Interfacial heat transfer during hot metal forming operations assuming scale failure effects

Abstract

Analysis of real contact area and thermal resistance combined with experimentally derived interfacial heat transfer coefficient values led to the development of an advanced finite element based model to simulate the heat transfer at the oxidised tool/workpiece interface during hot steel rolling. An extensive progress review and building on the Sellars 1990's core assumptions are discussed. Today, oxide scale failure is predicted, taking into account the main physical phenomena such as stress directed diffusion, fracture and adhesion of the oxide scale. The separation loads within the scale metal/system are measured during testing. They are sensitive to the chemical composition of steel. The assumption of several parallel heat flow systems at the roll/stock interface remains the core model for today's research.

Keywords:

• Hot metal forming
• Heat transfer
• Oxide scale failure
• Finite element modelling
• Roll-stock interface