QC/T 1256-2025 Hexagon bolts with flange for automobile 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
T
Professional Standard of the People's Republic of China
QC/T 1256-2025
Hexagon bolts with flange for automobile
汽车用六角法兰面螺栓
(English Translation)
Issue date: 2025-12-17 Implementation date: 2026-07-01
Issued by the Ministry of Industry and Information Technology of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Type Dimensions
5 Technical Requirements
6 Product NumberingHexagon Flange Bolts for Automotive Use
1 Scope
This document specifies the type dimensions, technical conditions, and marking for hexagon flange bolts for automotive use.
This document applies to hexagon flange bolts for automotive use with nominal thread diameter d=5 mm to 22 mm, performance classes 8.8 and 10.9, and product grade A.
2 Normative References
The following documents are essential for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including all amendments) applies.
GB/T 2 Fasteners — Ends of Parts with External Thread
GB/T 90.1 Fasteners — Inspection and Acceptance
GB/T 90.2 Fasteners — Marking and Packaging
GB/T 193 General Purpose Metric Screw Threads — Diameters and Pitches
GB/T 3098.1 Mechanical Properties of Fasteners — Bolts, Screws and Studs
GB/T 3103.1 Fasteners — Tolerances — Bolts, Screws, Studs and Nuts
GB/T 5276 Fasteners — Bolts, Screws, Studs and Nuts — Symbols and Designations of Dimensions
GB/T 5779.3 Fasteners — Surface Discontinuities — Bolts, Screws and Studs — Special Requirements
GB/T 9145 General Purpose Metric Screw Threads — Limit Dimensions for Medium Quality and Preferred Series
GB/T 30512 Requirements for Prohibited Substances in Automobiles
QC/T 326 Product Numbering Rules for Automotive Fasteners
QC/T 625 Coatings and Chemical Treatment Layers for Automotive Use
3 Terms and Definitions
This document does not define any specific terms and definitions.
4 Types and Dimensions
4.1 The types and dimensions for hexagon flange bolts for automotive use shall be as shown in Figures 1 to 4 and Table 1.
4.2 Symbols and designations of dimensions shall comply with the provisions of GB/T 5276.
4.3 In Table 1, threads with nominal lengths above the dividing line shall be full threads. If the product passes the inspection in Appendix A, it shall be considered to meet the requirements for dimensions c, e, and kw. In Table 1, lg max = l nominal - b; ls min = lg max - 5P, where P is the coarse pitch.
The top surface of the head shall be flat or recessed, at the manufacturer's option. The top surface shall be chamfered or rounded. The minimum starting diameter of the chamfer or rounding shall be the maximum width across flats minus 15% of its value. If the top surface of the head is made recessed, its edges may be rounded.
The length of incomplete threads u ≤ 2P (P is the coarse pitch).
Chamfered end (GB/T 2).
Figure 1 Hexagon Flange Bolts for Automotive Use — Reduced Shank (Standard Type)
5 Technical Conditions
Technical conditions shall comply with the provisions of Table 2.
6 Product Numbering
The product numbering for hexagon flange bolts for automotive use shall comply with the provisions of QC/T 326.
Appendix A
(Informative)
Inspection of Hexagon Flange Heads
A.1 Recommended Inspection Method for Hexagon Part
The recommended inspection method for the hexagon part is shown in Figure A.1 and Table A.1.
To determine whether the hexagon height, wrenching height, fillet, and width across corners meet the requirements, two smooth ring gauges, A and B, shall be used to measure the head. First, place gauge A over the hexagon part and onto the flange surface, then place gauge B on top of the hexagon. The two gauges shall not contact each other.
A.2 Recommended Inspection Method for Flange Thickness
The recommended inspection method for flange thickness is shown in Figure A.1 and Table A.1.
Gauge C is a feeler gauge or ring gauge. It is used to check whether the flange thickness at the junction of the gauge and the hexagon part is equal to or greater than the specified value. When the bolt is placed on a flat plate, gauge C shall be able to be inserted under gauge A without contact.
