Bearing made of abrasion-resistant aluminum alloy

Abstract

The invention relates to a bearing for supporting a moving member having a surface of a first arithmetical mean roughness. This bearing is made of an abrasion-resistant aluminum alloy containing 14.0-17.5 wt% of Si, 2.0-5.0 wt% of Cu, 0.1-1.0 wt% of Mg, 0.3-0.8 wt% of Mn, 0.1-0.3 wt% of Cr, 0.05-0.20 wt% of Ti, 0.003-0.05 wt% of P, not greater than 1.5 wt% of Fe, less than 0.005 wt% of Ca, and aluminum as a remainder. The aluminum alloy contains silicon primary crystals, and first and second intermetallic compounds. Each of the silicon primary crystals and these intermetallic compounds has an average particle diameter from 8 to 30 .mu.m. The silicon primary crystals and the first and second intermetallic compounds respectively have first, second and third fractions each ranging from 5 to 40 .mu.m in particle diameter. The total area of the first, second and third fractions on a two-dimensional section of the alloy is from 5 to 10% by area, based on the total area of the section. The bearing has a surface having a second arithmetical mean roughness which is greater than the first one and is from 0.3 to 3.0 .mu.m. The bearing is superior in abrasion resistance, seizure resistance and running-in characteristic, and is capable of reducing abrasion even if used under a condition of inferior lubrication.