Significance and Use
5.1 Fretting wear and corrosion are potential serviceability factors in many machines. They have always been factors in shipping finished goods by truck or rail. Packing materials rubbing on a product in transit can make the product unsalable. Beverage cans and food cans can lose their trade dress and consumers often equate container damage to content damage.
5.2 Clamping surfaces on injection molds are damaged by fretting motions on clamping. This damage is a significant cause for mold replacement.
5.3 Machines in shipment are subject to fretting damage in the real area of contact of the bearings on the machines.
5.4 Operating vibration and movement of mechanically clamped components, like screwed assemblies, can produce damage on the clamped faces and other faces that affects machine function or use. Many times fretting damage appears in the form of pits, which are stress concentrators that can lead to mechanical fractures.
5.5 Electrical contacts in any device that is subject to vibration are susceptible to failure (open circuit) due to fretting damage at real areas of contact.
5.6 This test method is intended to be used to identify mating couples that may be less prone to fretting damage than others. This information in turn is used to select materials of construction or surface treatments that are less prone to fretting damage for applications where fretting conditions are known or perceived to exist.
5.7 When using this test method to screen candidate material pairs for a specific application, the user should ensure that the prescribed geometry and test conditions described in Sections 6 – 8 adequately simulate the intended end use. The rationale for any deviations from the prescribed test conditions, if any, shall be explained in the test report and, accordingly, the user shall report that they used a modified version of the standard.
Scope
1.1 This test method may be used for either fundamental or applications-oriented studies of fretting damage. Accordingly, data from these tests may be used to rank the wear resistance of candidate material couples for certain types of machine components whose service life is limited by fretting.
1.2 This test method uses a tribological bench test apparatus with a mechanism or device that will produce the necessary relative motion between a contacting hemispherical rider and a flat counterface. The rider is pressed against the flat counterface with a loading mass. The test method is intended for use in room temperature air. Other configurations or test parameters may be needed to investigate fretting in the presence of lubricants or other environments.
1.3 The purpose of this test method is to rub two solid surfaces together under controlled fretting conditions and to quantify the damage to both surfaces in units of volume loss.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
1.6 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.
