OEM manufacturer ASME B16.11 · ASME B1.20.1
Threaded Full & Half Couplings — ASME B16.11
A threaded coupling joins two threaded pipes in line; a threaded half coupling is welded onto a pipe or vessel to give a threaded tapping. Teshi Group manufactures threaded full and half couplings to ASME B16.11 in Class 3000 and 6000, with NPT threads to ASME B1.20.1.
Also called: screwed coupling, NPT coupling, full coupling threaded, half coupling threaded
What is a Threaded Coupling?
A full coupling is a short forged sleeve threaded internally from both ends; two male-threaded pipes screw in from either side. A half coupling is threaded at one end only and the other end is welded to a pipe, tank or vessel to create a threaded connection for a gauge, thermowell, drain or vent. Both are among the most used small-bore fittings in plant piping and equipment fabrication.
Key features
- Full and half couplings per ASME B16.11
- Class 3000 and 6000
- NPT threads per ASME B1.20.1, gauged
- Half couplings for threaded tappings on pipes and vessels
Specification
| Supply | OEM manufacturer — Teshi Group, India, India |
|---|---|
| Standard | ASME B16.11 |
| Types | Full coupling, half coupling |
| Pressure class | Class 3000 and 6000; Class 3000 → Sch 160, Class 6000 → XXS pipe |
| Size range | NPS ⅛"–4" (DN 6–100) per ASME B16.11 |
| Threads | NPT per ASME B1.20.1; BSPT (ISO 7-1) on request |
| Materials — carbon & low-temp steel | ASTM A105; ASTM A350 LF2 Cl.1 |
| Materials — alloy steel | ASTM A182 F11 Cl.2, F22 Cl.3, F5, F9, F91 |
| Materials — stainless & duplex | ASTM A182 F304, F304L, F316, F316L, F321; F51, F53 duplex |
| Testing | Visual, dimensional and thread/socket gauge inspection; PMI on alloy and stainless grades; hardness check; MPI/DPT when specified |
| Documents | EN 10204 3.1 mill test certificate; 3.2 / third-party inspection when the order specifies; dimensional inspection report; IBR certification for boiler/steam service when specified |
Applications
- Joining threaded pipe lengths
- Gauge, thermowell and instrument tappings
- Tank and vessel drains and vents
- Utility and instrument air piping
Full coupling vs half coupling
A full coupling is threaded from both ends and joins two threaded pipes in line. A half coupling is threaded at one end and welded to a pipe or vessel at the other, giving a threaded tapping for a gauge, drain or vent. For branches on pressure piping where reinforcement must be shown, a threadolet to MSS SP-97 is often specified instead of a half coupling.
FAQ
Threaded Coupling: common questions
What is the difference between a coupling and a union?
A coupling joins two pipes but cannot be opened without unscrewing the pipe. A union has a nut that lets the joint be opened without rotating the pipe.
Are threaded couplings available in Class 2000?
Threaded couplings and half couplings are supplied in Class 3000 and 6000 to ASME B16.11. Check your piping specification for the class required for your pipe schedule.
Can you supply couplings with BSPT threads?
Yes. NPT threads to ASME B1.20.1 are standard. BSPT threads to ISO 7-1 can be supplied on request; please state the thread standard clearly in your enquiry.
How should threaded joints be sealed?
Use a thread sealant or PTFE tape suited to the service on NPT threads and tighten to normal make-up. For hazardous, cyclic or high-temperature service, many piping specifications require threaded joints to be seal welded.
Need a size or grade not listed here?
Our engineering team manufactures against your drawing or datasheet, with dimensional sign-off before dispatch.
Send us your specificationTraceability
From mill heat to your site
- 01
Approved mill material
Received against the mill certificate; heat number registered.
- 02
Forging & machining
Heat number carried through every stage in our Indian works.
- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
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