Laser Cladding of Ni-Co-W Composite Coating on Stainless Steel to Enhance Wear Resistance

Ni-Co-W composite coatings modified by different contents of Co-based alloy powder in the Ni-based alloy with 35 wt.% WC (Ni35WC) were deposited on stainless steel by laser cladding. The influence of compositional and microstructural modification on the wear properties has been comparatively investigated by XRD, SEM, and EDS techniques. It was found that the austenite dendrites in the modified coating adding 50 wt.% Co-based alloy were refined and a lot of Cr23C6 or M23(C, B)6 compounds with fine lamellar feature were formed around austenitic grain boundaries or in the intergranular regions. The contribution of element Co to the modification of Ni35WC coating is that it cannot only promote the formation of more hard compounds to refine austenite grains, but also refine the size of precipitates, and change the phase type of eutectic structure as a result of disappeared Cr boride brittle phases. A noticeable improvement in wear resistance is obtained in the Ni35WC coating with 50 wt.% Co-based alloy, which makes the wear rate decreased by about 53 % and 30% by comparison to that of the substrate and the Ni35WC coating, respectively. It is suggested that the improvement is closely related to the composite coating being strengthened owing to the increase of coating hardness, formation of a fine-grained microstructure caused by Co, and fine hard precipitate phases in the eutectic structure.

Investigation on influence of SiCp on three-body abrasive wear behaviour of glass/epoxy composites

The present study present the influence of SiCp incorporation on three-body abrasive wear behavior of glass/epoxy composites. The investigations was carried out using dry sand rubber wheel abrasive wear test apparatus. 2k factorial design of experiment was used to capture the experimental data. The parameters considered are abrading distance, load and speed. The wear volume loss found to increase with the increasing values of wear parameters. The applied load has exhibited significant effect on volume loss. Incorporation of SiCp contributed to enhance wear resistance of glass/epoxy composites. The linear regression was also presented in the study to correlate abrasion parameters with wear volume loss. SEM image analysis of abraded surface revealed the occurrence of ploughing, micro-cutting, matrix removal and fiber breakage.

Microstructure and Property of Sintered Fe-2Cu-0.8C-0.6Mo-2W Materials Prepared From Prediffused Powders

Prediffused Fe-W powder with 2 wt% of tungsten was prepared by heating Fe-W powder mixes at 800°C for 45 min in H2 atmosphere. Two kinds of Fe-2Cu-0.8C-0.6Mo-2W powder mixtures were obtained by mechanically mixing the prediffused Fe-W powders with the other elemental powders. After pressing and sintering, the sintered Fe-2Cu-0.8C-0.6Mo-2W materials were obtained from the two powder mixtures. The effects of the introducing methods of tungsten element and sintering conditions on microstructure, mechanical and wear properties of the sintered samples were investigated. The results show that with the increase of sintering temperature and time, hardness and strength of sintered samples increase. Prediffused treatment of Fe-W powder can improve density of green compacts and sintered samples. When W element introduced in the form of prediffused Fe-W powders, the compacts pressed at 700 MPa have a green density of 7.13 g/cm3, and after sintered at 1,150°C, the density, hardness, tensile strength and radial crushing strength of the sintered samples are 7.16 g/cm3, 95 HRB, 547 and 791 MPa, respectively, which are higher than those of the samples prepared from powder mixtures by mechanically mixing the elemental powders. Furthermore, the prediffused treatment of Fe-W powders can improve the distribution of W element and enhance wear resistance.

Enhancement of wear resistance of mulcher teeth with the help of electrochemical coats

Influence of alloying additives in electrolyte and conditions of electrolysis on microhardness, adhesive strength and wear resistance of iron and cobalt coats have been investigated. Conditions of creating coats which make it possible to considerably enhance wear resistance of the mulcher teeth under the conditions of abrasive wear have been established. The process of creating wear resistant coats have been approved and recommended to introduction after the service life of the mulcher teeth sets have been extended.

