GB/T 6728-2025 PDF English
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GB/T 6728: Historical versions
| Standard ID | USD | BUY PDF | Delivery | Standard Title (Description) | Status |
| GB/T 6728-2025 | 585 | Add to Cart | Auto, 9 seconds. | Cold forming sectional steel for general structure | Valid |
| GB/T 6728-2017 | 145 | Add to Cart | Auto, 9 seconds. | Cold forming hollow sectional steel for general structure | Valid |
| GB/T 6728-2002 | 70 | Add to Cart | Auto, 9 seconds. | Cold formed steel hollow sections for general structure -- Dimensions, shapes, weight and permissible deviations | Obsolete |
| GB/T 6728-1986 | 399 | Add to Cart | 3 days | Cold forming sectional steel--Hollow sectional steel for general structure--Dimension, form, weight and permissible deviations | Obsolete |
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GB/T 6728-2025: Cold forming sectional steel for general structure
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT6728-2025GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 77.140.70 CCS H 44 Replacing GB/T 6728-2017, GB/T 6723-2017 Cold forming sectional steel for general structure Issued on: AUGUST 29, 2025 Implemented on: MARCH 01, 2026 Issued by. State Administration for Market Regulation; Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 4 1 Scope... 6 2 Normative references... 6 3 Terms and definitions... 7 4 Ordering details... 7 5 Classification, codes... 8 6 Technical requirements... 8 6.1 Cross-section, dimensions and allowable deviations... 8 6.2 Length and allowable deviation... 91 6.3 Appearance... 92 6.4 Weight and allowable deviations... 95 6.5 Designation and chemical composition... 95 6.6 Raw materials... 96 6.7 Manufacturing process... 96 6.8 Mechanical properties... 96 6.9 Surface quality... 97 6.10 Weld quality... 97 6.11 Zinc coating... 98 7 Test methods... 99 8 Inspection rules... 99 8.1 Inspection and acceptance... 99 8.2 Batching rules... 100 8.3 Re-inspection and judgment rules... 100 8.4 Numerical rounding... 100 9 Packaging, marks, transportation, storage and quality certificate... 100 9.1 Packaging... 101 9.2 Marks... 102 9.3 Transportation... 103 9.4 Storage... 103 9.5 Quality certificate... 103 Annex A (informative) Formula for calculating cross-sectional properties... 104 Annex B (normative) Allowable deviation of sectional steel wall thickness... 106 Annex C (normative) Determination of the weight of zinc coating layer -- Antimony chloride method... 110 C.1 Specimen preparation... 110 C.2 Preparation of test solution... 110 C.3 Test procedure... 110 C.4 Test operation method... 110 Cold forming sectional steel for general structure1 Scope
This document specifies the ordering details, classification, codes, technical requirements, inspection rules, packaging, marks, transportation, storage, and quality certificate for cold forming sectional steel for general structure (hereinafter referred to as sectional steel). It also describes the corresponding test methods. This document applies to general-purpose cold forming open-sectional steel (hereinafter referred to as open-sectional steel), round, rectangular, and square cold forming closed-sectional steel (hereinafter referred to as closed-sectional steel) produced from cold-rolled or hot-rolled steel plates and strips on continuous roll forming units. It also applies to continuously hot-dip galvanized steel (hereinafter referred to as galvanized steel). This document does not apply to sectional steel formed by cold bending and welding of galvanized steel sheets and strips.2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 222, Steels and alloys - Allowable deviations of product analyzed chemical composition GB/T 228.1, Metallic materials - Tensile testing - Part 1.Method of test at room temperature GB/T 229, Metallic materials - Charpy pendulum impact test method GB/T 470-2008, Zinc ingots GB/T 699, Quality carbon structure steels GB/T 700, Carbon sectional steels GB/T 709, Dimension, shape, weight and tolerance for hot-rolled steel strip, plate and sheet GB/T 714, Sectional steel for bridge GB/T 1591, High strength low alloy sectional steels GB/T 2101, General Requirement of Acceptance, Packaging, Marking and Certification for Sectional steel GB/T 2102, Acceptance, packaging, marking and quality certification for steel tubular products GB/T 2975, Steel and steel products - Location and preparation of samples and test pieces for mechanical testing GB/T 3280, Cold rolled stainless steel plate, sheet and strip GB/T 4171, Atmospheric corrosion resisting sectional steel GB/T 8170, Rules of rounding off for numerical values and expression and judgement of limiting values GB/T 20066, Steel and iron - Sampling and preparation of samples for the determination of chemical composition GB/T 20878, Stainless steels - Designation and chemical composition GB/T 33162, Continuously Hot-rolled Steel Sheet and Strip for Cold-forming Sectional steels3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. 3.1 free edge In open-sectional steel, an edge that only one end has a rounded corner (R-angle). 3.2 non-free edge In open-sectional steel, an edge that both ends have rounded corners (R-angle).4 Ordering details
The contracts or orders placed in accordance with this document include the following. a) Reference to this document; b) Product name; c) Steel designation; d) Delivery weight; e) Dimensions and shape; f) Special requirements.5 Classification, codes
5.1 Closed-sectional steel is classified into square, rectangular, and circular shapes according to its external shape. Their codes are as follows. a) Square sectional steel (also known as square tube). F; b) Rectangular sectional steel (also known as rectangular tube). J; c) Circular sectional steel (also known as circular tube). Y (or ϕ). 5.2 Open-section sectional steel is classified into nine types according to the cross- sectional shape. Their codes are as follows. a) Cold forming equal angle steel. JD; b) Cold forming unequal angle steel. JB; c) Cold forming equal channel steel. CD; d) Cold forming unequal channel steel. CB; e) Cold forming inward-curled channel steel. CN; f) Cold forming outward-curled channel steel. CW; g) Cold forming Z-shaped steel. Z; h) Cold forming rolled-edge Z-shaped steel. ZJ; i) Cold forming rolled-edge equal angle steel. JJ.6 Technical requirements
6.1 Cross-section, dimensions and allowable deviations 6.1.1 Closed-sectional steel 6.1.1.1 The cross-sectional view of the square sectional steel is shown in Figure 1.The cross-sectional dimensions, allowable deviations, theoretical weight, cross-sectional area, and cross-sectional properties shall conform to the provisions of Table 1.The cross-sectional area, cross-sectional property parameters, and surface area per meter of length are for reference only. 6.1.1.2 The cross-sectional view of the rectangular sectional steel is shown in Figure 2. The cross-sectional dimensions, allowable deviations, theoretical weight, cross- sectional area, and cross-sectional properties shall conform to the provisions of Table 2.The cross-sectional area, cross-sectional property parameters, and surface area per meter of length are for reference only. 6.1.1.3 The cross-sectional view of the circular sectional steel is shown in Figure 3.The cross-sectional dimensions, allowable deviations, theoretical weight, cross-sectional area, and cross-sectional properties shall conform to the provisions of Table 3.The cross-sectional area, cross-sectional property parameters, and surface area per meter of length are for reference only. 6.1.1.4 The cross-sectional properties of closed-sectional steel can be calculated with reference to Annex A. Sectional steels with dimensions and allowable deviations other than those specified in Tables 1, 2, and 3 may be provided upon negotiation between the supplier and the purchaser and as specified in the contract. 6.1.1.5 The allowable deviation of the wall thickness of closed-sectional steel shall comply with the provisions of Annex B. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
