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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by China Iron and Steel Industry Association.
This standard is under the jurisdiction of the SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
Hot-rolled wire rod for quenched and tempered spring steel wires
1 Scope
This standard specifies the order information, dimension, shape, mass and tolerance, technical requirements, test methods, inspection rules, and packaging, marking and certification of hot-rolled wire rod for quenched and tempered spring steel wires.
This standard is applicable to hot-rolled wire rod for quenched and tempered spring steel wires (hereinafter referred to as “wire rod”).
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 223.5 Steel and iron - Determination of acid-soluble silicon and total silicon content - Reduced molybdosilicate spectrophotometric method
GB/T 223.11 Iron, steel and alloy - Determination of chromium content - Visual titration or potentiometric titration method
GB/T 223.14 Methods for chemical analysis of iron, steel and alloy - The N-benzoyl-N-phenylhydroxylamine extraction photometric method for the determination of vanadium content
GB/T 223.19 Methods for chemical analysis of iron steel and alloy - The neocuproine-chloroform extraction photometric method for the determination of copper content
GB/T 223.54 Methods for chemical analysis of iron, steel and alloy - The flame atomic absorption spectrophotometric method for the determination of nickel content
GB/T 223.60 Methods for chemical analysis of iron, steel and alloy - The perchloric acid dehydration gravimetric method for the determination of silicon content
GB/T 223.62 Methods for chemical analysis of iron, steel and alloy - The butyl acetate extraction photometric method for the determination of phosphorus content
GB/T 223.63 Methods for chemical analysis of iron, steel and alloy - The sodium (potassium) periodate photometric method for the determination of manganese content
GB/T 223.64 Iron, steel and alloy - Determination of manganese content - Flame atomic absorption spectrometric method
GB/T 223.72 Iron, steel and alloy - Determination of sulfur content - Gravimetric method
GB/T 224 Determination of depth of decarburization of steel
GB/T 226 Test method for macrostructure and defect of steel by etching
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature
GB/T 1979 Standard diagrams for macrostructure and defect of structural steels
GB/T 2101 General requirement of acceptance, packaging, marking, and certification for section steel
GB/T 2975 Steel and steel products - Location and preparation of samples and test pieces for mechanical testing
GB/T 4336 Standard test method for spark discharge atomic emission spectrometric analysis of carbon and low-alloy steel (routine method)
GB/T 6394 Determination of estimating the average grain size of metal
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 10561 Steel - Determination of content of nonmetallic inclusions - Micrographic method using standards diagrams
GB/T 11261 Steel and iron - Determination of oxygen content - The pulse heating inert gas fusion-infra-red absorption method
GB/T 13299 Steel - Determination of microstructure
GB/T 14981-2009 Dimension, shape, mass and tolerance for hot-rolled round wire rod
GB/T 20066 Steel and iron - Sampling and preparation of samples for the determination of chemical composition
GB/T 20123 Steel and iron - Determination of total carbon and sulfur content - Infrared absorption method after combustion in an induction furnace (routine method)
GB/T 20124 Steel and iron - Determination of nitrogen content - Thermal conductimetric method after fusion in a current of inert gas (routine method)
3 Ordering information
Contracts or orders made based on this standard shall cover the following items:
a) serial number of this standard;
b) product name;
c) steel grade;
d) product specifications and mass;
e) dimension, shape and accuracy grade;
f) other special requirements.
4 Dimension, shape, mass and tolerance
4.1 The wire rods shall be delivered according to accuracy grade B or C as specified in GB/T 14981-2009 in terms of dimension, shape and tolerance. The specific delivery grade shall be specified in the contract, or otherwise they shall be delivered according to Grade B.
4.2 Each coil of wire rod shall consist of one wire rod with a mass of not less than 1,500kg. Each delivery batch is allowed to have 5% of coils less than 1,500kg but not less than 1,000kg (coils less than two are regard as two coils).
5 Technical requirements
5.1 Grade and chemical composition
5.1.1 The grade and chemical composition (melting analysis) of wire rods shall meet those specified in Table 1.
5.1.2 The permissible tolerances for chemical composition of finished wire rods shall be in accordance with those specified in GB/T 222.
Table 1 Grade and chemical composition of wire rods
5.1.3 Except the elements required for smelting, the elements not listed in Table 1 shall not be intentionally added to steel without the consent of the purchaser, and measures shall be taken to reduce the content of elements from scrap steel or other auxiliary materials used in the smelting process that affect hardenability, mechanical properties and service performance.
5.1.4 The copper content shall be controlled below 0.12% for the wire rods for quenched and tempered spring steel wires of moderate fatigue grade (Grade TD) and high fatigue grade (Grade VD).
5.1.5 As required by the purchaser and indicated in the contract upon the agreement between the supplier and the purchaser, the wire rods of other grades and chemical composition may be supplied.
5.1.6 The oxygen and nitrogen content of the wire rods shall meet those specified in Table 2.
Table 2 Oxygen and nitrogen content
Grade Oxygen and nitrogen content (mass fraction)/%
Oxygen content Nitrogen content
65Mn and 70Mn — —
Other grades ≤25×104 ≤70×10-4
5.2 Smelting method
Steel is smelted in an electric furnace or converter and refined outside the furnace.
5.3 Delivery state
Wire rods shall be delivered in hot rolled state.
5.4 Mechanical properties
Wire rods shall be tested for mechanical properties. Table 3 gives the reference values of mechanical properties of wire rods, which is not the basis of delivery.
Table 3 Reference values of mechanical properties
Grade Tensile strength Rm/MPa Percentage reduction of area Z%
65Mn 900~1,130 ≥30
55SiCr 930~1,160
55SiCrV 960~1,190
60Si2Mn 930~1,160
Other grades As agreed As agreed
5.5 Decarburized layer
5.5.1 Wire rods shall be tested for the depth of decarburized layer.
5.5.2 The total depth of decarburized layer (fully decarburized layer + partially decarburized layer) on one side of the wire rod shall meet those specified in Table 4, where D is the nominal diameter of the wire rod.
5.5.3 Fully decarburized layer as shown in Figure 1 is sporadically allowed on the surface of wire rod, with the total arc length not greater than the arc length corresponding to 15° central angle and the depth meeting those specified in Table 4.
Foreword II
1 Scope
2 Normative references
3 Ordering information
4 Dimension, shape, mass and tolerance
5 Technical requirements
6 Test methods
7 Inspection rules
8 Packaging, marking and certification
