This standard is equivalent to the international standard ISO 8676:1999 Hexagon head screws with metric fine pitch thread - Product grades A and B.
This standard is part of the series standards on Hexagon drive fasteners. The series comprises:
a) Hexagon head bolts: GB/T 27, GB/T 28, GB/T 29.1, GB/T 29.2, GB/T 31.1, GB/T 31.2, GB/T 31.3, GB/T 32.1, GB/T 32.2, GB/T 32.3, GB/T 5780, GB/T 5781, GB/T 5782, GB/T 5783, GB/T 5784, GB/T 5785 and GB/T 5786;
b) Hexagon nuts: GB/T 41, GB/T 56, GB/T 802, GB/T 804, GB/T 805, GB/T 808, GB/T 889.1,/T 889.2, GB/T 923, GB/T 6170, GB/T 6171, GB/T 6172.1, GB/T 6172.2, GB/T 6173, GB/T 6174, GB/T 6175, GB/T 6176, GB/T 6178, GB/T 6179, GB/T 6180, GB/T 6181, GB/T 6182, GB/T 6184, GB/T 6185.1, GB/T 6185.2, GB/T 6186, GB/T 9457, GB/T 9458, GB/T 9459 and GB/T 18195;
c) Hexagon bolts with flange: GB/T 5789, GB/T 5790 and GB/T 16674;
d) Hexagon nuts with flange: GB/T 6177.1, GB/T 6177.2, GB/T 6183.1, GB/T 6183.2, GB/T 6187.1 and GB/T 6187.2;
e) Bolted joints for structural bolting: GB/T 1228, GB/T 1229, GB/T 1230, GB/T 3632, GB/T 16939, GB/T 18230.1, GB/T 18230.2, GB/T 18230.3, GB/T 18230.4, GB/T 18230.5, GB/T 18230.6 and GB/T 18230.7;
f) Hexagon head screws, wood screws, tapping screws and assemblies: GB/T 838, GB/T 102, GB/T 5285, GB/T 6563, GB/T 9456, GB/T 15856.4, GB/T 16824.1, GB/T 16824.2, GB/T 9074.11, GB/T 9074.12, GB/T 9074.13, GB/T 9074.14, GB/T 9074.15, GB/T 9074.16, GB/T 9074.17, GB/T 9074.20, GB/T 9074.21, GB/T 9074.22 and GB/T 9074.23.
ISO 8676 does not specify technical requirements for packaging, which are specified in this standard (Table 3).
Simplified designation is not specified in ISO 8676, while this standard provides a simplified example of designation (5.2) in accordance with the simplification principle of GB/T 1237.
This standard does not adopt the catalog attached to ISO 8676, which the contents are listed in foreword.
This standard is the revision of GB/T 5786-1986, the main changes in this standard are as follows:
a) The range of length specifications is expanded to 500mm;
b) Classified according to the degree of thread preference: Table 1 Preferred threads (equivalent to Tables 1 and 2 of the old standard); Table 2 Non-preferred threads (equivalent to Table 3 of the old standard), but M20×1.5 is listed in Table 1(preferred); M20×2 listed in Table 2 (non-preferred);
c) 5.6 levels is added;
d) The non-ferrous metal bolt, with reference to GB/T 3098.10 by the supply and demand sides agreed to choose the performance level is added (Table 3);
e) Non-electrolytic zinc powder coating is added (Table 3).
This standard replaces GB/T 5786-1986 from the implementation date hereof.
This standard was proposed by the State Bureau of Machine Building Industry.
This standard is under the jurisdiction of National Technical Committee on Fasteners of Standardization Administration of China.
The Secretariat of the National Technical Committee on Fasteners of Standardization Administration of China is in charge of the explanation of this standard.
ISO Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% approval by the member bodies voting.
International Standard ISO 8676 was prepared by Technical Committee ISO/TC 2, Fasteners.
This second edition cancels and replaces the first edition (ISO 8676:1988), which has been technically revised.
ISO Introduction
This International Standard is part of the complete ISO product standard series on External hexagon drive fasteners. The series comprises:
a) Hexagon head bolts (ISO 4014 to ISO 4016 and ISO 8765);
b) Hexagon head screws (ISO 4017,ISO 4018 and ISO 8676);
c) Hexagon nuts (ISO 4032 to ISO 4036,ISO 8673 to ISO 8675):
d) Hexagon bolts with flange (ISO 4162 and ISO 15071);
e) Hexagon nuts with flange (ISO 4161 and ISO 10663):
f) Structural bolts and nuts (ISO 4775, ISO 7411 to ISO 7414 and ISO 7417).
Hexagon head bolts with fine pitch thread - Full thread
1 Scope
This standard specifies hexagon head bolts with thread specifications M8×1 to M64×4, fine thread, full thread, performance grades 5.6, 8.8, 10.9, A2-70, A4-70, A2-50, A4-50, CU2, CU3 and AL4, product grades A and B. Grade A bolts are used for the bolts with d= 8 to 24mm and l ≤ 10d or l ≤ 150 mm (whichever is smaller); Grade B bolts are used for the bolts with d >24mm and l > 10d or l > 150mm (whichever is smaller).
If, in special cases, specifications other than those listed in this standard are required, they shall be selected from existing standards, for example GB/T 196, GB/T 3106, GB/T 3098.1, GB/T 3098.6 and GB/T 3103.1.
