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Improvement of Fatigue Strength of Automatic Transmission Gear by Developing Controlled Rolled Alloy Steel
Technical Paper
2000-01-0614
ISSN: 0148-7191, e-ISSN: 2688-3627
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Event:
SAE 2000 World Congress
Language:
English
Abstract
The controlled rolling process has been introduced to increase strength and toughness of alloy steels for the application of transmission gear. Cr-Mo alloy steel containing 0.02% Nb was controlled rolled in the temperature range of 870-970°C, showed fine austenite grain size, about ASTM No.11, resulted from the effects of recrystallization and Nb(C,N) precipitation. To investigate the effects of grain refinement on mechanical properties, several tests were conducted for the newly developed controlled rolled steel and conventional Ni-Cr-Mo alloy steel after carburizing. The new steel showed 2.1 times higher pitting resistance than the conventional steel. Fatigue limits of new and conventional steels were 950 and 930 MPa respectively. Charpy impact energy of new steel was improved about 35% compared with the conventional steel. Consequently, the pinion gear from the new steel instead of conventional one showed enhanced performance, especially pitting resistance, in dynamometer test.
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Citation
Ban, H., Jo, B., Ahn, S., and Jung, S., "Improvement of Fatigue Strength of Automatic Transmission Gear by Developing Controlled Rolled Alloy Steel," SAE Technical Paper 2000-01-0614, 2000, https://doi.org/10.4271/2000-01-0614.Also In
References
- Tsushima N. Muro H. “Influence of Various Factors of One Percent Cr carburizing Steel upon Rolling Contact Fatigue Life” SAE 820633
- Howes M.A.H. Sheehan J.P. “The Effect of Composition and Microstructure on the Pitting Fatigue of Carburized Steel Cases” SAE 720222
- Howes M.A.H. Sheehan J.P. “The Effect of Case Carbon Content and Heat Treatment on the Pitting Fatigue of 8620 Steel” SAE 720268
- Urita Tatsumi Namiki Kunio Likubo Tomohito “Effect of Carburizing Grain Size on the Fatigue Properties of Carburizing Steels” Electric steel co. 59
- Jung Seung Cheal Ahn Seung Gyun “Effects of Normalizing Microstructure in Alloy Steel on the Performance of Planetary Gear Sets of Automatic Transmission” SAE 970972
- Kurebayashi Yutaka Nakamura Sadayuki “Development of Ultra Fine Grain Size for Carburizing”
- Grace R.A. “Strengthening Steel by Austenite Grain Refinement” Transactions of The ASM 59 1966
- Speer J.G. Hansen S.S. “Austenite Recrystallization and Carbonitride Precipitation in Niobium Microalloyed Steels” Metallurgical Transactions A 20A January 1989
- Lee W. B. Kang K. B. “Growth Kinetics of Carbonitride Precipitates in Nb bearing HSLA Steels” J. of the Korean Inst. of Met. & Mater. 34 6 1996