Forged Full Coupling Manufacturer, Supplier & Exporter
A forged full coupling is a short, straight fitting that joins two small-bore pipes end to end. Raaj Fittings manufactures and exports full couplings with socket weld or threaded ends at both ends to ASME B16.11, from ⅛" to 4" NPS, in stainless steel, duplex and super duplex, nickel alloys, carbon steel and alloy steel. Reducing couplings, which join two different sizes, are also available.
The full coupling is one of the simplest and most widely used small-bore fittings. It extends a line, repairs a damaged section, or joins pipe lengths in instrument, hydraulic, utility and process piping, where a compact, high-strength in-line joint is needed.
All couplings are supplied with EN 10204 3.1 mill test certificates, with 3.2 certification and third-party inspection on request.
We export forged full couplings to EPC contractors, plant operators and stockists across the Middle East and GCC, Europe and the Americas — with NPT threads for US and Gulf projects or BSP threads where European and Middle Eastern specifications call for them.
Full Coupling Specifications
⅛" NPS to 4" NPS (DN 6 to DN 100)
Socket weld: Class 3000, 6000 and 9000. Threaded: Class 2000, 3000 and 6000
Full coupling and reducing coupling
NPT to ASME B1.20.1; BSPT and BSPP to BS 21 / ISO 7-1
Forged or machined from forged bar, then CNC machined
EN 10204 3.1 mill test certificate as standard; EN 10204 3.2 on request
Materials & Grades
We supply forged full couplings in the following materials and grades. All grades are supplied with EN 10204 3.1 / 3.2 Mill Test Certificates.
Stainless Steel Forged Full Couplings
Stainless steel forged fittings deliver excellent corrosion resistance in chemical, pharmaceutical, food processing, and marine environments. All grades supplied to ASTM A182 specification.
(ASTM A182 F304 / F304L) General corrosion resistance; food processing, dairy, and chemical service
(ASTM A182 F316 / F316L) Superior chloride and acid resistance; pharmaceutical, offshore, and chemical processing
(ASTM A182 F316H) Elevated-temperature creep strength for high-temperature process service
(ASTM A182 F317 / F317L) Higher molybdenum content; superior corrosion resistance in concentrated acid service
(ASTM A182 F321) Titanium-stabilised; resists sensitisation at sustained elevated temperatures
(ASTM A182 F347) Columbium-stabilised; used in heat exchangers and high-temperature piping
Duplex & Super Duplex Stainless Steel Forged Full Couplings
Delivering approximately twice the yield strength of austenitic stainless steel with excellent resistance to stress corrosion cracking, pitting, and erosion — ideal for offshore, subsea, and chemical processing environments.
(UNS S31803 / S32205, ASTM A182 F51) Offshore topsides, chemical plant, and seawater cooling systems
(UNS S32750, ASTM A182 F53) Subsea equipment, desalination, and high-chloride offshore service
(UNS S32760, ASTM A182 F55) High-temperature, high-chloride offshore and subsea service applications
Nickel Alloy Forged Full Couplings
For the most severe corrosive, high-temperature, and sour service environments where standard stainless steel grades are insufficient.
(UNS N06600) High-temperature oxidation and carburisation resistance
(UNS N06625) Outstanding corrosion resistance; offshore, chemical, and subsea service
(UNS N08825) Resistance to phosphoric and sulfuric acids; FGD and chemical plant
(UNS N10276) Universal corrosion resistance across the widest range of aggressive media
(UNS N06022) Superior resistance to oxidising and reducing acids and pitting attack
(UNS N04400) Seawater, hydrofluoric acid, and marine and alkali service
(UNS N08020) Engineered for sulfuric acid and aggressive chemical process service
Exceptional corrosion resistance in seawater and oxidising media at low density
Carbon Steel Forged Full Couplings
Carbon steel is the standard material for forged fittings in general-purpose, hydrocarbon, steam, and elevated-temperature service. The primary grade for forged carbon steel fittings is ASTM A105.
Primary grade for forged carbon steel fittings and flanges — covers ambient and elevated-temperature service in pressurised piping systems.
Low-temperature carbon steel, impact-tested for service down to -46°C (-50°F) — LNG, cold climate, and cryogenic piping applications.
Low-temperature carbon steel, impact-tested to -101°C (-150°F) — for the most demanding cold-temperature service applications.
Alloy Steel Forged Full Couplings
Chromium-molybdenum alloy steel grades for high-temperature, high-pressure service in power generation, petrochemical, and refinery applications. All grades supplied to ASTM A182 specification.
