Papers by Keyword: Adhesive Wear

Abstract: The sintering at (1.35x103) °C for 90 minutes under argon gas atmosphere formed a nickel aluminide NiAl-based composite strengthened with yttrium oxide Y₂O₃ with the addition of cobalt in the current sample. (ASTM E140 – 12b) was used to perform the Brinell hardness test. The addition of cobalt increases the hardness of the (NiAl-Y₂O₃) composite. The hardness of NiAl-30Y₂O₃ composite improved from 341HB to 359HB after 1.5 wt.% Co was added, although the hardness improved to (381-383)HB after 2-2.5 percent Co was added. According to the findings of the wear examination, the inclusion of cobalt decreases the wear intensity of NiAl-30Y₂O₃, according to the findings of the wear examination. The adhesion wear rate reduces from 7.61 * 10^-6 gr / cm to 6.72 * 10^-6 gr / cm when 1.5 wt. percent Co is added, thus inserting 2-2.5 wt. percent Co reduces the rate to 5.87* 10^-6 – 5.22* 10^-6 gr /cm.

Abstract: Al bronze are the choice of material for relatively high wear applications besides appreciable mechanical and corrosion properties. In present work, the effect of different heat treatment processes on tribological characteristics of Ni-Al bronze (CuAl10Ni5Fe4, UNS C63000) has been studied. The hot rolled bar of 30 mm diameter was subjected to annealing, quenching and aging processes separately, consequently their effect on microstructure was studied and co-related with tribological characteristics. The formation and nucleation of various phases due to the thermal treatments were observed using optical microscopy. The wear behavior was studied using ball on disk arrangement with 100Cr6 ball and Ni-Al Bronze samples as disk. The characteristics and mechanism of wear track was studied using scanning electron microscope. It was observed that the water quenched sample followed by aging at 300°C exhibited best tribological characteristics.

Abstract: Friction stir welding is a novel and promising joining process and most common welding tool failure is transformation of geometry caused by wear. In our point of view, this is adhesion wear. The lathe testing of adhesion wear was conducted to compare wear resistance of following materials: Co-25wt%Cr, TiC-25wt%Ni/Mo and WC-6wt%Co. According to characteristics of investigated materials, they are capable to become alternatives for conventional frictional stir welding (FSW) tool materials. Adhesive wear tests were performed by turning aluminium alloy AW6082-T6 at low speed – travel length, turning speed and feed rate were selected to simulate FSW conditions. The adhesive wear was determined as the change of the geometry of the cutting edges of the tool measured using SEM images. Most promising tool material in terms of adhesion wear resistance is WC-Co hardmetal. The two main stages of wear were distinguished: at first, the appearance of intensive adhesion wear followed by steady state wear. Surface fatigue wear complements development of the adhesive wear.

Abstract: Several machine components including a part of electrical circuit box, an electrical motor and an automotive part were common ferromagnetic materials used under the magnetic fields. In the general, their friction had occurred in the magnetized materials during operation. The friction coefficient of the sample under magnetic fields was different from the sample without magnetic field treatment. Its friction coefficient had correlation with wear behavior of specimens. The wear protection procedures for the ferromagnetic parts during operation are recognized different from others without magnetization. Its friction coefficient was thus used to measure the wear characteristics with a ball on disc friction tester. The microstructure of wear trace and debris was investigated by scanning electron microscope. From the results, the magnetic fields affected the change of friction coefficient. The friction coefficient was decreased with an increasing magnetic intensity. This was because the wear debris was induced and thus decreased the adhesive wear mode during friction test.

