ASTM A234 Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
Grade: WPB
Chemical Requirements Composition, %
C: 0.30
Mn: 0.29-1.06
P: 0.050
S: 0.058
Si:≥ 0.10
Cr: 0.40
Mo: 0.15
Ni: 0.40
Cu: 0.40
V:0.08
*Fittings made from bar or plate may have 0.35 max carbon.
*Fittings made from forgings may have 0.35 max carbon and 0.35 max silicon with no minimum.
*For each reduction of 0.01 % below the specified carbon maximum, an increase of 0.06 % manganese above the specified maximum will be permitted, up to a maximum of 1.35 %.
*The sum of Copper, Nickel, Chromium, and Molybdenum shall not exceed 1.00 %.
Tensile Requirements
Tensile strength, MPa: 415 − 585
Yield strength, min MPa: 240
| Elongation: | WPB | |
| Longitudinal | Transverse | |
| Standard round specimen, or small proportional specimen, min % in 4 D | 22 | 14 |
| Rectangular specimen for wall thickness 5⁄16 in. [7.94 mm] and over,and for all small sizes tested in full section; min % in 2 in. [50 mm] | 30 | 20 A |
| Rectangular specimen for wall thickness less than 5⁄16 in. [7.94 mm];min % in 2 in. [50 mm] (1⁄2-in. [12.7-mm] wide specimen) | B | B |
A Fittings manufactured from plate shall have a minimum elongation of 17 %.
B For each 1⁄32 in. [0.79 mm] decrease in wall thickness below 5⁄16 in. [7.94 mm], a deduction of 1.5 % for longitudinal and 1.0 % for transverse from the values shown above is permitted. The following table gives the minimum value for various wall thicknesses.
| Wall Thickness | WPB | ||
| in. | [mm] | Longitudinal | Transverse |
| 5⁄16 (0.312) | 7.94 | 30 | 20 |
| 9⁄32 (0.281) | 7.14 | 28.5 | 19 |
| 1⁄4 (0.250) | 6.35 | 27 | 18 |
| 7⁄32 (0.219) | 5.56 | 25.5 | … |
| 3⁄16 (0.188) | 4.76 | 24 | … |
| 5⁄32 (0.156) | 3.97 | 22.5 | … |
| 1⁄8 (0.125) | 3.17 | 21 | … |
| 3⁄32 (0.094) | 2.38 | 19.5 | … |
| 1⁄16 (0.062) | 1.59 | 18 | … |
This table gives the computed minimum % elongation value for each 1⁄32 in. [0.79 mm] decrease in wall thickness. Where the wall thickness lies between two values above, the minimum elongation value is determined by the following equations:
| Direction of Test | Equation |
| Longitudinal | E= 48t + 15.00 |
| Transverse | E= 32t + 10.00 |
where:
E = elongation in 2 in. or [50 mm], %, and
t = actual thickness of specimen, in. [mm].
Hardness: ≤197 HB
