What is the manufacturing process of ASTM A234 WPB pipe fittings?
The process of A234 WPB pipe fittings manufacturing is called “wrought” which means it could be casted or forged. Usually the ASTM A234 WPB elbows , tees, reducers are made from steel pipes,the caps are made from plates. But the large sizes pipe fittings are commonly manufactured in pieces and welded together .
ASTM A234 is standard of the pipe fitting material. However, this is indicating the properties of the material of various kinds of alloy steel and carbon steel. WPB is a steel grade in which W stands for weldable, B is grading B and P stands for pressure. Thus it is referring minimum yield strength.
What is ASTM A234 WPB
ASTM A234 is Standard Specification for steel pipe fittings includes carbon and alloy steel material for moderate and high temperature services. It covers steel fittings of seamless and welded types. Steel Pipe fittings are applied in pressure pipelines and in pressure vessel fabrications. These fittings material consist of killed steel, forgings, bars, plates, seamless or HFW (fusion welded) pipe products, with filler metal added.
ASTM A234 includes wrought carbon steel and alloy steel fittings of seamless and welded construction covered by the latest revision of ASTM B16.9, B16.11, MSS-SP-79, MSS-SP-83, MSS-SP-95, and MSS-SP-97. etc.
As we know, ASTM A234 steel pipe fittings are used in pressure piping and in pressure vessel fabrication, for services at moderate and elevated temperatures. The fittings material in this standard consist of killed steel, forgings, bars, plates, seamless or fusion-welded tubular products with filler metal added.
In this standard it covers the specification of elbows, tees, reducers, caps and cross, it usually adopt butt welding ends.
Grades in ASTM A234
ASTM A234 specification has many grades, such as WPB, WPC, WP5, WP9 WP11, WP12, WP22, WP91 and so on.
In these standard Grade WPB is the most common material used for medium and high temperature pipelines. W means weldable, P means pressure, B is grade b, refer to the minimum yield strength.
The source raw material of ASTM A234 WPB steel pipe fittings may be from steel pipe, such as ASTM A106 Gr.B and C. Also from steel plate, as ASTM A285 Gr.C, ASTM A516 Gr 70, ASTM A572 etc.
ASTM A234 WPB steel pipe fitting chemical and mechanical features
Grade WPB fittings made from the steel pipes or plates maximum C is 0.35%.
Forging fittings Carbon content 0.35% maximum and Silicon content 0.35% maximum, no minimum.
For each reduce of 0.01 of Carbon content, Manganese maximum content increase 0.06%, up to the maximum 1.35% for Mn.
Copper, Nickel, Niobium and Molybdenum sum content shall not exceed 1.00%.
Niobium + Molybdenum shall not exceed 0.32%.