Papers by Keyword: Wear Resistance

Abstract: To improve the service performance of Cr-series steel for cold roller, the combined effects of chromium and silicon on hardness and wear resistance of cold roll steel had been studied in this paper on the basis of MC5 cold roll steel. The results showed that, with increasing Si content the hardness tended to decrease when Cr content was about the same. The hardness was the highest and the wear resistance was the best when Cr content was about 6.7% and Si content about 0.6%. The reason for this found by microscopic analysis was that the carbide size was the finest and carbides were the most dispersively distributed. Meanwhile, the amount of carbides was also the largest.

Abstract: The influence of Nd on structure and properties of hypereutectic Al-Si alloys (Al-17.5%Si, Al-25%Si) was investigated in this paper. For Al-17.5%Si alloy, there is no obvious variation in morphology of primary Si before and after Nd modification, but the average size of primary Si is decreased from 34.73µm to 23.39µm after 0.3%Nd modification. Compared with initial sample, the tensile strength and yield strength of 0.3%Nd-modified sample are increased by 11.6% and 1.5%, and wear resistance of Al-17.5%Si alloy is enhanced to a factor of 2.1 after 0.3%Nd modification. However, for Al-25%Si alloy, the tensile strength and yield strength of 0.3%Nd-modified sample are respectively improved by 22.1% and 9.5% as compared to initial sample. Meanwhile, wear resistance of modified sample is improved to a factor of 3 relative to initial sample. The property improvement of two alloys can be attributed to the change in morphology and size of primary Si after Nd modification.

Abstract: The effects of the interface in alumina fiber reinforced Al-Si alloy composites prepared by squeeze casting on the wear resistance of the composites were studied. The results indicated that the fiber combined with the matrix well in the composites and had reinforcing effect on the alloy. The interface in the composites could hold back crack propagation, and the composites had the excellent wear resistance. The alloy elements in the matrix were favourable to forming the good interface to improve wear resistance of the composites.

Abstract: The active screen ion sulphurized layer was prepared on the surface of CrMoCu alloy cast iron by using active screen ion sulphurizing technology. Its key composition is FeS. Under epinoc grease lubrication condition, the friction factor and the wear volume of the active screen ion sulphurized layer is 24% and 40% lower than that of the plain surface and close to that of the sulphurized layer, respectively. The active screen ion sulphurized layer has excellent self-lubrication property, and its loose and porous structure tending to store the grease, which make it possess excellent friction reduction and wear resistance performances.

Abstract: The Ni-SiC nano-composite coatings were prepared on the ring of stainless steel by using of high frequency pulse electroplating. Orthogonal experiment was used to study optimal dosage of the dispersant. The effect of some factors, such as current density, pH value, temperature , addition agent and so on, were studied. The characterization of Ni-SiC nano-composite coatings were studied by wear test. The effect of pulse frequency and the SiC concentration in the electrolyte on the wear resistance of Ni-SiC nano-composite coatings were studied. The morphology of the nano-composite coatings in wear test before and after were analyzed by SEM and the metaloscope photographs. The results show that Ni-SiC nano-composite coatings of high frequency pulse electroforming have better performance of wear resistance.

Abstract: In order to improve the surface property of the steel tire mold, carbon steels were processed by electroless Ni-P and Ni-P-PTFE under contrast experiment. The coatings were characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS). The wear resistance and corrosion resistance of the coatings were explored by tribometer, salt spray cabinet and advanced electrochemical system. The experimental results showed that the Ni-P coating was amorphous structure, and the Ni-P-PTFE coating was micro-pore structure; The wear resistance of Ni-P-PTFE coating was superior to Ni-P coating; In view of the micro-pore structure, the corrosion resistance of Ni-P-PTFE coating was worse than Ni-P coating, but they were all superior to carbon steels, and the service life of the steel tire mold were improved.

Abstract: By using butyl titanate as the main material, the nano-TiO2/μm-SiC composite particles were prepared in acidic abundant aqueous solution at low temperature. The properties of the composite particles, including surface morphology, the phase composition of the coating layer, were characterized by SEM, XRD and XPS. The results show that the surfaces of composite particles were rougher after nano-TiO2 coating. Compared with uncoated powders as filler, the weight loss of composite coatings decreased by 43%, when the composite particles were filled in wear-resistant coatings based on the silicone modified epoxy resins.

Abstract: High yield strength and good wear resistance of hypereutectic steels in hardened and tempered condition made them attractive to manufacture rotating parts of mechanical systems. However, they suffered with poor corrosion, owing to high carbon content. The need for a material with improved strength, wear resistance and corrosion resistance for bearing application resulted in the design of a new steel having 17 wt.% Cr, up to 0.75 wt.% Mo and 1 wt.% C, which was christened as 440C. This martensitic grade of stainless steel was surface hardened by laser transformation hardening (LTH) technique using Pulsed Nd: YAG laser. Optimised process parameter could result in 300 µm thick hardened layer consisted of martensite, retained austenite and fine carbide with an average hardness of 540 VHN, while it was about 220 VHN in the core. Laser process parameter like energy/power density, pulse width, scanning speed and overlap ratio were responsible in influencing the microstructural constituents, hardness achievable and in turn dictates the wear resistance capability of the material. Experimental results such as temperature distribution, depth of hardening have been verified analytically. A reasonable agreement between the theoretical and experimental measurements was obtained. This paper highlights the details of experimental work.

Abstract: AZ31B magnesium alloy were irradiated by a high current pulsed electron beam (HCPEB) device with pulse times 10, 15 and 20 respectively. The morphology of the surface and cross-section of modified layer were investigated by optical microscope. The corrosion resistance of modified layer were tested by EG&G M273 potentiostat in 5% NaCl solution. Wear resistance were tested by HRS-2 high speed reciprocation frictional testing machines. The results indicated that magnesium alloy surface hardness obviously enhances, the wear volume reduces 7%, the corrosion resistance also improves obviously after electron beam processing.

Abstract: The current investigation discusses the effect of Mn and Si contents on the microstructure and abrasive wear characteristic in Fe-based hard-facing alloy. A series of Fe-based hard-facing alloys are successfully fabricated onto the S45C steel by gas tungsten arc welding (GTAW). Results reveal that microstructure contains great amounts of martensite phases and moderate amounts of austenite phases. Si element added into Fe-based hard-facing alloy can not obviously affect the properties of the claddings, such as martensite phase, hardness, and abrasive wear resistance. Nevertheless, Mn element added into Fe-based hard-facing alloy can efficiently affect the martensite phase, hardness, and abrasive wear resistance of the claddings. The martensite contents decreases with the increasing of Mn contents in the cladding layers. The hardness increases as the Mn contents decreases, because the martensite contents increases. The abrasive wear resistance is not only related to the hardness of the cladding layer but the martensite contents of the cladding layer. The abrasive wear resistance is an inverse proportion to Mn contents of the cladding layers. Especially, the cladding layers containing 1.4Si-0.3Mn has the highest hardness of HRC 60.1 and the lowest wear loss of 0.37g.