Temperature Distribution Inside the Billet in Extrusion of Lead

A numerical method had been used to determine the nonsteady-state temperature distributions in the billet during extrusion and to study the effects of ram speed, friction condition on temperature distribution. The necessary velocity, strain rate, and strain fields were obtained from visioplasticity experimental results. The speed of the billet was also considered in the heat conduction equation. Heat generation due to frictional work and deformation work was considered at a time. Average value of flow stress and average thermal properties of the billet material were used in the heat transfer equation. Heat generation and conduction were approximated in two consecutive steps during equal time increment Δt. The maximum temperature at a point inside the lead billet was found to be 82.14°C after 12.5 sees of extrusion with ambient temperature of 30°C and extrusion ratio=8.07, ram speed=0.042 cm/sec., coefficient of friction at the billet-container interface=0.10, coefficient of friction at die-material interface=0.577, die angle=45°. The procedure for determining the temperature distribution was programmed in FORTRAN IV Language and was run in TDC-316 Digital Computer.