ASTM A234 is the standard specification for pipe fittings of wrought carbon steel and alloy steel for moderate and high-temperature service. Carbon steel pipe fittings manufactured to ASMT A234 are usually furnished in butt-welding form in accordance with ASME B16.9 or ASME B16.49. There are two carbon steel grades: WPB and WPC, of which ASTM A234 WPB is mostly often used in pipeline industry. The A234 WPB butt-welding pipe fittings include elbows, bends, returns, tees, reducers, end caps, crosses, lap joint stub ends, nipples and couplings.
After forming at an elevated temperature, fittings are cooled to a temperature below the critical range under suitable conditions to prevent injurious defects caused by too rapid cooling, but in no case more rapidly than the cooling rate in still air. Heat treatment temperatures specified are metal (part) temperatures. Heat-treated fittings are to be treated according to paragraph 7 in Specification A960/A960M.