Coating effect on the fatigue strength of a free cutting steel

This paper deals with the effect of electrodeposited zinc and nickel coatings on the fatigue strength of a free cutting steel. This class of materials is frequently used in the mass production, due to their good machinability, in order to reduce the production costs. Moreover, free cutting steels often operate under high wear conditions, for instance in sliding components. Therefore, suitable coatings are usually applied to improve their tribological response. In addition, in many industrial applications, free cutting steels must withstand significantly high fatigue loads, even in corrosive environment. In order to assess the fatigue response, S–N curves and endurance limits at run-out of specimen sets with different features were determined. The tests involved samples with different coatings and plain geometry for comparison purposes. The experimental results, properly set up by tools of Design of Experiment, were statistically processed and compared. The outcome was that no significant difference in terms of fatigue strength between the three specimens set was encountered. It implies that coatings can be suitable to enhance wear resistance without detrimental effects on fatigue.

Toward the Development of AHSS for Wear Resistant Applications

Advanced High Strength Steel (AHSS) developments have largely focused on automotive applications using metallurgical approaches to develop retained austenite-containing microstructures in a variety of new steels, using the transformation-induced plasticity (TRIP) effect to achieve better combinations of strength and ductility. These efforts have been extended in recent studies to explore the potential to improve wear resistance, using metastable retained austenite to enhance wear resistance for earth-moving and other applications. This paper provides selected highlights of the authors’ efforts to develop wear resistant steels using AHSS processing approaches. Some attractive product/process development opportunities are identified, and it appears that martensite-austenite microstructures produced using “quenching and partitioning” exhibit increased wear resistance.

Effect of Galla сhinensis on the Wear Resistance of Dentine

The aim of this study was to investigate the effect of natural herb material Galla Chinensis extraction (GCE) on the wear resistance of dentine in vitro. Forty sound bovine dentine blocks were prepared and randomly divided into two groups. The samples were first treated with 4000 ppm aqueous solution of Galla chinensis and distilled deionized water (DDW) was used as a control. Then the samples were subjected to 5,000 cycles of attrition bathed under artificial saliva with 150 N loads. Wear measurement, scanning electron microscopy (SEM) examination and energy-dispersive X-ray spectrometry (EDX) analysis were utilized to evaluate the effects of GCE on the wear resistance. The depth of the wear scar of DDW-treated surface (mean = 32.5 μm, SD = 11.8 μm) was significantly greater than that of GCE-treated surface (mean = 26.4 μm, SD = 13.9 μm) (p < 0.05). Furthermore, the SEM images showed severe wear on the DDW specimens and less wear on the GCE-treated samples. Finally, from EDX data, GEC group had higher percentage of Ca and P than the control. In conclusion, our study suggested that Galla chinensis could enhance wear resistance of dentine.

The Anti Corrosion Performance of the Fracture Surface by Fine-Blanking with Negative Clearance with ASTM-Gr.D

The fine blanking with negative clearance is a process with characteristic of the high blanking precision and the better fracture quality, so the blanking fracture surface structure are intensity. This paper has carried on the contrast and analysis between common blanking and the fine-blanking with negative clearance fracture face and burrs zone cavity metallographic and further indicated the different process blanking work-piece fracture face characteristics, illuminated the anti-corrosion of blanking fracture surface between different blanking process by using corrupt principium. The anti-corrosion of blanking fracture face could enhance wear resistance of blanking work piece evidently. Therefore, it could improve fatigue strength and the working life of work piece greatly.

Custom Metal Occlusal Surface for Acrylic Resin Denture Teeth to Enhance Wear Resistance: A Case Report

Wear of the occlusal surface of the denture is a known fact which leads to subsequent changes in jaw relation, vertical dimension, loss of aesthetics, aged looks, and decrease in masticatory efficiency. Treatment modalities includes, change of denture set after a regular interval of 4-5 years, use of wear resistant denture teeth that includes wear resistant resin or porcelain teeth, teeth with cast metal occlusal surface, and altering occlusal contact areas of denture teeth by use of silver amalgam fillings. A case report of a patient who had increased tendency of occlusal wear was treated with custom made metal occlusal surface of denture teeth to enhance wear resistance and to improve the masticatory efficiency.