Overview
ISO 10597:2012 - Road vehicles - Flat attachment fixing nuts for commercial vehicles - Test methods - specifies test methods and performance requirements to ensure correct wheel or rim assembly using hexagonal nuts with a flat seating captive washer on 18 mm, 20 mm and 22 mm studs. Applicable to commercial vehicles as defined in ISO 3833 and to nuts dimensioned in ISO 7575, it defines proof-load, torque/tension and retorque tests and associated acceptance/rejection criteria for production-capable fasteners (not for uncommon or special fastener applications).
Key topics and requirements
- Scope: applies to flat-attachment wheel fixing nuts for commercial vehicles, used with M18 × 1.5, M20 × 1.5 and M22 × 1.5 studs.
- Proof-load (nut body) test:
- Three loadings at 0.6 × proof load F, then one loading at 1 × F held for 15 s.
- Proof load values (F):
- M18 × 1.5 - 235 kN
- M20 × 1.5 - 295 kN
- M22 × 1.5 - 360 kN
- After unloading, permanent nut height deformation (ΔH) must not exceed 0.13 mm.
- Thread go/no‑go gauge checks; rejection for cracks per ISO 6157-2.
- Torque/tension - Clamping force test:
- Measures tightening torque versus bolt tension using production-representative parts and test bolts.
- Tightening rotational speed: 2–10 r/min; washer reaction face secured against rotation.
- Test torques and tensions (initial → final):
- M18: initial 250 N·m (min tension 80 kN) → final 420 N·m (max tension 225 kN)
- M20: initial 339 N·m (min 100 kN) → final 610 N·m (max 295 kN)
- M22: initial 500 N·m (min 133 kN) → final 700 N·m (max 310 kN)
- Rejection criteria include inability to reach or exceeding specified tensions, thread stripping, visible cracks, or inability to withstand final torque.
- If bolt threads are damaged, the test is discarded; hardened mandrels can be used to determine failure source.
- Torque/tension - Retorque test:
- Retorque to the final torque five times; rejection includes same criteria as clamping test and a ≥30% drop in tension between initial and fifth retorque.
- Lubrication: if lubricant is required, its specification, treated surfaces and reapplication frequency must be recorded; coefficient of friction should represent production.
Applications and users
- Who uses ISO 10597:
- Wheel and rim manufacturers, commercial vehicle OEMs, fastener suppliers, test laboratories, quality and design engineers, maintenance and safety auditors.
- Practical uses:
- Verifying wheel nut assemblies for safe clamping force and durability.
- Establishing production acceptance tests and supplier quality control.
- Supporting type approval, maintenance procedures and failure analysis for commercial vehicle wheel fastening systems.
Related standards
Keywords: ISO 10597, flat attachment fixing nuts, wheel fasteners, proof load test, torque/tension, retorque, commercial vehicles, wheel nut test methods.