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API 5CT Coupling - Threaded Steel Pipe Connector for Casing and Tubing Oilfield Connections

API 5CT Casing Coupling - heavy-wall threaded connector for casing string connection

API 5CT Tubing Coupling - precision-machined connector for production tubing string

Line Pipe Coupling - threaded connector for API 5L pipeline and water/gas transmission

API 5CT coupling with heat treatment and phosphate coating - anti-galling surface finish for smooth make-up

Coupling

Keywords: Full Coupling, Half Coupling, Reducing Coupling, Tubing Coupling
Size: Tubing Coupling: 33.35mm * 80.96mm ~ 141.30mm * 158.75mm Casing Coupling: 127mm * 158.75mm ~ 553.4mm * 269.88mm
Standard & Grade: API 5CT / 5B; J 55, K 55, N 80-1, N80 Q, C 90, C 95, T 95, P 110, Q 125
Thread: NUE, EUE, VAM, STC, LTC, BTC, Special Clearance, XC, VAM TOP, NEW VAM
Packing: Protection Caps at Both Ends, Waterproof Paper Wrapped, Two Tags
Usage: Used for Connecting Two Joints of Oil Tubing / Casing
Connection Types: Socket Weld, Threaded Coupling(NPT & BSP)
Pressure Ratings: 3000#, 6000#, 9000#


Availability:



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Description of Coupling

Couplings are short lengths of pipe used to connect 2 joints of tubing or casing. They come with painted color codes on their external surface to indicate their grades. Standard: API Spec 5CT and 5B Tread types: NUE, EUE, VAM, STC, LTC, BTC, special clearance, XC, VAM TOP, NEW VAM.

Oil and Gas Couplings are short lengths of pipe used to connect 2 joints of tubing or casing. They come with painted color codes on their external surface to indicate their grades.

Oil casing couplings and oil tubing couplings have different thread types.

Standards and Technical Conditions for Supply: API Spec 5CT and 5B

Size: 1.9"---20”

Grade: J55,K55,N80-1,N80Q,L80-1,C90,C95,T95,P110,Q125

Thread types of couplings: NUE, EUE, VAM, STC, LTC, BTC, special clearance, XC, VAM TOP, NEW VAM.

Packing: by carton, wooden case, wooden pallet, or customized

Stainless Steel Coupling: ASTM / ASME SA A182 F304, 304H, 309, 310, 316, 316L, 317L, 321, 347, 904

Carbon Steel Coupling: ASTM/ ASME A 105, ASTM/ ASME A 350 LF 2

Alloy Steel Coupling: ASTM / ASME A182 F1/ F5/ F9/ F11/ F22/ F91

Nickel Alloy Coupling: ASTM / ASME SB 336 UNS 2200 (NICKEL 200) , UNS 2201 (NICKEL 201 ) , UNS 4400 (MONEL 400 ) , UNS 8020 ( ALLOY 20 / 20 CB 3 ) , UNS 8825 INCONEL (825) , UNS 6600 (INCONEL 600 ) , UNS 6601 (INCONEL 601) , UNS 6625 (INCONEL 625) , UNS 10276 (HASTELLOY C 276)

Duplex Steel Coupling: ASTM A 182 – F 51, F53, F55 S 31803, S 32205, S 32550, S 32750, S 32760

Steel Pipe Coupling are used to connect two pipes or tubes together by screwed ( threaded) or socket welding. It comes in many shapes and sizes.

Threaded Reducing Couplings

Full Threaded Couplings

Half Threaded Couplings

Coupling Pipe Grade Identification By Paint Color

Coupling colour code
Grade	Grade Type	Colour(s) for Coupling		Number andcolour of bandsfor product	Picture
Grade	Grade Type	EntireCoupling	Band(s)	Number andcolour of bandsfor product	Picture
H40		None	Same as for pipe	None/black band at the manufacturer’s option
J55 Tubing		Bright Green	None	One Bright Green
J55 Casing		Bright Green	One White	One Bright Green
K55		Bright Green	None	Two Bright Green
M65		M65Pipe uses L80Type 1Couplings		One Bright GreenOne Blue
N80	1	Red	None	One Red
N80	Q	Red	One Green	One RedOne Bright Green
R95		Brown	None	One Brown
L80	1	Red	One Brown	One RedOne Brown
L80	9Cr	None	Two Yellow	One Red,One Brown,Two Yellow
L80	13Cr	None	One Yellow	One Red,One Brown,One Yellow
C90	1	Purple	None	One Purple
T95	1	Silver	None	One Silver
C110		White	Two Brown	One White,Two Brown
P110		White	None	One White
Q125		Orange	None	One Orange

