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This standard is an equivalent adoption of international standard ISO 7091: 2000 "Plain washers-Normal series-Product grade C".
This standard is a part of the standards of "plain washer" products, which includes the following standards:
a) GB/T 95-2002 Plain Washers-Product Grade C;
b) GB/T 96.1-2002 Large Series-Product Grade A;
c) GB/T 96.2-2002 Large Series-Product Grade C;
d) GB/T 97.1-2002 Plain Washers-Product Grade A;
e) GB/T 97.2-2002 Plain Washers, Chamfered-Product Grade A;
f) GB/T 97.3-2000 Plain Washers for Clevis Pins;
g) GB/T 97.4-2002Plain Washers for Screw and Washer Assemblies;
h) GB/T 97.5-2002 Plain Washers for Tapping Sew and Washer Assemblies;
i) GB/T 848-2002Plain Washers-Small Series-Product Grade A;
j) GB/T 5287-2002 Plain Washers-Extra large Series-Product Grade C
Packing technology requirements, which are not specified in ISO 7091, shall be specified in this standard (Table 3).
Simplified marks are not specified in ISO 709, this standard provides the simplified example of marking (5.2) in accordance with the simplification principle of GB/T 1237.
This standard is a recension of GB/T 95-1985, main modifications are as follows:
a) Add the application scope of 100 HV grade washers (Chapter 1);
b) In accordance with the thread specification (big diameter of threads), optimization degree is divided into: Table 1 preferred dimension, Table 2 non-preferred dimension (Table 1 and Table 2);
c) Add nominal sizes: 1.6, 2, 2.5, 3, 3.5, 4, 18, 22, 27, 33, 39, 42, 45, 48, 52, 56, 60 and 64 mm (Table 1 and Table 2);
d) Provide hardness range and test methods corresponding to the hardness level (Table 3);
e) Add non- electrolytic zinc coating (Table 3).
This standard will replace GB/T 95-1985 from the implementation data hereof.
This standard is proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of Fastening Piece Technical Committee for Standardization of China.
This national standard was drafted by the Academy of Machinery Science & Technology.
Secretariat of National Technical Committee for Standardization of Fasteners is responsible for 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 whom 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 rules given in the ISO / IEC Directives, Part 3.
Draft International Standard adopted by the technical committee is circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for any or all such patent rights.
International Standard 7091 was prepared by Technical Committee ISO/TC 2 Fasteners.
This second edition cancels and replaces the first edition (ISO 7091:1983), which has been technically revised.
1 Scope
This standard specifies the characteristics of normal-series, product-grade-C plain washers in the 100 HV hardness class and of normal sizes (normal thread diameters) ranging from 1.6 to 64mm inclusive.
Washers of hardness class 100HV are suitable for:
-Hexagon bolts and screws of product grade C in property classes up to and including 6.8;
-Hexagonal nuts of product grade C in property classes up to and including 6;
-Case-hardened thread rolling screws.
If dimensions other than those listed in this standard are required, they should be selected from those given in ISO 887.
When soft material pieces are clamped, or large clearance holes in the workpiece are used, the user should check the technical suitability of this type of washer.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At time of publication, the editions indicated are valid As all the standards will be revised, each party using this standard shall discuss the feasibility of using the latest edition of the following standards.
GB/T 90.1-2002 Fasteners-Acceptance Inspection (idt ISO 3269:2000)
GB/T 90.2-2002 Fasteners-Marking and Packaging
GB/T 1237-2000 Designation System for Fasteners (eqv ISO 8991:1986)
GB/T 3103.3-2000 Tolerance for fasteners-Plain washers (idt ISO 4759-3:2000)
GB/T 4340.1-1999 Metallic materials-Vickers hardness test -Part 1: Test method (eqv ISO 6507-1:1997)
GB/T 5267.1-2002 Fasteners-Electroplated Coatings (ISO 4042:1999, IDT)
GB/T 5267.2-2002 Fasteners-Non-Electrolytically Applied Zinc Flake Coatings (ISO 10683:2000, IDT)
GB/T 5286-2001 Plain Washers for Metric Bolts, Screws and Nuts for General Purposes-General Plan (idt ISO 887:2000)
3 Dimensions
Figure 1
Table 1 Preferred Dimensions mm
Nominal size
(big diameter of the thread d) Internal diameter d1 External diameter d2 Thickness h
nom. (min) max nom. (max) min nom. max min
1.6
2
2.5 1.8
2.4
2.9 2.05
2.65
3.15 4
5
6 3.25
4.25
5.25 0.3
0.3
0.5 0.4
0.4
6.6 0.2
0.2
0.4
3
4
5 3.4
4.5
5.5 3.7
4.8
5.8 7
9
10 6.1
8.1
9.1 0.5
0.8
1 0.6
1.0
1.2 0.4
0.6
0.8
6
8
10 6.6
9
11 6.96
9.36
11.43 12
16
20 10.9
14.9
18.7 1.6
1.6
2 1.9
1.9
2.3 1.3
1.3
1.7
12
16
20 13.5
17.5
22 13.93
17.93
22.52 24
30
37 22.7
28.7
35.4 2.5
3
3 2.8
3.6
3.6 2.2
2.4
2.4
24
30
36 26
33
39 26.52
33.62
40 44
56
66 42.4
54.1
64.1 4
4
5 4.6
4.6
6 3.4
3.4
4
42
48
56
64 45
52
62
70 46
53.2
63.2
71.2 78
92
105
115 76.1
89.8
102.8
112.8 8
8
10
10 9.2
9.2
11.2
11.2 6.8
6.8
8.8
8.8
Table 2 Non-preferred Dimensions mm
Nominal size
(big diameter of the thread d) Internal diameter d1 External diameter d2 Thickness h
nom. (min) max nom. (max) min nom. max min
3.5
14
18 3.9
15.5
20 4.2
15.93
20.43 8
28
34 7.1
26.7
32.4 0.5
2.5
3 0.6
2.8
3.6 0.4
2.2
2.4
22
27
33 24
30
36 24.52
30.52
37 39
50
60 37.4
48.4
58.1 3
4
5 3.6
4.6
6 2.4
3.4
4
39
45
52
60 42
48
56
66 43
49
57.2
67.2 72
85
98
110 70.1
82.8
95.8
107.8 6
8
8
10 7
9.2
9.2
11.2 5
6.8
6.8
8.8
4 Technical Conditions and Normative References
Contents
Foreword I
ISO Foreword II
1 Scope
2 Normative References
3 Dimensions
4 Technical Conditions and Normative References
5 Designations
