The post shows the common OCTG pipe materials like API H40, J55, K55, L80, N80, P110, and Q125 (casing and tubing pipes). These API grades feature increasing mechanical properties (tensile and yield strength).

 

API H40

API H40 grade is for general purpose OCTG pipe material with the following mechanical properties:

H40 Chemical Composition

C Mn Mo Cr Ni Cu Ti P S Si V Al
Min
Max 0.030 0.030

H40 Mechanical Properties

Min Tensile Strength 414 MPa 60,000 psi min
Min Yield Strength 276 MPa 552 MPa max
40,000 psi 80,000 psi max
Total Elongation Under Load 0.500 %

 

 

API J55

The J55 API-5CT casing pipe is a comparatively low steel grade in oil drilling. It is widely applied to shallow oil and gas extraction. Because of its low cost among other grades of steel, it enjoys wider applications,  can be generally used in shallow wells, geothermal wells, and water wells.

J55 Chemical Composition

C Mn Mo Cr Ni Cu Ti P S Si V Al
Min
Max 0.030 0.030

J55 Mechanical Properties

Min Tensile Strength 517 MPa 75,000 psi min
Min Yield Strength 379 MPa 552 MPa max
55,000 psi 80,000 psi max
Total Elongation Under Load 0.500 %

 

 

API L80

L80 belongs to steel grades group of the corrosion-resistant casing. L80 API oilfield casing pipe includes L80-1, L80-9Cr, and L80-13Cr. L80-1 is used in the H2S environment, while L80-9Cr and L80-13Cr are used in the CO2 environment. In the corrosive environment in which carbon dioxide predominates, Super 13Cr has a higher corrosion resistance than L80-13Cr. With a relatively high price, the product applies to more complicated geological conditions and runs down deeper into the well. In the exploitation of oil and gas, the use of L80 is less frequent than J55, N80, and other materials.

L80 Chemical Composition

C Mn Mo Cr Ni Cu Ti P S Si V Al
Min
Max 0.430 1.900 0.250 0.350 0.030 0.030 0.450

L80 Mechanical Properties

Min Tensile Strength 655 MPa 95,000 psi min
Min Yield Strength 552 MPa 655 MPa max
80,000 psi 95,000 psi max
Total Elongation Under Load 0.500 %
Hardness 23 Max HRC 241 Max HBW

9Cr-L80 Chemical Composition

C Mn Mo Cr Ni Cu Ti P S Si V Al
Min 0.300 0.900 8.000
Max 0.150 0.600 1.100 10.000 0.500 0.250 0.020 0.010 1.000

9Cr-L80 Mechanical Properties

Min Tensile Strength 655 MPa 95,000 psi min
Min Yield Strength 552 MPa 655 MPa max
80,000 psi 95,000 psi max
Total Elongation Under Load 0.500 %
Hardness 23 Max HRC 241 Max HBW

 

API N80

API-5CT N80 oilfield casing pipe contains N80-1 and N80-Q types. Those two materials are absolutely consistent regarding the chemical composition and mechanical attributes, they are just variations in the heat treatment. During the heat treatment, N80-1 steel is treated by normalizing and tempering, while N80Q steel is treated by quenching and tempering. Therefore, the collapsing strength and internal pressure strength of N80Q are higher than that of N80-1. N80-1 or N80Q should be clearly shown by the designer when N80 casing is selected. As its mechanical properties are higher than J55 and K55 types, it may very well be utilized to certain a little more challenging formations. With deeper downhole depth than J55 and K55 types, it can be applied for the exploitation of middle-level oil and gas. Due to the high capability of the N80 material, those API-5CT casing pipes are broadly applied in natural gas as well as coal bed methane extraction, and geothermal wells.

N80 Chemical Composition

C Mn Mo Cr Ni Cu Ti P S Si V Al
Min
Max 0.030 0.030

N80 Mechanical Properties

Min Tensile Strength 689 MPa 100,000 psi min
Min Yield Strength 552 MPa 758 MPa max
80,000 psi 110,000 psi max
Total Elongation Under Load 0.500 %
Hardness

API P110

The P110 API-5CT steel casing pipe is the high grade amongst other grades of steel.  The white band is marked on the finished casing to point out the materials. During petroleum drilling and producing, this pipe is generally used in a variety of complicated territory due to its higher tensile strength and higher yield. It goes down the deepest into the well among other types. However, the price is comparatively high, as well as the quantity of usage is comparatively few. P110 casing pipe is mainly used in a particular surrounding and when the drilling depth extends to a particular level.

 

API Q125 

This API grade is generally used for deep wellbore service and not in sour condensate wells. The hardness testing (quadrant) is required without any specified limits other than the variation between readings. The impact test is required for each heat and production lot. Non-destructive examination and inspection are required.

The tables below list the materials used for OCTG casing and tubing pipes. For details about oil country tubular goods, refer to this article.

 

OCTG PIPE MATERIALS PROPERTIES

API5CT MATERIALS CHEMICAL COMPOSITION

Group OCTG pipe materials Type C Mn Mo Cr Ni max. Cu max. P max. S max. Si max.
min. max. min. max. min. max. min. max.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
H40
0.03
0.03
J55
0.03
0.03
K55
0.03
0.03
N80
1
0.03
0.03
N80
Q
0.03
0.03
R95
0.45 c
1.9
0.03
0.03
0.45
2
M65
0.03
0.03
L80
1
0.43 a
1.9
0.25
0.35
0.03
0.03
0.45
L80
9Cr
0.15
0.3
0.6
0.9
1.1
8
10
0.5
0.25
0.02
0.01
1
L80
13Cr
0.15
0.22
0.25
1
12
14
0.5
0.25
0.02
0.01
1
C90
1
0.35
1.2
0.25 b
0.85
1.5
0.99
0.02
0.01
T95
1
0.35
1.2
0.25 d
0.85
0.4
1.5
0.99
0.02
0.01
C110
0.35
1.2
0.25
1
0.4
1.5
0.99
0.02
0.005
3
P110
e
0.030 e
0.030 e
4
Q125
1
0.35
1.35
0.85
1.5
0.99
0.02
0.01
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.
NL = no limit. Elements shown shall be reported in product analysis.

 

OCTG PIPE MATERIALS – MECHANICAL PROPERTIES

Group OCTG pipe materials Type Total elongation under load % Yield strength MPa Tensile strength min. MPa Hardness a max. Specified wall thickness mm Allowable hardness variation b HRC
min. max . HRC HBW
1 2 3 4 5 6 7 8 9 10 11
1
H40
0.5
276
552
414
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
R95
0.5
655
758
724
2
M65
0.5
448
586
586
22
235
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
1
0.5
621
724
689
25.4
255
≤ 12.70 12.71 to 19.04 19.05 to 25.39 ≥ 25.40
3.0 4.0 5.0 6.0
T95
1
0.5
655
758
724
25.4
255
≤ 12.70 12.71 to 19.04 19.05 to 25.39 ≥ 25.40
3.0 4.0 5.0 6.0
C110
0.7
758
828
793
30
286
≤ 12.70 12.71 to 19.04 19.05 to 25.39. ≥ 25.40
3.0 4.0 5.0 6.0
3
P110
0.6
758
965
862
4
Q125
1
0.65
862
1034
931
b
≤ 12.70 12.71 to 19.04 ≥ 19.05
3.0 4.0 5.0
a In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method.
b No hardness limits are specified, but the maximum variation is restricted as a manufacturing control in accordance with 7.8 and 7.9 of API Spec. 5CT.

The API5CT specification can be purchased here.