Standard
QC/T 1256-2025 Hexagon bolts with flange for automobile (English Version)
QC/T 1256-2025 Hexagon bolts with flange for automobile 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
T
Professional Standard of the People's Republic of China
QC/T 1256-2025
Hexagon bolts with flange for automobile
汽车用六角法兰面螺栓
(English Translation)
Issue date: 2025-12-17 Implementation date: 2026-07-01
Issued by the Ministry of Industry and Information Technology of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Type Dimensions
5 Technical Requirements
6 Product NumberingHexagon Flange Bolts for Automotive Use
1 Scope
This document specifies the type dimensions, technical conditions, and marking for hexagon flange bolts for automotive use.
This document applies to hexagon flange bolts for automotive use with nominal thread diameter d=5 mm to 22 mm, performance classes 8.8 and 10.9, and product grade A.
2 Normative References
The following documents are essential for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including all amendments) applies.
GB/T 2 Fasteners — Ends of Parts with External Thread
GB/T 90.1 Fasteners — Inspection and Acceptance
GB/T 90.2 Fasteners — Marking and Packaging
GB/T 193 General Purpose Metric Screw Threads — Diameters and Pitches
GB/T 3098.1 Mechanical Properties of Fasteners — Bolts, Screws and Studs
GB/T 3103.1 Fasteners — Tolerances — Bolts, Screws, Studs and Nuts
GB/T 5276 Fasteners — Bolts, Screws, Studs and Nuts — Symbols and Designations of Dimensions
GB/T 5779.3 Fasteners — Surface Discontinuities — Bolts, Screws and Studs — Special Requirements
GB/T 9145 General Purpose Metric Screw Threads — Limit Dimensions for Medium Quality and Preferred Series
GB/T 30512 Requirements for Prohibited Substances in Automobiles
QC/T 326 Product Numbering Rules for Automotive Fasteners
QC/T 625 Coatings and Chemical Treatment Layers for Automotive Use
3 Terms and Definitions
This document does not define any specific terms and definitions.
4 Types and Dimensions
4.1 The types and dimensions for hexagon flange bolts for automotive use shall be as shown in Figures 1 to 4 and Table 1.
4.2 Symbols and designations of dimensions shall comply with the provisions of GB/T 5276.
4.3 In Table 1, threads with nominal lengths above the dividing line shall be full threads. If the product passes the inspection in Appendix A, it shall be considered to meet the requirements for dimensions c, e, and kw. In Table 1, lg max = l nominal - b; ls min = lg max - 5P, where P is the coarse pitch.
The top surface of the head shall be flat or recessed, at the manufacturer's option. The top surface shall be chamfered or rounded. The minimum starting diameter of the chamfer or rounding shall be the maximum width across flats minus 15% of its value. If the top surface of the head is made recessed, its edges may be rounded.
The length of incomplete threads u ≤ 2P (P is the coarse pitch).
Chamfered end (GB/T 2).
Figure 1 Hexagon Flange Bolts for Automotive Use — Reduced Shank (Standard Type)
5 Technical Conditions
Technical conditions shall comply with the provisions of Table 2.
6 Product Numbering
The product numbering for hexagon flange bolts for automotive use shall comply with the provisions of QC/T 326.
Appendix A
(Informative)
Inspection of Hexagon Flange Heads
A.1 Recommended Inspection Method for Hexagon Part
The recommended inspection method for the hexagon part is shown in Figure A.1 and Table A.1.
To determine whether the hexagon height, wrenching height, fillet, and width across corners meet the requirements, two smooth ring gauges, A and B, shall be used to measure the head. First, place gauge A over the hexagon part and onto the flange surface, then place gauge B on top of the hexagon. The two gauges shall not contact each other.
A.2 Recommended Inspection Method for Flange Thickness
The recommended inspection method for flange thickness is shown in Figure A.1 and Table A.1.
Gauge C is a feeler gauge or ring gauge. It is used to check whether the flange thickness at the junction of the gauge and the hexagon part is equal to or greater than the specified value. When the bolt is placed on a flat plate, gauge C shall be able to be inserted under gauge A without contact.
