Lubrication in forming

In this dossier, which follows on from the fascicule [M 3 015] , we present friction and wear tests, an essential means of specifying the performance of a shaping lubricant. We will present the following in turn:

• the objectives and conditions of the tests;

• standard tribometric tests ;

• plastic crush tests ;

• how to characterize wear.

Further details on test equipment are given in the following files, which also deal with this subject.

It should be noted that the development of numerical simulation techniques [1][2][3] in recent years has made it possible to dispense with most of the simplifying, but sometimes unrealistic, assumptions concerning the geometry of forming operations or tests and the rheology of the metal; as a result, it has greatly modified the approach to these problems and the implementation of friction tests. Numerical simulation methods make it possible to analyze in detail the conditions of metal/tool contact in tests and processes: contact pressure, sliding speed, temperature... Numerical simulation improves the reliability of test results by optimizing the conditions under which tests are carried out, interpreted and applied. We illustrate this point in this dossier. Numerical simulation also makes it possible to model the physical phenomena which, on a microscopic scale, determine lubricant performance. This last aspect, the most complex, is however the least complete (see the following files which deal with this subject).

This dossier is part of a series of texts on "Lubrication in shaping".

Most of the symbols used in this text were introduced at [M 3 015] . Readers may wish to refer to their own table of symbols.

References are given in the "Further information" section: [Doc. M 3 016]...