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This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.
This document replaces GB/T 4357-2009 Cold-drawn non-alloy steel wire for springs. In addition to structural adjustment and editorial changes, the following main technical changes have been made with respect to GB/T 4357-2009:
a) the normative references are added (see Clause 2; Clause 2 of 2009 Edition);
b) the term "patented" and its definition are added, the terms “cold-drawn non-alloy steel wire for springs" and “coil” as well as their definitions are deleted, and the definitions of other terms are changed (see Clause 3; Clause 3 of 2009 Edition);
c) Table 1 and order contents are changed (see Table 1; Clauses 4 and 5 of 2009 Edition);
d) the technical requirements of wire rod are changed (see 7.1.1; 7.1.2 and Table 5 of 2009 Edition);
e) the reduction of area is added as an index (see Table 6), some torsion property indexes (see Table 6, Table 8 of 2009 Edition) and some strength index in the range of 0.40~0.48mm (see Table 6; Table 8 of 2009 Edition) are changed;
f) the allowable fluctuation range of tensile strength of the same roll of steel wire is changed (see Table 7; 7.4.2 of 2009 Edition);
g) the inspection method of pitch is added (see 8.1.4);
h) the inspection method of aluminum content in zinc-aluminum alloy coating is added (see 8.2.1);
i) the "nominal diameter" on which tensile strength is based is changed to "measured diameter" (see 8.4; 7.4.1 of 2009 Edition);
j) the "Summary of inspection items, applicability, requirements, sampling ratios, test methods and technical requirements" is changed (see Table 8; Table 9 of 2009 Edition);
k) the requirements for transportation and storage are added (see 10.1; 10.1 of 2009 Edition);
l) Annex C is added to provide guidance and suggestions for the selection of steel wire.
This document is modified in relation to ISO 8458-2: 2002 Steel wire for mechanical springs - Part 2: Patented cold-drawn non-alloy steel wire.
Multiple structural adjustments have been made to this document with respect to ISO 8458-2: 2002. See Annex A for the comparison of structure numbers between these two documents.
Many technical differences have been made to this document with respect to ISO 8458-2:2002, which are marked with perpendicular single line (|) in the outside page margin of the provisions concerned. See Annex B for these technical differences and their causes.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This document was proposed by China Iron and Steel Association.
This document is under the jurisdiction of National Technical Committee on Iron and Steel of Standardization Administration of China (SAC/TC 183).
This document was firstly issued in 1984, firstly revised in 1989, secondly revised in 2009, and this is the third revision.
Cold-drawn unalloyed steel wire for springs
1 Scope
This document specifies the classification and labeling, order contents, dimension and shape requirements, technical requirements, test methods, inspection rules, packaging, transportation, storage, marking and quality certificate of cold-drawn unalloyed steel wire for springs.
This document is applicable to the cold-drawn unalloyed steel wire with circular cross section for the manufacture of mechanical springs for static and dynamic load applications (hereinafter referred to as steel wire). The standard tensile strength of shaped (such as square) steel wire for springs may be that corresponding to the specification of the equivalent cross-sectional area in this document.
This document is not applicable to the steel wire for the manufacture of springs with high fatigue strength (such as valve springs).
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 222 Permissible tolerances for chemical composition of steel products
GB/T 224 Determination of the depth of decarburization of steels
(GB/T 224-2019, ISO 3887: 2017, MOD)
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature (GB/T 228.1-2010, ISO 6892-1: 2009, MOD)
GB/T 239.1 Metallic materials - Wire - Part 1: Simple torsion test (GB/T 239.1-2012, ISO 7800:2003, MOD)
GB/T 341 Steel wire - Classification and terminology
GB/T 342-2017 Dimension, shape, mass and tolerance for cold-drawn round, square and hexagonal steel wires
GB/T 1839 Test method for gravimetric determination of the mass per unit area of galvanized coatings on steel products (GB/T 1839-2008, ISO 1460:1992, MOD)
GB/T 2103 General provisions for checking, packing, marking and quality certification of steel wire
GB/T 2976 Metallic materials - Wire - Wrapping test (GB/T 2976-2020, ISO 7802:2013, MOD)
GB/T 18253-2018 Steel and steel products - Types of inspection documents (ISO 10474-2013, IDT)
GB/T 24242.1 Non-alloy steel wire rods for conversion to wire - Part 1: Specific requirements (GB/T 24242.1-2020, ISO 16120-1:2017, MOD)
GB/T 24242.2 Non-alloy steel wire rods for conversion to wire - Part 2: Specific requirements for general purpose wire rod (GB/T 24242.2-2020, ISO 16120-2:2017, MOD)
GB/T 24242.4 Non-alloy steel wire rods for conversion to wire - Part 4: Specific requirements for wire rod for special applications (GB/T 24242.4-2020, ISO 16120-4:2017, MOD)
GB/T 40342 Method for determination of aluminum content in hot dipped zinc-aluminum alloy coating on steel wire
YB/T 081 Rule for rounding off of numberical values and judgment of testing values for technical standards of metallurgy
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 341 and the following apply.
