ISO 11125-3:2018

Overview

ISO 11125-3:2018 is an international standard that specifies the test method for determining the Vickers hardness of metallic blast-cleaning abrasives. It is a critical part of the ISO 11125 series, which focuses on the sampling and testing of metallic abrasives used for the preparation of steel substrates prior to the application of paints and related products. This standard ensures that the abrasives meet quality and performance benchmarks necessary for effective blast-cleaning operations.

This standard applies primarily to metallic abrasives with particle sizes above 0.3 mm, as measuring hardness on smaller particles is considered unreliable. ISO 11125-3:2018 is designed to be used together with standards from the related ISO 11124 series, which specify types and requirements for metallic abrasives.

Key Topics

• Vickers Hardness Test Method
  The standard prescribes the use of the Vickers hardness test for metallic abrasives, specifying test forces based on particle size:

  • 9.807 N force (HV 1) for particles greater than 0.5 mm in diameter
  • 4.904 N force (HV 0.5) for particles between 0.3 mm and 0.5 mm

• Sample Preparation
  Abrasive particles are mounted in metallurgical sample mounting materials that cure below 140 °C, avoiding alteration of test results due to tempering effects. Samples are polished to expose about half the particle diameter, ensuring accurate hardness indentation.

• Testing Procedure
  Hardness measurements must be performed at ambient temperature and in duplicate to verify consistency. Indentations are located between the particle edges and centers, avoiding regions close to sample edges or defects such as internal voids.

• Accuracy and Calibration
  Calibration of hardness testers must be checked before measurements using comparison plates of similar hardness. Indentations with excessive discrepancy in diagonal measurements (>5%) are discarded to maintain accuracy.

• Result Expression
  The test results are expressed as a percentage conforming to the requirements in the corresponding part of ISO 11124. The arithmetic mean hardness may also be calculated for additional insight.

• Limitations
  The method is unsuitable for particles smaller than 0.3 mm due to difficulties in accurate testing.

Applications

ISO 11125-3:2018 is essential for industries involved in:

• Surface Preparation in Coatings and Painting
  Ensures that metallic abrasives used to clean steel substrates prior to painting have the appropriate hardness, which directly affects cleaning efficiency and quality adherence.

• Quality Control of Abrasives
  Facilitates consistent hardness testing for blast-cleaning abrasives, allowing manufacturers and end-users to verify that abrasives meet international quality standards.

• Industrial Blast-Cleaning Operations
  Supports maintenance of optimal abrasive properties to improve steel substrate preparation, extend lifespan of abrasives, and ensure compliance with safety and performance regulations.

• Standardization in Abrasive Manufacturing
  Provides a uniform methodology accepted internationally, promoting harmonization in test results and product specifications.

Related Standards

ISO 11125-3:2018 is part of a comprehensive system of standards on blast-cleaning abrasives, which includes:

• ISO 11125 Series – Test Methods for Metallic Blast-Cleaning Abrasives

  • Part 1: Sampling of abrasives
  • Part 2: Determination of particle size distribution
  • Part 4: Determination of apparent density
  • Part 5: Determination of defective particles and microstructure
  • Part 6: Determination of foreign matter
  • Part 7: Determination of moisture
  • Part 9: Wear testing and performance (under preparation)

• ISO 11124 Series – Specifications for Metallic Blast-Cleaning Abrasives

  • Part 1: General introduction and classification
  • Part 2: Chilled-iron grit
  • Part 3: High-carbon cast-steel shot and grit
  • Part 4: Low-carbon cast-steel shot
  • Part 5: Cut steel wire (under preparation)

• ISO 6507-1

  • Vickers hardness test method for metallic materials, referred to in the execution of hardness testing.

These interconnected standards collectively ensure the quality, consistency, and performance of metallic abrasives used in steel substrate preparation within the painting and coating industry.

Keywords: ISO 11125-3:2018, metallic blast-cleaning abrasives, Vickers hardness test, steel substrate preparation, paint application standards, hardness determination, blast-cleaning quality control, ISO 11124, abrasive sampling and testing, surface preparation standards.