Overview - EN ISO 7623:2022 (Steel cord conveyor belts)
EN ISO 7623:2022 specifies a standardized method to determine the bond strength between steel (metal) cords and their surrounding rubber coating in steel-carcass conveyor belts. The method covers both the initial state (as-manufactured) and after thermal treatment, and is intended for quality control, comparative testing and acceptance of metal-carcass (steel cord) conveyor belts.
Key topics and technical requirements
- Scope: Applies exclusively to metal-carcass (steel cord) conveyor belts; replaces EN ISO 7623:2015.
- Principle: Measure the tensile force required to tear a single steel warp cord out of the carcass along its axis.
- Apparatus:
- Dynamometric tensile testing machine with jaws (in accordance with ISO 7622-2).
- Heated platen press capable of 145 °C ± 5 °C and surface pressures between 1 MPa and 5 MPa for thermal treatment.
- Test conditions: Standard atmosphere B - 23 °C ± 2 °C and (50 ± 5) % RH (per ISO 18573).
- Thermal treatment: Typical procedure is heating specimens between platens at 145 °C ± 5 °C for 150 min ± 1 min at ~1 MPa (details must be reported if changed).
- Specimens: Three specimens containing five warp cords; specimen length, width and thickness specified. Test length L is defined by cord diameter (e.g., 25 mm, 50 mm or 100 mm depending on diameter).
- Procedure: Condition specimens (≥3 h), mount in jaws (250 mm ± 10 mm spacing), apply tensile speed (100 ± 10 mm/min) and record tear-out (peak) force until cord is completely torn out.
- Results: Report arithmetic mean tear-out force (N) and cord-to-coating bond strength A = F / L (N/mm). Include details of test state, environment and any deviations.
Practical applications and users
This standard is essential for:
- Conveyor belt manufacturers - incoming/outgoing quality control and product development.
- Third-party testing laboratories - certification and comparative testing.
- End-users and specifiers (mining, bulk handling, ports) - procurement acceptance and supplier verification.
- Maintenance, reliability and failure-analysis teams - root-cause analysis of belt failures related to cord-coating adhesion.
Practical value includes consistent acceptance criteria, reproducible lab testing, and evaluation of effects of heat ageing or bonding improvements.
Related standards
- ISO 18573 - Conveyor belts: test atmospheres and conditioning periods (used for atmosphere B).
- ISO 7622-2 - Steel cord conveyor belts: longitudinal traction test - measurement of tensile strength (referenced for tensile apparatus).
Keywords: EN ISO 7623:2022, steel cord conveyor belts, cord-to-coating bond test, bond strength, thermal treatment, conveyor belt testing, metal-carcass belts.
