Wrought aluminium and aluminium alloys — Cold-drawn rods/bars, tubes and wires — Part 4: Tolerances on form and dimensions for drawn rectangular bars and wires
1Key Takeaways
This document specifies the tolerances on form and dimensions of wrought aluminium and aluminium alloy drawn rectangular bars and wires with thicknesses ranging from 2 mm up to and including 60 mm and widths up to and including 200 mm. For wires, this document does not apply to electrical, welding and aeronautical purp…
2Expert Interpretation
In-depth analysis of the geometric tolerance requirements for cold-drawn aluminum and aluminum alloy rectangular bars and wires in ISO 6363-4:2022 international standard, covering key indicators such as width/thickness tolerance, length tolerance, straightness, etc., comparing the differences between alloy groups and providing implementation suggestions. Applicable to the production and inspection of industrial aluminum materials with a thickness of 2-60mm and a width of ≤200mm.
Analysis of the core content of the standard
ISO 6363-4:2022 standard clearly stipulates the geometric tolerances of cold-drawn aluminum rectangular bars and wires. The main technical points include:
| Technical parameters | Alloy group I | Alloy group II | Measurement method |
|---|---|---|---|
| Width tolerance (when b≤30mm) | ±0.15mm | ±0.23mm | Exclude the influence of rounded corners |
| Thickness tolerance (2-6mm) | ±0.08mm | ±0.12mm | Three-point measurement method |
| Maximum fillet radius (a≤10mm) | 0.4mm | 0.6mm | Profile projector |
Details of key tolerance requirements
5.1 Width and thickness tolerance
The standard divides aluminum alloys into two process groups:
- Group I: includes 1xxx pure aluminum, 3xxx aluminum-manganese, 5xxx aluminum-magnesium and 6xxx aluminum-magnesium-silicon alloys
- Group II: covers 2xxx aluminum-copper-magnesium series, high-magnesium 5xxx series and 7xxx aluminum-zinc-magnesium series alloys
When width-to-thickness ratio (b/a)>10, special tolerances need to be negotiated between the supplier and the buyer.
5.5 Shape tolerance
Actual case: The straightness requirement of a 6061 aluminum alloy guide rail (b=50mm) for a certain automobile is 0.3mm. When measuring, the sample needs to be placed freely on the reference platform and the maximum gap is detected using a feeler gauge.
Technological evolution and standard update
Main changes compared to the 2012 version:
- The alloy table is divided into two independent tables of Group I/II
- Added 6026 (Group I) and 2033 (Group II) alloys
- Corrected many technical description errors
Implementation suggestions
Key points of production control
- For 7075 alloy for aerospace, it is recommended to use 80% of the tolerance of Group II as the internal control standard
- The verticality of the end face needs to be controlled synchronously during cut-to-length (≤50% of the length tolerance)
- For plates with thickness＞40mm, the measurement of the middle point should be added
Testing equipment configuration
| Test items | Recommended equipment | Accuracy requirements |
|---|---|---|
| Dimension tolerance | Digital caliper | ±0.01mm |
| Straightness | Optical flatness meter | 0.005mm/m |
| Distortion | Laser scanner | ±0.1° |