ASTM D4940

ASTM D4940 – Standard Test Method for Conductimetric Analysis of Water Soluble Ionic Contamination of Blast Cleaning Abrasives

Description:

Significance and Use

4.1 Abrasive media may contain ionic contamination naturally (for example, mineral abrasives), from manufacturing (quenching with contaminated water), transportation, storage or use (in the case of abrasive that is reused). Ionic contamination on the abrasive may transfer to the surface during abrasive blast cleaning, resulting in potential osmotic blistering, accelerated underfilm corrosion and premature coating failure.

4.2 This test method describes a shop/field procedure for assessing the level of conductive species on an abrasive.

4.3 Abrasive standards published by AMPP (AB) and ISO 11126 provide tolerance levels for water soluble contaminants of the abrasive.

Scope

1.1 This test method describes a procedure for assessing blast cleaning abrasives for the presence of conductive-potential, ionic contaminants by determining the total concentration of water soluble conductive species using a conductivity test.

1.2 This test method does not identify the ionic species present nor provide quantitative results on each species.

1.3 This test method is based on a volume comparison among abrasives of similar sizes. A volume comparison is more closely related to surface area of the abrasives than is a weight comparison.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.