Specification of Coupling

Size and Specifications for Tubing and Casing Couplings for oil and gas
Descriptions and size		Type of Therad	O.D*L	Weight	Descriptions and size		Type of Therad	O.D*L	Weight
			(mm)	(kg)				(mm)	(kg)
Casing Coupling	4-1/2″	STC	127.00*158.75	5.23	Tubing Coupling	1.05	NUE	33.35*80.96	0.23
	4-1/2″	LTC	127.00*177.80	4.15		1.05	EUE	42.16*82.55	0.38
	4-1/2″	BTC	127.00*225.42	4.55		1.315	NUE	42.16*82.55	0.38
	5″	STC	141.30*165.10	4.66		1.315	EUE	48.26*88.90	0.57
	5″	LTC	141.30*196.85	5.75		1.66	NUE	52.17*88.90	0.59
	5″	BTC	141.30*231.78	5.85		1.66	EUE	58.88*95.25	0.68
	5-1/2″	STC	153.67*171.45	5.23		1.9	NUE	55.88*95.25	0.56
	5-1/2″	LTC	153.67*203.20	6.42		1.9	EUE	63.50*98.42	0.84
	5-1/2″	BTC	153.67*234.95	6.36		2-3/8″	NUE	73.02*107.95	1.28
	6-5/8″	STC	187.71*184.15	9.12		2-3/8″	EUE	77.80*132.82	1.55
	6-5/8″	LTC	187.71*222.25	11.34		2-7/8″	NUE	88.90*130.18	2.34
	6-5/8″	BTC	187.71*244.48	11.01		2-7/8″	EUE	93.17*133.35	2.4
	7″	STC	194.46*184.15	8.39		3-1/2″	NUE	107.95*142.88	3.71
	7″	LTC	194.46*228.60	10.83		3-1/2″	EUE	114.30*146.05	4.1
	7″	BTC	194.46*254.00	10.54		4″	NUE	120.65*146.05	4.35
	7-5/8″	STC	215.90*190.50	12.3		4″	EUE	127.00*152.40	4.82
	7-5/8″	LTC	215.90*234.95	15.63		4-1/2″	NUE	132.08*155.58	4.89
	7-5/8″	BTC	215.90*263.52	15.82		4-1/2″	EUE	141.30*158.75	6.05
	8-5/8″	STC	244.48*196.85	16.23
	8-5/8″	LTC	244.48*254.00	21.67
	8-5/8″	BTC	244.48*269.88	20.86
	9-5/8″	STC	269.88*196.85	18.03
	9-5/8″	LTC	269.88*266.70	25.45
	9-5/8″	BTC	269.88*269.88	23.16
	10-3/4″	STC	298.45*203.20	20.78
	10-3/4″	BTC	298.45*269.88	25.74
	11-3/4′	STC	323.85*203.20	22.64
	11-3/4′	BTC	323.85*269.88	28.03
	13-3/8″	STC	365.12*203.20	25.66
	13-3/8″	BTC	365.12*269.88	31.77
	16″	STC	431.80*228.6	34.91
	16″	BTC	431.80*269.88	40.28
	18-5/8″	STC	508.00*228.60	51.01
	18-5/8″	BTC	508.00*269.88	62.68
	20″	STC	533.40*228.6	43.42
	20″	LTC	533.4*292.10	57.04
	20″	BTC	533.40*269.88	50.1

Standard of Coupling

API 5CT – Specification for Casing and Tubing

Spec 5CT specifies the technical delivery conditions for steel pipes (casing, tubing, plain end casing liners, and pup joints) and accessories.

Applicable to the following connections in accordance with

（1）short round thread casing (STC);

（2）long round thread casing (LC);

（3）buttress thread casing (BC);

（4）extreme-line casing (XC);

（5）non-upset tubing (NU);

（6）external upset tubing (EU);

（7）integral joint tubing (IJ).

This standard specifies the technical delivery conditions for steel pipes (casing, tubing, and pup joints), coupling stock, coupling material, and accessory material, and establishes requirements for three Product Specification Levels (PSL-1, PSL-2, PSL-3). The requirements for PSL-1 are the basis of this standard. The requirements that define different levels of standard technical requirements for PSL-2 and PSL-3, for all grades except H-40, L-80 9Cr, and C110, are contained in Annex H. This standard can also be applied to tubulars with connections not covered by API standards. Not applicable to threading requirements.

API 5B-Specification for Threading, Gauging, and Thread Inspection of Casing, Tubing, and Line Pipe Threads

API 5B is the standard specification for threading, gauging, and inspection of casing, tubing, and line pipe threads.

