Manufacture of a β-titanium hollow shaft by incremental forming
Excellent mechanical properties and corrosion resistance combined with low weight qualify β-titanium materials for lightweight applications in aviation, automotive and energy engineering. Thus far, actual applications of these materials have been limited due to high material costs and limited processing knowledge. One approach for developing resource-efficient manufacturing methods is the application of incremental forming methods. This article focuses on the development of the incremental spin extrusion process, which creates hollow profiles from solid bars. This method allows hollow shape manufacturing with a much higher flexibility than other forming methods and a significantly improved material utilization in comparison to machining methods, such as deep hole drilling. Beta-titanium alloys basically have very good cold forming suitability and the resulting material properties can be controlled. The application of incremental forming methods with high hydrostatic compressive stress is a promising manufacturing approach. The β-titanium Ti-10V-2Fe-3Al material has an excellent combination of the properties strength, ductility and fatigue strength. In order to utilize these properties the forming conditions and the temperature control need to be optimized. The investigations show that the Ti-10V-2Fe-3Al material can be formed only in a narrow semi-hot forming temperature window. The paper describes the investigation and presents results on the design of partial forming process sequences, forming properties, microstructure formation and failure prevention. The process design objective is a very fine microstructure with a homogeneous secondary α-phase and very small grained β-phase.
Kinematic and stochastic surface topography of machined tial6v4-parts by means of ball nose end milling
Abstract Ball nose end mills are usually applied during 5-axes machining of high functional parts especially in the aerospace industry. The systematical study of the relationship between process forces and kinematics, surface topography and subsurface properties is fundamental to ensure a high surface integrity. This paper deals with the topography of machined surfaces of TiAl6V4 parts by means of ball nose end milling. The machined surface has been analyzed and the kinematic topography, influenced by the process parameters and the geometry of the cutting tool, has been computed. By subtracting the surface measurements from the computed topography, the stochastic topography of the machined surface, e.g. roughness and cracks, can be determined. Furthermore, an approach is given for predicting the stochastic topography based on the process forces during machining of TiAl6V4.
A revision of the genus Rhinotorus Förster, 1869 (Hymenoptera, Ichneumonidae, Ctenopelmatinae), with descriptions of three new species and an illustrated identification key
The genus Rhinotorus Forster, 1869 is revised. Thirteen species are recognized including 3 species that are new to science ( R. jussilai sp. nov., R. campester sp. nov., R. tarsilatus sp. nov.). Saotis brachycerus (Kasparyan & Kopelke, 2009) comb. nov. is considered to be a member of the genus Saotis . Rhinotorus similis (Brischke, 1892) is tentatively recorded from Austria and Sweden for the first time. A number of new host records are also provided: Cladius pectinicornis (Geoffroy, 1785) for R. leucostomus (Gravenhorst, 1829), Nematus lucidus (Panzer, 1801) for R. nasutus (Gravenhorst, 1829) and N. papillosus (Retzius, 1783) for R. jussilai sp. nov.