Name: Socket Weld Full Coupling
Brand: Cunimet Alloy International

Socket Weld Full Coupling – Forged SS 304 316 Duplex Super Duplex

Product Overview

Forged SW Full Coupling

The Socket Weld Full Coupling is a two-socket forged fitting used to join two equal-diameter pipe lengths in a straight run with permanent welded joints. Both pipe ends are inserted into the sockets at each end of the coupling and secured with fillet welds. The full coupling provides a compact, fully enclosed connection that is significantly stronger than threaded alternatives for high-pressure service.

Cunimet Alloy International manufactures SW full couplings through a closed-die forging process. The resulting dense, wrought grain structure through the coupling body ensures maximum pressure-bearing capacity and fatigue resistance. Both sockets are precision-bored on CNC turning centres to ASME B16.11 socket diameter and depth tolerances, ensuring correct pipe seating before welding.

ASME B16.11 MSS SP-79 1/8" to 4" NPS 3000# • 6000# Two Equal SW Sockets

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ASME Standard B16.11

2 SW Sockets Equal Bore, Both Ends

1/8–4" Size Range NPS

3000# Pressure Class Also 6000#

3 Material Grades SS / Duplex / S.Duplex

Technical Dimensions

SW Full Coupling — ASME B16.11 Dimensions

“L” = Overall End-to-End length of the coupling. Socket bore and depth are equal at both ends. A 1.6 mm gap must be maintained between pipe ends inside the coupling before welding per ASME B31.3. All dimensions in millimetres.

NPS	Pipe O.D. (mm)	Overall Length “L” (mm)		Socket Bore (mm)	Socket Depth (mm)	Min. Wall Thickness (mm)
NPS	Pipe O.D. (mm)	Class 3000#	Class 6000#	Socket Bore (mm)	Socket Depth (mm)	Min. Wall Thickness (mm)
1/8"	10.3	37	44	10.5	9.5	2.4
1/4"	13.7	41	48	14.0	11.1	2.4
3/8"	17.1	46	54	17.3	12.7	2.8
1/2"	21.3	52	64	21.6	15.9	3.7
3/4"	26.7	59	73	26.9	19.1	4.1
1"	33.4	70	92	33.6	22.2	4.5
1-1/4"	42.2	83	105	42.4	25.4	4.9
1-1/2"	48.3	92	114	48.5	28.6	5.1
2"	60.3	108	130	60.5	31.8	5.5
2-1/2"	73.0	127	159	73.2	38.1	7.0
3"	88.9	146	178	89.1	44.5	7.6
4"	114.3	178	222	114.5	50.8	8.6

Dimensions are nominal per ASME B16.11 latest edition. Subject to applicable manufacturing tolerances. Note: maintain 1.6 mm (1/16") gap between pipe ends before welding per ASME B31.3. All dimensions in millimetres.

Available Materials

Material Grades for SW Full Couplings

Grade 01

Stainless Steel 304 / 316

Austenitic stainless steel offering broad corrosion resistance for water, chemical and process applications. SS 316 is preferred where resistance to chloride pitting and marine environments is required.

ASTM A182 F304 ASTM A182 F316 ASME B16.11

Grade 02

Duplex Steel

Dual-phase austenitic-ferritic alloy with twice the yield strength of standard austenitic grades. Excellent resistance to stress corrosion cracking in chloride environments, offshore and chemical plant service.

ASTM A182 F51 UNS S31803 UNS S32205

Grade 03

Super Duplex Steel

Premium alloy with PREN greater than 40 for aggressive chloride-bearing, subsea and offshore environments where standard duplex grades cannot meet the corrosion resistance requirements.

ASTM A182 F53 UNS S32750 UNS S32760

Quality & Compliance

Standards, Testing & Documentation

Applicable Standards

Standard	Description
ASME B16.11	Forged Fittings, Socket-Welding & Threaded — dimensional standard
ASTM A182	Material specification for forged alloy and stainless steel fittings
ASME B31.3	Process piping code — governs socket weld gap and weld requirements
MSS SP-25	Standard marking system for fittings
MSS SP-55	Visual inspection acceptance criteria for forgings
EN 10204	3.1 MTC as standard; 3.2 with TPI on request

Quality Tests Performed

Test	Method / Scope
Chemical Analysis	OES per ASTM A182 for each heat of material
Mechanical Testing	Tensile, yield, elongation, Charpy impact where specified
Hardness Testing	Brinell or Vickers per ASTM A182 requirements
PMI	100% Positive Material Identification by XRF on request
Dimensional Inspection	100% per ASME B16.11 — socket bore, depth, OD and wall
Visual Inspection	100% per MSS SP-55 acceptance criteria

Applications

Where SW Full Couplings Are Used

01

Pipe-to-Pipe Joining

Connecting two equal-diameter pipe sections in straight runs on process lines, steam systems and hydraulic circuits where a permanent, leak-free joint is required without the use of flanges.

02

Extension of Existing Lines

Adding pipe length to existing piping runs during plant modifications or tie-ins where a compact, welded coupling is preferred over threading or flanging.

03

Valve & Instrument Connections

Connecting instrumentation, inline valves and flow elements into process lines where the full coupling provides a strong, corrosion-resistant body around the connection point.

04

Offshore & Subsea Piping

Permanent pipe joins on offshore topsides, subsea manifolds and seawater handling systems in Duplex and Super Duplex Steel where corrosion resistance and weld integrity are critical.

Socket Weld Fittings Range

Socket Weld Full Coupling