Development of Rotary-Arm Type Test System with a Small Platinum Ball Probe for Determination of Cooling Characteristics of Quenchants

Quenchants should be maintained based on their cooling characteristics for keeping their performance using a test system on a daily basis at every worksite. A rotary-arm type test system with a small platinum ball probe has been developed for the purpose after making two prototypes. This development was based on a concept in the classic apparatus reported by Tawara in 1941, which is derived mainly from a circular motion of a small ball probe in quenchants. The system has been realized by current heating, measuring and mechatronics techniques. Finally platinum has been selected for the probe material offering generally extreme durability although nickel alloy was applied to the original and prototype systems. The performance of the system was verified by systematic tests using polymer solutions under various operating conditions. The results suggest the rotation of small probe contributes to improving the accuracy in the measurement.