Papers by Keyword: Tool Material

Abstract: To increase the durability of the cutting tool when machining parts in mechanical engineering and engine building, the method of applying a diffusion discrete oxide layer with a polycrystalline structure can be used. By identifying the durability of the cutting tool with the period of its durability, we obtain an expression for the effective molar activation energy. Comparative tests have shown that a cutting tool with a diffusion discrete oxide layer can increase the durability when machining parts in comparison with a tool coated with TiСN, which in turn allows to increase the service life of parts by at least 2 times.

Abstract: Since the early 90’s, and from the very early investigations of steel thixoforming, tool materials as well as different kinds of coatings, including different tool steels and fully ceramic systems have been evaluated. The failure mechanisms have been carefully investigated by experiments and simulations and are nearly fully understood. Analysis of the reported literature on this topic shows that there is still a lot to do in this field and no excellent solution exists now a days for steel thixoforming. The aim of this work is to evaluate the thermal and mechanical loadings applied to the tools during steel thixoforming process in order to determine appropriate tool materials and solutions. This evaluation was realized thanks to experimental trials and to the finite elements simulations. The effect of these loadings on the tool’s failure modes are highlighted and compared to the ones observed in classical forming processes. Beyond this, the failure modes of different tool materials and solutions are presented. The tested materials are hot-working tool steels. Other possibilities and tool coating or surface treatments are discussed as well.

Abstract: The high temperature oxidation phenomenon will occur on the tool-workpiece contact area when machining the superalloy. Two kinds of cemented carbide tools (YG6X, YG8) are selected, the coated carbide tool and coated ceramic tool which are suitable for machining superalloy are selected. The resistance furnace is used for heating tool material, and the oxidation resistance experiments are carried out. The results show that: WC which is included in the cemented carbide tool is oxidized to WO₃ and the Co is oxidized to Co₃O₄, Ti which is included in the coated carbide tool is oxidized to TiO₂. The grain of the tool is smaller, the oxidation resistance is better. The oxidation resistant of coated carbide tool is better than the non-coated tools. The coated ceramic tool is not substantially oxidized in high temperature situation. The merits order of the oxidation resistant properties is that: coated ceramic tool>coated carbide tool > YG6X>YG8.

Abstract: The aim of this work is to evaluate the thermal and mechanical loadings applied to the tools during steel thixoforming process in order to determine appropriate tool materials and solutions. This evaluation was realized thanks to experimental trials and to the finite elements simulations. The effect of these loadings on the tool’s failure modes are highlighted and compared to the ones observed in classical forming processes. Beyond this, the failure modes of different tool materials and solutions are presented. The tested materials are hot-working tool steels. Other possibilities and tool coating or surface treatments are discussed as well.

Abstract: This work presents the research results on the structure and mechanical properties of coatings deposited by PVD methods on the X40CrMoV5-1 hot work tool steel substrates. It was found that tested coatings have nanostructural character with fine crystallites, while their average size fitted within the range 10–15 nm, depending on the coating type. The morphology of the fracture of coatings is characterized by a dense microstructure. The coatings demonstrated good adhesion to the substrate, the latter not only being the effect of interatomic and intermolecular interactions, but also by the transition zone between the coating and the substrate, developed as a result of diffusion and high-energy ion action that caused mixing of the elements in the interface zone and the compression stresses values. The critical load LC2 lies within the range 66–85 N, depending on the coating type. The coatings demonstrate a high hardness (4000 HV).

Abstract: In this research, effect of tool material and tool offset on tool erosion and metallurgical and mechanical properties of dissimilar friction stir welding of Al alloy to carbon steel are investigated. As the tool erosion is one of the important parameters on the defect-free friction stir welding, especially in butt joint of Al alloy to steel. In present work, different tool material and offset are used in friction stir welding at Al alloy to carbon steel with a constant tool speed and feed rate named as 710 rpm and 28 mm/min respectively. The result of experimental observation is shown better performance by tungsten carbide (WC) tool material with 1 mm offset on Al alloy area.

Abstract: The purpose of this research paper is focused on the high speed steel surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the high speed steel alloying with carbides using high power diode laser HPDL. Investigation indicate the influence of the alloying carbides on the structure and properties of the surface layer of investigated steel depending on the kind of alloying carbides and power implemented laser (HPDL). In the effect of laser alloying with powder of carbides occurs size reduction of microstructure as well as dispersion hardening through fused in but partially dissolved carbides and consolidation through enrichment of surface layer in alloying additions coming from dissolving carbides. Introduced particles of carbides and in part remain undissolved, creating conglomerates being a result of fusion of undissolved powder grains into molten metal base. The structural mechanism was determined of surface layers development, effect was studied of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer, and especially on its hardness, abrasive wear resistance, and roughness. It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.

Abstract: Aiming at the key problem of tool choice presented at high speed machining, this paper analyses the characteristic of existing materials of high speed machining tool from three aspects of mechanics, physics and chemistry, and sums up the cutting property of work materials combining with some experimental results and literatures. By integrated comparison of the property of materials of tool and workpiece, a method of choosing tool material for corresponding to workpiece is offered. Finally, some matched materials of tool and work are provided for convenient choice, which can acquire better effects than used testing or experience ways and means.

Abstract: TiB₂/TiN composites with various content of Ni and Mo as sintering aid were hot-pressed at 1530°C. Effect of the content of sintering aid on microstructure and mechanical properties is investigated. Experimental results show that the fracture toughness of the composites increases consistently with an increase in the sintering aid content, however, the flexural strength gets to the maximum when the content of sintering aid is 10vol%. A new eutectic phase of MoNi can be found in the composites by X-ray diffraction (XRD) when the amount of sintering aid is over 7vol%. Scan electron microscope (SEM) analysis shows that the density of the composites increases consistently with the increasing of the sintering aid. But the abnormal-growth grains can be found and deteriorates the flexural strength in the composite No.4 because of the excessive sintering aid.

Abstract: High speed machining is one of the advanced manufacturing technologies which have developed quickly in recent years. Tool technology is key factor which will make influence to the efficiency and precision of HSM. The paper has analysis the HSM tool technology in terms of material, shank structure and tool balance. It brings forward that tool material with high property must match with workpiece to get high efficiency and precision in HSM. Three type of shank are introduced and using HSK can get better working performance due to its double-surface positioning and short tapered shank. The paper finally put forward the online balancing test technology which can achieves the actual signal collection of dynamic balance, and make technical analysis as well as processing in high-speed cutting.