• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.11a
• /
• pp.59-62
• /
• 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 Korea Foundry Society
• /
• v.13 no.6
• /
• pp.563-573
• /
• 1993

The wear resistance of Hyper-eutectic Al-Si alloy, have recently been noticed as a new automobile material, was investigated. For the purpose of developing wear resistant Al-Si alloy, some factors which attribute to wear resistance are examined as follows; refinement of primary Si particle during solidification, and effect of refinement on wear resistance and other mechanical properties. The most effective refinement was accomplished by adding both NaF and S, and this improve wear-resistance in abrasive wear type. The wear losses of specimens cast in metal mold were ruduced to 80% of those in sand mold. T6 heat treatment increases hardness, which resulted in reduction of wear loss about $3{\sim}18%$.

• Transactions of Materials Processing
• /
• v.9 no.1
• /
• pp.43-51
• /
• 2000

The die wear is one of the main factors affecting product accuracy and die life in hot forging process. It is desired to analyze die wear by developing wear prediction method combined with FE-simulatin and experiment. Lots of researches have been done into the wear analysis of cold forging die, and the results of those researches were successful, but there have been little applications to hot forging die giving successful results. That is because hot forging process has many factors influencing die wear, and there was not accurate in-process data. In this research, change of die surface hardness by thermal softening during the lifetime was obtained by experiment, and hardness distribution of cross section was measured. This wear analysis was applied to hot forging die, and gave comparatively good results compared with actual wear profile.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.879-880
• /
• 2006

Effect of phase transformation and grain-size variation of hot-pressed cobalt on its dry sliding wear was investigated. The sliding wear test was carried out against glass (83% $SiO_2$) beads at 100N load using a pin-on-disk wear tester. Worn surfaces, cross sections, and wear debris were examined by an SEM. Phases of the specimen and wear debris were identified by an XRD. Thermal transformation of the cobalt from the hcp $\varepsilon$ phase to the $\gamma$ (fcc) phase during the wear was detected, which was deduced as the wear mechanism of the sintered cobalt.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.05a
• /
• pp.87-92
• /
• 1999

This paper was undertaken to do morphological analysis of wear particles for sliding members hydraulic rotary actuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four-shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of presuming wear volume for three kinds of materials on driving time.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.6
• /
• pp.127-132
• /
• 2000

Morphological analysis of wear particles is one of useful methods for machine condition monitoring because it is well reflected in machine driving state. This paper was undertaken to apply to the condition monitoring of hydraulic piston motor. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of calculating presumed wear volume for three kinds of materials on driving time to foresee as damage condition of lubricating materials.

• Journal of Power System Engineering
• /
• v.6 no.4
• /
• pp.56-61
• /
• 2002

This study is to investigate the wear behaviors of thermally sprayed ceramic coating by a pin-on-disk wear testing machine. The test specimens were plasma sprayed TiO2 coating material on carbon steel substrate(S45C) with Ni-4.5%Al alloy bond coating. Wear characteristics, friction coefficient and wear rates, were conducted at the three kinds of loads and velosities. Wear environments were dry and lubrication friction. The friction coefficients of TiO2 coating specimen in dry friction were almost same according to increase the friction velocity. The wear rate increased when the friction force is high. In lubrication friction, the wear hardly occured and friction coefficient was about 0.1. The adhesiveness of TiO2 in lubrication friction is larger than that in dry one.

• Journal of Power System Engineering
• /
• v.18 no.6
• /
• pp.174-179
• /
• 2014

The wear behavior of epoxy matrix composites filled with nano sized silica particles is discussed in this paper. Especially, the variation of the coefficient of friction and the specific wear rate under the various applied load and sliding velocity were investigated for these materials. Wear tests of pin-on-disc mode were carried out and followed by scanning electron microscope observations. The presence of silica filler in epoxy composites was demonstrated significant influence on the friction and wear behavior of epoxy nanocomposites. With the incorporation of silica filler into the epoxy matrix, reduction of the coefficient of friction and specific wear rate were identified. Wear mechanism was discussed by analyzing the worn surface by scanning electron microscope as well.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.06a
• /
• pp.319-326
• /
• 2001

The sliding wear characteristics of carbon steel castings were Investigated using a ball on disk type tester. The experiment was conducted using high carbon steel wire rods as ball material and carbon steel castings as disk material and different operating conditions, at room temperature under a lubrication and dry conditions. The results showed that the carbon steel castings appeared average wear volume Is lowed after annealing under a lubrication conditions and wear curve linear Increased. The specific wear rate of carbon steel castings Increased with wire diameter lubrication and dry also Increased 125 times In Ory. The sliding wear mechanism were Investigated due to fatigue wear lubrications and abrasive wear dries also wire Included fatigue and abrasive wear by plastic flow.

• Tribology and Lubricants
• /
• v.17 no.4
• /
• pp.335-340
• /
• 2001

It was reviewed that the kinds of lubricating oil, viscosity, temperature and strength of materials affected the wear of the surface heat treatment. When lubricants is used under severe running conditions, their tribological characteristics are very important. We have studied the lubricating oil viscosity, kinds of additives and their amounts, and lubricating oil temperatures were changed. In order to study the effect of oil temperature on the wear of the surface, the temperature of the oil was changed for the same sample. It was shown from the test results that wear is not greatly affected by the amount of ZnDTP (Zinc dialkyl dithio phosphate) antiwear agent, but EP (Extreme pressure) additives are less effective against wear than ZnDTP additives. The viscosity of lubricating oil and its temperature greatly affect the wear of the surface. Combining all the wear data with those of the surface strength, it was observed that the higher the load, the lower the scratch of wear, and also in the case of the same running load, the lower the wear, the longer the life of the surface strength.