engleski

PROPERIES OF THE QUENCHANTS MEASURED WITH LIŠČIĆ/QRC AND ISO 9950 OR ASTM D6200 PROBES

For evaluation of quenchants under real industrial conditions, the new Liščić/QRC probe is designed. The Liščić/QRC 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 centre 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 centre. Comparative testing was recently performed with the Liščić/QRC probe and standard probe with one vegetable oil (Palm Oil) and a commercially available 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 behaviour of these two quenchant media.

quenching intensity, Liscic/ QRC probe, standard ISO 9950 probe, palm oil, mineral oil

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