1973-02-01

The Effect of Impact Fatigue Prestressing on the High Cycle Fatigue Resistance of Carburized Gear Steels 730142

Gears are frequently exposed to conditions involving random or repeated high strain rate loading in addition to high cycle bending fatigue stresses. Although gears usually fail ultimately by high cycle fatigue, random impact loads superimposed on the predictable bending fatigue stress may lead to premature fatigue failure. The present study examined the effect of repeated prior impact loading on the high cycle fatigue properties of carburized 4118, 4820 and EX-1 steels. It was found that impact prestressing does affect the endurance limit and that this effect can either be detrimental or beneficial. Case microstructure, particularly retained austenite content, and nickel content both affected sensitivity to impact prestressing. The greatest resistance to impact fatigue damage was found in EX-1 steel which had been heat treated to contain approximately 20% austenite. The results of this study have been interpreted in terms of the Troiano theory of ductility in high carbon alloy steels.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Assessment of Bending Fatigue Limits for Carburized Steel

910140

View Details

TECHNICAL PAPER

Impact Properties of Selected Gear Steels

780772

View Details

TECHNICAL PAPER

Improvement on the Fatigue Strength of Case Hardened Gears by a New Heat Treatment Process

821102

View Details

X