Spec 5B covers dimensions and marking requirements for API Master thread gauges. Additional product threads and thread gauges, as well as instruments and methods for the inspection of threads for line pipe, round thread casing, buttress casing, and extreme-line casing connections, are included. It is applicable when so stipulated in the API standard governing the product. The inspection procedures for measurements of taper, lead, height, and angle of thread are applicable to threads having 111/2 or fewer turns per in. (111/2 or fewer turns per 25.4 mm). All thread dimensions shown without tolerances are related to the basis for connection design and are not subject to measurement to determine acceptance or rejection of the product.

Chemical Composition(%)
Grade	C	Mn	Mo	Cr	Ni	Cu	P	S	Si
H40							≤0.03	≤0.03	—
J55/K55							≤0.03	≤0.03	—
N80-1/N80Q							≤0.03	≤0.03	—
R95	≤0.45ᶜ	≤1.9					≤0.03	≤0.03	—
L80	≤0.43ᵃ	≤1.9					≤0.03	≤0.03	—
L80-1	≤0.15	0.30~0.60	0.90~1.10	8.00~10.0	—	—	≤0.03	≤0.03	≤0.45
L80-13Cr	0.15~0.22	0.25~1.00		12.0~14.0	≤0.25	≤0.35	≤0.03	≤0.03	≤0.45
C90	≤0.35	≤1.20	0.25ᵇ~0.85	≤1.50	≤0.5	≤0.25	≤0.02	≤0.01	≤1
T95	≤0.35	≤1.20	0.25ᵇ~0.85	0.40~1.50	≤0.5	≤0.25	≤0.02	≤0.01	≤1
C110	≤0.35	≤1.20	0.25~1.00	0.40~0.15	≤0.99	—	≤0.02	≤0.01	—
P110					≤0.99	—	≤0.02	≤0.01	—
Q125	≤0.35	1.35	≤0.85	≤1.50	≤0.99	—	≤0.02	≤0.005	—

Mechanical properties
Grade	Total elongation under load（%）	Yield strength（Mpa）	Tensile strength（Mpa）	Hardness（HRC）	Hardness（HBW）
H40	0.5	276~552	414	—	—
J55	0.5	379~552	517	—	—
K55	0.5	379~552	655	—	—
N80-1/N80Q	0.5/0.5	552~758/552~758	689/689	—	—
R95	0.5	655	724	—	—
L80	0.5	552	655	23.0	241
L80-1/L80-9Cr	0.5	552	655	23.0	241
L80-13Cr	0.5	552	655	23.0	241
C90	0.5	621	689	25.4	255
T95	0.5	655	724	25.4	255
C110	0.7	758	793	30.0	286
P110	0.6	758	862	—	—
Q125	0.65	862	931	b	—

Q: What types of steel couplings do you manufacture and supply?

A: We provide a comprehensive range of steel couplings to meet diverse industrial and mechanical requirements. Our main products include steel pipe couplings (such as threaded and flanged fittings), steel shaft couplings (like jaw/spider couplings and rigid couplings), and specialized industrial machine couplings. All our products strictly comply with international standards, including ASME B16.9, MSS SP-43, DIN 2605, and JIS B2313.

Q: What materials and steel grades are available for your couplings?

A: Our couplings are manufactured using high-quality carbon steel and stainless steel to ensure durability and corrosion resistance. We supply various grades including 304, 304L, 316, 316L, and 321 stainless steel, as well as iron alloys and SS400. For specialized mechanical couplings, we also offer components with polyurethane elastic sleeves (available in 92 and 98 hardness) to absorb vibration and compensate for misalignment.

Q: What are the available size ranges and forming techniques?

A: We offer a wide range of specifications. For seamless pipe couplings, sizes range from 1/2" to 20" (DN15-DN500), and welded versions are available from 1/2" to 48" (DN15-DN1200), with wall thicknesses ranging from SCH5S to SCH160. Our manufacturing techniques include precision casting, mandrel-forming, and CNC machining, ensuring sophisticated accuracy with an error rate as low as 0.001mm for custom mechanical parts.

Q: What are the advantages of using your steel jaw/spider couplings?

A: Our steel jaw couplings are specifically designed for high-torque transmission. They feature a middle elastic body connection that effectively absorbs vibrations and compensates for radial, angular, and axial deviations. Additionally, they offer identical clockwise and anticlockwise rotational characteristics, ensuring stable performance in both directions.

Q: What is the Minimum Order Quantity (MOQ), and do you offer OEM/ODM services?
A: We are highly flexible with our MOQ, which can be as low as 1 piece for many standard sizes currently in stock. We fully support OEM and ODM services. Whether you require custom keyway machining, specific bore sizes, or non-standard dimensions, our engineering team can tailor the product to your exact project specifications.

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