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Budinski K.G.,Bud Labs | Budinski S.T.,Bud Labs
Wear | Year: 2017

The dry sand rubber wheel abrasion test (ASTM G 65) is probably the most widely used abrasion test. It has been used for decades with favorable results. However, this test was developed when tool steels and fusion hardfacings were the materials usually ranked with this low-stress sand abrasion test. Two major problems have emerged in the use of this test: 1. The abradant (silica sand) is not aggressive enough for many modern materials. 2. There are many issues with the variability and availability of the rubbers used to force the abrasive against the test surface. This project was initiated to investigate the viability of using the ASTM G 174 loop abrasion test to replace or supplant the ASTM G 65 test. Friction tests were conducted on various substrates with rubbers wheels used in the three-body testing to understand the interface between the rubber and the abrasive. Limited tests were also conducted on replacing the rubber wheel in the three-body test with a steel wheel. Finally tests were conducted to develop a correlation between ASTM G 65 test results and ASTM G 174 test results. The friction tests confirm that various rubbers interact very differently with abrasives and substrates. A steel wheel cannot be used with the current ASTM G 65 force. The sand crushes to powder. However, a correlation curve was developed to allow conversion of historical ASTM G 65 data to results obtained with the ASTM G 174 two-body abrasion test. Overall this study suggests that two -body abrasion testing with aluminum oxide eliminates rubber issues and the aluminum oxide is abrasive enough to rank modern composites and cermets that are too wear-resistant for a sand abrasion test. © 2017 Elsevier B.V.


Budinski K.G.,Bud Labs
Proceedings - International Brazilian Conference on Tribology | Year: 2010

The ASTM G 65 dry-sand rubber wheel test is a popular low-stress abrasion test in the USA. It uses coarse silica sand as the abradant and this abradant is thought to simulate the kind of abrasion that occurs in mining and agriculture. The sand is forced against the test specimen with a chlorobutyl rubber wheel. The wheel wears and requires periodic replacement. However, in 2008 the only USA supplier of these wheels stopped making them, A search was launched to find a new supplier, but concurrent with this search this study was conducted to identify a lower-cost and more available rubber to replace the chlorobutyl rubber. This paper describes tests of four candidate replacement rubbers. Wheels were made from these rubbers and the ASTM G 65 test was performed on a reference material with these rubbers. The candidate rubbers did not perform the same as the chlorobutyl rubber and tests were performed to explain these results.


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.


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.


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.

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