Abstract: In this study it was evaluated the performance of coatings based on Cr₃C₂-25 (80Ni-20Cr) and CrC-30NiCr. The coatings were deposited by high velocity oxygen fuel (HVOF), with an average thickness of layer equal to 7.8μm. Samples were subjected to adhesive wear test (according ASTM G99) with a pin Ø 6 mm (SAE 52100). In the test was applied normal force equal to 50 N and tangential speed equal to 0.5 m/s. The test time was 30 minutes at room temperature, without lubrification. The wear surfaces were characterized by optical microscopy, scanning electron microscopy and X-ray diffraction. The microhardness of the coatings was also evaluated. The results showed that the coating based on Cr₃C₂-25(80Ni-20Cr) presented a performance ten times higher in wear resistance when compared to coating CrC-30NiCr.

Abstract: This paper aims to develop a new systematic analysis model to predict the wear of ball screw in stabilization condition. In order to investigate the wear behavior between the ball and raceway, a proper contact mechanics model should be established. Then, the wear model of ball screw based on Archard will be proposed and calculated by substituting the ball screw parameters. It has been proved that the effectiveness of the wear model on ball screw is verified through experiments in a specialized test system, which provides the theory basis of reasonably reducing the wear and improving the mechanical efficiency of a ball screw.

Abstract: The friction and wear properties of Cu-Te-Li alloys under dry sliding condition were studied by M-200 wear testing machine. The morphology and chemical composition of worn surfaces were analyzed by SEM and EDS, thus the effect of aging treatment on friction coefficient, wear rate and wear mechanism was discussed. The results showed that Te element could improve the wear resistance of copper alloys. With Te content increasing, the friction coefficient of Cu-Te-Li alloys declined slightly and tended to be stable as a whole, while the wear rate decreased obviously. During the process of dry sliding friction, adhesive wear was the dominant mechanism, with oxidative wear coexisting. But for the Cu-Te-Li alloys after aging treatment, abrasive wear appeared and adhesive wear was intensified, especially at higher friction velocity.

Abstract: NiCoCrAlY coating with high density was prepared on the surface of the magnesium alloy by cold spraying. Compared with the magnesium alloy prepared by the methods of the semi-continuous casting, the wear resistance and wear mode were analyzed by the experiments. The results showed that, under the dry friction condition, the conditions of the weightlessness of wear of NiCoCrAlY coating were better than that of the magnesium alloy. After the frictional experiment for 20 minutes, the weightlessness of wear of NiCoCrAlY coating was 10mg. Compared with that of the magnesium alloy, the weightlessness of wear was lower than 28%. Consequently, the NiCoCrAlY coating had the capacity of the weightlessness of wear resistance. By the comparisons of the every samples friction morphology, the wear modes of the NiCoCrAlY coating were adhesive wear and abrasive wear. And the wear modes of magnesium alloy were also adhesive wear and abrasive wear with corrosive wear and fatigue wear.

Abstract: This work contributes to a better understanding of wear mechanisms of ultrafine cemented carbide cutting tools used in turning operation of superalloy and high strength steels at high cutting speeds. The main objective of this work is to verify the influence of grain size and the cobalt content of ultrafine cemented carbide tools on tool life and tool wear mechanism. The main conclusions are that grain size and the cobalt content of ultrafine cemented carbide tools strongly influence tool life and tool wear involve different mechanisms. The wear mechanisms of different grain size and the cobalt content of ultrafine cemented carbide tools observed on the rake face at these conditions were adhesion and notch, at the end of tool life, adhesion was the main wear mechanism at higher cutting speeds.

Abstract: Tool life tests of continuous cutting superalloy GH2132 were carried out by WC/Co cemented carbide cutting inserts of different grain size and cobalt content, and flank surface wear morphology of the cutting inserts were observed by ZEISS continuous zoom stereo microscope and microphotograph system. The results show that grain size and cobalt content strongly influence the cutting tool life and tool wear, grain refinement and proper cobalt content are help to improve the tool life and the wear resistance of WC/Co cemented carbide. The wear mechanisms of different grain size and cobalt content of ultrafine cemented carbide tools were adhesion and notch, among them, adhesive was the main wear mechanism at higher cutting speeds.