ASTM A234 WPB is the most prevalent carbon steel grade for ASME B16.9 pipe fittings. Hot-formed WPB fittings upon which the final forming operation is completed at a temperature above 1150°F [620°C] and below 1800°F [980°C] need not be heat treated provided they are cooled in still air. Hot-formed WPB fittings finished at temperature in excess of 1800°F [980°C] shall subsequently be annealed, normalized, or normalized and tempered. Cold-formed WPB fittings, upon which the final forming operation is completed at a temperature below 1150°F [620°C], shall be normalized, or shall be stress relieved at 1100 to 1275 °F [595 to 690 °C]. The WPB fittings produced by fusion welding and having a nominal wall thickness at the welded joint of 3/4″ [19 mm] or greater shall be post-weld heat treated at 1100 to 1250 °F [595 to 675 °C].

Chemical Composition (%) of ASTM A234 WPB

Notes:

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%.

The sum of Cu, Ni, Cr, and Mo shall not exceed 1.00%.

The sum of Cr and Mo shall not exceed 0.32%.

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 WPB