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FEATURE A D V A N C E D M A T E R I A L S & P R O C E S S E S | N O V E M B E R / D E C E M B E R 2 0 2 0 6 3 Fig. 8 — Digital quench concentration monitor. Courtesy of Inductoheat Inc. DIGITAL REFRACTOMETRY Digital refractometry offers much more precise mea- surements of quenchant concentration (Fig. 7). A known light source is applied to the prism present in a moving stream of quenchant media. The reflected light is then reg- istered by a CCD camera. The camera can respond to those wave lengths of light that are applicable to the intended refraction eliminating the fuzzy picture found when trying to optically read a handheld refractometer. Digital refractometry is made simple by connective devices to most heat treatment cells where quenchants are used. The Inductoheat GreenLight quench concen- tration monitor (Fig. 8) installs with a low voltage power connection and a 5/16-in. supply and return quench line. It communicates via Windows protocol and can provide part by part acceptance of quenchant concentration. Digital refractometry removes the human element from the measuring system, and reduces false readings that may be caused by external contamination in the quen- chant media. More accurate concentration readings can reduce the amount of maintenance time for quenchant changes, increase productivity, and ensure metallurgi- cal properties because the refractometry is centered on the desired element, the quenchant concentration. Heat treated parts are less subject to cracking and distortion while maintaining their targeted hardness values when the quenchant concentration is controlled using digital refrac- tometry. ~HTPro For more information: Robert Madeira, vice president and global manager of heat treat technologies, Inducto- heat Inc., and president, Inductotherm Heating & Welding Mexico, 32251 North Avis Dr., Madison Heights, MI 48071, 800.624.6297, rmadeira@inductoheat.com , inductoheat. com. References 1. V. Rudnev, D. Loveless, and R.L. Cook, Handbook of Induction Heating, CRC Press, 2017. 9 Interested in advertising with the ASMHeat Treating Society? Contact Kelly “KJ” Johanns at kelly.johanns@asminternational.org .