The cooling of hot forging dies by spraying: set up of testing procedure and numerical analysis.

The paper describes the experimental and numerical investigation aimed at estimating the temperature profile inside the die during the spraying of the lubricant. The analysis is focused on the determination of the heat transfer coefficient between the die and the lubricant. The work has been carried out in two main phases: i) the design and setting up of the testing apparatus to simulate in a laboratory scale the die lubrication process, and ii) the development of an automatic inverse analysis technique based on FEM to identify the heat transfer coefficient. A cylindrical specimen equipped with twelve thermocouples at three different depths is heated up and then cooled by the lubricant spraying. The inverse analysis for the determination of the heat transfer coefficient based on a 2D FEM code operates on the assumption of two-dimensional heat flow. The heat transfer coefficient is evaluated by minimising the difference between the measured temperatures and those evaluated by the FE analysis.