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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 342-1997 Dimension shape mass and tolerance for cold-drawn round square and hexagonal steel wires. The following main changes have been made with respect to GB/T 342-1997:
——The Scope is modified;
——The clause "Normative References" is added;
——Coding is added;
——Classification of steel wires is added;
——The designation examples are deleted;
——The nominal dimension, sectional area and theoretical weight of steel wires are modified;
——The dimension tolerances of steel wires are modified;
——The application scope of dimension tolerance levels of steel wires is modified;
——The requirements for the appearance of steel wires are modified;
——The length and tolerance of straight steel wires are modified.
This standard is redrafted by reference to and not equivalent to ISO 22034-2:2016 Steel wire and wire products - Part 2: Tolerances on wire dimensions.
This standard was proposed by the China Iron and Steel Industry Association.
This standard is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
The previous editions of this standard are as follows:
——GB/T 342-1964, GB 342-1982 and GB/T 342-1997.
Dimension, shape, mass and tolerance for cold-drawn round, square and hexagonal steel wires
1 Scope
This standard specifies the dimension, shape, mass and tolerance of cold-drawn round, square and hexagonal steel wires.
This standard is applicable to cold-drawn round steel wires with a diameter of 0.05mm~20mm, cold-drawn square steel wires with an edge length of 0.50mm~10mm and cold-drawn hexagonal steel wires with a distance across flat of 1.60mm~10mm.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 321-2005 Preferred numbers - Series of preferred numbers
GB/T 1800.1-2009 Geometrical product specifications (GPS) - Limits and fits - Part 1: Bases of tolerances, deviations and fits
3 Sectional sketches and marked symbols
3.1 The sectional sketch for the round steel wire and the marked symbol in the sketch are given in Figure 1.
Key:
d——the diameter of round steel wire.
Figure 1 Sectional sketch for round steel wire
3.2 The sectional sketch for the square steel wire and the marked symbols in the sketch are given in Figure 2.
Keys:
a——the edge length of square steel wire;
r——the arc radius of the angle.
Figure 2 Sectional sketch for square steel wire
3.3 The sectional sketch for the hexagonal steel wire and the marked symbols in the sketch are given in Figure 3.
Keys:
s——the distance across flat of hexagonal steel wire;
r——the arc radius of the angle.
Figure 3 Sectional sketch for hexagonal steel wire
4 Classification and coding
4.1 The steel wires are classified into three classes according to the section shape, which are coded respectively with the uppercase initials of the words “round”, “square” and “hexagonal”:
a) round steel wire: R
b) square steel wire: S
c) hexagonal steel wire: H
4.2 Straight steel wires are classified into three levels according to the length tolerance: Level I, Level II and Level III.
5 Dimension, sectional area and theoretical weight
5.1 The nominal dimension, sectional area and theoretical weight of steel wires shall be in accordance with those specified in Table 1.
5.2 As required by the demander, the steel wires of middle dimensions may be supplied upon negotiation between the supplier and demander.
Table 1 Nominal dimension, sectional area and theoretical weight of steel wires
Nominal dimension a/mm Round Square Hexagonal
Sectional area/mm2 Theoretical weight b/(kg/1,000m) Sectional area/mm2 Theoretical weight b/(kg/1,000m) Sectional area/mm2 Theoretical weight b/(kg/1,000m)
Nominal dimension a/mm Round Square Hexagonal
Sectional area/mm2 Theoretical weight b/(kg/1,000m) Sectional area/mm2 Theoretical weight b/(kg/1,000m) Sectional area/mm2 Theoretical weight b/(kg/1,000m)
Note: The nominal dimension in the table represents the diameter for round steel wires, edge length for square steel wires and distance across flat for hexagonal steel wires, which applies to the following tables, too.
a The R20 series of preferred numbers specified in GB/T 321-2005 is adopted for the nominal dimension of steel wires listed in the table;
b The theoretical weight listed in the table is calculated as the density is 7.85g/cm3 and the standard value of π is taken; as for special alloy steel wires, the density of responding designations shall be used in calculation of theoretical weight.
6 Dimension tolerance
6.1 The nominal dimension tolerance of steel wires shall be in accordance with those specified in Table 2. The special requirements from the demander, if any, shall be indicated in the contact.
6.2 The level of nominal dimension tolerance of steel wires shall be in accordance with those specified in Table 3.
6.3 The out-of-roundness of round steel wires shall not be greater than half of the diameter tolerance.
6.4 The diagonal difference of square steel wires shall not be greater than 0.7 times the edge length tolerance of corresponding level.
6.5 For square and hexagonal steel wires, the special requirements for the arc radius of the angle, if any, are subject to agreement between the supplier and the demander.
Foreword II
1 Scope
2 Normative references
3 Sectional sketches and marked symbols
4 Classification and coding
5 Dimension, sectional area and theoretical weight
6 Dimension tolerance
7 Shape
8 Length and its tolerance of straight steel wires
