IBR Approved · Carbon Steel
ASTM A234 WPB Buttweld Pipe Fittings
The standard carbon steel grade for buttweld fittings — elbows, tees, reducers and caps to ASME B16.9 / B16.28, 1/2" to 48" NB, SCH 20 to XXS. IBR approved with Form III-C, EN 10204 3.1 / 3.2 traceable.
Grade Overview
ASTM / ASME A234 WPB is the workhorse carbon steel grade for wrought buttweld pipe fittings. It covers seamless and welded fittings for moderate-temperature service in refineries, power plants, boiler auxiliaries and general process and utility piping. Fittings are formed from A106 / A53 seamless or EFW pipe and normalised where required to meet the mechanical and toughness requirements of the specification.
For boiler and steam service under the Indian Boiler Regulations, WPB fittings are supplied IBR approved with Form III-C certification, within the pressure and temperature limits applicable to carbon steel.
Chemical Composition — A234 WPB
| Element | Requirement | Note |
|---|---|---|
| Carbon (C) | ≤ 0.30% | Weldability / strength balance |
| Manganese (Mn) | 0.29 – 1.06% | Strength & deoxidation |
| Silicon (Si) | ≥ 0.10% | Deoxidiser |
| Phosphorus (P) | ≤ 0.050% | Impurity limit |
| Sulphur (S) | ≤ 0.058% | Impurity limit |
| Cr, Cu, Mo, Ni, V | Residual limits | Cr/Cu/Ni ≤0.40, Mo ≤0.15, V ≤0.08 (sum limit applies) |
Mechanical Properties — A234 WPB
| Property | Requirement |
|---|---|
| Tensile Strength | 415 – 585 MPa (60 – 85 ksi) |
| Yield Strength (min) | 240 MPa (35 ksi) |
| Elongation (min) | ≥ 22% (longitudinal, per specification formula) |
| Heat Treatment | As-formed / normalised as required by forming method |
Equivalent Grades
| Product Form | Specification |
|---|---|
| Buttweld fittings | ASTM / ASME A234 WPB |
| Seamless pipe | ASTM A106 Gr. B |
| Forgings / flanges | ASTM A105 |
| Welded / seamless pipe | ASTM A53 Gr. B |
Fitting Types Available in WPB
- Elbows — 45° / 90° / 180°, LR & SR (B16.9 / B16.28)
- Tees — equal & reducing (B16.9)
- Reducers — concentric & eccentric
- Caps — buttweld end closures
- Stub Ends — Type A & B for lap joints
- Laterals & Crosses — branch connections