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http://dx.doi.org/10.5228/KSPP.2007.16.4.293

A study on Cavity Closure Behavior During Hot Open Die Forging Process  

Kwon, Y.C. (한국기계연구원 부설 재료연구소 소재성형연구센터)
Lee, J.H. (한국기계연구원 부설 재료연구소 소재성형연구센터)
Lee, S.W. (포스코특수강(주) 기술연구소)
Jung, Y.S. (포스코특수강(주) 기술연구소)
Kim, N.S. (포스코특수강(주) 기술연구소)
Lee, Y.S. (한국기계연구원 부설 재료연구소 소재성형연구센터)
Publication Information
Transactions of Materials Processing / v.16, no.4, 2007 , pp. 293-298 More about this Journal
Abstract
Recently, there is a need to produce a large forged part for the flight, shipping, some energies, and military industries, etc. Therefore, an open die forging technique of cast ingots is required to obtain higher quality of large size forged parts. Cogging process is one of the primary stages in many open die forging processes. In the cogging process prior to some open die forging processes, internal cavities have to be eliminated for defect-free. The present work is concerned with the elimination of the internal cavities in large ingots so as to obtain sound products. In this study, hot compression tests were carried out to obtain the flow stress of cast microstructure at different temperature and strain rates. The FEM analysis is performed to investigate the overlap defect of cast ingots during cogging stage. The measured flow stress data were used to simulate the cogging process of cast ingot using the practical material properties. Also the analysis of cavity closure is performed by using the $DEFORM^{TM}-3D$. The calculated results of cavity closure behavior are compared with the measured results before and after cogging, which are scanned by the X-ray scanner. From this result, the criteria for deformation amounts effect on the cavity closure can be investigated by the comparison between practical experiment and numerical analysis.
Keywords
Finite Element Method; Ingot; Cogging; Open Die Forging; Cavity; Hydrostatic Stress; Effective Stress;
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  • Reference
1 S. P. Dudra, Y. T. IM, 1990, Investigation fo metal flow in open-die forging with different die and bil1et geometries, J. of Materals Processing Technology, Vol. 21, pp. 143-154   DOI   ScienceOn
2 B.V. Kiefer, K. N. Shah, 1991, Three dimensional simulation of open-die press forging, ASME Trans. J. of Eng. Mat. and Tech, Vol. 112, pp. 477-485
3 J. H. Yoon, D. Y. Yang, 1990, Three dimensional rigid-plastic finite element analysis of bevel gear forging by using remeshing technology, Int. J. Mech. Sci, Vol. 32, pp. 277-291   DOI   ScienceOn
4 N. A. Wilkinson, 1989, Proceeding of the International Symposium on the Metal-Iurgy and Applications of Superalloy 718, TMS, Pittsburgh, Pennsylvania, p. 119
5 D. Y. Yang, Y. Choi, J. H. Kim, 1991, Analysis of upset forging of cylindrical billet considering the dissimilar frictional conditions at two flat die surfaces, Int. J. Mach. Tools Manufact. Vol. 31, No. 3, pp. 397-404   DOI   ScienceOn
6 Jong Taek Yoem, 2006, Finite-element analysis of microstructure evolution in the cogging of an Alloy 718 ingot
7 J. Ohnaka, T. Fukusako, 1981, Solidfication Analtsis of steel ingots with consideration on fluid flow, Trans. ISIJ, Vol. 21, pp. 488-494
8 C. Y. Park, J. R. Cho, D. Y. Yang, D. J. Kim, I. S. park, 1992, Analysis of cavity Closure in the Upsetting Process of Large-Ingot
9 S. Spencer et al, 1981, Mathematical Model for Simulation of solidification and cooling of cast rolls, Ironmaking and Steelmaking, No.3, pp. 129-136
10 Toshihiko Oshima et al, 1985, Predication of the formation region of eutectic NbC in a large 12Cr-Mo-V-Nb steel ingot, Trans. ISIJ, Vol. 1, pp.78-84