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Rochester, NY, United States

Budinski K.G.,Bud Labs
Wear | Year: 2011

The definition of "abrasive wear" endorsed by the ASTM G2 Committee on Wear And Erosion is: "wear due to hard particles or hard protuberances forced against and moving along a solid surface" [1]. There are many models applied to abrasion that are based upon idealized cones (and other shapes) as an abrasive particle imposed on and moving in contact with a counterface. Wear is calculated as the volume of material fractured or displaced by the sliding cone as it indents and moves through the material. In this study we conducted two and three-body abrasion tests on a variety of materials with alumina and silica abrasive to observe the early stages of abrasion. Optical microscopy on abrasive particles and profilometry of counter faces led to the conclusion that adhesive transfer of material to abrasive particles is a significant component of both two body and three body abrasion. © 2011 Elsevier B.V. Source

During the development of a standardized laboratory fretting test it was observed that the fretting damage to austenitic stainless steel samples taken from wrought bar stock was significantly different from damage to the same alloy in cold-finished strip form. These unexpected results suggested that hardness differences between the mating members might play a significant role in how a couple damages under fretting motion. Is a hardness differential between contacting members better from the damage standpoint than mating members at the same hardness?The newly developed ASTM G 204 standard fretting test was used to address this question. This test uses a reciprocating ball on a flat with amplitude of 50. μm, normal force of 10. N, and duration of one million rubbing cycles at 13. Hz. A hardened steel ball rider (52100 steel at 670. HV) was mated with type O1 tool steel at different hardnesses (690. HV to 280. HV) and the relative fretting damage was assessed. Tests were conducted in air and in light mineral oil.The oil significantly reduced system damage at all hardness differentials. In addition, the damage went from fretting corrosion to fretting wear. In both air and oil a hard/soft couple produced a significant increase in system damage compared to a hard/hard couple. Both air and oil tests suggested that a slightly reduced hardness (10%) of one member may reduce damage by about 10%, but the benefit was marginal. The test conducted in mineral oil demonstrated that adhesive wear is the prevailing mechanism for damage to both members. Adhesive wear appeared to be the origin of the pitting that is often typical in fretting contacts. © 2013 Elsevier B.V. Source

Budinski K.G.,Bud Labs | Budinski S.T.,Bud Labs
Wear | Year: 2015

Galling as defined by ASTM G40 [1] Terms and Definitions relating to wear and erosion, requires the formation of protrusion (excrescences) from a surface after rubbing contact. However, there are other forms of damage that can occur that can affect the serviceability of a tribosystem. For example, a couple in relative sliding may not form excrescences, but the wear rate can be so large that the test couple would be unsuitable for use. A similar situation can exist if adhesive transfer dominates on the rubbing surfaces.This paper describes some of the standard galling tests and proposes interpretation of galling results using a multifaceted evaluation matrix that leads to a compatibility rating for a particular sliding couple. The ASTM standard test employs visual inspection of rubbed surfaces to determine if galling occurred. The proposed interpretation uses visual as well as low-powered binocular microscope examination.The pros and cons of the existing standard tests (ASTM G 98 and G 196) are discussed and it is shown that the proposed rating system solves problems that arise with the present "gall" or not galled" rating system. © 2015 Elsevier B.V. Source

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