Metallic semi-finished parts are nowadays processed in ever more complex forming processes. To lower mechanical tool loads and the energy requirements for forming, processes at elevated temperatures arise. Preheating of the unmachined part is economic, if less process steps need to be carried out during the production and is necessary, if high-strength materials need to be processed. For the forming at elevated temperature, the deformation behaviour of the material and the behaviour of the lubrication system under these conditions must be studied precisely.
The aim of this master’s thesis is, to evaluate the suitability of different lubrication systems for forming at elevated temperatures. To achieve this, material behaviour and adhesion strength of phosphate layers on various steels during forming in a Gleeble forming simulator are determined in a first step. The thermal degradation behaviour of the selected lubricants is analysed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) in the temperature range from 25 to 700°C. Finally, the lubrication effect of the lubrication system of coated test specimen after exposure to temperature in the furnace is investigated.