Zerspanung warmkompaktierter Sinterstähle im Grün- und Sinterzustand

The decisive advantage of PM manufacturing is the cost saving potential of producing net shaped parts with tight tolerances. Nevertheless, secondary operations such as machining are a major part in the manufacturing process of an increasing number of PM parts, since e.g. undercuts or holes perpendicular to the pressing direction cannot be produced by uniaxial pressing. Supplementary machining, mainly turning, drilling, and tapping, leads to noticeably increasing production costs, since machining is more difficult with porous PM parts than with pore-free materials. Especially the machining of high strength PM steels with martensitic or partially martensitic microstructure is often extremely difficult and cost intensive. Consequently, up to now heavy duty PM parts are often produced by double pressing, double sintering technology. With this technique, machining is usually done after the first sintering. From the economical point of view, it would certainly be preferable to save the second pressing and sintering steps and to produce the parts by alternative production routes. One of these alternative routes is the warm compaction technology, which can be combined either with green machining or with machining after sintering as a secondary shaping operation. The investigations presented in this thesis were started to provide for the first time reliable data on both process alternatives. The first part describes the chances and the limitations of green machining for the most important machining processes, drilling, tapping, and turning in interrupted cutting. The criterion for successful green machining is the product quality. The aim of the investigations is the optimisation of the cutting processes by variation of the cutting parameters and the tools. The optimum product quality which can be achieved by green machining is described quantitatively for all machining processes investigated. Additionally, the wear behaviour of different tool materials is tested in a spot check for one of the processes, the green drilling, to get a first impression of the relevance of tool wear for green machining applications. In the second part of the investigations, the machining behaviour after sintering is investigated for the same machining processes and for the same materials. For a comparison of the machining properties, cost optimum cutting speeds and the minimum cutting costs are established by tool life tests according to the Taylor and to the exponential model. Together with the results of the green machining tests, these data facilitate to decide which of both processes is favourable for a given application.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Benner, Andreas

Contributors dc:contributor

• Beiss, Paul

• info:eu-repo/classification/ddc/620
• Sinterstahl
• Warmkompaktieren
• Grünling <Technik>
• Spanende Bearbeitung
• Qualität
• Sintern
• Ingenieurwissenschaften
• Pulvermetallurgie
• Grünzerspanung
• Drehen
• Bohren
• Gewindebohren
• Zerspanung

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-120982%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:59172