Overview - EN ISO 7622-2:2022 (Steel cord conveyor belts)
EN ISO 7622-2:2022 specifies a standardized, destructive method to measure the tensile strength in the longitudinal direction of steel cords that form the carcass of conveyor belts. It applies exclusively to conveyor belts with a steel carcass and is intended primarily for verification (for example in litigation or when a cord manufacturer’s certificate is not available). The document is the European adoption of ISO 7622-2:2022 and supersedes the 2015 edition.
Key topics and technical requirements
- Scope: Determination of longitudinal tensile strength of steel cords in conveyor belt carcasses.
- Test principle: Prepare specimens so only one warp cord is stressed and break the specimen in a dynamometric tensile testing machine.
- Apparatus requirements
- Machine capacity such that the maximum test load is 15% to 85% of machine capacity.
- Jaw separation rate set to (100 ± 10) mm/min and maintained constant.
- Minimum jaw separation ≥ 250 mm.
- Jaws designed to prevent slippage; cross-ribbed jaws with at least 80 mm ribbed length are recommended.
- Test specimens
- Cut three specimens parallel to belt axis, at least 50 mm from edge; width containing five warp cords.
- Length depends on cord diameter (examples): 500 mm for Ø0–3.9 mm, 700 mm for Ø4.0–5.9 mm, up to 1 500 mm for Ø13.1–15.0 mm.
- Three specimen types (A, B, C) with defined preparation (removal of covers/weft or cutting adjacent cords to isolate the central cord).
- Conditioning: Follow ISO 18573 (use atmosphere A or B) and test immediately after conditioning.
- Procedure and results
- Grip specimen ends (≈100 mm each) in jaws, ensure correct alignment, run test at required rate, record breaking force.
- Tensile strength R (N/mm) is calculated as R = (F × C) / b, where F is the mean breaking force of three specimens, C the number of warp cords in the belt, and b the belt nominal width (mm).
- The reported value is the maximum theoretical tensile strength; an effective tensile strength requires corrective factors (not detailed in this part).
Applications and who uses it
- Primary users: belt manufacturers, testing laboratories, quality assurance teams, procurement engineers, legal experts in transport/conveying disputes, and maintenance departments responsible for conveyor systems.
- Practical uses
- Verifying compliance of steel-cord belts to contractual or forensic requirements.
- Quality control on incoming or installed belts when manufacturer certificates are unavailable or disputed.
- Supporting failure analysis and litigation where destructive proof of cord strength is required.
Related standards
- ISO 7622‑1 - method for determination of elongation (related part of the series).
- ISO 18573 - conveyor belts - test atmospheres and conditioning periods (normative reference used for specimen conditioning).
Keywords: EN ISO 7622-2:2022, steel cord conveyor belts, longitudinal traction test, tensile strength measurement, conveyor belt testing, test specimens, ISO 18573.
