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 required 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.

Note 1: The National Lubricating Grease Institute (NLGI)2 classified greases according to their consistency as measured by the worked penetration. The classification system is as follows:

NLGI
Consistency Number

Worked Penetration Range,
25 °C (77 °F)

000

445 to 475

 00

400 to 430

  0

355 to 385

  1

310 to 340

  2

265 to 295

  3

220 to 250

  4

175 to 205

  5

130 to 160

  6

 85 to 115

1.1.1 The procedures for unworked, worked, and prolonged worked penetration are applicable to greases having penetrations 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 accetpable 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.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.