How to choose between buttweld and forged fittings

Almost every plant piping job comes down to the same early question: do you specify buttweld fittings or forged fittings? The answer depends on pipe size, operating pressure, the fluid and how the joint will be made on site.

What each fitting type is

Buttweld fittings are cut from seamless or welded pipe or plate and finished with a bevelled end so they weld directly to the pipe. They give a smooth bore and a continuous profile, which keeps pressure drop low.

Forged fittings are shaped from a solid billet under pressure. The thick walls and compact bodies make them the usual choice for small bore piping, up to NPS 4, where socket weld or threaded joints are practical.

Where each one fits best

• Large bore process and utility piping: buttweld fittings
• Small bore, high pressure and instrument lines: forged fittings
• Lines that need frequent dismantling: threaded forged fittings

A quick comparison

How to specify the order

Material and grade

Choose the grade for the service: carbon steel such as ASTM A234 WPB for general duty, stainless steel such as A403 WP304 or WP316 for corrosive fluids, and alloy steel for high temperature lines.

Size, schedule and quantity

List nominal size, wall thickness or schedule, fitting type and quantity for every line item. A complete list lets us quote faster and avoids a second round of clarification.