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GB/T 18052-2025Methods of gauging and inspection of casing, tubing and line pipe threads (English PDF)

套管、油管和管线管螺纹的测量和检验方法

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

October 5, 2025

Implementation date

May 1, 2026

Scope

GB/T 18052-2025 is the English-translated version of 套管、油管和管线管螺纹的测量和检验方法.

GB/T 18052-2025 is the Chinese standard "Methods of gauging and inspection of casing, tubing and line pipe threads". Its scope clause reads: This document describes the appearance and dimensions of round threaded sleeves and tubing, trapezoidal threaded sleeves, special threaded sleeves and tubing, and line pipe threads.

Methods for measuring and inspecting individual parameters such as inch, tightness, and thread. This document applies to the measurement and inspection of casing, tubing, and pipeline threads. Its clauses include terms, definitions, symbols and abbreviations.

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Document preview — GB/T 18052-2025

National Standard of the People's Republic of China

ICS: 75.180.10
Classification: E 92
Replacing: GB/T 18052-2000

Issued by: State Administration for Market Regulation; Standardization Administration of the PRC

Preface
1.Scope
2 Normative References
3.Terms, Definitions, Symbols, and Abbreviations
3.1 Terms and Definitions
3.2 Symbol
3.3 Abbreviations
4 Threaded connectors
4.1 General Rules
4.2 Pipeline threads
4.3 Round threads of tubing and casing
4.4 Casing with trapezoidal thread
4.5 Special threads for tubing and casing
4.6 Thread Measurement and Inspection Items
5 Inspectors
5.1 General Rule
5.2 Training Content
5.3 Qualification
6.Calibration, use and storage of measuring instruments
6.1 General Rules
6.2 Calibration
6.3 Use
6.4 Store
7.Visual inspection
7.1 General Rule
7.2 Inspection Tools
7.3 Visual Inspection Steps
7.4 Visual inspection of external threads
7.5 Visual inspection of internal threads
8.Thread measurement
8.1 General Rules
8.2 Measurement Location and Measurement Interval
8.3 Thread length
8.4 Triangle with 28-point marking
8.5 taper
8.6 Pitch
8.7 Tooth height
8.8 Tooth crest height
8.9 Thread major diameter and ovality
8.10 Sealing diameter and ovality
8.11 Thread profile measurement
8.12 Screw tail
8.13 Tooth thickness/alveolar width
8.14 Coupling thread axis overlap
8.15 Internal thread torque shoulder depth
8.16 Close distance
Appendix A (Informative) Typical Thread Measuring Instrument Configuration
Appendix B (Normative) Requirements for Automated Thread Measurement Systems
Appendix C (Normative) Requirements for Thread Digital Inspection Systems
Appendix D (Informative) Factors Affecting the Repeatability of Measurement Results
Appendix E (Normative) Measurement of Sealing Ring Groove Depth
Appendix F (Informative) Thread Measurement and Inspection Record Format

1 Scope

This document describes the appearance and dimensions of round threaded sleeves and tubing, trapezoidal threaded sleeves, special threaded sleeves and tubing, and line pipe threads.

Methods for measuring and inspecting individual parameters such as inch, tightness, and thread.

This document applies to the measurement and inspection of casing, tubing, and pipeline threads.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.

For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.

This document.

GB/T 9253 Machining, Measurement and Inspection of Casing, Tubing and Line Threads in the Oil and Gas Industry

GB/T 14791 Thread Terminology

JJF1063 Oil Thread Single Parameter Checker

JJF1108 Calibration Specification for Petroleum Thread Working Gauges

SY/T 6445 Terminology for Common Defects in Oil Pipes

3 Terms, definitions, symbols and abbreviations

3.1 Terms and Definitions

The following terms and definitions apply to this document.

3.1.1 tooth top height addendum

The radial distance between the crest of a threaded tooth and its mid-diameter.

[Source. GB/T 14791-2013, 4.15]

3.1.2 tooth height of thread

The radial distance between the crest and the root of a threaded tooth.

[Source. GB/T 14791-2013, 4.14]

3.1.3 Thread profile

The thread profile shape over a pitch length in the axial plane.

3.1.4 black-crested threads

Incomplete threads are formed due to the original rolled surface not being removed.

[Source. GB/T 9253-2022, 3.1.4]

GB/T 18604 | GB/T 23258 | SY/T 5164 | GB/T 29169 | GB/T 17389 | […]

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 78 pages — is available in the English PDF.

Referenced standards

Normative references

JJF1063 · JJF1108

Cited by

Editions of GB/T 18052

Edition	Title	Revision	Status
GB/T 18052-2025	Methods of gauging and inspection of casing, tubing and line pipe threads	current edition	Current

This page sells the current edition, GB/T 18052-2025. Earlier editions are listed for reference only.

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