Case: Hot Extrusion of Thin-Wall Multichannel Copper Profiles
First Defined the entire problems?
First stage is heating up the material. We will have cylindrical billet that is setting in a die and we heat it up. Heat coming in from anywhere else. How is the temperature changing? What are the energy going in and out and how they influence the temperature change? We have to define the heat transfer problem. What are the boundary condition that apply here and how we can solve this problem. What is the assumption that we can make to reduce the problem to smaller scale.
The second one. We have a billet. The billet is transfer into a convicting environment. The billet is at higher temperature and the environment at low temperature. Heat lost. So, we will have different heat profiles or temperature profiles in the materials as the convection coefficient changes and as the time you leave it out changes. So, what again the boundary conditions and how we can solve this problem.
The third one: when we have again the billet setting in the die, and heat it again to bring its temperature from T2 to T3. This situation is very close to the first one. How much heat is coming in to take the temperature from T2 to T3.
The fourth stage: We have the billet and applying pressure and we have a die. The flow stress will push the copper down and it is going to deform. So, whatever deformation energy and heat that you put in will be dissipated see the picture. We have to consider the Temperature deformation zoon in extrusion.
The final stage: sort of wire and the temperature of the wire changes. How much heat does it lose.