Engenharia Mecânica

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Navegando Engenharia Mecânica por Assunto "Abrasion"

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    Artigo
    Effect of pressure on abrasive wear mode transitions in micro-abrasive wear tests of WC-Co P20
    (2013) Camara Cozza R.
    The purpose of this work was to analyse the effect of the pressure (variable and constant) on the wear mode transition in ball-cratering wear tests. It was conducted using balls of 52100 steel, specimens of WC-Co P20 and abrasive slurry prepared with SiC particles and distilled water. The results showed that the conditions of variable and constant pressure had significant effects on the occurrence of the abrasive wear modes and their transitions. Under the condition of variable pressure, the transition from grooving to rolling abrasion occurred earlier than for constant pressure and the ratio A g/A p was larger for the condition of constant pressure; A p is the projected area of the crater, and A g is the projected area with grooving abrasion. © 2012 Elsevier Ltd.
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    Artigo
    Effect of sliding distance on abrasive wear modes transition
    (2015) Cozza R.C.
    © 2014 Brazilian Metallurgical, Materials and Mining Association.This work presents a study on the effect of sliding distance on abrasive wear modes transition in micro-abrasive wear. Ball-cratering wear tests were conducted with specimens of P20 cemented carbide (WC-Co) and M2 tool steel, balls of 52100 steel and abrasive slurry prepared with SiC particles and distilled water. Results were analyzed in terms of Ag (area with grooving abrasion) and Ar (area with rolling abrasion) as a function of sliding distance and pressure; they have indicated that with the increasing of sliding distance and, a consequent decreasing of pressure, there is the transition from grooving abrasion to rolling abrasion.
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    Artigo
    Friction coefficient and wear mode transition in micro-scale abrasion tests
    (2011) Cozza R.C.; Tanaka D.K.; Souza R.M.
    The purpose of this work was to conduct ball-cratering wear tests to monitor both normal and tangential forces. Balls of 52100 steel, a specimen of H10 tool steel and an abrasive slurry prepared with silicon carbide particles and distilled water were used. Optical microscopy analysis of the worn craters revealed the presence of only 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 also showed that the normal force plays an important role in the scattering of the values of the friction coefficient. © 2011 Elsevier Ltd. All rights reserved.
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    Artigo
    INFLUENCE OF ABRASIVE WEAR MODES ON THE COEFFICIENT OF FRICTION OF THIN FILMS
    (2018-11-05) Ronaldo Câmara Cozza; WILCKEN, JORGE THIAGO DE SOUSA LIMA; SCHÖN, CLÁUDIO GERALDO
    The purpose of this work is to study the influence of abrasive wear modes on the coefficient of friction (μ) of thin films. Initially, free rotative-ball micro-abrasive wear testing equipment was designed and constructed to measure the coefficient of friction on the tribological system “thin film – abrasive slurry – test sphere”. Experiments were conducted with thin films of TiN, CrN, TiAlN, ZrN, TiZrN, TiN/TiAlN, TiN/TiAlN (multi-layer), TiHfC and TiHfCN using a ball of AISI 52100 steel and abrasive slurries prepared with black silicon carbide (SiC) particles and glycerine. The aim of this design was to produce “grooving abrasion” and “rolling abrasion” on the surface of thin films. The normal force (N) and the tangential force (T) were monitored throughout the tests, and the coefficient of friction was calculated as μ = T/N. Aside from the thin film type, e.g., for all thin films studied, the results that have been obtained in this work show that the abrasive slurry concentration affected the abrasive wear modes (“grooving abrasion” or “rolling abrasion”) and, consequently, the magnitude of the coefficient of friction: i) a low abrasive slurry concentration was related with grooving abrasion and a relatively high coefficient of friction; ii) a high abrasive slurry concentration was related with rolling abrasion and a relatively low coefficient of friction.
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    Artigo
    Third abrasive wear mode: Is it possible?
    (2014) Ronaldo Câmara Cozza
    The objective of this paper is to propose an initial discussion on the characterization of a third abrasive wear mode. The results obtained in a previous work [1] under different test conditions revealed the occurrence of the superposition of the "rolling" and "grooving" abrasive wear modes. This phenomenon was denoted "micro-rolling abrasion" due to the observation that "rolling abrasion" was found to act on "grooving abrasion". © 2014 Brazilian Metallurgical, Materials and Mining Association.