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Zhang Y.,Chongqing University | Shi W.,Chongqing University | Yang L.,China First Automobile Works Group Corporation | Gu Z.,Inner Mongolia First Machinery Group Corporation | Li Z.,DANTE Solutions Inc.
Journal of Materials Engineering and Performance | Year: 2016

The hardenability of gear steel is dependent on the composition of alloying elements and is one of important criteria to assess process of phase transformation. The variation of hardenability has to be considered in control of the microstructures and distortion during gear quenching. In this paper, the quantitative effect of hardenability has been investigated on phase transformations of spiral bevel gears in die quenching. The hardenability deviation of 22CrMoH steel was assessed by using Jominy test. The dilatometry experiments were conducted to build phase transformation kinetic models for steels with low and high hardenability, respectively. The complete die quenching process of spiral bevel gear was modeled to reveal the significant difference on microstructures and temperature history with variation of hardenability. The final microstructures of the gear are martensite in surface layer after quenching process. There are bainite inside the gear tooth and the mixture of bainite and ferrite inside gear for the gear with low hardenability. The microstructure is bainite inside the gear with high hardenability. © 2016, ASM International. Source

Charlie Li Z.,DANTE Solutions Inc.
ASME 2015 International Manufacturing Science and Engineering Conference, MSEC 2015 | Year: 2015

A hollow R.R. Moore rotation fatigue sample made of AISI 9310 is processed using vacuum carburization and high pressure gas quenching. The vacuum carburization schedule is designed to through carburize the thin wall section of the fatigue sample to 0.7% wt.% carbon, followed by 10 bar nitrogen quench. Some samples showed significant bow distortion after quench hardening, and further investigations indicated that the unbalanced wall thickness from machining is the main cause of the bow distortion. In this paper, DANTE, a commercial heat treatment software is used to study the cooling, phase transformation, and stress evolution during quenching. The effect of unbalance wall thickness on distortion is also investigated. Residual stress state in the quench hardened sample is critical to the fatigue performance during rotational bending fatigue tests. In this study, the unbalanced geometry has insignificant effect on the residual stresses after quench hardening. However, the unbalanced geometry will affect the applied stress significantly during a rotation fatigue test. Copyright © 2015 by ASME. Source

Wang G.,Tsinghua University | Zhang Y.,Tsinghua University | Yang L.,China First Automobile Works Group Corporation | Cui L.,China First Automobile Works Group Corporation | Li Z.C.,DANTE Solutions Inc.
ASM International - 28th Heat Treating Society Conference, HEAT TREATING 2015 | Year: 2015

Press quenching is one of effective methods to improve the strength and control the distortion for auto gears. However, it could be challenging to understand, predict and further minimize the deformation of circular-arc bevel gear in industrial application because of multiple influencing factors. In this paper, a comprehensive model with phase change was built to reproduce the gear quenching process with consideration of quenching machine, process parameters and variation of steel compositions. The phase content and temperature history predicted by the model agrees with the gear quenching experiment results, which prove the accuracy of the material model. © 2015 ASM International®. Source

Reardon A.C.,Gleason Works | Freborg A.,DANTE Solutions Inc. | Li Z.C.,DANTE Solutions Inc. | Ferguson B.L.,DANTE Solutions Inc.
ASM International - 28th Heat Treating Society Conference, HEAT TREATING 2015 | Year: 2015

Press quenching is a specialized quenching technique used in heat treating operations to minimize the distortion of complex components such as spiral bevel gears and high quality bearing races. The quenching machine is designed to control the geometrical characteristics of components such as out-of-round, flatness, and (if the tooling is designed to accommodate it) taper. The achievement of final dimensional tolerances is accomplished through a trial and error process where the incoming machined sizes of the components are adjusted based upon measurement data taken from the initial sets of quenched and tempered components that have already been processed through the press quenching operation. Oil flow rates can be altered during the different stages of the quenching cycle, and through the use of specialized tooling the oil flow pathways can be selectively adjusted to meter the oil flow towards specific areas of the part surface while baffling it away from others in order to provide a more uniform overall quench. Complex metallurgical changes take place during austenitizing and quenching, resulting in corresponding mechanical property changes. Accompanying these changes are the generation of thermal and transformation induced stresses, which produce in-process and final residual stresses. During press quenching, dimensional restrictions add additional complexity to the combined effects of thermal and mechanical process sensitivities on these stresses. And if the stresses are severe enough, quench cracking can result. In this investigation the quench cracking of an asymmetrical AISI 52100 bearing ring is evaluated through physical experiments and through corresponding heat treatment process modeling using DANTE. The effects of quench rate, die load pulsing, and several other process variables are examined experimentally and/or analytically to illustrate how they can impact the resulting stresses generated during the press quenching operation. © 2015 ASM International®. Source

Ferguson B.L.,DANTE Solutions Inc. | Li Z.,DANTE Solutions Inc. | Freborg A.M.,DANTE Solutions Inc.
Journal of Materials Engineering and Performance | Year: 2014

Quench probes have been used effectively to characterize the quality of quenchants for many years. For this purpose, a variety of commercial probes, as well as the necessary data acquisition system for determining the time-temperature data for a set of standardized test conditions, are available for purchase. The type of information obtained from such probes provides a good basis for comparing media, characterizing general cooling capabilities, and checking media condition over time. However, these data do not adequately characterize the actual production quenching process in terms of heat transfer behavior in many cases, especially when high temperature gradients are present. Faced with the need to characterize water quenching practices, including conventional and intensive practices, a quench probe was developed. This paper describes that probe, the data collection system, the data gathered for both intensive quenching and conventional water quenching, and the heat transfer coefficients determined for these processes. Process sensitivities are investigated and highlight some intricacies of quenching. © 2014, ASM International. Source

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