Papers by Keyword: Hardness

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Authors: Md Abdul Maleque, Belal Ahmed Ghazal, Mohammad Yeakub Ali, Maan Hayyan, Abu Saleh Ahmed
Abstract: Coating possesses superior wear resistance which makes the material suitable for components subjected to dynamic applications under sever wearing condition and high temperature applications. In this study, TiC coating layer was synthesized by preplacing a 1 mg/mm2 of fine size (~40 μm) TiC powder on the surface of AISI 4340 steel. The composite layer was produced by rapidly melting TiC powder together with the substrate steel using tungsten inert gas (TIG) torch welding at a fixed heat input of 1344 J/mm. The wear behaviour of the coated steel was investigated using a universal pin-on-disc tribometer. The microhardness profile of the coating showed increment of the hardness value (almost 5 times higher) than the substrate material. The wear test results showed that the TiC coated steel has lower wear volume loss hence, higher wear resistance compared to the substrate AISI 4340 steel. Incorporation of TiC into the steel surface has improved the wear behaviour of the steel by reduction of plastic deformation and ploughing of the steel surface. The SEM micrograph of the wear worn surface showed mild type of abrasive wear for coated steel whereas, the AISI 4340 steel showed severe type wear with excessive plastic deformation and ploughing.
Authors: Naoji Yoneta, Kazumichi Shimizu, Hiroya Hara, Masahito Tanaka, Yoshihiro Nawa
Abstract: Spheroidal carbides cast irons (SCIs) are used in severe conditions where often occur erosion and due to their excellent wear resistance characteristics. In this study, three kinds of SCIs with a variation in matrices are tested and evaluated as shredding blade of uniaxial rotary glass shredder in recycling factories where often occurs extreme abrasion with the crushed glass. They are SCI-VCrNi, SCI-VMn, and SCI-Vw with hard (2400Hv) spheroidal vanadium carbides (VC). As a result, SCI-Vw reveals excellent wear resistance, approximately 1/12 of wear removal in weight, compare to other two materials of SCI-VCrNi and SCI-VMn. Spheroidal carbides nodularity(70%) and volume fraction of VCs(approximately 20%) are similar in three kinds of SCIs. The hardness of matrix of SCI-Vw (800Hv) is greater than that of SCI-VCrNi (320Hv) and SCI-VMn (380Hv). Therefore the experimental results are interpreted that hardness of matrix are dominant factor for abrasion. Based on this experimental study, SCI-Vw is an effective material for abrasion occurred on the blade of the glass shredder.
Authors: A.V. Eremeev
Abstract: The paper provides brief classification of wear types of tillage machines working tools. Also factors influencing abrasive wear process are determined in the case of cultivator shank of Kuzbass 8.5 seeding machine. Principles of development of wear-resistant materials and coatings are discussed.
Authors: Asitha C. Athukorala, Dennis V. de Pellegrin, Ben T. Battaglia, Kyriakos I. Kourousis
Abstract: Particle analysis methodology is presented, together with the morphology of the wear debris formed during rolling contact fatigue. Wear particles are characterised by their surface topography and in terms of wear mechanism. Rail-wheel materials are subjected to severe plastic deformation as the contact loading progresses, which contributes to a mechanism of major damage in head-hardened rail steel. Most of the current methodologies involve sectioning of the rail-wheel discs to trace material damage phenomena such as crack propagation and plastic strain accumulation. This paper proposes methodology to analyse the development of the plastically deformed layer by sectioning wear particles using the focussed ion beam (FIB) milling method. Moreover, it highlights the processes of oxidation and rail surface delamination during unlubricated rolling contact fatigue.
Authors: Kazuhiro Nakata, Takenori Hashimoto, Kyu Cheon Lee, Fukuhisa Matsuda
Authors: Gabriel Andrei, Constatin Gheorghies, Laurenţia Andrei, Iulian Gabriel Birsan
Abstract: The main purpose of this work is to reveal the structural changes occured after the impact test on ball bearing steel samples, relative to their ferrite-pearlite phase. The XRD analysis has been used to investigate the level of first and second order internal stresses, the dimensions of mosaic blocks as well as the dislocation density in crystal lattice. The influence of the impact velocity, material hardness and surface roughness on fine structural parameters, mentioned above, is also analysed. On the basis of structural changes it is possible to control the material response during the impact loading.
Authors: Seyed Ebrahim Vahdat, Keyvan Seyedi Niaki
Abstract: Successful employment of advanced tool steel in engineering applications is related to its ability in terms of meeting service life requirements and fabrication with proper dimensions. Deep cryogenic treatment may be used to produce advanced tool steel by simultaneously increasing toughness, strength, and hardness. Twelve sets of specimens were tested in this paper, 9 of which were deep cryogenic treated and then tempered. Tensile properties, hardness, X-ray diffraction, and scanning transmission electron microscopy were applied for macroscopic and microscopic investigations. The best results of simultaneous improvement in toughness, hardness, and strength were obtained for 36 h soaking time and 1 h tempering time.
Authors: Jef Vleugels, Omer Van der Biest
Authors: Olivério Moreira Macedo Silva, Maria do Carmo de Andrade Nono, José Vitor C. Souza, M.V. Ribeiro
Abstract: The α-SiAlON ceramic cutting tool insert is developed. Silicon nitride and additives powders are pressed and sintered in the form of cutting tool inserts at temperature of 1900 oC. The physics and mechanical properties of the inserts like green density, weight loss, relative density, hardness and fracture toughness are evaluated. Machining studies are conducted on grey cast iron workpiece to evaluate the performance of α-SiAlON ceramic cutting tool. In the paper the cutting tool used in higher speed showed an improvement in the tribological interaction between the cutting tools and the grey cast iron workpiece resulted in a significant reduction of flank wear and roughness, because of better accommodation and the presence of the graphite in gray cast iron. The above results are discussed in terms of their affect at machining parameters on gray cast iron.
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