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Casing Pipe
Casing Pipe
Casing Pipe
Casing Pipe
Casing Pipe

Casing Pipe

Product: Casing Pipe, Oil Casing, API Casing, Well Casing, Casing
Application: Used for oil casing and tubing in oil wells as well as sidewall
Size: OD: 114.3mm-508mm
WT: 5-16mm
LENGTH: R1, R2, R3
Pipe Standard: API 5CT PSL1/PSL2  J55,K55,N80-1,N80-Q,
API 5CT PSL1/PSL2  L80-1, L80-9Cr,L80-13Cr,C90, C95, P110, Q125
Thread: NUE, EUE, STC, LTC, BTC, XC,HYDRILL CS
Special Service Sweet Service, Sour Service, Anti-H2S, NACE MR0175/ISO15156
Accessories: Pup Joint, Coupling, Drill Collar, Crossover etc.
  • Products details
  • Tolerance table
  • Chemical composition
  • Specification

OCTG Casing Introduction

Product:

Casing Pipe, Oil Casing, API Casing, Well Casing, Casing

Application:

Used for oil casing and tubing in oil wells as well as sidewall

Size:

OD: 114.3mm-508mm

WT: 5-16mm

LENGTH: R1, R2, R3

Pipe Standard:

API 5CT PSL1/PSL2  J55,K55,N80-1,N80-Q,

API 5CT PSL1/PSL2  L80-1, L80-9Cr,L80-13Cr,C90, C95, P110, Q125

Thread:

NUE, EUE,  STC, LTC, BTC, XC,HYDRILL CS

Special Service

Sweet Service, Sour Service, Anti-H2S, NACE MR0175/ISO15156

Accessories:

Pup Joint, Coupling, Drill Collar, Crossover etc.



Oil casing

R1

R2

R3

4.88-7.62m

7.62-10.36m

10.36-14.63m



OCTG Casing Pipe Connections

API 5CT is applicable to following connections which complied with API SPEC 5B:

• SC: Short round thread casing

• LC: Long ound thread casing

• BC: Buttress thread casing

• NU: Non-upset tubing

• EU: External upset tubing

• IJ: Integral tubing connections


Steel Casing Pipe Application

1, API SPCE 5L For the function of transport of gas, water, oill in oil & gas sector.
2, API SPEC 5CT Tubes is used in drawing out oil & gas. casing pipe works as wall surface of well.
3, ASTM A106 For the objective of the pipeline task of central heating boiler, water & oil.
4, ASTM A53 It is made use of for sharing water, petroleum, gas as well as various other typical liquids.
5, ASTM A179 For tubed warm exchanger and also similar warm sharing equipments.

6, ASTM A192 For manufacture wall panel, economizer, reheater, superheater and vapor pipe of central heating boilers.


More casing pipes and their colors

  • Process

Casing pipe manufacturing process includes steelmaking, continuous casting, hot rolling, heat treatment, and quality inspection.

  • Tests
Quality Control System
1. In order to ensure that the original and auxiliary materials used are qualified products, the company evaluates and selects qualified suppliers according to GB/T19001-2000-ISO9001:2000 and API standards. Inspected by the raw material inspector of the Quality Management Department, unqualified raw materials and accessories may not be put into use.
2. Casing pipe diameter test: This test is used to detect the straightness of the pipe body and detect whether there is a bump in the pipe wall.
3, Quality inspection is for the finished product testing, quality inspection staff need to check to ensure that the product has no obvious defects and all the tubes are in compliance with the required parameters and length.
4. Tubing collar size and appearance inspection: QC staff inspects the size and surface of the steel pipe to ensure compliance.
5. Hydrostatic test: The pipe body will be rolled into the hydrostatic tester and water will be injected into the pipe body to ensure that the pipe body can withstand the internal water pressure and ensure that the pipe body does not leak.
6. Physical and chemical analysis of casing collar: This test is used to analyze the chemical composition, mechanical properties, and metal structure of the raw materials in the pipe.
7. Casing pipe thread test: The production personnel will physically inspect the thread after the yarn stage in the production process to ensure compliance.
  • Packing & Delivery
Casing pipes are bundled with steel strips, wrapped with waterproof plastic bags, and loaded into containers or bulk vessels.
  • Tolerance table

