Challenges in Tribometry for Warm and Hot Sheet Metal Forming of High Strength Aluminum with Tool Lubrication

Abstract

For conventional sheet metal forming at room temperature, numerous tribometers were developed in the 20th century. At the present state of the art, unsolved issues for tribometry remain for temperature-supported forming processes of high strength aluminum (e.g. EN AW-7075), in which the sheet is heated to temperatures between 200 and 480 °C. The tribological design of these processes remains a major challenge, which needs to be addressed by investigations with adapted tribometers. In this study, a recently adapted strip drawing test for aluminum warm and hot forming is presented – including a newly developed strip heating unit, a die lubrication system and a die tempering system for efficient tribological testing. The contribution is completed with both, experimental results and a numerical investigation of temperature gradients in the strip drawing test. Finally, it is discussed whether transient process conditions of non-isothermal forming processes with die lubrication should be considered in tribometers for warm and hot sheet metal forming.