Fatigue Strength of Steel Rollers and Gears Treated by Cavitation Peening with Short Processing Time

Abstract

In this study, steel rollers and gears were treated by the cavitation peening with processing times of 1 min and 5 min, and they were fatigue-tested using a roller testing machine and a gear testing machine. The surface hardness and the compressive residual stress of the rollers and gears were increased by the cavitation peening, while, the surface roughness of the cavitation-peened rollers and gears was almost the same as that of the non-peened ones. As a result of the fatigue tests, the fatigue strength of the test specimens were improved by the increase in surface hardness due to the cavitation peening, and those without the increase in surface hardness were not increased so much. The fatigue strength of the cavitation-peened test specimens was similar to that of the shot-peened ones obtained by the previous fatigue tests. This study revealed that the cavitation peening is expected to put to practical use in the improvement in fatigue strength of steel gears.

Keywords

• gear
• surface treatment
• cavitation
• steel
• fatigue strength
• pitting
• hardness
• surface roughness
• normal stress