Evidence-first editorial standard
This guide separates observed facts, engineering assumptions and data that still require confirmation. It does not promise a universal service life or replace the exact product data and project specification.
ASTM G65 measures resistance to low-stress sliding abrasion, and nothing else
The standard, titled for measuring abrasion with a dry sand and rubber wheel apparatus, presses a flat specimen against a rotating rubber-rimmed wheel while a controlled flow of sand passes between them. The sand scratches the surface under a modest load, which reproduces the gentle three-body sliding wear of a chute bottom or a hopper wall far better than it reproduces anything else.
The result is a volume loss, and lower is better
The specimen is weighed before and after the test; the mass lost is converted to a volume using the material’s density, so that dense and light materials can be compared fairly. A data sheet that quotes a mass loss without the density, or a volume loss without saying which procedure was run, cannot be compared with another figure.
The procedure letter matters as much as the number
The standard defines several procedures that differ in load and test duration, chosen for materials of different wear resistance. Two figures are comparable only if they come from the same procedure and, ideally, the same laboratory. When comparing ceramic offers, ask which procedure was used and request the test report rather than a single number.
A G65 ranking does not predict life in impact, slurry or wet service
The test applies no impact, so it cannot rank a brittle ceramic against a tough material in a zone where lumps land — that question is covered in ZTA or alumina. It uses dry sand, so it says little about slurry erosion, for which ASTM G75 and the Miller number were designed. And it tests the material, not the lining: joints, edges and retention, which end most linings early, are outside it.
How to use G65 figures when choosing a lining
Use them to rank candidate wear faces for sliding abrasion in the same procedure, then check the result against the wear mechanism actually seen on the equipment, described in the guide to abrasion, impact and erosion. Where the mechanism is sliding, a better G65 ranking usually points the right way; where it is impact or erosion, other evidence weighs more, and a trial area on the worst zone remains the most reliable test.
What to ask a supplier who quotes G65
Ask for the procedure, the volume loss with its units, the number of specimens tested, the laboratory and the date of the report, and the exact grade and format tested. A figure for one grade does not transfer to another grade, a different tile format or a ceramic-filled coating. Figures for Induscoat ranges are published only from verified data sheets.