(5% Cr · ½% Mo) Refinery hydroprocessing and high-temperature service
(9% Cr · 1% Mo) High-temperature steam and hydrogen-rich process service
(1¼% Cr · ½% Mo) Thermal power plant steam, feedwater, and reheat piping
(2¼% Cr · 1% Mo) Reactors and high-temperature pressure piping in petrochemical plants
(9% Cr · 1% Mo · V · Nb) Ultra-supercritical power plant main steam and hot reheat piping
Socket Weld and Threaded Couplings
A socket weld coupling has a socket at each end, separated by a central shoulder that stops the pipe at the correct depth. Each pipe is inserted, withdrawn about 1.6 mm (1/16") from the shoulder to leave an expansion gap, and fillet-welded. A threaded coupling has a female thread running from each end and joins two pipes with male threads.
- In-line joint — joins two pipes of the same size on one axis.
- Reducing coupling — joins two different sizes in one fitting.
- Compact — the shortest way to join small-bore pipe.
- High pressure — up to Class 9000 in socket weld.
Full, Half and Union
A full coupling has connections at both ends. A half coupling has a connection at one end only and is welded to a pipe or vessel to form a branch. Where the joint must be opened again without turning the pipe, a forged union is used instead. Threaded couplings are often combined with pipe nipples to build short threaded assemblies.
Choosing the Class
Match the coupling class to the pipe schedule: socket weld 3000 with SCH 80, 6000 with SCH 160, 9000 with XXS; threaded 2000 with SCH 80, 3000 with SCH 160, 6000 with XXS. For threaded joints, specify NPT or BSP, as the two thread forms are not interchangeable.
Applications & Industries
- Small-bore process and utility piping in refineries and chemical plants
- Instrument and impulse line connections
- Hydraulic, lube oil and seal oil systems
- Fire water and compressed air lines (threaded)
- Repairs and extensions of existing small-bore lines
- Offshore small-bore piping in duplex and super duplex
When ordering, give the size (or both sizes for a reducing coupling), class, end type, thread form and material grade — for example 1" Class 6000 socket weld coupling, ASTM A182 F316L. Couplings for repairs to existing lines can be matched to the original pipe schedule and material.
See the complete range of forged fittings.
Testing, Inspection, Marking & Packing
Forged couplings are produced under our quality assurance process:
- Incoming material verification with PMI testing
- Chemical and mechanical testing to ASTM A105, A350, A182 or the applicable nickel alloy specification
- Heat treatment as required, with pickling and passivation for stainless steels
- Dimensional inspection of length, socket bores and depths, and thread gauging
- Marking with manufacturer’s mark, grade, size, class and heat number
Supplied with EN 10204 3.1 mill test certificates; EN 10204 3.2 certificates and third-party inspection are available on request.
Fittings are packed for export with plastic caps protecting threads and sockets, rust-preventive or VCI wrapping on carbon and alloy steel, and seaworthy wooden cases; marking, tagging and packing to your specification are available on request.
Why Choose Raaj Fittings for Forged Full Couplings?
Raaj Sagar Steels has supplied piping components since 2003 and today manufactures forged fittings at two plants in India for buyers in the Middle East, Europe and the Americas.
- Manufactured in-house — Forged full couplings are made in our own plants, so material, dimensions and delivery stay under our control.
- Ready stock, short lead times — common sizes and grades are held in stock for prompt dispatch; other sizes, grades and specials are manufactured to order.
- Certified quality — ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certified; PED 2014/68/EU and IBR supply available, and NACE MR0175 / ISO 15156 material on request.
- 100% material verification — PMI testing on incoming material and EN 10204 3.1 mill test certificates with every order; 3.2 certificates on request.
- Third-party inspection ready — we regularly work with SGS, Bureau Veritas, TÜV and DNV.
- Export documentation — MTCs, certificates of origin, packing lists and inspection reports to suit projects in the GCC, Europe and the Americas.
- Export packing — seaworthy packing with end and face protection, and packing to your specification on request.
- Fast response — our team replies to enquiries within one business day.
Forged Full Couplings — FAQs
A full coupling is a short straight fitting with a socket or female thread at each end, used to join two small-bore pipes end to end.
A full coupling has connections at both ends and joins two pipes. A half coupling has a connection at one end only and is welded onto a pipe or vessel to create a branch.
A reducing coupling joins two pipes of different sizes, with a larger socket or thread at one end and a smaller one at the other.
Each pipe is withdrawn about 1.6 mm (1/16") from the central shoulder before welding, so it can expand as the weld cools without cracking it.
From ⅛" to 4" NPS; socket weld in Class 3000, 6000 and 9000, threaded in Class 2000, 3000 and 6000.
Yes. We supply forged full couplings for projects under the European Pressure Equipment Directive (PED 2014/68/EU), and with IBR certification for Indian boiler applications. NACE MR0175 / ISO 15156 compliant material is also available on request for sour service in the Middle East and the Americas.
