Papers by Keyword: High Speed Steels

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Authors: V.Yu. Popov, A.S. Yanyushkin, Y.I. Zamashchikov
Abstract: The problems of practical application of the combined electric diamond grinding (CEDG) are examined. Experiments were conducted on the grinding tool materials with metal-bonded diamond grinding wheels. In the presented part of the work, the roughness of the machined surface of specimens made of high-speed steel is investigated. It was established that the CEDG makes it possible to decrease the roughness of the machined surface to 30-40 % in comparison with other combined methods and 1.5-2 times in comparison with usual grinding. The application ensures the grinding by diamond wheels in the mode of self-sharpening and guarantees the continuity of its geometric form, which eliminates the defect layer on the machined surface and gives a longer period of wheel stability. The results obtained show that diamond wheels can be successfully used for grinding wide spectrum of tool materials.
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Authors: Marcin Madej
Abstract: Attempts have been made to describe the influence of copper infiltration on properties of HSS based composites with different iron additions. Iron powder were used to reduce price of composites. The powder compositions used to produce skeletons for further infiltration were M3/2, M3/2 + 7,5%Cu, M3/2+20%Fe and M3/2+50%Fe. The powders were cold pressed at 800 MPa. These as-pressed specimens were used for direct copper infiltration.
141
Authors: Oscar Olimpio de Araújo Filho, Rodrigo Tecchio Antonello, Cezar Henrique Gonzalez, Severino Leopoldino Urtiga Filho, Francisco Ambrozio Filho
Abstract: High speed steels processed by Powder Metallurgy (PM) techniques present better mechanical properties when compared with similar steels obtained by the conventional process of cast to ingot and hot working. PM techniques produce improved microstructures with smaller and better distribution of carbides. Liquid phase sintering high speed steel seems to be a cheaper processing route in the manufacturing of tool steels if compared to the well-known and expansive hot isostatic pressing high speed steels. The introduction of niobium as alloying element began with the object of replacing elements like vanadium (V) and tungsten (W). Phase liquid sintering consists in a manufacturing technique to process high speed steels by powder metallurgy. The aim of this work of research is to process and obtain AISI M2 and M3:2 with and without the addition of niobium carbide by high energy milling, cold uniaxial compaction and vacuum sintering in the presence of a liquid phase. The powders of the AISI M2 and M3:2 were processed by high energy milling adding a small quantity of niobium carbide (6% in mass), then the powders were characterized by means of X-ray diffraction (XRD) and scanning electron Microscopy (SEM) plus energy dispersion spectroscopy (EDS) in order to evaluate the milling process. The powders of the AISI M2 and M3:2 with the addition of niobium carbide (NbC) were uniaxially cold compacted and then submitted to vacuum sintering. The sintered samples had their microstructure, porosity and carbide distribution observed and evaluated by means of Scanning Electron Microscopy (SEM) and the mechanical property of hardness was investigated by means of Vickers hardness tests. At least five samples of each steel were investigated.
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