ASTM WK65096

    Revision of D5133 - 15 Standard Test Method for Low Temperature, Low Shear Rate, Viscosity/Temperature Dependence of Lubricating Oils Using a Temperature-Scanning Technique

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    Active Standard: D5133 - 15

    Developed by Subcommittee: D02.07 | Committee D02 | Contact Staff Manager



    WK65096


    Keywords

    borderline pumping temperature; critical pumpability temperature; critical pumpability viscosity; engine oil; gelation; Gelation Index; Gelation Index temperature; low-temperature engine oil pumpability; low-temperature rheology; Scanning Brookfield technique; temperature-scanning technique; viscosity;;

    Rationale

    The changes to this method are intended to eliminate unclear language and give specifics, particularly regarding calibration frequency. Two areas of change may not seem to add specificity, but both are included to help the user: 1)For the viscosity calibration, the ramp rate for the calibration has changed to 1 2 C per hour instead of being listed at 2 C per hour. There has not been any difference seen in running the calibration at the two ramp rates. The 2 C per hour ramp rate is practical because it allows the calibration in half the time compared to a sample run, which must be conducted at 1 C per hour. However, giving the option of 1 C allows the user of a multi-position bath to run a calibration on one viscometer head while running a sample test on another viscometer head. This has been common practice recommended by the equipment manufacturer for years, but has not been part of the method. 2)There remains no specific frequency for the calibration of the preheat system. Experience has shown that pre-heating the sample to any temperature over 80 C sufficiently removes the structural memory in the sample. Since the method calls for a temperature of 90 C +/- 2 C, the sensor calibration is unlikely to drift beyond where it needs to be even if it is calibrated infrequently. Thus, adding a specific calibration frequency for the preheat system would likely add burden to the user without benefit. This ballot was prompted by requests from users participating in TMC monitoring and has been discussed in two previous SC7 meetings. This is the first time these changes are being balloted.

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    Work Item Status

    Date Initiated:
    09-11-2018

    Technical Contact:
    Sarah Nuss-Warren

    Item:
    002

    Ballot:
    D02.07 (18-07)

    Status:
    In Balloting