ASTM G99-17 pdf free.Standard Test Method for Wear Testing with a Pin-on-Disk Apparatus.
Wear results are usually obtained by conducting a testfor a selected sliding distance and for selected values of loadand speed.One set of test conditions that was used in aninterlaboratory measurement series is given in Tables 1-3.Other test conditions may be selected depending on thepurpose of the test. In such cases, the user should report theirresults as“following the procedure of ASTM G99.”Wear results may in some cases be reported as plots ofwear volume versus sliding distance using different specimensfor different distances. Such plots may display non-linearrelationships between wear volume and distance over certainportions of the total sliding distance, and linear relationshipsover other portions. Causes for such differing relationshipsinclude initial “break-in”processes，transitions between re-gions of different dominant wear mechanisms，and so forth.The extent of such non-linear periods depends on the details ofthe test system, materials,and test conditions.
It is not recommended that continuous wear depth dataobtained from position-sensing gages be used because of thecomplicated effects of wear debris and transfer films present inthe contact gap, and interferences from thermal expansion orcontraction.
The amount of wear in any system will, in general,depend upon the number of system factors such as the appliedload, machine characteristics，sliding speed,sliding distance,the environment, and the material properties. The value of anywear test method lies in predicting the relative ranking ofmaterial combinations.Since the pin-on-disk test method doesnot attempt to duplicate all the conditions that may beexperienced in service (for example;lubrication，load,pressure,contact geometry，removal of wear debris，andpresence of corrosive environment), there is no insurance thatthe test will predict the wear rate of a given material underconditions differing from those in the test.
In one typicalsystem, the stationary specimen holder is attached to a leverarm that has a pivot.Adding weights, as one option of loading,produces a test force proportional to the mass of the weightsapplied. Ideally, the pivot of the arm should be located in theplane of the wearing contact to avoid extraneous loading forcesdue to the sliding friction.The pin holder and arm must be ofsubstantial construction to reduce vibrational motion during thetest.Instruments to obtain linearmeasures of wear should have a sensitivity of 2.5 um or better.Any balance used to measure the mass loss of the test specimenshall have a sensitivity of 0.1 mg or better; in low wearsituations greater sensitivity may be needed.ASTM G99 pdf download.