• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.59-62
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• 2001

Flow induced vibration in steam generators has caused dynamic interactions between tubes and contacting materials resulting in fretting wear . Series of experiments have been performed to examine the wear properties of Inconel 690 steam generator tubes in various environmental conditions. For the present study, the test rig was designed to examine the fretting wear and rolling wear properties in high temperature(room temperature - 290。C) water. The test was performed at constant applied load and sliding distance to investigate the effect of test temperature on wear properties of the steam generator tube materials. To investigate the wear mechanism of material, the worn was observed using scanning electron microscopy. The weight loss increase at higher test temperature was caused by the decrease of water viscosity and the mechanical property change of tube material. The mechanical property changes of steam generator tube material, such as decrease of hardness or yield stress in the high temperature tests. From the SEM observation of worn surfaces, the severe wear scars were observed in specimens tested at the higher temperature.

• Journal of the Korean Chemical Society
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• v.14 no.2
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• pp.179-184
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• 1970

Four-ball EP and wear testers were used to study the effects of thickeners and additives on the EP and wear properties of some Korean greases. The EP property improved in the order of Li < Al < Ca, and the concentration of thickener did not affect the property when the same base oil and additives were used. The anti-wear property was improved in general when the additives were used.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.89-90
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• 2006

Austenitic stainless steel has been used as a corrosion resistance material. However, austenitic stainless steel has poor wear resistance property due to its low hardness. In this investigation, we apply powder composite process to obtain hard layer of Stainless steel. The composite material was fabricated from planetary ball milled SUS316L stainless steel powder and WC powder and then sintered by Pulsed Current Sintering (PCS) method. We also added TiC powder as a hard particle in WC layer. Evaluations of wear properties were performed by pin-on-disk wear testing machine, and a remarkable improvement in wear resistance property was obtained.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1875-1881
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• 2016

The wear behavior for the two types of composites, those are epoxy matrix composites filled with silica particles and aluminium matrix composites filled with SiC particles, were compared to investigate the wear mechanism for these composites. Especially, the effect of the volume fraction for the epoxy matrix composites and the particle size for the aluminium matrix composites according to the apply load and sliding velocity were investigated. Wear tests of the pin-on-disc mode were carried out and followed by scanning electron microscope observations for the worn surface. The addition of the fillers in the composites were improved the wear resistance significantly and changed the wear mechanism for the both composites. These results were identified by the observation of the worn surface after testing.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.3
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• pp.397-410
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• 2018

This study investigated the flame retardant, anti-static property and wear comfort of knitted fabrics made of two kinds of composite yarns comprised of modacryl, antistatic PET, cotton and excel(R) fibers. A Low Oxygen Index (LOI) above 28 was observed in the modacryl knitted fabric specimens. The flame retardant was superior at the excel(R) fiber (including modacryl knitted fabric) than the one including cotton fiber. Anti-static properties of the modacryl knitted fabrics imbedded by 3wt% of antistatic PET fibers were observed by rubbing with wool fabric attached to the measuring apparatus, which showed a better anti-static property than the excel(R) fiber (including modacryl knitted fabric). Wear comfort indicated that quick perspiration absorption and the fast dry property of excel(R) (including modacryl knitted fabric) was better than one that included cotton fiber. Warmth keepability and breathability of the knitted fabrics indicated good results in the excel(R) (including cotton and the modacryl knitted fabrics). However, the tactile hand property of cotton fiber (including modacryl knitted fabric) was better than excel(R) fiber due to high extensibility and compressibility, and low bending and shear rigidity of the cotton fiber (including modacryl knitted fabrics).

