Influência dos carbonitretos de titânio na usinabilidade do aço VP100 utilizado em moldes de injeção de plástico

Abstract

This work aims to investigate the influence of titanium cabonitride and other microstructural elements, on the machinability of VP100 steel with 270 and 350 parts per million of titanium, have the VP20 ISO steel with comparator. Such a study is justified considering that the VP100 is a steel for plastic injection molds on the market whose recently released its machinability aspects have not yet been fully exploited, there is still a big gap in knowledge about this material to be investigated. The results are discussed considering initially, the variation of machining forces due to the variation of cutting speed, feed and depth of cut in turning tests. Next, are evaluated the volume of material removed, and the mean square roughness Rq values for each type of material machined and cutting condition applied, depending on the evolution of the tool wear used in milling tests. The performance of the tests was made from a statistical design of experiments, where the relevant variables on the parameters of both the chemical composition of alloys and their machinability, define the factors and responses of interest in research. The tools used were the same in all conditions tested, therefore not constituted in a process variable, and the use of cutting fluid, since all tests were performed dry. The VP20 ISO showed better performance in machining followed by the VP100 with 350 ppm titanium, and the VP100 with 270 ppm titanium had a worse performance. Significant differences were observed in the microstructure of materials such as quantity, size, shape and distribution of titanium carbonitrides in the two modes of VP100, which contributed to the differences in the behavior of materials in machining.