Figure 602 Hammer Union — Butt Weld Ends, Sour Gas Service, 6,000 psi

The Figure 602 is the 6,000 psi union for line connections, manifolds, mud and service systems, available with threaded and butt weld ends.

Applications

Line connections, manifolds, mud and service systems at 6,000 psi.

Construction and sealing

• Resilient nitrile seal ring that assists the seal and protects the steel-to-steel seating of the union.
• Available with threaded and butt weld ends.
• Available in different materials to suit well testing company specifications.
• Sealing: Nitrile seal ring over steel-to-steel seating.

Working pressure

6,000 psi (414 bar) cold working pressure, tested at 9,000 psi.

Sour gas service unions are supplied in H2S trim and are rated below the standard service union of the same figure number wherever the source publishes a separate H2S rating. Confirm the service class, the trim and the certification you need on your enquiry - we quote against the line specification.

Butt weld types

Three butt weld Figure 602 unions are built, for different applications:

• Standard — Fully rated union for welding to pipe sections up to Sch XXS, in sour gas or standard service trim.
• 602-LC (A350 LF2) — Low-carbon type for welding to ASTM A106 Grade B or ASTM A333 Grade 6 tubulars of Sch 80 section. Chosen by well test companies as a low-cost, readily available union for pipework that does not have to work above the pressures set out in API RP 14E, which in turn follows the allowable stress values in ANSI/ASME B31.3. Made in 2 in and 3 in only.
• 602-18 — Made from low-carbon steel forgings that hold their ductility at high strength, so they stay readily weldable. Available in 2 in, 3 in and 4 in with pipe sections up to and including Sch XXS. Depending on the wall section and the pipe used, this union can be fully rated at 6,000 psi cold working pressure.

How a hammer union makes up

A hammer union is a three-piece connection. A male sub and a female sub carry the two line ends, and a wing nut turns on a thread cut into the male sub and pulls a shoulder on the female sub down onto the seat. The lugs standing proud of the nut are struck with a hammer to tighten it, which is where the name comes from — the joint is made up and broken out with a sledgehammer rather than a wrench, so a line can be rigged and stripped quickly in the field. The seal is made by the seat, not by the thread: the nut only supplies the load that holds the two seating faces together. That is why a union will leak from a scored seat or a perished seal long before the thread is at fault, and why a worn union is usually a sub or a seal replacement rather than a scrap part.

Specifying one

Four things fix a hammer union: the figure number, which sets the pressure class and decides what it will mate with; the service class, standard or sour gas; the end connection, threaded or butt weld; and the nominal size. Figure numbers are an industry series, so a union of the same figure and size from another maker will mate — but the pressure rating stamped on the union is what governs, not the figure number on its own. Send us the line specification and we will confirm the match before quoting.

Sizes and part numbers

Published in 1" to 4" with butt weld ends in Sch 80 and Sch XXS. Every orderable size, its weight, its dimensions and its working pressure are in the size table on this page. Where dimensions and weight are critical, ask us to confirm them against the build before you order.