API 5CT K55

API 5CT K55 is a pipe grade specified by the American Petroleum Institute. API 5CT K55 is a type of well casing that is typically used in well drilling operations. The casing and tubing are OCTG (oil country tubular goods) that are used to form the walls of the well. The steel pipe is placed in the well and held in place by cement. The cement helps to protect the well from collapse and keeps the well fluids from escaping. API 5CT K55 is a popular choice for well drilling because it is durable and can withstand high temperatures and pressures.

Why choose tuspipe?

Since 1998, Tianjin United Steel Pipe Co., Ltd (TUSPIPE) has been committed to supplying high-quality line pipes.

With over 500,000 tons annual production capacity, the company serves various fields and industries, such as oil & gas exploitation and transmission, ship & auto-building, water & electricity, environmental protection, mechanical engineering, infrastructure construction and etc.

TUSPIPE places a premium on product quality and rigorous product quality control. In order to maintain good product quality, the company has established a Test & Inspection Center since 2004. With a series of state-of-the-art tests and inspection equipment, the test & inspection center is able to perform the tensile tests, hydro tests, impact tests, DWTT, etc.

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Chemical Composition of API 5CT K55

Grade	Type	C		Mn		Mo		Cr		Ni max.	Cu max.	P max.	S max.	Si max.
Grade	Type	min.	max.	min.	max.	min.	max.	min.	max.	Ni max.	Cu max.	P max.	S max.	Si max.
K55	–	0.34	0.38	1.25	1.5	–	–	–	0.15	–	0.2	0.02	0.015	–
a) The carbon content for L80 may be increased up to 0.50 % maximum if the product is oil-quenched. b) The molybdenum content for Grade C90 Type 1 has no minimum tolerance if the wall thickness is less than 17.78 mm. c) The carbon content for R95 may be increased up to 0.55 % maximum if the product is oil-quenched. d) The molybdenum content for T95 Type 1 may be decreased to 0.15 % minimum if the wall thickness is less than 17.78 mm. e) For EW Grade P110, the phosphorus content shall be 0.020 % maximum and the sulfur content 0.010 % maximum. f) NL = no limit. Elements shown shall be reported in product analysis.

Mechanical Analysis of API 5CT K55

API 5CT Casing Pipe Standard	API 5CT Casing Pipe Type	API 5CT Casing Pipe Tensile Strength MPa	API 5CT Casing Pipe Yield Strength MPa	API 5CT Casing Pipe Hardness Max.
API SPEC 5CT	–	≥517	≥655	—

API Casing/ API 5CT K55 Casing Tubing Specifications

- Specification & Size of API 5CT K55 Tubing

DN	O. D.		Weight		W. T.		End Processing
	O. D.		Non-upset coupling-thread	Upset coupling-thread	W. T.		Steel Grade
	in	mm	lb./ft.	lb./ft.	in	mm	H40	J55	L80	N80	C90	T95	P110
2 3/8	2.38	60.3	4	–	0.167	4.24	PU	PN	PN	PN	PN	PN	–
			4.6	4.7	0.19	4.83	PNU	PNU	PNU	PNU	PNU	PNU	PNU
			5.8	5.95	0.254	6.45	–	–	PNU	PNU	PNU	PNU	PNU
			6.6	–	0.295	7.49	–	–	P	–	P	P	–
			7.35	7.45	0.336	8.53	–	–	PU	–	PU	PU	–
2 7/8	2.88	73	6.4	6.5	0.217	5.51	PNU	PNU	–	–	–	–	–
			7.8	7.9	0.276	7.01	–	–	–	–	–	–	–
			8.6	8.7	0.308	7.82	–	–	PLB	PLB	PLBE	–	PLB
			9.35	9.45	0.34	8.64	–	–	PLB	PLB	PLBE	–	PLB
			10.5	–	0.392	9.96	–	–	PLB	PLB	PLB	–	PLB
			11.5	–	0.44	11.18	–	–	–	–	PLB	–
3 1/2	3.5	88.9	7.7	–	0.216	5.49	PN	PN	PN	PN	PN	PN	–
			9.2	9.3	0.254	6.45	PNU	PNU	PNU	PNU	PNU	PNU	PNU
			10.2	–	0.289	7.34	PN	PN	PN	PN	PN	PN	–
			12.7	12.95	0.375	9.52	–	–	PNU	PNU	PNU	PNU	PNU
			14.3	–	0.43	10.92	–	–	P	–	P	P	–
			15.5	–	0.476	12.09	–	–	P	–	P	P	–
			17	–	0.53	13.46	–	–	P	–	P	P	–
4	4	102	9.5	–	0.226	5.74	PN	PN	PN	PN	PN	PN	–
			–	11	0.262	6.65	PU	PU	PU	PU	PU	PU	–
			13.2	–	0.33	8.38	–	–	P	–	P	P	–
			16.1	–	0.415	10.54	–	–	P	–	P	P	–
			18.9	–	0.5	12.7	–	–	P	–	P	P	–
			22.2	–	0.61	15.49	–	–	P	–	P	P	–
4 1/2	4.5	114	12.6	12.75	0.271	6.88	PNU	PNU	PNU	PNU	PNU	PNU	–
			15.2	–	0.337	8.56	–	–	P	–	P	P	–
			17	–	0.38	9.65	–	–	P	–	P	P	–
			18.9	–	0.43	10.92	–	–	P	–	P	P	PLB
			21.5	–	0.5	12.7	–	–	P	–	P	P	PLB
			23.7	–	0.56	14.22	–	–	P	–	P	P	PLB
			26.1	–	0.63	16	–	–	P	–	P	P	PLB
P——Plain；N—— Non-upset coupling-thread；U—— Upset coupling-thread； L——Integral

