How to choose high-quality hot-rolled wire rod?

2025-04-28

1. Performance index analysis: core dimensions determine quality

Chemical composition: The content of elements such as carbon (C), silicon (Si), and manganese (Mn) must meet international standards. For example, low-carbon Steel Wire rods (C≤0.25%) are suitable for cold drawing, while medium- and high-carbon steel wire rods must ensure uniform composition to avoid brittle fracture.

Mechanical properties: Tensile strength, yield strength, and elongation are key parameters. Taking wire rods for construction as an example, the tensile strength must be ≥420MPa and the elongation must be ≥25% to ensure seismic performance.

Dimensional accuracy: The diameter tolerance should be controlled within ±0.3mm, and the ovality deviation should be ≤0.4mm to avoid wire breakage or thread processing defects caused by uneven size.

Surface quality: There should be no defects such as cracks, folds, and scars, and the surface oxide scale thickness should be ≤15μm to reduce pickling costs and subsequent processing losses.

2. Purchase Guide: Four Steps to Avoid Purchasing Risks

Select materials according to purpose

Construction field: low carbon steel wire rod such as Q195 and Q235 is preferred, taking into account both economy and welding performance.

Machinery manufacturing: high carbon steel (such as 45#, 60#) or alloy steel (such as 20CrMnTi) is required to meet high strength and wear resistance requirements.

Automobile spring materials: 65Mn, 55SiCr and other grades are recommended, and attention should be paid to fatigue resistance and hardenability.

Verify supplier qualifications

Check whether the manufacturer has relevant certifications and product test reports; give priority to large steel mills or reputable dealers to avoid small workshops selling inferior products as good ones.

Strictly control the acceptance process

After arrival, sampling is required to test the chemical composition (spectral analysis) and mechanical properties (tensile test); Use a metallographic microscope to observe the microstructure, and use an eddy current flaw detector to check surface defects.

Pay attention to after-sales service

Sign a quality assurance agreement and clarify the quality dispute resolution plan; Give priority to suppliers who provide technical support to assist in solving processing technology problems.