Temperatura in temperaturni gradient med fretting preizkusom 1 % C in 1.5 % Cr jekla

F. Vodopivec, J. Vižintin

Kovine zlitine tehnologije 30 (1996) 9–14.

Abstract

Pri fretting preizkusu je material izpostavljen obrabi pri majhni amplitudi in veliki frekvenci. Zaradi specifičnih pogojev preizkusa nastajajo mikroskopsko majhne točke torne preobremenitve, v katerih močno zraste temperatura. Toplota se močno širi po torni površini in nastajajo veliki temperaturni gradienti. Pri primernih pogojih preizkusa nastane tako imenovana bela faza, za katero smo na osnovi mikrostrukture ugotovili, da je izločilno utrjeni avstenit. Sodeč po mikrostrukturi, lokalna temperatura presega 1000 °C, temperaturni gradient ob površini trenja pa presega 1000 °C/mm.Predložen je geometrični model dogajanja ob tej površini.

At the fretting test the material is submitted to wear by small amplitude and high frequency. The temperature is strongly increased in small islands which grow at greater amplitude by coalescence. The generated heat is rapidly dissipated on the worn surface and a great temperature gradient is formed forward the bulk of the specimen. By appropriate test conditions a white phase is formed, which was identified as precipitation hardened austenite. The microstructure also indicates, that in the white phase the temperature is above 1000 °C/mm. A geometrical model of the process on the worn surface as well as the explanation of the effect of amplitude on the wear coefficient areproposed.

Keywords: steel, amplitude, temperature, white phase, fretting wear


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