Oil Tubing	Range 1	Range 2	Range 3
	6.10~7.32	8.53~9.75	11.58~12.80

Label				D Outside diameter mm	Wall thickness mm	C type of end-finish
1	2
	NU T&C	EU T&C	IJ			H40	J55	L80	N80	C90	T95	P110
1.9	2.75	2.9	4	48.26	3.68	PNUI	PNUI	PNUI	PNUI	PNUI	PNUI
	3.65	3.73	2.76	48.26	5.08	PU	PU	PU	PU	PU	PU	PU
	4.42	-	-	48.26	6.35	-	-	P	-	P	P	-
2 3/8	4	-	-	60.32	4.24	PU	PN	PN	PN	PN	PN	-
	4.6	4.7	-	60.32	4.83	PNU	PNU	PNU	PNU	PNU	PNU	PNU
	5.8	5.95	-	60.32	6.45	-	-	PNU	PNU	PNU	PNU	PNU
	6.6	-	-	60.32	7.49	-	-	P	-	P	P	-
	7.35	7.45	-	60.32	8.53	-	-	PU	-	PU	PU	-
2 7/8	6.4	6.5	-	73.02	5.51	PNU	PNU	PNU	PNU	PNU	PNU	PNU
	7.8	7.9	-	73.02	7.01	-	-	PNU	PNU	PNU	PNU	PNU
	8.6	8.7	-	73.02	7.82	-	-	PNU	PNU	PNU	PNU	PNU
	9.35	9.45	-	73.02	8.64	-	-	PU	-	PU	PU	-
	10.5	-	-	73.02	9.96	-	-	P	-	P	P	-
3 1/2	7.7	-	-	88.9	5.49	PN	PN	PN	PN	PN	PN	-
	9.2	9.3	-	88.9	6.45	PNU	PNU	PNU	PNU	PNU	PNU	PNU
	10.2	-	-	88.9	7.34	PN	PN	PN	PN	PN	PN	-
	12.7	12.95	-	88.9	9.52	-	-	PNU	-	PNU	PNU	PNU
	14.3	-	-	88.9	10.92	-	-	P	-	P	P	-
	15.5	-	-	88.9	12.09	-	-	P	-	P	P	-
4	9.5	-	-	101.6	5.74	PN	PN	PN	PN	PN	PN	-
	10.7	11	-	101.6	6.65	PU	PU	PU	PU	PU	PU	-
	13.2	-	-	101.6	8.38	-	-	P	-	P	P	-
	16.1	-	-	101.6	10.54	-	-	P	-	P	P	-
4 1/2	12.6	12.75	-	114.3	6.88	PNU	PNU	PNU	PNU	PNU	PNU	-
	15.2	-	-	114.3	8.56	-	-	P	-	P	P	-

Note: P—plain-end；N—non-upset, with threaded and coupled；U—external-upset, with threaded and coupled；I—whole joint

Pipe Types	Pipe Size (mm)		Tolerances
Hot Rolled	OD	≤159	±1.0%
		>159	±1.20%
	WT	≤20	±12.5%
		>20	±10.0%
Cold Drawn	OD	≤30	±0.20mm
		30-50	±0.30mm
		>50	±0.8%
	WT	≤3	+12%  -10%
		>3	±10%

API Spec 5CT – Specification 5CT/ISO 11960, Specification for Casing and Tubing, Eighth Edition, Petroleum and natural gas industries-Steel pipes for use as casing or tubing for wells

Mechanical Properties:

Group	Grade	Type	Total elongation  under load %	Yield Strength M pa		Tensile strength  min Mpa	Hardness
				min	max		HRC	HBW
1	2	3	4	5	6	7	8	9
2	J55	-	0.5	379	552	517	-	-
	K55	-	0.5	379	552	655	-	-
	N80	1	0.5	552	758	689	-	-
	N80	Q	0.5	552	758	689	-	-
3	L80	1	0.5	552	655	655	23	241
	L80	9Cr	0.5	552	655	655	23	241
	L80	13Cr	0.5	552	655	655	23	241
	C90		0.5	621	689	689	25.4	255
	C95	-	0.5	655	724	724	-	-
	T95		0.5	655	724	724	25.4	255
	P110	-	0.6	758	862	862	-	-
4	Q125	All	0.65	862	931	931	-	-

