Acoustic Emission Waves from the Onset of Galling between Tool and Sheet Material

作者：Mostafavi S^*; Sindi C Teymuri; Pashmforoush F; Zinati R Farshbaf

来源：Materials Evaluation, 2013, 71(11): 1335-1342.

• friction
• galling
• acoustic emission
• condition monitoring

Galling is one of the most important problems in sheet metal forming processes. However, determination of the onset of galling has been difficult to study because there is no access to the contact area and, thus, only indirect measurements can be made. In this investigation, the acoustic emission testing method was used to record and study the elastic waves generated during the different stages of galling. The experimental setup designed for this study contained a double radius hardened tool, which was slid over a stainless steel sheet. Results demonstrated that the onset of galling is associated with relatively low amplitude acoustic emission waves corresponding to stage 1 of galling, followed by a gradual rise in the acoustic emission activities related to stage 2 of galling. Eventually, high amplitude acoustic emission waves were generated, which were related to stage 3 of galling. The key characteristic of these waves was the quasi-linear increase in amplitude, which eventually resulted in a very high amplitude acoustic emission signal. Surface studies showed that the last wave with the highest amplitude and energy corresponded to the rupture of the lumped welded sheet material, which was detached from the tool or sheet surface. This paper explains the relationship between acoustic emission activities and galling. It also discusses how the detected acoustic emission waves can be correlated to the tribological performance of the frictional pairs during galling events.

• 出版日期2013-11