GB/T 2673.2-2020Hexalobular socket high countersunk head screws (English PDF)

1 Scope

This Part of GB/T 2673 specifies the type dimensions, technical conditions and markings of hexalobular socket high countersunk head screws, as well as gauge size that controls the height of the head.

This Part is applicable to hexalobular socket high countersunk head screws with the thread specification of M3 ~ M10, the performance grade of 4.8, 8.8 and 10.9, and the product grade of Grade-A.

NOTE 1: in comparison with ordinary countersunk head screws, the height of the head is slightly increased, so that the screws can have the full load-bearing capacity that complies with the stipulations of GB/T 3098.1.

NOTE 2: due to the increased head height, the screws specified in this Part are not completely interchangeable with other metric countersunk head screws. The countersink of the assembled parts also needs to be slightly deeper than the depth specified in GB/T 152.2.

2 Normative References

The following documents are indispensable to the application of this document. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 2 Fasteners - Ends of Parts with External Thread (GB/T 2-2016, ISO 4753:2011, MOD)

GB/T 90.1 Fasteners - Acceptance Inspection (GB/T 90.1-2002, idt ISO 3269:2000)

GB/T 90.2 Fasteners - Marking and Packaging

GB/T 193 General Purpose Metric Screw Threads - General Plan (GB/T 193-2003, ISO 261:1998, MOD)

GB/T 1237 Designation System for Fasteners (GB/T 1237-2000, eqv ISO 8991:1986)

GB/T 3098.1 Mechanical Properties of Fasteners - Bolts, Screws and Studs (GB/T 3098.1-2010,

ISO 898-1:2009, MOD)

GB/T 3103.1 Essential Oils and Aromatic Extracts - Determination of Residual Benzene

Content (GB/T 3103.1-2002, idt ISO 4759-1:2000)

GB/T 5267.1 Fasteners - Electroplated Coatings (GB/T 5267.1-2002, ISO 4042:1999, IDT)

GB/T 5267.2 Fasteners - Non-electrolytically Applied Zinc Flake Coatings (GB/T 5267.2-2017,

ISO10683:2014, MOD)

GB/T 5267.3 Fasteners - Hot Dip Galvanized Coatings (GB/T 5267.3-2008, ISO 10684:2004,

IDT)

GB/T 5276 Fasteners - Bolts, Screws, Studs and Nuts - Symbols and Descriptions of

Dimensions (GB/T 5276-2015, ISO 225:2010, MOD)

GB/T 5279 Countersunk Head Screws - Head Configuration and Gauging (GB/T 5279-1985, idt ISO 7721:1983)

GB/T 5779.1 Fasteners - Surface Discontinuities - Bolts, Screws and Studs for General

Requirements (GB/T 5779.1-2000, idt ISO 6157-1:1988)

GB/T 6188 Hexalobular Internal Driving Feature for Bolts and Screws (GB/T 6188-2017, ISO 10664:2014, IDT)

GB/T 9145 General Purpose Metric Screw Threads - Limits of Sizes for the Screw Threads of

Medium Quality and Preferable Plan (GB/T 9145-2003, ISO 965-2:1998, MOD)

GB/T 16938 Fasteners - General Requirements for Bolts, Screws, Studs and Nuts (GB/T 16938-

2008, ISO 8992:2005, IDT)

3 Type Dimensions

The type dimensions of the screws are shown in Figure 1, Figure 2 and Table 1.

The symbols and descriptions of dimensions shall comply with GB/T 5276. […]