Coarse thread screws according to GB/T 5783 should be first choice.
2 Normative references
The following standards contain provisions which, through reference in this standard, constitute provisions of this standard. At the time of publication, all editions listed were valid. All normative references are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the latest editions of the normative standards indicated below.
GB/T 2-1985 Fasteners - Ends of parts with external thread (eqv ISO 4753: 1983)
GB/T 90-1985 Acceptance inspection, marking and packaging of fasteners (eqv ISO 3269:1984)
GB/T 196-1981 General purpose screw threads-Basic dimensions for diameter from 1 to 600 mm
GB/T 197-1981 General purpose screw threads - Tolerances and fits for diameter from 1 to 355 mm
GB/T 1237-2000 Designation system for fasteners (eqv ISO 8991:1986)
GB/T 3098.1-2000 Mechanical properties of fasteners - Bolts, screws and studs (idt ISO 898-1:1999)
GB/T 3098.6-2000 Mechanical properties of corrosion-resistant stainless-steel fasteners - Part 1:Bolts,screws and studs (idt ISO 3506-1:1997)
GB/T 3098.10-1993 Mechanical properties of fasteners Bolts,screws,studs and nuts made of non-ferrous metals (eqv ISO 8839:1986)
GB/T 3103.1-1982
(confirmed in 1988) Tolerances for fasteners - Bolts,screws and nuts
GB/T 3106-1982 (confirmed in 1988) Bolts,screws and studs; Nominal lengths and thread lengths for general purpose bolts (eqv ISO 888:1976)
GB/T 5267-1985 Electroplated coatings on threaded fasteners
GB/T 5276-1985 Fasteners; Bolts, screws,studs and nuts; Symbols and designations of dimensions (eqv ISO 225:1983)
GB/T 5779.1-2000 Fasteners - Surface discontinuities-Bolts,screws and studs for general requirements (idt ISO 6157-1:1988)
GB/T 5779.3-2000 Fasteners - Surface discontinities-Bolts,screws and studs for special requirements (idt ISO 6157-3:1988)
GB/T 5783-2000 Hexagon head bolts - Full thread (eqv ISO 4017:1999)
GB/T 16938-1997 Fasteners - General requirements for blots,screws,studs and nuts (idt ISO 8992:1986)
ISO 10683:2000 Fasteners - Non-electrolytically applied zinc flake coatings
3 Dimensions
Note: designations and symbols of dimensions shall meet GB/T 5276.
1) β＝ 15° to 30°.
2) Point shall be chamfered (see GB/T 2)
3) Incomplete thread u ≤ 2P.
4) Reference datum for dw
5) Ds≈ pitch diameter
Figure 1
Table 1 Preferred threads
Thread d×P M8×1 M10×1 M12×1.5 M16×1.5 M20×1.5 M24×2 M30×2 M36×3 M42×3 M48×3 M56×4 M64×4
1) kwmin＝0.7kmin.
2) Range of popular lengths between the solid, boldface, stepped lines.
for product grade A, above the dashed, stepped line; for product grade B, below this stepped line.
Table 2 Non-preferred threads
Thread d×P M10×1.25 M12×1.25 M14×1.5 M18×1.5 M20×2 M22×1.5 M27×2 M33×2 M39×3 M45×3 M52×3 M60×4
1) kwmin＝0.7kmin.
2) Range of popular lengths between the solid, boldface, stepped lines
for product grade A, above the dashed, stepped line; for product grade B, below this stepped line.
4 Technical conditions and normative references
Table 3 Specifications and reference standards
Material Steel Stainless steel Non-ferrous metal
General requirements GB/T 16938
Thread Tolerance 6g
Standard GB/T 196 and GB/T 197
Mechanical properties
Grade d ≤ 39mm: 5.6, 8.8, 10.9
d > 39mm: as agreement; d ≤ 24mm: A2-70, A4-70
24mm < d ≤ 39mm: A2-50, A4-50
d > 39mm: as agreement; CU2, CU3, AL4
Standard d ≤ 39mm: GB/T 3098.1
d > 39mm: as agreement; d ≤ 39mm: GB/T 3098.1
d > 39mm: as agreement; Materials specified in GB/T 3098.10.
Tolerance Product grades d ≤ 24mm and l ≤ 10d or l ≤ 150mm (whichever is smaller) : A
d > 24mm or l > 10d or l > 150mm (whichever is smaller) : B
Standard GB/T 3103.1
Surface defect GB/T 5779.1, GB/T 5779.3
Finish Oxidation Simple treatment Simple treatment
Requirements for electroplating are covered in GB/T 5267.
Requirements for non-electrolytically applied zinc flake coatings are covered in ISO 10683.
If different electroplating requirements are desired or if requirements are needed for other finishes, they shall be agreed between customer and supplier.
Acceptance and packaging GB/T 90
5 Designation
5.1 Designation system shall comply with the requirements of GB/T 1237.
5.2 Designation example
Thread d= M12×1.5, nominal length l= 80mm, fine thread, performance grade 8.8, surface oxidation, full thread, product grade A hexagon head bolt marking:
Foreword I
ISO Foreword III
ISO Introduction IV
1 Scope
2 Normative references
3 Dimensions
4 Technical conditions and normative references
5 Designation