Chemical Composition

Standard

Grade

Composition（%）

C

Si

Mn

P

S

Cr

Ni

Cu

Mo

V

AIs

API SPEC 5CT

J55K55

0.34～0.39

0.20～ 0.35

1.25～1.50

≤0.020

≤0.015

≤0.15

≤0.20

≤0.20

≤0.020

(37Mn5)

N80

0.34～0.38

0.20～ 0.35

1.45～1.70

≤0.020

≤0.015

≤0.15

0.11 ～0.16

≤0.020

(36 Mn2V)

L80(13Cr)

0.15～0.22

≤1.00

0.25～1.00

≤0.020

≤0.010

12.0～ 14.0

≤0.20

≤0.20

≤0.020

P110

0.26～0.35

0.17～ 0.37

0.40～0.70

≤0.020

≤0.010

0.80～ 1.10

≤0.20

≤0.20

0.15 ～0.25

≤0.08

≤0.020

Ingot heating→Perforation→Rolling and sizing→Cooling→Straightening→NDT→End cutting→Coupling thread→Hydraulic test→Painting and thread protecting→Packing

Ingot heating

Ingot heating is a working procedure which make ingot meet the required temperature of the hot working process. The purpose of the ingot heating is to make the steel ingot have enough plasticity, reduce rolling deformation resistance, improve the internal organization.
Heating process of ingots mainly has two stages: heating stage (including low temperature and high temperature), the ingot surface temperature is increased to the tapping temperature; Uniform heating, to make ingot inside and outside temperature uniformity.

Rolling and sizing

Hot rolling can reduce energy consumption and cost significantly. The high metal plastic deformation and low deformation resistance, greatly reduce the energy consumption of hot rolled steel.
Hot rolling can improve the process performance of metal, eliminate casting defects and improve the processing performance of the alloy.
Hot rolled usually adopt large ingot casting, which not only improve the production efficiency, but also improve the rolling speed, to achieve continuous rolling process and create the conditions for automation.

Cooling

After the cooling, hot rolled steel tube is in a specific range. Compared to the traditional process of making the process, it can simplify the process, save energy, get the same or better mechanical properties.

NDT

Nondestructive Testing, shorted for NDT, is a widely-used method in pipeline inspection. It is a process of testing, inspecting and evaluating the quality and characteristics of the material without damaging the pipeline itself or affecting the later regular work of the pipe. In other words, after NDT testing, the part can still be put into practical use. NDT utilizes the changes in heat, sound and magnets caused by abnormal inner structure or flaws to inspect the internal and external defects of the material.
The common inspection methods of NDT are visual testing (VT), ultrasonic testing (UT), radiographic testing (RT), hydrostatic testing.

Coupling thread

Threaded joints refers to the pipeline connecting piece with the screw thread, is a most common pipe in industry. Coupling thread makes connection of the pipe becomes more simple, replacement are also more easily and greatly saves the cost of the pipeline connection.
Threaded joints of industrial is generally made of metal and it can withstand high pressure. The material contents carbon steel, stainless steel, alloy steel, brass, etc.

Hydraulic test

Hydrostatic test is an inspection method to reduce the risk of flaws in the pipe that might threaten its ability to withstand the maximum operating pressure. Hydrostatic testing inspects the integrity of pipelines by filling in the pipe with a non-compressible liquid (often water, dyed) to increase the pressure level above the normal pressure to see if there is any defect exists. It can either carried out on pipes prior to being put into service or on existing pipes that are already in service