ISO 6312:2010

Overview

ISO 6312:2010 - "Road vehicles - Brake linings - Shear test procedure for disc brake pad and drum brake shoe assemblies" defines a standardized method to measure the shear strength of the bond between friction lining and carrier in brake pad and shoe assemblies. It covers integrated (moulded), bonded and mechanical retention systems (MRS) used on road-vehicle brakes, and explicitly excludes riveted assemblies.

Key topics and technical requirements

• Objective: Measure the load at failure (shear force F) and compute shear strength τ = F / A, where A is the bond area at the bond line.
• Samples: Test full assemblies or coupons/sections; five samples recommended for standard testing. Specify orientation (radial or tangential) when using sections.
• Test conditions: Ambient testing at (23 ± 5) °C by default. Optional elevated-temperature tests with defined dwell and temperatures (typical recommendations: ~200 °C for drum linings, ~300 °C for disc pads).
• Load application: Controlled average load rate of (4 500 ± 1 000) N/s or, for constant-crosshead machines, 10 ± 1 mm/min. Avoid shock loads.
• Fixtures and tooling: Loading tool radius ≤ 2 mm; tool contact within (1 ± 0.2) mm of the carrier/backplate. Disc pad fixtures require a face load of (0.5 ± 0.15) N/mm of lining area (to prevent movement) while minimizing friction influence.
• Failure assessment: Record failure load and shear pattern (percentages of clean carrier, adhesive failure, or failure within lining). Optional chemical staining test (CuSO4/NaCl/HCl solution) to distinguish fracture surfaces.
• Reporting: Include supplier and batch ID, sample type and orientation, number of samples, minimum and mean shear strength (MPa), shear pattern percentages, test deviations and tooling details.

Applications and users

ISO 6312:2010 is used to:

• Validate manufacturing processes for brake linings (bond integrity).
• Compare material formulations and retention methods (bonded vs. MRS).
• Support quality control, product development and supplier qualification.
• Assess effects of service or conditioning (e.g., after ISO 6314 treatments or dynamometer testing).

Typical users:

• Brake component manufacturers and OEMs
• Material and adhesive suppliers
• Test laboratories and certification bodies
• R&D and quality assurance teams in the automotive industry

Related standards

• ISO 6314 - Test procedures for resistance to liquids (water, saline, oil, brake fluid)
• ISO 15484 - Brake lining product definition and quality assurance
• ISO 611 - Braking vocabulary (terms referenced by ISO 6312)

ISO 6312:2010 provides a reproducible shear test method to benchmark bond performance of disc pads and drum shoes, helping manufacturers, test labs and OEMs ensure safe, consistent brake-lining attachment and performance.