Příspěvek k obrábění Ni superslitiny a hodnocení řezivosti vybraných řezných materiálů

Abstract

Constantly increasing requirements for machine parts used in many industrial branches place demands for material which they are made of. Super alloys based on nickel are predetermined for parts used in extreme conditions. Nickel superalloys are characterized by heat resistance, being fireproof in high temperatures and an excellent corrosion resistance which surpasses qualities of other commonly used steels. However, due to their specific and desirable properties, super alloys are the materials that have, compared with other metallic materials in the cutting conditions, worse machinability. The term “worse machinability” is commonly connected with machining of superalloys because those cannot be machined as common steels. There are higher demands not only on the manufacturing technologies but also on implement material, cutting geometry, cutting conditions and environment. This is because of physical and mechanical properties of the nickel super alloys, which they have because of their chemical structure and complicated microstructure. Worse machinability of the superalloys has negative influence on the process of machining, increases the strain of the machining system, makes the quality of the machined parts worse and in some cases even worsens the productivity and the economy of the production. The nickel alloy 625 according to ASM 5666F (W. Nr. 2.4856) was selected for machining and determination of cutting property of the cutting materials. It is completely alloyed, Ni - Cr based material, which is commonly used for manufacturing components in industry. To determine suitable cutting parameters of the Alloy 625, with regard to achieved integrity of the machined surface, choice exchangeable cutting inserts made from cutting ceramic and cubic boron nitride were used. The main aim of this thesis is to determine an analysis of the current state of machining of nickel super alloys, to prove experimentally and suggest the way we can easily and effectively machine these materials. It is necessary to consider the machining of super alloys to be a complex issue and work with a lot of influences at the same time. The results of the experimental part will be compared with existing knowledge of the machining of the superalloys in the manufacturing and can be used as a recommendation for possible increasing of effectiveness of the superalloys machining.