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Nagoya-shi, Japan

Arimoto K.,Arimotech Ltd. | Yamanaka S.,Maruemu Works Co. | Funatani K.,IMST Institute
ASTM Special Technical Publication

Case carburizing is recognized as a suitable process for realizing low distortion and high compressive stresses near the surfaces under optimal conditions. Patterns of distortion and residual stresses in carburized cylinders and rings under different conditions have been identified from measurements performed for many years. Some pioneers of the heat treatment simulation compared their simulated results of carburized and quenched parts with experimental data for verifying their programs. However, these early researchers did not sufficiently explain their distortion and stress generation mechanism using their simulated results. Although one of the authors tried to illuminate their mechanism of a carburized and quenched ring, the work has not been finished because the purpose was limited in examining the role of transformation plasticity in the process. In this paper, the same simulated results were analyzed more comprehensively for explaining the origin of distortion and residual stress in the ring based on a concrete strategy newly developed. Copyright © 2008 by ASTM International. Source

Funatani K.,IMST Institute
Quenching Control and Distortion - Proceedings of the 6th International Quenching and Control of Distortion Conference, Including the 4th International Distortion Engineering Conference

Distortion control is one of the key issues for quality heat treatment of gears used for various mechanical and automotive components. Beside the through process management from Steel refining, pre-heat treatment, manufacturing processes and to control of quenching process is especially important to minimize gear distortion. Especially, the quench process relate directly with Martensite transformation to give hardness, case depth, residual stresses and gear distortion that affects tooth contact, surface durability and bending strength. In this paper, historical measure of distortion control and recent challenges to minimize tooth shape distortion by appropriate management of quench media properties and cooling process control in Japan will be presented. Copyright © 2012 ASM International® All rights reserved. Source

Funatani K.,IMST Institute
International Heat Treatment and Surface Engineering

The review of worldwide research trends undertaken as part of the Global 21 project (initiated by IFHTSE in 2005 to inform future research and to promote collaboration to advance basic technology) revealed differences in emphasis among Europe, the USA and Japan. Scientific research is strong in Europe, whereas Japanese activity is focused on practical research, and activity in the USA is rather low, with a tendency to reduced R&D spending. In the present contribution, trends in heat treatment and surface engineering technologies are analysed from a survey of R&D papers and industrial development work published around the world over the period from 1980 to 2010. On the basis of these results, some technical proposals to strengthen joint activities are made. The trends demonstrated by the analysis, in particular those relating to environmentally friendly and economical atmosphere control systems and to distortion control, are summarised. © 2013 IHTSE Partnership. Source

Arimoto K.,Arimotech Ltd. | Ikuta F.,NETUREN Co. | Yamanaka S.,Maruemu Works Co. | Funatani K.,IMST Institute
International Journal of Microstructure and Materials Properties

By the use of computational simulation techniques for nitriding processes, diffusion and nitride precipitation phenomena in compound layers and diffusion zones have been predicted in low alloy steels, Fe-Cr alloys, and so on. They have been also applied to examining formations of the expanded austenite in nitrided austenitic stainless steels. However, the application of the simulation approach was so far limited to the one-dimensional problems along the depth direction in simple shape specimens, since it is built on the finite difference method. In order to innovate the simulation, the software tool based on the finite element method has been expanded for studying on arbitrary-shaped parts by using the latest models for nitriding. The tool, having the function to analyse stress and strain, contributes not only to resolving various practical problems but also to explaining the unsettled mechanisms of distortion and residual stress generations caused by nitriding. Furthermore, the models are also expected to be enhanced by considering stress and strain effects precisely. In this paper, some verification examples on distortions and residual stresses relating to the expanded austenite formation in nitrided austenite stainless steels are described after clarifying the theory and implementation of the expanded simulation tool. Copyright © 2010 Inderscience Enterprises Ltd. Source

Funatani K.,IMST Institute
International Heat Treatment and Surface Engineering

The average fuel consumption of Japanese vehicles is improving constantly and the material share of non-ferrous and non-metal materials is constantly evolving. There is too little general understanding of the role advanced steel products are playing in power train systems to improve fuel mileage. Future developments in automotive materials, and steel in particular, are considered. © 2010 Maney Publishing. Source

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