| Popis: |
For evaluation of quenchants under real industrial conditions, the new Liščić/Petrofer probe is designed. Liščić/Petrofer is special upon design, because it is instrumented with 3 thermo-couples on the same radius of the cross- section at the middle of the probe length. The outer thermocouple measures the temperature at 1 mm below surface, the second one at 4.5 mm below surface, and the third one at the center of the probe. The working principle of the probe is the measurement of the dynamics of heat extraction which is best represented by the change of temperature gradients. Second type of probe developed to evaluate the cooling properties of relatively small samples of a quenchant used in this paper is standard ASTM D6200 probe, which consists from cylindrical test specimen having one thermocouple at its geometrical center. Comparative testing was recently performed with the Liščić/Petrofer probe and standard probe with one vegetable oil (Palm Oil) and a commercially available conventional mineral oil (Kalenol 32). The work was performed at the Quenching Research Centre (QRC) of the Faculty for Mechanical Engineering, University of Zagreb, Croatia. The results of this paper showed distinctive differences in the quenching behavior of these two quenchant media. The results of this comparative study are reported herein. |
