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ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

EXPERIMENTAL STUDY OF THE THERMAL BOUNDARY CONDITION AT THE WORKPIECE-DIE INTERFACE DURING HOT FORGING

Get access (open in a dialog) DOI: 10.1615/IHTC11.30
pages 15-20

Resumo

The present paper reports on an experimental study of the thermal boundary condition at the workpiece-die interface during hot forging operation. It is based on the close investigation of main forging parameters effects on the thermal contact resistance (TCR) at the workpiece-die interface. The originality of the procedure resides in the precise instrumentation and utilisation of a nonlinear inverse technique in data processing. The TCR is considered as a time-dependent function.
The die is made of Inconel 718 while the workpieces are made of Titanium and Aluminium. The main results concern the influence of forging velocity, die temperature and lubricated interface on the TCR.
During hot forging operation, for dry contact, we have observed a thermal boundary condition of the third kind, followed by an establishment of a quasi perfect contact. The transition period from imperfect contact to quasi perfect contact decreases with the increase of the forging velocity. In addition, on the forging velocity domain of 1 to 5 mm/s, the die temperature plays an insignificant part on the TCR evolution.
For lubricated contact, we have observed that the value of the thermal resistance, which is opposed to the heat transfer from the workpiece to the die, is markedly larger than the TCR value observed for dry contact.