ISO 5718-1:2023

Overview

ISO 5718-1:2023 - "Harvesting equipment - Requirements for cutting elements - Part 1: Blades used on rotary disc mowers and rotary drum mowers" defines material, testing and marking requirements for cutting blades used in forage-crop harvesting (as defined in ISO 4254-12). The standard applies to blades on mounted, semi‑mounted, trailed or self‑propelled rotary disc and rotary drum mowers and is focused on ensuring blade toughness and durability under high centripetal forces and impacts with foreign objects.

Key topics and technical requirements

• Scope and applicability

  • Applies only to agricultural forage harvesting blades on rotary disc and drum mowers.
  • Not applicable to flail mowers, large rotary mowers covered by ISO 4254-13, arm‑type large rotary mowers, pedestrian‑controlled motor mowers, or lawn mowers covered by ISO 5395.

• Material requirements

  • Blades shall be made of steel selected by the manufacturer.
  • Minimum hardness: 38 HRC (Rockwell), tested in accordance with ISO 6508-1.

• Bend test (brittleness check)

  • Blades are progressively bent within a defined bending zone (inside radius R = 16 mm).
  • Required bend angles depend on blade thickness:
    • thickness < 3.5 mm → 75°
    • ≥ 3.5 mm and < 4.5 mm → 45°
    • ≥ 4.5 mm → 30°
  • Acceptance: No visible cracks after bending. Spring‑back is not considered.
  • Alternate procedure: A test producing ~14.5% permanent elongation across the blade surface (neutral axis assumed at 40% thickness) may be used if equivalent.

• Impact test (toughness check)

  • Blade mounted as in service and rotated at a minimum tip speed of 90 m/s.
  • A 30 mm diameter steel rod (tensile strength 490–550 N/mm²) is inserted into the blade path at 3–5 m/s; several insertion geometries are specified (straight, tangential, circular).
  • Dwell: minimum 1 s with at least 29 impacts.
  • Acceptance: No breakage (deformation allowed); cutting-edge chipping not considered failure. Mass loss per tested side ≤ 5% of initial blade mass.

• Marking & documentation

  • Each blade must bear manufacturer/trademark, date or lot/production number, and direction of movement if necessary.
  • Packing should note the standard ("ISO 5718-1"). Test procedures and results must be documented for traceability.

Applications - who uses this standard

• Blade and mower manufacturers for product design and quality control.
• Test laboratories conducting bend and impact tests.
• Procurement and OEMs specifying vendor compliance.
• Safety and compliance engineers, certification bodies and maintenance teams focused on reliability and operator safety in agricultural forage harvesting.

Related standards

• ISO 6508-1 (Rockwell hardness test)
• ISO 4254-12 (safety for rotary disc/drum mowers)
• ISO 4254-13 (large rotary mowers)
• ISO 5395 (lawn mower safety)

Keywords: ISO 5718-1, blades, rotary disc mowers, rotary drum mowers, bend test, impact test, Rockwell hardness, forage crop harvesting, blade marking, agricultural equipment standards.