Influence of Test Conditions on the Cooling Curve Response of Polymer Quenchants (Tensi Agitation Device)

摘要

A statistical analysis on the effect of test conditions on cooling curve test results for polymer quenchants is presented herein. These results apply to tests conducted with the use of the Tensi agitation device. Results of this analysis shows that relatively small differences in probe heating temperature can have a strong influence on the time to cool to 600, 400 and 200℃. Similarly, quenchant temperature is shown to have a statistically significant effect on the maximum cooling rate and on the cooling time to 400 and 200℃. The influence of test conditions is also shown to be dependent upon the quenching speed of the polymer solution. Quenchant flow rate variation within the range of flow rates examined in this study did not cause any statistically significant changes in the test results. NEW COOLING CURVE TEST METHODS for polymer quenchants have been published by ASTM: ASTM D6482-99 "Determination of Cooling Characteristics of Quenchants by Cooling Curve Analysis with Agitation (Tensi Method)" and D6549-00 "Determination of Cooling Characteristics of Quenchants by Cooling Curve Analysis with Agitation (Drayton Unit)". These standards are extensions of the standard test method ASTM D6200-00 "Determination of Cooling Characteristics of Quench Oils by Cooling Curve Analysis" which has been used to test oils under static (non-agitated) conditions. Since all new ASTM test methods are required to have statements of precision and bias that are determined by interlaboratory testing, members of the ASM-HTS Quenching and Cooling Committee have initiated an interlaboratory test program. The specific ASTM committee under which these test methods are listed, requires that the interlaboratory tests be conducted per the requirements of ASTM D6300-98 "Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants", which also suggests that a preliminary ruggedness test be conducted to assess the influence of test conditions on test results. Test method conditions are nomally evaluated per ASTM El 169 "Guide for Conducting Ruggedness Tests".