.10 – 0.35 |
| Chromium (Cr) | 0.90 – 1.20 | 1.90 – 2.30 |
| Molybdenum (Mo) | 0.45 – 0.60 | 0.90 – 1.05 |
| Nickel (Ni) | ≤ 0.30 | ≤ 0.30 |
| Copper (Cu) | ≤ 0.30 | ≤ 0.30 |
AS A234 WP11 Elbow Fittings - Mechanical Properties
| Property | WP11 | WP22 |
|---|---|---|
| Tensile Strength (MPa / N/mm²) | 415 – 550 | 415 – 550 |
| Yield Strength (MPa / N/mm²) | ≥ 205 | ≥ 205 |
| Elongation (%) | ≥ 20 | ≥ 20 |
| Impact Test (Charpy V-Notch, J at -29°C) | ≥ 27 | ≥ 27 |
| Hardness (HB) | 137 – 187 | 137 – 187 |
| Maximum Operating Temperature | ~540°C | ~560°C |
Cr-Mo A234 WP11 / WP22 Buttweld Fittings – Available in Seamless and Welded
How do WP11 and WP22 differ?
Chromium & Molybdenum Content: WP22 has nearly double the Cr and Mo compared to WP11.
Temperature Resistance: WP22 is more suitable for higher-temperature applications (~560°C vs. 540°C for WP11).
Creep Resistance: WP22 provides better long-term strength under sustained high temperature and pressure.
Application Preference: WP11 for moderate high-temperature services, WP22 for more severe service conditions like high-pressure steam lines in power plants.
Are WP11 and WP22 weldable?
Yes, both WP11 and WP22 have excellent weldability due to controlled carbon content and alloying elements.
Suitable welding methods include:
SMAW (Shielded Metal Arc Welding)
GMAW (Gas Metal Arc Welding)
GTAW (Gas Tungsten Arc Welding)
Preheating is recommended in high-temperature applications to avoid cracking during welding.
Why choose WP11 and WP22 for high-pressure piping?
High-Temperature Strength: Maintains mechanical integrity under extreme temperatures.
Corrosion Resistance: Cr-Mo alloying resists oxidation and scaling at elevated temperatures.
Long Service Life: High creep strength ensures long-term reliability in critical piping systems.
Weldability & Fabrication: Easily fabricated into complex buttweld fittings without compromising strength.
International Standard Compliance: Compatible with ASME, ASTM, EN, DIN, and JIS standards.