Mill processing helped minimize the MAD to less than the amount removed in the final processing step of turning
and burnishing. Figure 6 shows data for a number of specimens where the surface scan was removed by glassbead
blasting after hardening and bulk Rockwell C tests were made on the OD surfaces at a number of locations and
averaged. Bars were sectioned, metallographically prepared, and rated for maximum free-ferrite depth (when present) and maximum affected depth of decarburization. The plot shows a much better correlation between HRC and MAD when free ferrite was not present versus when it was present.