N. Kobasko, M. Aronov, J. Powell, IQ Technologies, Inc., Akron, OH; B. L. Ferguson, A. Freborg, Z. Li, Deformation Control Technology, Inc., Cleveland, OH
The paper presents the results of DANTE computer simulations of residual stress conditions for two identical gears: one gear is made of a carburized low alloy steel that is quenched in oil, while the second gear is made of low-hardenability steel that is quenched intensively in water. The low hardenability steel chemistry is optimized to provide an optimal hardened layer, thus producing maximum residual surface compressive stresses. It is shown that residual surface compressive stresses are greater in the gear made of low-hardenability steel and quenched intensively compared to the carburized oil quenched gear. Modeling is used to investigate the mechanisms for heat treating low hardenability steels to optimize surface compression. The paper presents experimental data on fatigue testing of the carburized gears and gears made of the low-hardenability steels. The data obtained proved that gears made of low-hardenability intensively quenched steels have longer service life compared to the gears made of carburized oil quenched steels. The use of low-hardenability steels with the intensive quenching process allows in many cases a full elimination of the energy consuming costly carburization process.
Summary: The paper presents the results of DANTE computer simulations of residual stress conditions for two identical gears: one gear is made of a carburized low alloy steel that is quenched in oil, while the second gear is made of low-hardenability steel that is quenched intensively in water. The low hardenability steel chemistry is optimized to provide an optimal hardened layer, thus producing maximum residual surface compressive stresses. It is shown that residual surface compressive stresses are greater in the gear made of low-hardenability steel and quenched intensively compared to the carburized oil quenched gear. Modeling is used to investigate the mechanisms for heat treating low hardenability steels to optimize surface compression. The paper presents experimental data on fatigue testing of the carburized gears and gears made of the low-hardenability steels. The data obtained proved that gears made of low-hardenability intensively quenched steels have longer service life compared to the gears made of carburized oil quenched steels. The use of low-hardenability steels with the intensive quenching process allows in many cases a full elimination of the energy consuming costly carburization process.
