Overview
ISO 4345:2025 - Steel wire ropes - Fibre main cores - Specifications defines the construction, characteristics and test methods for fibre main cores used in steel wire ropes. It covers both natural fibres (sisal, abaca/manila, jute) and man-made fibres (e.g., polyolefin forms) and specifies materials, tolerances, lubrication, moisture, acidity and salt limits. The standard is not applicable to ropes for mine hoisting purposes and notes that fibre cores are adversely affected by high ambient temperatures.
Key topics and technical requirements
- Materials: Permitted natural fibres (sisal, abaca, jute) and man-made fibre types (fibre‑forming polyolefins or mutually agreed alternatives). Mixed cores may be used if agreed by purchaser and manufacturer.
- Construction & designation: Cores must be laid up from at least three strands, continuous without splices. Core designation includes nominal diameter, nominal linear density, fibre type, construction and direction of twist; linear density must be stated as lubricated or unlubricated.
- Tolerances: The document sets tolerances on length, nominal diameter and nominal linear density that vary by fibre type and core size (see Tables 1–3 in the standard).
- Core lubricants: Lubricants shall be acid‑free and moisture‑free; lubricant content for pre‑lubricated cores is agreed and measured per Annex C.
- Moisture regain: Specified limits for natural fibres (e.g., hard fibres ≤14.0 %, jute ≤13.0 %) with test procedures in Annex C.
- Water‑soluble acids: Acidity limit of not more than 2.0 mL of 0.1 mol/L alkali per 100 g of core (Annex D).
- Salt content: Maximum 0.3 % NaCl by mass, test method in Annex E.
- Packaging & marking: Continuous unspliced coils/reels, protected for transit, labelled with supplier name, nominal diameter, linear density, length and fibre type.
Practical applications and users
ISO 4345:2025 is essential for:
- Steel wire rope manufacturers specifying or sourcing fibre cores
- Fibre core producers and supply-chain quality managers
- Testing laboratories performing dimensional, moisture, acidity and salt analyses
- Procurement engineers and designers who specify rope constructions for lifting, mooring, rigging and general engineering applications (excluding mine hoisting)
The standard helps ensure compatibility between core and rope construction, consistent material quality, and reliable test methods for acceptance and quality control.
Related standards
- ISO 139 - Textiles: standard atmospheres for conditioning and testing (referenced)
- ISO 1968 - Fibre ropes and cordage: vocabulary (referenced)
- Prepared by ISO/TC 105 (Steel wire ropes); this edition replaces ISO 4345:1988.
Keywords: ISO 4345:2025, steel wire ropes, fibre main cores, natural fibre cores, man-made fibre cores, moisture regain, core lubricants, core diameter, linear density, salt content, water-soluble acids, testing methods.
