ASTM D217 - Cone Penetration of Lubricating Grease
Signiﬁcance and Use
5.1 These cone penetration tests not only evaluate the consistency of lubricating greases over the full range of NLGI numbers from 000 to 6, but also evaluate the consistency of stiff greases having penetration numbers less than 85. In contrast, Test Method D937 is aimed at petrolatums and Test Method D1403 uses less precise 1⁄4 and 1⁄2-scale equipment intended for use when the sample quantity is limited.
5.2 Cone penetration test results provide one measure of the consistency of a grease. Worked penetration results are re-quired to determine to which NLGI consistency grade a grease belongs. Undisturbed penetration results provide a means of evaluating the effect of storage conditions on grease consistency.
5.3 Although no correlation has been developed between cone penetration results and ﬁeld service, the cone penetrations obtained by the four procedures are widely used for speciﬁcation purposes, such as in users’ material speciﬁcations and suppliers’ manufacturing speciﬁcations.
1.1 These test methods cover four procedures for measuring the consistency of lubricating greases by the penetration of a cone of speciﬁed dimensions, mass, and ﬁnish. The penetration is measured in tenths of a millimetre.
1.1.1 The procedures for unworked, worked, and prolonged worked penetration are applicable to greases having penetra-tions between 85 and 475, that is, to greases with consistency numbers between NLGI 6 and NLGI 000. An undisturbed penetration test, described in Appendix X1, is similar to the unworked penetration test.
1.1.2 The block penetration procedure is applicable to greases that are sufficiently hard to hold their shape. Such greases usually have penetrations below eighty-ﬁve tenths of a millimetre.
1.1.3 Unworked penetrations do not generally represent the consistency of greases in use as effectively as do worked penetrations. The latter are usually preferred for inspecting lubricating greases.
1.2 None of the four procedures is considered suitable for the measurement of the consistency of petrolatums by penetration. Test Method D937 should be used for such products.
1.3 The dimensions of the equipment described in these test methods are given in SI units as the primary unit of measure with equivalent imperial units as acceptable alternatives where applicable. In cases where equivalent SI conversions are not known, notes are added for clariﬁcation. Temperatures and other dimensions are given in the preferred SI units; the values shown in parentheses are provided for information.
Extracted, with permission, from ASTM D217-21a - Cone Penetration of Lubricating Grease, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be purchased from ASTM International, astm.org