• Korean Journal of Materials Research
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• v.15 no.12
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• pp.824-828
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• 2005

In this study the effect of the content of $TiB_2$ on wear properties was investigated. $Cu-TiB_2$ composites have been fabricated by hot extrusion. Sliding wear tests were peformed by a pin-on-disk type wear test machine under dry condition and loads varied with from 20N to 80N at sliding speed 3.5Hz. The test results showed that the wear losses and the friction coefficients decreased with increasing $Cu-TiB_2$ volume fraction and increasing the size of $Cu-TiB_2$ particle. Wear property of $10{\mu}m,\;5 vol\%\; TiB_2$ specimen was excellent all of the wear specimens. It is thought that the increase of plastic flow resistivity due to uniform distribution of $10{\mu}m,\;5 vol\%\; TiB_2$ wear specimen would improve wear property. The worn surface and wear debris were examined by optical microscope and scanning electron microscope.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.149-155
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• 2001

New semi-fluorinated polyol esters were synthesized by condensation reaction of polyols (NPG and TMP) and carboxylic acids such as 2-ethylhexanoic acid, stearic acid and perfluorooctanoic acid. The structures of polyol esters were confirmed by FT-IR and H-NMR etc. And, the fluorinated polyol esters were insoluble in several oils, however, the semi-fluorinated polyol esters were soluble in several oils depended on the structure of polyol esters. The physical properties such as 4-ball wear property and extreme-pressure (EP) properties were characterized by measuring wear scar diameter through ASTM D2266 and by determining the load-carrying through ASTM D2783 method, respectively. As the results, wear scar diameters of oils in which the semi-fluorinated polyol esters were added were not changed compared to those of not added oils. While extreme-pressure properties remarkably Increased with fluorine contents of the esters depended on the structure of acid moiety and polyol moiety. Also, the extreme-pressure property of semi-fluorinated NPG polyol ester in gasoline engine oil was better than that of commercial Teflon coating additive.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.3
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• pp.51-59
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• 2001

A diesel engine oil formulated in KRICT and a commercial diesel engine oil (API CG-4) were tested by car and their Kinematic Viscosity, TAN, TBN, metal content, additive depletion, anti-wear property and IR analysis were analyzed. From the research, both of the tested oils had almost the same properties f3r the change of TAN and TBN, but the change of Kinematic Viscosity of formulated oil was slightly higher than that of commercial oil. The iron content in the commercial oil increased rapidly from 7000 km while that of the formulated oil was still low. These results were confirmed by the anti-wear test with a 4-ball wear test machine for the each samples. Also, for the commercial oil, the depletion factor of the Zn-DTP which was added as an anti-wear property did not change any more after 7000 km. But, that of the formulated oil changed continuously to 8000 km, which means that the ability to prevent wear of the sliding pairs exists for the formulated oil. From the analysis results of oil properties obtained by field test, it was found that the commercial oil could be used only within 7000 km, but the formulated oil could be used more than 8000 km without severe wear of the sliding parts in the diesel engine.

• Journal of Ocean Engineering and Technology
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• v.23 no.3
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• pp.30-34
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• 2009

Oil hydraulic piston pumps are being extensively used in the world, because of simple design, light weight and effective cost etc. An oil hydraulic pump is likely to have serious problems of high leakage, friction and low energy efficiency according to large time use. In the oil hydraulic piston pumps the clearance between the valve block and piston plays an important role for volumetric and overall efficiency. In this paper, the wear property of the SACM645 material used the hydraulic piston pump has been work out by experimentation with variable heat treatment. To investigate the effect according to the piston surface condition, seven different types specimen were prepared. From the wear test results, induction hardening and nitration were definitely superior to the others. On the whole, nitration was estimated for high strength material to wear resistance.

• Journal of Powder Materials
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• v.22 no.3
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• pp.203-207
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• 2015

This study investigated the microstructure and wear resistance property of HPHT(high pressure high temperature) sintered PDC(polycrystalline diamond compact) in accordance with initial molding pressure. After quantifying an identical amount of diamond powder, the powder was inserted in top of WC-Co sintered material, and molded under four different pressure conditions (50, 100, 150, $200kgf/cm^2$). The obtained diamond compact underwent sintering in high pressure, high temperature conditions. In the case of the $50kgf/cm^2$ initial molding pressure condition, cracks were formed on the surface of PDC. On the other hand, PDCs obtained from $100{\sim}200kgf/cm^2$ initial molding pressure conditions showed a meticulous structure. As molding pressure increased, low Co composition within PDC was detected. A wear resistance test was performed on the PDC, and the $200kgf/cm^2$ condition PDC showed the highest wear resistance property.