GB/T 8-2021 English PDF (GBT8-2021)

This document specifies the types, dimensions, technical conditions, and marking of square head bolts. This document is applicable to square head bolts with thread specifications of M10~M48 and product grade C.

GB/T 8-2021
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 21.060.10
CCS J 13
Replace GB/T 8-1988
Square head bolts -- Product grade C
ISSUED ON. DECEMBER 31, 2021
IMPLEMENTED ON. JULY 1, 2022
Issued by. State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative references... 5
3 Terms and definitions... 6
4 Type and dimensions... 6
5 Technical conditions and reference standards... 7
6 Marking... 8
Foreword
This standard is drafted in accordance with the provisions of GB/T 1.1-2020 “Directives for standardization - Part 1.Rules for the structure and drafting of standardizing documents”.
This document is one of the national standards for the “Square head bolts” series, in the series the following documents have been issued.
--- GB/T 8 Square head bolts -- Product grade C;
--- GB/T 35 Square head bolts with small head.
This standard replaces GB/T 8-1988 “Square head bolts -- Product grade C”. Compared with GB/T 8-1988, except for the structural adjustment and editorial revisions, the main technical content changes are as follows.
a) The reference thread standards are unified as GB/T 193 and GB/T 9146 (see Table 2; see Table 2 of the 1988 edition);
b) “Commodity specification range” is replaced with “Preferred length range” (see Table 1; see Table 1 of the 1988 edition);
c) “The general technical conditions are in accordance with GB/T 16938”, the provision is added (see Table 2);
d) The oxidation surface treatment is deleted (see Table 2 of the 1988 edition); e) “The technical requirements for non-electrolytically applied zinc flake coatings are in accordance with GB/T 5267.2”, the provision is added (see Table 2); f) “If other technical requirements or surface treatment are required, they shall be agreed upon by the supplier and the buyer”, the provision is added (see Table 2); g) “The requirements for surface defects are in accordance with GB/T 5779.1”, the provision is added (see Table 2).
Please note that some of the contents of this document may involve patents. The issuing agency of this document is not responsible for identifying patents.
This document was proposed by China Machinery Industry Federation.
This document shall be under the jurisdiction of the Technical Committee on Fasteners of Standardization Administration of China (SAC/TC85).
Square head bolts -- Product grade C
1 Scope
This document specifies the types, dimensions, technical conditions, and marking of square head bolts.
This document is applicable to square head bolts with thread specifications of M10~M48 and product grade C.
2 Normative references
The following documents contain the provisions which, through normative reference in this document, constitute the essential provisions of this document. For the dated referenced documents, only the versions with the indicated dates are applicable to this document; for the undated referenced documents, only the latest version (including all the amendments) is applicable to this document.
GB/T 2 Fasteners -- Ends of parts with external thread
GB/T 90.1 Fasteners -- Acceptance inspection
GB/T 90.2 Fasteners -- Marking and packaging
GB/T 193 General purpose metric screw threads -- General plan
GB/T 1237 Designation system for fasteners
GB/T 3098.1 Mechanical properties of fasteners -- Bolts, screws and studs GB/T 3103.1 Tolerances for fasteners -- Bolts, screws, studs and nuts
GB/T 5267.1 Fasteners -- Electroplated coatings
GB/T 5267.2 Fasteners -- Non-electrolytically applied zinc flake coatings GB/T 5276 Fasteners -- Bolts, screws, studs and nuts -- Symbols and descriptions of dimensions
GB/T 5779.1 Fasteners -- Surface discontinuities -- Bolts, screws and studs for general requirements
GB/T 9146 General purpose metric screw threads -- Limits of sizes for the screw