Diamante A&T Contents
Year XIV - December 2018
Front Cover: SAGWELL USA INC
With over 20 years' experience in the research and production of micro and nano metal powder materials, Sagwell core business is to supply micro and nano iron powder, copper powder and pre-alloyed powder. Sagwell can supply a comprehensive series of metal powder to meet different needs of diamond tool industry.
In the Spotlight
08) Sagwell - Micro & nano metal powder supplier - Since 1999
12) Euro PM2018 Congress & Exhibition basks in a successful Bilbao event
17) Effect of the processing conditions on the diamond stability during the production of diamond impregnated toolsby N.G. Polvorosa1,2, G. Pena1, C. Luno-Bilbao 1,2, I. Iturriza1,2
1 Ceit, Donostia/San Sebastian, Spain
2 Tecnun, University of Navarra, Donostia/San Sebastian, Spain
Abstract: The cutting ability of Diamond Impregnated Tools (DIT) depends strongly on the diamond-bond interaction. Diamond particles are the real cutting element in a DIT and need to be retained by the bond without degradation/graphitization by an excessive diamond-bond interaction. During production, processing conditions could be an issue for diamond stability. The higher the Fe content in the bond and processing temperature/time, the higher the probability of diamond-bond interaction. Two different Fe-rich powders have been mixed with four diamond grades (three of them coated) and subsequently cold-pressed and sintered by hot-pressing and free-sintering. Results have been analysed in terms of powder characteristics, diamond stability, microstructure, three-point bending, hardness, retention and diamond friability. Significant differences have been found from negligible interaction to partial graphitization, increase in friability and surface degradation, with the Cr coating more effective than the Ti coating in protecting diamonds.
26) Development and characterization of Fe/Cu-based, functionally graded metal-matrix systems for the use as thermal conductive diamond toolsby W. Tillmann, M. Pinho Ferreira, S. Gollner
Institute of Materials Engineering, TU Dortmund, Germany
Abstract: Diamond impregnated metal-matrix composites are used in the broad area of machining of mineral materials. The main industrial applications cover the field of cutting and grinding natural stone and concrete. Powder metallurgically fabricated diamond grinding segments, which are attached to saws and drill bits, are made of synthetic coarse diamond particles, sintered in a metal-matrix. The compositions of the metal-matrix powders usually contain iron and cobalt with additions of bronze or copper. Regarding the hardness, such binder compositions have proven to be suitable matrix elements for diamond tools. Based on existing metal-matrix components, this paper focuses on the development and characterization of functionally graded metal-matrix-systems to enhance the thermal conductivity of the diamond segment. A high copper content in the central area of the matrix ensures an increasing thermal transfer out of the grinding zone that leads to a reduction of the cooling water in grinding applications.
34) The influence of powder mix on densification and compaction mechanics in uniaxial cold compactionby Ilaria Cristofolini1, Gianluca Pederzini2, Alex Rambelli2, Alberto Molinari 1
1 University of Trento, Trento, Italy
2 Sacmi Imola S.C., Powder Metal B.U., Imola, Italy
Abstract: In previous work the relationships were determined which describe the densification of the powder column during uniaxial cold compaction and the stress field for the constitutive model. An improved processing method totally based on experimental data was defined. The present work exploits this improved experimental method to highlight the influence of material, investigating the behaviour of two commercial iron based powder mixes, which differ in chemical composition, alloying method, and apparent density. Densification is described by means of a new densification equation, based on the in-situ density and its correlation to the deformation experienced by the powder mix within the die cavity. The parameters in the power law equation allow to identify and compare the influence of the powder mix. The stress field acting on the powder column is investigated, and the relationships and parameters describing the constitutive model of the powder column are determined and compared for both materials.
45) Cutting techniques of PCD and PcBN compactsby Tai-quan Zhang1, Hong-bo Nie2
1 China National R&D Center for Tungsten Technology, Xiamen Tungsten Co., Xiamen, China
2 Xiamen Golden Egret Special Alloy Co. Ltd, Xiamen, China
Abstract: Aiming at improving cutting efficiency, material utilization to save cost, and cutting precision to manage the grinding allowance, this paper investigates the advantages and disadvantages of WEDM and laser cutting for cutting PCD and PcBN compacts. Some novel practical techniques are proposed, which indicate that laser cutting is generally the better choice but WEDM should be considered when cutting PCD and PcBN compacts with lower hard phase content and finer grain sizes.
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