Overview
ISO/PAS 22596:2022 specifies dynamometer test procedures to evaluate metal pick-up (MPU) on disc brakes caused by interactions between brake lining friction materials and discs. The publicly available specification covers controlled laboratory methods to assess how pressure, temperature, water and saltwater influence MPU formation for different friction material types (notably NAO and low‑metallic materials). The standard is intended to support friction‑material development, material selection for new brake applications and troubleshooting MPU‑related NVH (noise, vibration and harshness) issues.
Key Topics and Requirements
- Description of MPU and related defects (e.g., grooves) and their impact on disc surface and NVH.
- Three principal dynamometer test procedures:
- Water and saltwater MPU testing (wet conditions typical for low‑metallic materials).
- Low temperature / low pressure MPU testing.
- High temperature / high pressure (heat and pressure) MPU testing (typical for NAO materials).
- Detailed test‑condition and preparation requirements, including:
- Inertia for brake testing, pressure ramp rate and maximum pressure
- Sampling rate, initial brake temperature and brake temperature measurement
- Cooling air conditioning, air speed/flow and exhaust conditions
- Disc lateral run‑out, caliper/disc/pad condition, and wear measurement
- Water and saltwater specifications and nozzle requirements
- Data collection and optional NVH measurements
- Test reporting requirements: disc and lining identification, disc surface characterisation, photographs of setup and test parts, MPU area/number documentation, disc surface profile and acceptance criteria.
Applications
- Development and optimization of brake friction materials to reduce MPU risk.
- Selection of appropriate friction materials for specific vehicle brake systems.
- Root‑cause analysis of disc scoring, grooves and NVH issues (squeal, wire‑brush).
- Design verification and development validation plans (DVP) using dynamometer simulations of critical environmental and operational conditions.
Who Should Use This Standard
- Brake friction‑material developers and manufacturers
- Automotive OEMs and component engineers
- Test laboratories performing dynamometer or vehicle durability testing
- NVH engineers and failure analysis teams
- Certification and quality assurance teams evaluating material selection
Related Standards
- ISO 611 - Road vehicles: Braking vocabulary
- ISO 15484 - Brake lining friction materials: Product definition and quality assurance
- ISO 21920‑2 - Surface texture (profile): Terms and parameters
Keywords: metal pick‑up, MPU, brake lining friction materials, dynamometer, disc brakes, saltwater, NAO, low metallic, brake testing, NVH, test procedure.