Tribological aspect of selecting filler metal for repair surfacing of gears by hardfacing

Abstract

Analysis of repaired gears made of case-hardening steel 20MnCr5 by hardfacing method is presented in this paper. Hardfacing repaired gears are tested on the closed power circuit device with variation of the torque value. During testing the wear intensity is measured and the gears' working life is predicted. Samples made of the same material as the gear are tested on tribometer of the 'block-on-disc' type. The gears are repaired in two ways: (1) by hardfacing with filler metal, which is subsequently case-hardened and heat-treated and then mechanically machined, and (2) by hardfacing with filler metal of high hardness (≈ 60 HRC).

U radu je predstavljena analiza zupčanika izrađenih od čelika za cementaciju 20MnCr5 koji je repariran tvrdim navarivanjem. Zupčanici reparirani tvrdim navarivanjem su ispitivani na uređaju sa zatvorenim strujnim kolom sa varijacijom veličine prenosnog momenta. Tokom ispitivanja, izmeren je intenzitet habanja i procenjen je radni vek zupčanika. Uzorci napravljeni od istog materijala kao zupčanik su ispitivani na tribometru tipa 'blok-na-disku'. Zupčanici su reparirani na dva načina: (1) putem tvrdog navarivanja dodatnim materijalom, koji je onda termohemijski i termički obrađen a zatim obrađen mašinski, a (2) putem tvrdog navarivanja sa dodatnim materijalom visoke tvrdoće (≈ 60 HRC).