Acoustic method of test of abrasive materials.
Sound Index (SI)
Acoustic method of test of abrasive materials’ hardness is based on definition of sound velocity in article. This velocity depends on recipe features of the article and its operation parameters. We can calculate sound velocity quite quickly and precisely using results of measurement of natural oscillation frequency (NOF).
Russian Standard 25961-83 specifies an application of acoustic method to control physical and mechanical features of abrasive articles.
The range of sound velocity parameters in abrasive articles divided into intervals of 200 m/c in step. These intervals are called Sound Indexes (SI). They are designated by odd two-valued figure. And if you multiply the figure to 100 you will get medial parameter (m/c) of sound velocity in given interval.
Use of acoustic method of test implies the output parameters which characterize physical and mechanical features of abrasive articles (hardness). These parameters are sound velocity and SI.
Acoustic method entered to several Russian Standards (2424-83, 2464-82, 2456-82) among with traditional mechanical hardness control. It was entered as a main method of control physical and mechanical properties of cutting-off wheels to Russian Standard 21963-82 “Cutting-off wheels. Technical descriptions”. Since 1.01.1986 according to this standard cutting-off wheels less than 600 mm in diameter are marked SI instead of hardness.