3.1
patented
heat treatment method for obtaining or mainly obtaining patented structure by austenitizing the medium-carbon steel and high-carbon steel by heating and then cooling them in hot bath (such as lead bath, salt bath, water bath, etc.) or forced air flow (such as controlled air cooling after steel rolling in steel mills) at an appropriate temperature
[Source: GB/T 7232-2012, 5.50 and GB/T 341-2008, 3.3.14, modified]
3.2
static load
constant load on the spring, variable load with a design stress of not greater than 0.1 times of fatigue strength, or load with a design stress of greater than 0.1 times of fatigue strength and a cycle number of not greater than 10,000
Note: For general spring, "design stress" refers to design stress, for tension spring and pressure spring, it refers to torsional stress, for torsional spring, it refers to bending stress.
[Source: GB/T 23935-2009, 5.1.1, modified]
3.3
dynamic load
variable load with the number of changes of not less than 10,000 when the design stress of spring is greater than 0.1 times of fatigue strength
[Source: GB/T 23935-2009, 5.1.2, modified]
3.4
cast
shape of each coil in a steel wire roll under unconstrained conditions
[Source: GB/T 341-2008, 3.6.2.4, modified]
3.5
wap
arithmetic mean of the outer diameters of steel wire coil measured in two mutually perpendicular directions by placing the coil on a smooth horizontal plane
3.6
pitch
horizontal distance between the two ends of a free-hanging steel wire coil
Note: For thin steel wires of which the pitch cannot be measured by hanging, the pitch shall be replaced by the head elevation of a whole coil when placed on a smooth horizontal plane.
4 Classification and labeling
4.1 Classification
4.1.1 Classification and designation of steel wires according to tensile strength grade and type of spring load
According to the spring stress grade, the tensile strength of steel wire may be classified into three grades: low tensile strength (L), medium tensile strength (M) and high tensile strength (H); according to the type of spring load, the load of steel wire may be classified into Class S (for static load) and Class D (for dynamic load or mainly dynamic load, or with small spring index, or subject to severe bending during molding). Table 1 lists the classification and designation of steel wires corresponding to different tensile strength grades and different types of spring load.
Table 1 Tensile strength grade, classification and designation of steel wires
Tensile strength grade Type of spring load and designation of steel wire
Class S Class D
Low tensile strength
Medium tensile strength
High tensile strength SL
SM
SH –
DM
DH
4.1.2 Classification and designation according to surface state
Steel wires are classified into phosphated (PH), galvanized (ZN), galvanized aluminum alloyed (ZA) and copper plated (CU) according to the surface state.
4.1.3 Classification according to delivery state
Steel wires are classified into rolled and straightened wires according to the delivery state.
4.2 Labeling
Steel wires are labeled according to nominal diameter, wire classification, surface state classification and this document number.
Example 1:
2.00mm steel wire for springs with a medium tensile strength for dynamic load applications is labeled as:
2.00-DM-PH-GB/T 4357-2022
Example 2:
4.50mm galvanized steel wire for springs with a high tensile strength for static load applications is labeled as:
4.50-SH-ZN-GB/T 4357-2022
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Classification and labeling
5 Order contents
6 Dimension and shape requirements
6.1 Dimension and tolerance
6.2 Out-of-roundness
6.3 Cast
6.4 Straightness of straightened steel wire
7 Technical requirements
7.1 Material
7.2 Surface states and requirements
7.3 Surface quality
7.4 Mechanical properties
7.6 Welding
8 Test methods
8.1 Dimension and shape
8.2 Coating
8.3 Surface quality
8.4 Mechanical properties
8.5 Processing properties
8.6 Other test methods
9 Inspection rules
9.1 Inspection and acceptance
9.2 Batching rules
9.3 Sampling
9.4 Re-inspection
9.5 Rounding off and judgment of numerical value
10 Packaging, transportation, storage, marking and quality certificates
10.1 Packaging, transportation and storage
10.2 Marking and quality certificate
Annex A (Informative) Comparison of structure numbers between this document and ISO 8458-2:
Annex B (Informative) Technical differences between this document and ISO 8458-2: 2002 and their causes
Annex C (Informative) Reference suggestions for the application of steel wire
Bibliography
