Untitled in english

Author(s)

Felipe Gustavo Bernardes

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2005-11-18

Examining board members

Amilton Sinatora; José Daniel Biasoli de Mello; Giuseppe Pintaúde

• Advisor: Amilton Sinatora

Abstract

Previous results showed that friction coefficient depends on abrasive size just in severe wear regime, and that wear rate depends on this parameter only in mild wear regime. In order to verify if this behavior is observed for multi-component white cast iron, it was studied the influence of abrasive size and matrix hardness on friction coefficient and wear rate of this material. Two-body abrasive wear tests were conduced under different severities. Severity variation was imposed by means of different material and abrasive hardness. The less severe conditions were applied using glass sand paper, in the other hand, for most aggressive conditions alumina sand paper was used. Macrohardness values of material were 550 and 700 HV. Results showed similar behavior to the one depicted in literature. The exception occurred when abrasive hardness was lower than matrix hardness. Under this condition it was observed that abrasive size had no influence on the relative wear resistance results. As a technological view of this work, the results obtained for multi-component white can be used as a guide for using this material in abrasive wear applications. In severe wear regime the hardness change, from 550 to 700 HV, promoted 50% of increasing in wear resistance. On mild wear regime the same hardness change promoted 250 to 1700% of increasing in wear resistance. Hardness increasing caused reduction of friction coefficient on both wear regimes. Then both energy (frictioncoefficient decreasing) and material consume (wear decreasing) can be reduced by means of adequate heat treatment of multi-component white cast iron, i. e. by means of hardness increasing. (AU)