Aluminium 6061 Flange Rings Specification

Aluminium 6061 Equivalent Designation
| UNS Designation | British STD | Werkstoff No. | European STD | Swedish STD | Japanese STD |
|---|---|---|---|---|---|
| A6061 | – | 3.3211 | Almg1sicu | – | Sus 6061 |
Aluminium 6061 Flange rings are seamless rolled or open-die forged components used as pressure-vessel flanges, valve bodies, hub-mount blanks, and shaft-end retention rings. TorqBolt supplies Aluminium 6061 Flange rings per ASTM A182 (forged flange standard), ASTM A266/A668 (carbon ring), and EN 10222 (pressure-purpose forging), in OD sizes from 50 mm up to 3000 mm.
Rings are produced via either seamless ring rolling (radial-axial mill, for OD > 200 mm) or open-die hammer forging (for short-run / oversize parts). Reduction ratio ≥ 4:1 from billet to final ring is enforced for grain-flow continuity. Heat treatment is per the alloy spec — solution-anneal + quench + age for precipitation-hardening alloys; quench & temper for low-alloy steels.
Aluminium 6061 Flange rings are supplied to ASTM A788 dimensional tolerances by default: OD ±1.5 mm or ±1% (whichever is larger), ID ±1.5 mm, height ±0.8 mm. Tighter tolerances (machined finish, ±0.1 mm) available for direct-mount applications. Out-of-roundness controlled to 1.5 mm; concentricity 0.2 mm/100 mm.
Each ring lot ships with full mechanical certification: tensile (ASTM E8), Charpy impact (ASTM E23) at the application's MDMT, hardness traverse, and grain size per ASTM E112. For Aluminium 6061 Flange ring stock destined for hydrogen / sour service, additional HIC testing (NACE TM0284) and SSC testing (NACE TM0177) per the customer's spec.
Aluminium 6061 Flange rings ship rough-machined or finish-machined per drawing. Standard NDT: 100 % UT (ASTM A388 reference) and surface MT/PT to ASTM E709 / E165. Radiography on request. Each ring is hard-stamped with heat number, lot, and certification reference for traceability through the dispatch chain.
Aluminium alloys are specified for fasteners where weight reduction, electrical conductivity, or non-magnetic / non-sparking properties dominate the design envelope — aerospace structures, marine spars, electronics enclosures, and industries where reducing reciprocating mass directly improves performance. Density of ~2.7 g/cm³ (one-third of steel) combined with self-passivating Al₂O₃ surface gives respectable corrosion resistance in atmospheric service.
2024 (Al-Cu-Mg) is the high-strength aerospace alloy: yield ~325 MPa in T3 condition, used for airframe structural fasteners. 6061 (Al-Mg-Si) is the general-purpose grade with excellent weldability and corrosion, the standard for marine + structural fasteners. 7075 (Al-Zn-Mg-Cu) is the highest-strength aluminium fastener alloy: yield ~505 MPa in T6 condition, comparable to mild steel at one-third the weight — the dominant material for civilian + military aircraft assembly.
Aluminium fasteners ship per AMS 7222 / 7223 / ASTM F468 (rod) with full mechanical certification including hardness (Rockwell B 60-87), tensile, and conductivity testing. Galvanic isolation is critical when aluminium fasteners contact dissimilar metals in moist environments — cadmium plating or insulating washer + sleeve combinations are commonly specified.