Vergleich der Drehbearbeitungsoperationen von TiAl6V4 und Ti6242 unter Berücksichtigung optimaler Spanparameter für die Erzeugung höchster Oberflächenqualitäten

Abstract

Titanium is one of the most abundant materials in the Earth, but it was not possible to start to work with it until 1940. From that moment the great properties and characteristics of this element were seen and it was compared with other materials like aluminium or iron. The highlight properties that make titanium especial are its low density, its high strength and its capacity to maintain high hardness at elevated temperatures, qualities that make it important in all fields where the resource of efficiency is remarkable as such as the aeronautic, aerospace or automotive field. The most typical applications in these areas for titanium are the high-pressure compressors and exhausts. In the automotive sector its applications are every day higher, since it allows the production of lighter cars. Another characteristic that make titanium important in other sectors such as the medicine, is its biocompatibility with the human organism, because of the higher corrosion resistance that makes titanium suitable to prosthesis (knee, dental...). Titanium has also a low thermal conductivity which makes it difficult to be machined, since the cutting tool is submitted to a huge wear that decreases its time of life. This fact, along with its expensive process of obtaining makes titanium an expensive material to work with. This project is divided into two distinct parts. The first one is a general study of titanium, which explains the two crystal structures that titanium can be formed depending on the temperature at which it is submitted, their main properties, its various production and manufacturing processes and heat treatments that may be subjected for changing its qualities. The second part will take place in the workshop of the PTW (Institut für Produktionsmanagement, Technologie und Werkzeugmaschinen) of the TUD (Technische Universität Darmstadt) with the intention to improve the situation of the titanium machining. The practical part will consist in two different tests to machining the alfa+beta Ti-6Al-4V alloy and the near alfa Ti-6242S alloy. The first test will be in dry conditions to see the behavior of the wear of the cutting tool depending on the cutting speed to have a clearer idea of the best cutting speeds for each kind of alloy. The second test will be discussed with coolant to study, using a range of temperature between -100ºC and 100ºC, the cutting forces, the surface roughness after machining titanium and tool wear based on cutting speed and temperature.