Standard No.:	GB/T 16866-2026
English Name:	Dimensions and tolerances of copper and copper alloy seamless tubes
Chinese Name:	铜及铜合金无缝管材外形尺寸及允许偏差
Professional Classification:	GB    National Standard
Source Content Issued by:	SAMR, SAC
Issued on:	2026-05-22
Implemented on:	2026-12-1
Status:	to be valid
Superseding:	GB/T 16866-2006 Dimensions and tolerances of copper and copper alloy seamless tubes
Target Language:	English
File Format:	PDF
Word Count:	9500 words
Translation Price(USD):	285.0
Delivery:	via email in 1~3 business day

GB/T 16866-2026 Dimensions and tolerances of copper and copper alloy seamless tubes English, Anglais, Englisch, Inglés, えいご This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered. ICS CCS National Standard of the People's Republic of China ‌GB/T 16866-2026 Dimensions and tolerances of copper and copper alloy seamless tubes 铜及铜合金无缝管材外形尺寸及允许偏差 Issue date: 2026-01-28 Implementation date: 2027-02-01 Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China the Standardization Administration of the People's Republic of China Contents Foreword 1 Scope 2 Normative references 3 Terms and definitions 4 Technical requirements 5 Test methods Seamless copper and copper alloy tubes — Dimensions and tolerances 1 Scope This document specifies the technical requirements and test methods for dimensions and tolerances of seamless copper and copper alloy tubes. This document is applicable to the production and delivery of extruded seamless round tubes and drawn seamless round, rectangular (square) tubes of copper and copper alloys. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies. GB/T 8170, Rules of rounding off for numerical values and expression and judgement of limiting values GB/T 26303.1-2010, Measuring methods for dimensions of wrought copper and copper alloy products — Part 1: Tubes 3 Terms and definitions For the purposes of this document, the terms and definitions given in GB/T 26303.1-2010, as well as the following, apply. 3.1 average outside diameter The average of the maximum outside diameter and minimum outside diameter at any cross-section of a round tube. [Source: GB/T 26303.1-2010, 2.4, modified] 3.2 roundness The difference between the maximum and minimum outside diameters at any cross-section of a round tube. [Source: GB/T 26303.1-2010, 2.7] 3.3 straightness The maximum arc depth of a straight tube over a specified length. Note: The maximum arc depth is expressed as the maximum distance of the tube centreline from the axis. [Source: GB/T 26303.1-2010, 2.8, modified] 3.4 fixed length A specified length to which tubes are uniformly cut, complying with the specified permissible tolerances. 3.5 twist The relative torsional angle (or maximum vertical distance) between two cross-sections over a certain length of a rectangular (square) tube. [Source: GB/T 26303.1-2010, 2.10, modified] 3.6 squareness of cut The maximum vertical distance between the cut surface of a tube and the cross-section. [Source: GB/T 26303.1-2010, 2.11] 3.7 minor axis The minimum outside diameter at any cross-section of a round tube after elliptical deformation caused by uncontrollable factors.