GB/T 3429-2025Wire rods for welding (English PDF)

6.1 Smelting Method

Steel used for wire rods is typically smelted using oxygen converters or electric furnaces.

6.2 Delivery Condition

Wire rods shall be delivered in the hot-rolled condition; however, subject to agreement between the supply and demand sides, they may also be delivered in conditions such as annealed or isothermally heat-treated states.

7.1 Grades and Chemical Composition

7.1.1 The grades and chemical composition (product analysis) of the wire rods shall comply with the provisions of Table 1.

7.1.2 The supplier shall guarantee that the chemical composition (product analysis) of the wire rods complies with the provisions of Table 1; however, subject to agreement between the supply and demand sides—and explicitly stated in the contract—delivery based on chemical composition (melting analysis) is also permissible.

7.1.3 Subject to agreement between the supply and demand sides—and explicitly stated in the contract—wire rods of other grades and chemical compositions may also be supplied.

7.2 Surface Quality

7.2.1 Harmful defects at the head and tail ends of the wire rods shall be cropped off; the cross- section shall be free of shrinkage cavities, laminations, and inclusions.

7.2.2 The surface of the wire rods shall be smooth and free of defects harmful to their intended use, such as cracks, folds, fins, and scabs. Localized indentations, protrusions, pits, scratches, and roughness shall have a depth or height (measured from the actual dimension) not exceeding 0.10 mm.

7.3 Dimensions, Shape and Weight

7.3.1 Dimensions and shape of wire rods

The dimensions and shape of the wire rods shall comply with the requirements for Grade B or Grade C precision as specified in GB/T 14981-2009.The specific precision grade required shall be explicitly stated in the contract or agreement; in the absence of such a specification, the requirements for Grade B precision shall apply.

7.3.2 Weight of coils

Each coil shall consist of a single continuous wire rod and shall contain no joints; the minimum weight of each wire rod coil shall be no less than 1 000 kg. In the event of special requirements, these shall be determined through negotiation between the supply and demand sides and explicitly stated in the contract or agreement.

7.4 Special Requirements

7.4.1 For wire rods delivered in the isothermally heat-treated condition, the mechanical

properties of grades H08Mn2Si, H07Mn2Si, and H08MnSiCrNiCuE shall comply with the provisions of Appendix A.

7.4.2 The supplier shall provide test data regarding the tensile strength and reduction of area of the wire rods; furthermore, upon the demander’s request, inspections for non-metallic inclusions, microstructure, and other characteristics may be conducted. The specific criteria for these inspections shall be established through mutual agreement between the supply and demand sides and explicitly stipulated in the contract.