Pitting Durability of Electrolytically Polished Medium Carbon Steel Gears

Abstract

It is well known that the smooth finishing of tooth faces is quite effective in improving the pitting durability of gears. In practice, however, gear tooth faces are rough ground or hobbed because of the low cost of production. As an effective surface finishing at moderate cost, the present authors reconsidered the usefulness of electrolytic polishing after rough grinding or bobbing. To show the effectiveness of electrolytic polishing, pitting durability of the electrolytically-polished gear is compared with that of the unpolished, rough ground gear under various operating conditions, including poor lubrication conditions and/or severe loading conditions which are often experienced in an actual power transmission. The test pieces were made of normalized medium carbon steel of 0.35%-C having good run-in characteristics in order to emphasize the effect of electrolytic polishing. The result reveals that the electrolytic polishing after rough grinding improves the durability by about 50 percent at the maximum Hertzian contact stress.

Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Lahaina, Hawaii, October 16–20, 1994

KEY WORDS:

• Spur Gears
• Finishing
• Roughness Effects
• Fatigue

Notes

Presented as a Society of Tribologists and Lubrication Engineers paper at the ASME/STLE Tribology Conference in Lahaina, Hawaii, October 16–20, 1994