ISO 11124-4:2018

Overview

ISO 11124-4:2018 - Preparation of steel substrates before application of paints and related products - Part 4: Low‑carbon cast‑steel shot defines requirements for metallic blast‑cleaning abrasives in their new condition. The standard covers 12 grades of low‑carbon cast‑steel shot supplied for blast‑cleaning processes, specifying particle sizing (grade codes), hardness, apparent density, permissible defects, microstructure and chemical composition. It is intended for surface preparation of steelwork and is generally applicable to other substrates prepared by blast cleaning.

Key topics and technical requirements

• Grade and designation: Products are designated e.g. “Abrasive ISO 11124 M/LCS/S100” where M/LCS = metallic low‑carbon cast‑steel, S = shot, and the 3‑digit code denotes nominal particle size.
• Particle size distribution: 12 grades with sieve retention limits defined (see Table 1 of the standard). Grade codes map to common national codings (Annex A, e.g., SAE J444 equivalences).
• Hardness: 90% of tested particles must be within 390 HV to 520 HV (ISO 11125‑3).
• Apparent density: Minimum 7.0 × 10^3 kg/m^3 (7.0 kg/dm^3) (ISO 11125‑4).
• Defects and shape (ISO 11125‑5):
  • Max 15% non‑round particles
  • Max 15% voids; max 5% shrinkage defects
  • No cracks allowed; total defects max 20%
  • Foreign matter (including slag) max 1% (ISO 11125‑6)
• Microstructure: Bainitic or martensitic structure required; grain boundary ferrite/pearlite < 5% per particle; undesirable microstructure limited to ≤15% of sampled particles.
• Chemical composition (mass fraction): Carbon 0.08–0.20%, Manganese 0.35–1.50%, Silicon 0.10–2.00%, Sulfur ≤ 0.05%, Phosphorus ≤ 0.05% (test methods ISO 9556, ISO 629, ISO 439, ISO 4935, ISO 10714).
• Moisture: Max 0.2% (ISO 11125‑7).
• Sampling and testing: Refer to ISO 11125 series (Parts 1–7) for sampling and test methods.
• Traceability and labelling: Packaging must show full product coding; lot traceability is recommended and test reports must be provided on request.

Applications and users

• Used in static and site blast‑cleaning equipment, especially where recovery and reuse of abrasives is practiced.
• Typical users: surface preparation engineers, paint and corrosion control specifiers, blast‑cleaning contractors, steel fabricators, coatings manufacturers, and procurement teams requiring certified abrasives.
• Practical benefits: consistent abrasive performance, improved blasting efficiency, predictable surface profile for coating adhesion, and conformity with procurement/specification requirements.

Related standards

• ISO 11125 (Parts 1–7) - test methods for metallic blast‑cleaning abrasives
• ISO 8504‑2 - blast‑cleaning techniques
• National/industry equivalents referenced in Annex A (e.g., SAE J444, SAE J2175, JIS standards)

Keywords: ISO 11124‑4, low‑carbon cast‑steel shot, metallic blast‑cleaning abrasives, blast cleaning, surface preparation, abrasive grading, hardness, apparent density, ISO 11125.