Overview
ISO 8094:2013 specifies a standardized test method to determine the adhesion strength of the rubber cover to the steel cord core layer of steel cord conveyor belts. The standard applies exclusively to steel cord conveyor belts and is intended for use in quality control, acceptance testing and product development to ensure reliable belt performance and operational safety.
Key Topics
- Test principle: measurement of the force required to peel the rubber cover from the steel cord core (core layer).
- Apparatus: tensile testing machine with suitable jaws, in accordance with the apparatus described in ISO 36.
- Specimen preparation:
- Six specimens are taken from the belt.
- For belts without fabric ply (with or without textile reinforcement): length ≥ 150 mm (longitudinal), width ≥ 25 mm and must contain at least two cords, thickness = full belt thickness.
- For belts with metallic weave: length ≥ 150 mm (in weft direction), width 25 mm ± 0.5 mm, thickness = full belt thickness.
- Specimens must be cut parallel to the belt axis and at least 50 mm from the belt edge. The rubber cover is trimmed alongside the cord edges to allow reliable gripping in the test jaws.
- Conditioning and timing: test performed at least five days after belt manufacture; unless otherwise specified, conduct at 23 °C ± 2 °C and 50 % ± 5 % relative humidity in accordance with ISO 18573 (Atmosphere B).
- Test procedure:
- Fix the upper cover of three specimens in one jaw and the cord layer (without lower cover) in the other; perform peel test.
- Repeat for the remaining three specimens with the lower cover fixed.
- Maintain jaw separation speed at 100 mm/min ± 10 mm/min and record force graphically.
- Carry out three tests per side.
- Result expression:
- Determine the median force (F̃) from the recorded peel-force traces using ISO 6133.
- Adhesion T (N/mm) is computed as T = F̃ / b, where b is specimen width in millimetres.
- Report separate averages for upper and lower cover adhesion and round values to 0.1 N/mm.
Applications
- Quality control: routine verification of cover-to-core bonding during production.
- Acceptance testing: contractual checks on delivered belts.
- Failure analysis: investigating belt delamination or premature wear.
- Design validation: comparing cover compounds or bonding procedures.
Related Standards
- ISO 36 - Apparatus and procedures for adhesion testing of rubber to textiles.
- ISO 6133 - Analysis of multi-peak traces for tear and adhesion tests.
- ISO 18573 - Conditioning atmospheres and durations for conveyor belt testing.
Practical value: ISO 8094:2013 provides a reproducible, traceable method for measuring cover adhesion on steel cord conveyor belts, helping manufacturers, inspectors and end users improve belt reliability, safety and service life.