API 5CT Casing Pipe Dimension Tolerance

Types of steel tubes

Outer Diameter

Wall Thickness

Cold-rolled tubes

Tube sizes(mm)

Tolerances(mm)

Tolerances(mm)

＜114.3

±0.79

－12.5％

≥114.3

－0.5％，＋1％

  • Chemical composition

API 5CT Casing Pipe Chemical Compositions

Standard

Grade

Chemical compositions（％）

API SPEC 5CT

J55

C

Si

Mn

P

S

Cr

Ni

Cu

Mo

V

K55

0.34～0.39

0.20～0.35

1.25～1.50

≤0.020

≤0.015

≤0.15

≤0.20

≤0.20

/

/

N80

0.34～0.38

0.20～0.35

1.45～1.70

≤0.020

≤0.015

≤0.15

/

/

/

0.11～0.16

L80

0.15～0.22

≤1.00

0.25～1.00

≤0.020

≤0.010

12.0～14.0

≤0.20

≤0.20

/

/

P110

0.26～0.395

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


API 5CT Casing Pipe Mechanical Properties

Grade Type Total elongation under load (%)
 Yield strength (min)
 Yield strength (max)
 Tensile strength min Mpa
 Hardness Max (HRC)
 Hardness Max (HBW)
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

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
 621 724 689 25.4 255
C95 - 0.5
 655 758 724

T95 - 0.5 655 758 724 25.4 255
P110 - 0.6 758 965 862

Q125 All 0.65 862 1034 931

  • Inquiry

Frequently Asked Questions

1. What is the difference between API 5CT casing grades?

API 5CT casing grades differ in strength and corrosion resistance:

J55/K55 - standard strength for shallow wells

N80 - higher strength with better corrosion resistance

L80 - contains chromium for H2S resistance

R95 - higher yield strength

P110 - highest strength for deep wells

Q125 - ultra-high strength for extreme depths

Selection depends on well depth, pressure, and service conditions.

2. What are the main types of casing thread connections?

Three main types:

(1) BTC (Buttress Thread Casing) - most common, excellent sealing for high-pressure wells

(2) LTC (Line Pipe Thread Casing) - uses gasket seal, good for medium pressure

(3) STC (Short Thread Casing) - economical option for low-pressure applications

Premium connections are also available for critical applications.

3. How do you ensure casing quality and traceability?

Every casing undergoes:

(1) 100% visual inspection per API 5CT

(2) Dimensional inspection including OD, wall thickness, roundness

(3) Thread inspection with gauge tools

(4) Hydrostatic test per API 5CT

(5) Eddy current testing for defect detection

All casing is traceable by heat number with full MTC (Mill Test Certificate) per EN 10204 3.1.

4. What is the difference between short string and long string casing?

Short string casing has thread connections at both ends with standard length (approx 9.6m), used for most completions.

Long string casing has continuous thread from one end to the other, eliminating couplings in the string, used for deep wells to reduce potential leak points.

Long string requires special handling and is more expensive.

5. What coating and protection options are available for casing?

Available options:

(1) Phosphating - improves thread lubrication and storage life

(2) Cement coating - for cementing operations

(3) Internal coating - epoxy or zinc for corrosion protection

(4) Thread compound - API-compliant compounds for running

We recommend specific coating based on well conditions (temperature, H2S, CO2 content).

6. What certifications and testing reports do you provide?

Every shipment includes:

(1) EN 10204 3.1 mill test certificate

(2) Chemical composition report

(3) Mechanical properties report (tensile, yield, hardness)

(4) Dimensional report

(5) Hydrostatic test report

(6) Thread inspection report

Third-party inspections (SGS, BV, API) can be arranged upon request.