Overview
ISO 22034-2:2016 - "Steel wire and wire products - Part 2: Tolerances on wire dimensions" defines dimensional tolerances for round steel wire. The standard covers bright (uncoated), metallic‑coated (e.g., zinc), and non‑metallic/organic‑coated round wires in the diameter range 0.050 mm to 25.00 mm. It specifies acceptable limits for wire diameter, out‑of‑roundness (ovality), coating thickness and concentricity (for organic coatings), cut‑length tolerances and straightness, and guidance on determining coil length by weight.
Key topics and technical requirements
- Diameter tolerances: Defined by tolerance classes T1–T5. Classes are calculated proportionally where T1 = 0.035 × d, T2 = 0.027 × d, T3 = 0.021 × d, T4 = 0.015 × d, T5 = 0.010 × d (d = measured diameter in mm). Table 1 in the standard maps these classes to specific diameter ranges.
- Out‑of‑roundness (ovality): The difference between maximum and minimum diameter at any cross‑section shall not exceed one‑half of the total diameter tolerance from Table 1.
- Organic‑coated wire: Table 2 gives tolerances on the overall diameter D, minimum coating thickness (different for extruded vs. sintered coatings), and minimum concentricity. Example values: for D ≤ 1.00 mm the overall tolerance is ±0.10 mm; minimum coating thickness typically 0.20 mm (extruded) or 0.12 mm (sintered); concentricity requirements commonly 75% (extruded) and 65% (sintered).
- Cut‑length tolerances and straightness: The purchaser selects among three length tolerance classes depending on nominal length. Straightness is classified (1–3) with defined out‑of‑straightness limits and a rolling test for classes 1 and 2 (e.g., class 1: for 500 mm test length a = 0.5 mm; for 1 000 mm a = 2 mm; will roll down an incline of 1 in 10).
- Coil length calculation: Length of wire in a coil may be determined by weighing and calculating length from known size and density.
Applications and users
- Manufacturers and producers of steel wire (bright, galvanized, coated)
- Quality control and metrology teams ensuring compliance with dimensional tolerances
- Purchasing and procurement professionals specifying wire tolerances for components and assemblies
- Designers and engineers in fasteners, springs, fencing, automotive parts, and wire‑forming industries requiring predictable dimensional performance
- Test laboratories performing acceptance checks against international tolerances
Related standards
- ISO 22034‑1 - Steel wire and wire products - General test methods (related part for testing procedures)
- ISO 6929 - Steel products - Vocabulary (terms and definitions referenced)
Keywords: ISO 22034-2, tolerances on wire dimensions, steel wire tolerances, wire diameter tolerances, cut lengths, coated wire, out‑of‑roundness, straightness, wire specification.
