BUTTWELD FITTINGS IN PIPING

Buttweld fittings are pipe fittings used to change the pathway of a pipeline (elbows), reduce/increase the pipe bore size (reducers), branch (tees, cross) or blind a pipeline (butt weld cap). ASME B16.9 (and MSS-SP 43) Buttweld fittings are used for piping systems above 2 inches in diameter, whereas socket weld and threaded fittings are used for smaller size pipes (ASME B16.11).

Buttweld fittings are available in multiple shapes (elbows, tees, reducers, crosses, caps, stub ends), material grades (carbon, high-yield carbon, low-alloy, stainless, duplex, and nickel alloys), and dimensions (2 to 24 inches in seamless execution, and welded for larger pipe sizes).

The key specifications for buttweld fittings are the ASME B16.9 (carbon and alloy fittings) and the MSS SP 43 (that integrates ASME B16.9 for stainless steel, duplex, and nickel alloy BW fittings).

Buttweld fittings have the following benefits

allow strong, and leak-proof, piping connections

minimize pressure drops and the turbulence inside the pipeline

have a long service life

are rather cheap to purchase and deploy

Types of pipe fittings: elbow, tee, reducer, cap, cross

For piping systems below 2 inches in diameter, socket weld and threaded (forged) fittings are generally used (ASME B16.11).