Effect of Flow Stress, Friction, Temperature, and Velocity on Finite Element Predictions of Metal Flow Lines in Forgings

- Journal title : Transactions of Materials Processing
- Volume 24, Issue 4, 2015, pp.227-233
- Publisher : The Korean Society for Technology of Plasticity
- DOI : 10.5228/KSTP.24.4.227

Title & Authors

Effect of Flow Stress, Friction, Temperature, and Velocity on Finite Element Predictions of Metal Flow Lines in Forgings

Choi, M. H.; Jin, H. T.; Joun, M. S.;

Choi, M. H.; Jin, H. T.; Joun, M. S.;

Abstract

In this paper, the effect of flow stress, friction, temperature, and velocity on finite element predictions of metal flow lines after cylindrical upsetting is presented. An actual three-stage hot forging process involving an upsetting step is utilized and experimental metal flow lines are measured to study the effect of the various process variables. It was found that temperature and velocity for reasonable values of friction have little influence on metal flow lines especially those located deep within the cylinder but that flow stress has a direct influence on the flow lines. It was shown that a pure power law material model cannot reflect the real flow stress of hot material because it underestimates the flow stress especially around the dead-metal zone for the upsetting of a cylindrical specimen. It is thus recommended that a proper lower limit of flow stress be assumed to alleviate this issue.

Keywords

Metal Flow Lines;Forging Simulation;Flow Stress;Upsetting Process;Lower Limit of Flow Stress;

Language

Korean

References

1.

FAG Bearing Korea Corp., 2003, The History of FAG Bearing Korea Corp. Fifty years, FAG bearing Korea Corp., KOR., pp. 343~344.

2.

T. Altan, G. Ngaile, G. Shen, 2005, Cold and Hot Forging: Fundamentals and Applications, ASM Int., Metals Park, Ohio 44073, U.S.A.

3.

S. R. Lampman, B. R. Sanders, G. J. Anton, M. Tramble, J. Kinson, K. Muldoon, S. D. Henry, 2005, Metalworking: Bulk Forming, ASM Int., Metals Park, Ohio 44073, U.S.A.

4.

S. I. Oh, W. T. Wu, J. P. Tang, A. Vedhanayagam, 1991, Capabilities and Applications of FEM Code Deform: the Perspective of the Developer, J. Mater. Process. Technol., Vol. 27, No. 1, pp. 25~42.

5.

M. S. Joun, 2013, Forging Simulation, Jinsaem Media, Seoul, KOR.

6.

M. S. Joun, H. K. Moon, R. Shivpuri, 1998, Automatic Simulation of a Sequence of Hot-former Forging Processes by a Rigid-thermoviscoplastic Finite Element Method, J. Eng. Mat. Tech., ASME, Vol. 120, No. 4, pp. 291~296.

7.

M. S. Joun, S. W. Lee, J. H. Jung, 1998, Finite Element Analysis of a Multi-stage Axisymmetric Forging Process Having a Spring-attached Die for Controlling Metal Flow Lines, Int. J. Mach. Tools Manuf., Vol. 38, No. 7, pp. 843~854.

8.

H. K. Moon, S. C. Moon, J. G. Eom, M. S. Joun, 2005, Optimization of a Hot Forging Process using Six Sigma Scheme and Computer Simulation Technology Considering Required Metal Flow Lines, Trans. Mater. Process., Vol. 14, No. 9, pp. 798~803.

9.

H. K. Moon, J. S. Lee, S. J. Yoo, M. S. Joun, J. K. Lee, 2007, Hot Deformation Behavior of Bearing Steels, J. Eng. Mat. Tech., ASME, Vol. 129, No. 3, pp. 349~355.

10.

J. G. Eom, S.W. Jeong, M. S. Joun, 2013, Metal Forming Simulation with Emphasis on Metal Flow Lines and its Applications, Trans. Mater. Process., Vol. 22, No. 6, pp. 323~327.

11.

M. S. Joun, H. G. Moon, I. S. Choi, M. C. Lee, B. Y. Jun, 2009, Effects of Friction Laws on Metal Forming Processes, Tribology Int., Vol. 42, No. 2, pp. 311~319.

12.

N. Jones, 1989, Structural Impact, Cambridge University Press, Cambridge, GBR.