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Shipbuilding Industry

High-performance steel grit and steel shot for hull blasting and structural surface preparation — engineered to achieve Sa 2.5 and Sa 3 cleanliness standards and extend marine coating life in the world's most corrosive environments.

Sa 2.5 Surface ProfileRz 40–70 µm AnchorHRC 40–51 Hardness

Industry Overview

Marine corrosion — why surface preparation is everything

The marine environment is among the most corrosive on earth. A vessel's hull is continuously exposed to seawater — a concentrated electrolyte — combined with mechanical abrasion from marine growth, cavitation, and impact at the waterline. Without proper surface preparation, even the highest-quality anti-corrosion coating systems will fail prematurely through adhesion loss and under-film corrosion.

Industry research consistently shows that surface preparation accounts for more than 80% of the variation in marine coating service life. Macloid Metalix supplies angular steel grit and spherical steel shot formulated for the high-throughput demands of shipyard blast rooms, where abrasive cycling rates are continuous and consistent surface preparation quality directly determines vessel maintenance schedules.

Surface Standard

Sa 2.5 / Sa 3

Anchor Profile

Rz 40–100 µm

Compliance

SSPC / NACE

Classification

ISO 8501-1

Recommended Products

Abrasives selected for marine applications

Steel Grit

Grade rangeG16 – G25
StandardSAE J1993
Best forHull external blasting, ballast tank prep, Sa 2.5/Sa 3 preparation
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Steel Shot

Grade rangeS460
StandardSAE J827
Best forAutomated blast rooms, shop-primer lines, structural plate preparation
View specifications →

Steel Grit — Fine

Grade rangeG10 – G14
StandardSAE J1993
Best forSa 3 tank lining preparation, aggressive angular profiling
View specifications →

Applications

Key uses in this industry

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Hull External Blasting

The external hull requires Sa 2.5 preparation before anti-corrosive primers and anti-fouling systems. Angular steel grit creates the Rz 60–100 µm anchor profile demanded by high-build epoxy coating systems, maximising adhesion and long-term corrosion protection in permanently immersed and splash-zone conditions.

  • Achieves Sa 2.5 cleanliness per ISO 8501-1
  • Angular profile Rz 60–100 µm for epoxy coating systems
  • Faster mill scale removal vs spherical shot on corroded steel
  • Compatible with SSPC-SP 10 / NACE No. 2 specifications

Recommended media

Steel Grit G16 – G25

Ballast Tank Lining

Ballast tanks alternate between flooding with seawater and drying out — among the harshest environments on a vessel. Sa 3 preparation is frequently specified by IMO PSPC for internal epoxy tank linings, requiring complete removal of all mill scale and corrosion to reveal uniformly clean, bright steel.

  • Sa 3 / SSPC-SP 5 White Metal preparation achievable
  • IMO PSPC requirement for ballast tank coating systems
  • Maximises adhesion for glass-flake and high-build epoxy liners
  • Low residual chloride contamination — <5 µg/cm²

Recommended media

Steel Grit G10 – G18

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Steel Plate Preparation

New-build plate lines and section lines use automated blast rooms with multiple blast wheels to prepare structural steel plates and profiles before shop-primer application. Steel shot is preferred for durability and low media breakdown in high-throughput automated systems with continuous recycling.

  • High throughput — compatible with automated blast rooms
  • Spherical shot for shop-primer lines and automated systems
  • Consistent Sa 2.5 with controlled anchor profile depth
  • High recycling life reduces media consumption costs

Recommended media

Steel Shot S460

Standards Reference

ISO 8501-1 cleanliness grades

Sa 1

Grade name

Light Blast Cleaning

Applications

Secondary steel, non-structural internal areas

Recommended abrasive

Steel Grit G25–G40

Sa 2

Grade name

Thorough Blast Cleaning

Applications

Secondary structure, internal voids, tanks below ballast waterline

Recommended abrasive

Steel Grit G18–G25

Sa 2.5Marine Standard

Grade name

Very Thorough Blast Cleaning

Applications

Hull external, waterline zones, ballast tanks, superstructure

Recommended abrasive

Steel Grit G10–G18 / Steel Shot S460

Sa 3

Grade name

Blast to Visually Clean Steel

Applications

Tank linings, high-performance coating systems, immersed zones

Recommended abrasive

Steel Grit G10–G14 (angular profile)

Ready to optimise your shipyard blasting operations?

Our technical team can recommend the correct steel grit or shot grade to achieve your target cleanliness and anchor profile — with bulk supply capability to support continuous shipyard production schedules.

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