- Specification & Size of API 5CT K55 Casing

DN	O. D.		Weight		W. T.			End Machining Form
	O. D.		Weight		W. T.			Steel Grade
	in	mm	lb/ft	kg/m	in	mm	H40	J55	L80	N80	C90	P110
	in	mm	lb/ft	kg/m	in	mm	H40	K55	L80	N80	T95	P110
4 1/2	4.500	114.3	9.5	14.14	0.205	5.21	PS	PS	–	–	–	–
			10.5	15.63	0.224	5.69	–	PSB	–	–	–	–
			11.6	17.26	0.250	6.35	–	PSLB	PLB	PLB	PLB	PLB
			13.5	20.09	0.290	7.37	–	–	PLB	PLB	PLB	PLB
			15.1	22.47	0.337	9.56	–	–	–	–	–	PLB
5	5.000	127	11.5	17.11	0.220	5.59	–	PS	–	–	–	–
			13	19.35	0.253	6.43	–	PSLB	–	–	–	–
			15	22.32	0.296	7.52	–	PSLB	PLB	PLB	PLBE	PLB
			18	26.79	0.362	9.19	–	–	PLB	PLB	PLBE	PLB
			21.4	31.85	0.437	11.1	–	–	PLB	PLB	PLB	PLB
			23.2	34.53	0.478	12.14	–	–	–	–	PLB	–
			24.1	35.86	0.500	12.7	–	–	–	–	PLB	–
5 1/2	5.500	139.7	14	20.83	0.244	6.2	PS	PS	–	–	–	–
			15.5	23.07	0.275	6.98	–	PSLB	–	–	–	–
			17	25.3	0.304	7.72	–	PSLB	PLB	PLB	PLBE	PLB
			20	29.76	0.361	9.17	–	–	PLB	PLB	PLBE	PLB
			23	34.23	0.415	10.54	–	–	PLB	PLB	PLBE	PLB
			26.8	39.88	0.500	12.7	–	–	–	–	–	–
			29.7	44.2	0.562	14.27	–	–	–	–	–	–
			32.6	48.51	0.625	15.88	–	–	–	–	–	–
			35.3	52.53	0.687	17.45	–	–	–	–	–	–
			38	56.55	0.750	19.05	–	–	–	–	–	–
			40.5	60.27	0.812	20.62	–	–	–	–	–	–
			43.1	64.14	0.875	22.22	–	–	–	–	–	–
6 5/8	6.625	168.28	20	29.76	0.288	7.32	PS	PSLB	–	–	–	–
			24	35.72	0.352	8.94	–	PSLB	PLB	PLB	PLBE	PLB
			28	41.67	0.417	10.59	–	–	PLB	PLB	PLBE	PLB
			32	47.62	0.475	12.06	–	–	PLB	PLB	PLBE	PLB
7	7.000	177.8	17	25.3	0.231	5.87	PS	–	–	–	–	–
			20	29.76	0.272	6.91	PS	PS	–	–	–	–
			23	34.23	0.317	8.05	–	PSLB	PLB	PLB	PLBE	–
			26	38.69	0.362	9.19	–	PSLB	PLB	PLB	PLBE	PLB
			29	43.16	0.408	10.36	–	–	PLB	PLB	PLBE	PLB
			32	47.62	0.453	11.51	–	–	PLB	PLB	PLBE	PLB
			35	52.09	0.498	12.65	–	–	PLB	PLB	PLBE	PLB
			38	56.55	0.540	13.72	–	–	PLB	PLB	PLBE	PLB
			42.7	63.54	0.625	15.88	–	–	–	–	–	–
			46.4	69.05	0.687	17.45	–	–	–	–	–	–
			50.1	74.56	0.750	19.05	–	–	–	–	–	–
			53.6	79.77	0.812	20.62	–	–	–	–	–	–
			57.1	84.97	0.875	22.22	–	–	–	–	–	–
7 5/8	7.625	193.68	24	35.72	0.300	7.62	PS	–	–	–	–	–
			26.4	39.29	0.328	8.33	–	PSLB	PLB	PLB	PLBE	PLB
			29.7	44.2	0.375	9.52	–	–	PLB	PLB	PLBE	PLB
			33.7	50.15	0.430	10.92	–	–	PLB	PLB	PLBE	PLB
			39	58.05	0.500	12.7	–	–	PLB	PLB	PLBE	PLB
			42.8	63.69	0.562	14.27	–	–	PLB	PLB	PLB	PLB
			45.3	67.41	0.595	15.11	–	–	PLB	PLB	PLB	PLB
