Estudo do desgaste e atrito em ensaios micro-abrasivos por esfera rotativa fixa em condições de força normal constante e pressão constante. / Wear and friction study in micro-abrasive wear testing by rotative fixed ball under conditions of constant normal force and constant pressure.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

01/06/2011

RESUMO

The micro-scale abrasive wear test by rotative ball has gained large acceptance in universities and research centers, being widely used in studies on the abrasive wear of materials. Two wear modes are usually observed in this type of test: rolling abrasion results when the abrasive particles roll on the surface of the tested specimen, while grooving abrasion is observed when the abrasive particles slide; the type of wear mode has a significant effect on the overall behaviour of a tribological system. Several works on the friction coefficient during abrasive wear tests are available in the literature, but only a few were dedicated to the friction coefficient in micro-abrasive wear tests conducted with rotating ball. Additionally, recent works have identified that results may also be affected by the change in contact pressure that occurs when tests are conducted with constant applied force. Thus, the purpose of this work is to study the relationship between friction coefficient and abrasive wear modes in ball-cratering wear tests conducted at constant normal force and constant pressure. Micro-scale abrasive wear tests were conducted with a ball of AISI 52100 steel and a specimen of AISI H10 tool steel. The abrasive slurry was prepared with black silicon carbide (SiC) particles (average particle size of 3 m) and distilled water. Two constant normal force values and two constant pressure values were selected for the tests. The tangential and normal loads were monitored throughout the tests and their ratio was calculated to provide an indication of the friction coefficient. In all cases, optical microscopy analysis of the worn craters revelated only the presence of grooving abrasion. However, a more detailed analysis conducted by SEM has indicated that different degrees of rolling abrasion have also occurred along the grooves. The results have also shown that: i) the sliding distance presents an important role on the wear mode transition, ii) for the selected values of constant normal force and constant pressure, the friction coefficient presented, approximately, the same range of values and ii) the friction coefficient was independent of the wear rate.

ASSUNTO(S)

ball-cratering ball-cratering coeficiente de atrito desgaste desgaste abrasivo por riscamento desgaste abrasivo por rolamento desgaste micro-abrasivo friction coefficient grooving abrasion micro-abrasive wear pressão pressure rolling abrasion wear

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