• Journal of Ocean Engineering and Technology
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• v.13 no.3 s.33
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• pp.83-91
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• 1999

Taking a view of joining by welding the IN713C to SCM440 and SCM415 steel in production of turbochargers, the frictin welding process may be utilized as a new approach for joining them of other conventional welding processes. It is because the friction welding has more technical and technical and economic advantages than the other welding processes. As this welding process has the characteristics such as curtaliment of production time and materials and cost reduction, etc.. So, this paper deals with determining the preper friction welding condition and analyzing various mechanical properties of friction welded joints of the super heat resisting steel to alloy stee(IN713C to SCM440 and SCM415). And the in-process real-time weld quality evaluation technique by acoustic emission during friction welding of IN713C to SCM440 and SCM415 steels with higher confidence and relibility has been much required even though it might be the first trial approach for developing it. Then, this first study aimed to develop the optimization of dissimilar friction welding of heat resisting steels (INC713 to SCM440, SCM415) for turbine, considering on strength and toughness.

• Journal of Ocean Engineering and Technology
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• v.13 no.3 s.33
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• pp.77-82
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• 1999

The compleete joining method for dissimilar hot die punch materials and its real-time evaluation method are not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction wleding with a diffusion mechanism in bonding was applied in this study. So, this work was carried out to determine the optimal friction welding conditions and to analyze mechanical properties of friction welded joints of hot die punch materials (STD61 for the blade part of hot die punch) to alloy steel (SCM440 for the shank park of hot die punch) such as plunger. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.1-10
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• 1999

The engine exhaustive valve became essential as the important element. The dissimmilar welding method of exhaustive valve head to stem was asked for manufacturing the engine exhaustive valve, for which the electric resistance are welding has been conventionally used, resulting in poor quality of the welded joint. In this paper, not only the development of optimizing of friction welding with more reliability and more applicability but also the development of in-process real-time weld qudlity(such as strength and toughness) evaluation technique by acoustic emission for friction welding of the engine exhaustive valve(SUH3-SUH35 dissimilar steels) were perfomed. The high temperature(500, 500, 600$^{circ}$C) creep properties prediction of the friction welded joint of SUH3-SUH35 was investigated relating to the initial strain meethod(ISM) as a new approach, resulting in obtaining an experimental equation of creep life prediction.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.101-108
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• 2000

In this paper, the real-time prediction of high temperature creep life was carried out for the friction welded joints of dissimilar heat resisting steels(SUH3-SUH35). Various life prediction methods such as LMP(Larson-Miller Parameter) and ISM(initial strain method) were applied : The creep behaviors of those steels and the welds under static load were examined by ISM combined with LMP at 500, 600 and $700^{\circ}C$, and the relationship between these two methods was investigated. A real-time creep life( $t_{r}$ , hr) prediction equation by initial strain($\varepsilon$$_{0}$ , %) under any creep stress ($\sigma$, MPa) at any high temperature(T, K) was developed as follows : $t_{r}$ =$\alpha$$\varepsilon$$_{0}$ $^{\beta}$$\sigma$$^{1}$ where, (equation omitted) for SUH3-SUH35 friction weld of =16mm and =20mm, respectively.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.46-52
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• 2001

In this paper, the real-time prediction of high temperature creep life was carried out for the friction welded joints of dissimilar heat resisting steels (SUH3-SUH35). various life prediction method such as LMP (Larson_miller Parameter) and ISM (initial strain method) were applied. The creep behaviors of those steels and the welds under static load were examined by ISM combined with LMP at 500, 600 and $700^{\circ}C$, and the relationship between these two methods was investigated. A real-time creep lie (tr, hr) prediction equation by initial strain (${\varepsilon}_0$, %) under any creep stress ($\sigma$, MPa) at any high temperature (T, K) was developed as follows: $t_r={\alpha}{\varepsilon}_0^{\beta}{\sigma}^{-1}$ where, ${\phi}=16: {\alpha}=10^{51.412-0.104T+5.375{\times}10^5T^2}$, $ {\beta}=-83.989+0.180T-9.957{\times}10^{-5}T^2,{\phi}=20:$ ${\alpha}=10^{69.910-0.146T+7.744{\times}10^{-5}T^2$, ${\beta}=-51.442+0.105T-5.595{\times}10^{-5}T^2$ for SUH3-SUH35 friction weld of =16mm and 20mm, respectively.