			47.1	70.09	0.625	15.88	–	–	PLB	PLB	PLB	PLB
			51.2	76.19	0.687	17.45	–	–	–	–	–	–
			55.3	80.3	0.750	19.05	–	–	–	–	–	–
8 5/8	8.625	219.08	24	35.72	0.264	6.71	–	PS	–	–	–	–
			28	41.62	0.304	7.72	PS	–	–	–	–	–
			32	47.62	0.352	8.94	PS	PSLB	–	–	–	–
			36	53.57	0.400	10.16	–	PSLB	PLB	PLB	PLBE	PLB
			40	59.53	0.450	11.43	–	–	PLB	PLB	PLBE	PLB
			44	65.48	0.500	12.7	–	–	PLB	PLB	PLBE	PLB
			49	72.92	0.557	14.15	–	–	PLB	PLB	PLBE	PLB
9 5/8	9.625	244.48	32.3	48.07	0.312	7.92	PS	–	–	–	–	–
			36	53.57	0.352	8.94	PS	PSLB	–	–	–	–
			40	59.53	0.395	10.03	–	PSLB	PLB	PLB	PLBE	–
			43.5	64.73	0.435	11.05	–	–	PLB	PLB	PLBE	PLB
			47	69.94	0.472	11.99	–	–	PLB	PLB	PLBE	PLB
			53.5	79.62	0.545	13.84	–	–	PLB	PLB	PLBE	PLB
			58.4	86.91	0.595	15.11	–	–	PLB	PLB	PLB	PLB
			59.4	88.4	0.609	15.47	–	–	–	–	–	–
			64.9	96.58	0.672	17.07	–	–	–	–	–	–
			70.3	104.62	0.734	18.64	–	–	–	–	–	–
			75.6	112.5	0.797	20.24	–	–	–	–	–	–
10 3/4	10.750	273.05	32.75	48.74	0.279	7.09	PS	–	–	–	–	–
			40.5	60.27	0.350	8.89	PS	PSB	–	–	–	–
			15.5	67.71	0.400	10.16	–	PSB	–	–	–	–
			51	75.9	0.450	11.43	–	PSB	PSB	PSB	PSBE	PSB
			55.5	82.59	0.495	12.57	–	–	PSB	PSB	PSBE	PSB
			60.7	90.33	0.545	13.84	–	–	–	–	PSBE	PSB
			65.7	97.77	0.595	15.11	–	–	–	–	PSB	PSB
			73.2	108.93	0.672	17.07	–	–	–	–	–	–
			79.2	117.86	0.734	18.64	–	–	–	–	–	–
			85.3	126.94	0.797	20.24	–	–	–	–	–	–
11 3/4	11.750		42	62.5	0.333	8.46	PS	–	–	–	–	–
			47	69.94	0.375	20.24	–	–	–	–	–	–
			54	80.36	0.435	8.46	–	–	–	–	–	–
			60	89.29	0.489	9.53	–	–	–	–	–	–
			65	96.73	0.534	11.05	–	–	–	–	–	–
			71	105.66	0.582	14.42	–	–	–	–	–	–
13 3/8	13.375	339.73	48	71.43	0.330	8.38	PS	–	–	–	–	–
			54.5	81.1	0.380	9.65	–	PSB	–	–	–	–
			61	90.78	0.430	10.92	–	PSB	–	–	–	–
			68	101.19	0.480	12.19	–	PSB	PSB	PSB	PSB	PSB
			72	107.15	0.514	13.06	–	–	PSB	PSB	PSB	PSB
16	16.000	406.4	65	96.73	0.375	9.53	PS	–	–	–	–	–
			75	111.61	0.438	11.13	–	PSB	–	–	–	–
			84	125.01	0.495	12.57	–	PSB	–	–	–	–
			109	162.21	0.656	16.66	–	P	P	P	–	P
18 5/8	18.625	473.08	87.5	130.21	0.435	11.05	PS	PSB	–	–	–	–
20	20.000	508	94	139.89	0.438	11.13	PSL	PSLB	–	–	–	–
			106.5	158.49	0.500	12.7	–	PSLB	–	–	–	–
			133	197.93	0.635	16.13	–	PSLB	–	–	–	–
P——Plain；S——Short-thread；L——Long-thread；B——Buttress thread；E——Extreme thread

API 5CT K55 Tolerance

Item		Allowable Tolerance
Outer diameter	Pipe body	D≤101.60mm±0.79mm
		D≥114.30mm+1.0%
		-0.50%