A new technique described below for the automatic digital rating of iron specimens has been developed to offer an unbiased optional rating to the inherently difficult visual assessment referenced in section 13 of D665.
During the last D02.C0.02 section meeting in Seattle, it was approved to start a new work item to add to the test method an automatic procedure for the test specimen rating (interpretation of results) as an alternative to the manual visual inspection. The detailed description of automated technique will be created and added as an Appendix. All other aspects of the method such as sampling, test rod preparation and test procedures remain the same as it is in current D665-19.
Adding objective metrological rating to the test method will improve its reliability and due to the ability of digital raters to report the result as a numerical value of rust in percentage of the total surface exposed, it makes possible to determine a precision for the method with repeatability and reproducibility values.
For now, two studies have been conducted using several samples with different level of corrosion and different models of automated apparatuses (see Research Report attached to this ballot). As of today, at least two suitable instruments from different manufacturers are available on the market.
These studies allowed to estimate the temporary precision (repeatability) and evaluate how ratings calculated by automated instrument are matching with visual rating on a matrix of test rods.
The intent for this revision is to encourage laboratories to gather experience with automated rating procedure so that a full ILS can be conducted to demonstrate equivalence of the automated ratings to visual ratings with the considerations of all sample types described in the method scope and included in all ASTM product specification standards.
Date Initiated: 09-09-2022
Technical Contact: Igor Borissov
Item: 008
Ballot: D02 (23-01)
Status: Negative Votes Need Resolution