ASTM A234 WPB Standard Specification

ASTM A234 WPB is the Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service.

Pipe bend

A bend is typically of the same material and typically a more gentle bend to prevent kinking.

ASTM A234 Scope

1.1 This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction covered by the latest revision of ASME B16.9, B16.11, MSS-SP-79, MSS-SP-83, and MSS-SP-95. These fittings are for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures. Fittings differing from these ASME and MSS Standards shall be furnished in accordance with Supplementary Requirement S58 of Specification A 960/A 960M.
1.2 Optional supplementary requirements are provided for fittings where a greater degree of examination is desired. When desired, one or more of these supplementary requirements may be specified in the order.
1.3 This specification does not cover cast welding fittings or fittings machined from castings. Cast steel welding fittings are governed by Specifications A 216/A 216M and A 217/A 217M.
1.4 This specification is expressed in both inch-pound units and in SI units. However, unless the order specifies the applicable “M” specification designation (SI units), the material shall be furnished to inch-pound units.
1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.

Chemical Composition (%) of ASTM A234

Grade C Mn P S Si
WPB 0.3 0.29-1.06 0.05 0.058 0.1min
WPC 0.35 0.29-1.06 0.05 0.058 0.1min
WP11 CL1 0.05-0.15 0.30-0.60 0.03 0.03 0.50-1.00
WP11 CL2/3 0.05-0.20 0.30-0.80 0.04 0.04 0.50-1.00
Grade Cr Mo Ni Cu V Nb
WPB 0.4 0.15 0.4 0.4 0.08 0.02
WPC 0.4 0.15 0.4 0.4 0.08 0.02
WP11 CL1 1.00-1.50 0.44-0.65 - - - -
WP11 CL2/3 1.00-1.50 0.44-0.65 - - - -

GENERAL NOTE:
All values are maximum unless otherwise indicated.

NOTES:

  1. For each reduction of 0.01% below the specified C maximum, an increase of 0.06% Mn above the specified maximum will be permitted, up to a maximum of 1.35%.
  2. The sum of Cu, Ni, Cr, and Mo shall not exceed 1.00%.
  3. The sum of Cr and Mo shall not exceed 0.32%.
  4. The maximum carbon equivalent (C.E.) shall be 0.50, based on heat analysis and the formula C.E.=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15.

Mechanical properties of ASTM A234

Tensile Requirements WPB WPC, WP11CL2 WP11CL1  WP11CL3
Tensile Strength, min, ksi[MPa] 60-85 70-95 60-85  75-100
(0.2% offset or 0.5% extension-under-load) [415-585] [485-655] [415-585]  [520-690]
Yield Strength, min, ksi[MPa] 32 40 30 45
[240] [275] [205] [310]

Where the wall thickness lies between two values above, the min elongation value is determined by the following equations:

Longitudinal E=48t+15.00
Transverse E=32t+10.00
E = elongation in 2in [50mm], %
t = actual thickness of specimen, in [mm]

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