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Eastern Steel Manufacturing Co.,Ltd is a leading manufacturer and distributor of seamless steel pipe, welded steel pipe, OCTG products and fittings. We supply first-step processing, semi-finished parts and finished parts to help our clients meet fabrication requirements beyond their capacity or to improve operations by moving forward the pre-production processing.
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In this column you can find the steel pipe related articles you need, including industry trends, product standards and materials, and some technical guidelines.
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Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
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Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
Projects
Many years of large-scale project experience in various fields（Oil & Gas, Construction, Power Energy, Marine & Offshore, Water Treatment, Exploration & Drilling Services, Pipeline & Petrochemical etc.）, professional project team is responsible from receiving until the end of the project.
API 5CT oil casing sizes are specified by nominal size, outside diameter, wall thickness, inside diameter, drift diameter, and nominal weight.
OCTG Casing — Dimensions, Weights and Grades
| Nominal Weight | Wall Thickness | ID | Drift Diameter | Connections | Common Grades |
|---|---|---|---|---|---|
| 10.50 lb/ft (15.63 kg/m) | 0.224 in (5.69 mm) | 4.052 in (102.92 mm) | 3.927 in (99.75 mm) | STC, LTC | H40, J55, K55, M65 |
| 11.60 lb/ft (17.26 kg/m) | 0.250 in (6.35 mm) | 4.000 in (101.60 mm) | 3.875 in (98.43 mm) | STC, LTC, BTC | J55, L80, N80, P110 |
| 13.50 lb/ft (20.09 kg/m) | 0.290 in (7.37 mm) | 3.920 in (99.57 mm) | 3.795 in (96.39 mm) | LTC, BTC, Premium | L80, C90, T95, P110, Q125 |
| Nominal Weight | Wall Thickness | ID | Drift Diameter | Connections | Common Grades |
|---|---|---|---|---|---|
| 15.50 lb/ft (23.07 kg/m) | 0.275 in (6.98 mm) | 4.950 in (125.73 mm) | 4.825 in (122.56 mm) | LTC, BTC | J55, K55, L80, N80 |
| 17.00 lb/ft (25.30 kg/m) | 0.304 in (7.72 mm) | 4.892 in (124.26 mm) | 4.767 in (121.08 mm) | LTC, BTC, Premium | J55, L80, N80, C90, P110 |
| 20.00 lb/ft (29.76 kg/m) | 0.361 in (9.17 mm) | 4.778 in (121.36 mm) | 4.653 in (118.19 mm) | LTC, BTC, Premium | L80, C90, T95, P110, Q125 |
| Nominal Weight | Wall Thickness | ID | Drift Diameter | Connections | Common Grades |
|---|---|---|---|---|---|
| 23.00 lb/ft (34.23 kg/m) | 0.317 in (8.05 mm) | 6.366 in (161.70 mm) | 6.241 in (158.52 mm) | LTC, BTC | J55, K55, L80, N80 |
| 26.00 lb/ft (38.69 kg/m) | 0.362 in (9.19 mm) | 6.276 in (159.41 mm) | 6.151 in (156.24 mm) | LTC, BTC, Premium | J55, L80, N80, C90, P110 |
| 29.00 lb/ft (43.16 kg/m) | 0.408 in (10.36 mm) | 6.184 in (157.07 mm) | 6.059 in (153.90 mm) | LTC, BTC, Premium | L80, C90, T95, P110, C110 |
| 32.00 lb/ft (47.62 kg/m) | 0.453 in (11.51 mm) | 6.094 in (154.79 mm) | 5.969 in (151.61 mm) | LTC, BTC, Premium | L80, P110, Q125 |
| Nominal Weight | Wall Thickness | ID | Drift Diameter | Connections | Common Grades |
|---|---|---|---|---|---|
| 36.00 lb/ft (53.57 kg/m) | 0.352 in (8.94 mm) | 8.921 in (226.60 mm) | 8.765 in (222.63 mm) | LTC, BTC | J55, K55, L80, N80 |
| 40.00 lb/ft (59.53 kg/m) | 0.395 in (10.03 mm) | 8.835 in (224.41 mm) | 8.679 in (220.45 mm) | LTC, BTC, Premium | J55, L80, N80, C90, P110 |
| 47.00 lb/ft (69.94 kg/m) | 0.472 in (11.99 mm) | 8.681 in (220.50 mm) | 8.525 in (216.54 mm) | LTC, BTC, Premium | L80, C90, T95, P110, Q125 |
| Nominal Weight | Wall Thickness | ID | Drift Diameter | Connections | Common Grades |
|---|---|---|---|---|---|
| 54.50 lb/ft (81.10 kg/m) | 0.380 in (9.65 mm) | 12.615 in (320.42 mm) | 12.459 in (316.46 mm) | STC, BTC | J55, K55 |
| 68.00 lb/ft (101.19 kg/m) | 0.480 in (12.19 mm) | 12.415 in (315.34 mm) | 12.259 in (311.38 mm) | STC, BTC, Premium | J55, L80, N80, P110 |
The same nominal casing size can have different dimensions depending on the nominal weight and wall thickness. For a given size, such as 7", increasing the nominal weight generally means a thicker wall and a smaller inside diameter (ID).
Steel grade: Common API 5CT grades include H40, J55, K55, N80, L80, P110, and Q125. The same casing size and weight can be available in different grades.
Not all combinations exist: The available grade and weight combinations vary by size. Never assume an arbitrary grade can be paired with any size/weight.
Casing connections join individual casing joints and provide the mechanical connection and seal between them.
Connection types: Common API 5CT connections include STC (Short Thread and Coupling), LTC (Long Thread and Coupling), and BTC (Buttress Thread and Coupling).
Why they matter: STC and LTC are standard API connections, while BTC is chosen for higher joint strength and improved sealing in specific well conditions.
Length ranges (R1/R2/R3): Casing joints are classified into Range 1, Range 2, and Range 3 based on their length.
Q1. What are the common API 5CT oil casing sizes?
Common API 5CT oil casing sizes include 4-1/2", 5-1/2", 7", 9-5/8", and 13-3/8".
Q2. What dimensions are specified for API 5CT casing?
API 5CT casing dimensions include nominal size, outside diameter (OD), wall thickness, inside diameter (ID), drift diameter, and nominal weight. The available dimensions vary by casing size and weight.
Q3. What is the difference between casing ID and drift diameter?
Casing ID is the calculated internal diameter based on the casing OD and wall thickness. Drift diameter is the minimum internal diameter used to verify that a specified gauge can pass through the casing.
Q4. Are all API 5CT grades available for every casing size and weight?
No. API 5CT grade availability varies by casing size and weight. A specific grade, size, and weight combination should be checked against the applicable API 5CT specifications.
E-mail: sales@eastern-steels.com
