Analysis of Scoring Resistance on Coated Spur Gears by Considering Surface Roughness

Abstract

W ith the rise of velocity and momentum in machines as a result of technological developments, on gears, alongside refraction from the bottom of the gears and pitting formation, and scoring formation has showed up. In the scoring formation phase because of the fact that many parameters are influential, resistance calculations could not be stated precisely. In experiments made for this purpose, 20MnCr5 steel gears were coated using various coating materials chrome, nickel and manganese , thus usage of coating material on gear mechanisms in terms of scoring was analyzed. In the experiments, gears were rotated with a speed of 3000 rpm and the oil temperature constant at 323±2 °K. Gears were exposed to loading at 15.2 Nm and continued by increasing 20 % until scoring formation was observed. It is seen in the experiments that coated gears have more scoring resistance than uncoated ones. It is also observed that coating materials increases the scoring strength of gears. According to the experiments, when gears run at the same conditions speed, torque and lubrication , chrome coated gears are 10 times longer, nickel coated gears are 5 times and manganese coated gears are 1.5 times longer resisted when compared with uncoated gears. After the scoring formation, experiments continued for determining how the scoring formation developed. It is seen in the experiments that when scoring occurs the wear increases rapidly on the tooth of gears

Keywords

• Scoring,Spur gear,Surface roughness,Coating material,Pitting

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