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

Foreword

This Part is one of the series standards of "Hexalobular Socket Screws". This series includes:

---GB/T 2671.1 Hexalobular Socket Cheese (short) Head Screws;

---GB/T 2671.2 Hexalobular Socket Head Cap Screws;

---GB/T 2672 Hexalobular Socket Pan Head Screws;

---GB/T 2673.1 Hexalobular Socket Countersunk Flat Head Screws;

---GB/T 2673.2 Hexalobular Socket High Countersunk Head Screws;

---GB/T 2674 Hexalobular Socket Raised Countersunk Head Screws.

This is Part 2 of GB/T 2673.

This Part was drafted in accordance with the rules provided in GB/T 1.1-2009.

This Part uses the re-drafting method in the modification and adopt of ISO 14582:2013

Fasteners - Hexalobular Socket Countersunk Head Screws, High Head.

In comparison with ISO 14582:2013, the technical differences and the causes for these

differences are as follows:

---The stipulation of ISO 14582:2013 "if other technical requirements are required, ......

choose from ISO 4759-1." is deleted (see Chapter 1 of ISO 14582:2013), because it

does not belong to the content specified in this Part;

---In Normative References, Chinese standards are used to replace international standards

(see Chapter 2), and the references GB/T 2, GB/T 90.2 (see Table 2), GB/T 1237 (see

Chapter 6) and GB/T 5267.4 (see Table 2) are added, so as to comply with the

fundamental standards on fasteners in our country;

---The technical requirements for packaging are added (see Table 2), so as to comply with

the fundamental standards on fasteners in our country;

---The designation example is modified into simplified designation example (see 6.2), so

as to comply with the stipulations of GB/T 1237.

This Part also makes the following editorial modifications:

---The title of the Standard is modified;

---The "Bibliography" is modified.

This Part was proposed by China Machinery Industry Federation.

Hexalobular Socket High Countersunk Head Screws

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.

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