• Tribology and Lubricants
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• 제13권1호
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• pp.42-52
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• 1997

This paper deals with wear characteristics of ion-nitrided metal theoretically and experimentally in order to analysis of wear phenomena. Wear tests show that compound layer of ion-nitrided metal reduces wear rate when the applied wear load is mall. However, as th load becomes large, the existence of compound layer tends to increase wear rate. The residual stress at the surface of ion-nitrided metal is measured, and the internal stress distribution is calculated when the normal and tangential forces are applied to the surface of metal. Compressive residual stress is largeest at the compound layer, and decreases as the depth from the surface increases. Calculation shows that the maximum stress exists at a certain depth from the surface when normal and tangential force are applied, and that the larger the wear load is the deeper the location of maximum stress becomes. In the analysis, it is found that under small applied wear load the critical depth, where voids and cracks may be created and propagated, is located at the compound layer, as the adhesive wear, where hardness is an important factor, is created the existence of compound layer reduces the amount of wear. When the load becomes large the critical depth is located below the compound layer, and delamination, which may be explained by surface deformation, crack nucleation and propagation, is created, and the existence of compound layer increases wear rate.

• Tribology and Lubricants
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• 제18권4호
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• pp.299-304
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• 2002

This paper reports the studies on the wear-corrosion behavior of ductile cast iron in the acidic environment. In atmosphere and variety of pH solution, specific wear rate and wear-corrosion characteristics of GCD 60 with various sliding speed and distance were investigated. And electrochemical polarization test of GCD 60 was examined in the environment of various pH values. The main results are as following : As the contact pressure increases, the critical velocity of specific wear rate becomes transient at low sliding speed. As pH value becomes low, wear-corrosion loss increases in the aqueous solution. As the corrosion environment is acidified, corrosion potential of GCD 60 becomes noble and corrosion current density increases.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.313-318
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• 2001

The sliding wear behavior of Plasma-Sprayed Al$_2$O$_3$-TiO$_2$ Coating against Cemented Carbide were Investigated using a pin on disk type tester. The experiment was conducted using Al$_2$O$_3$-TiO$_2$ Coaling as pin material and Cemented Carbide as disk material and different operating conditions, at room temperature under a dry conditions. The results showed that the type B(250kw power) appeared average wear rate Is lowed than type A(80kw power). The specific wear rate of Specimen A1 Increased with normal load. But The specific wear rate of Specimen B1 decreased with normal load. Average wear rate of specimen A3, B3 are lowed than other but the sliding wear mechanism of edge were rough.

• 복식
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• 제51권2호
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• pp.53-64
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• 2001

The purpose of this study is to create the program for efficient inventory management and reduction, investigating the present conditions and factors of the inventory throughout current apparel industry. The research method applied in this study is to survey 92 domestic companies which were randomly selected with respect to the kinds of goods produced : men′s wear, women′s wear, and unisex wear. The research can be summarized as follows : 1. The seasonal stock rate of current apparel industry was 28.75%, and the rate of men′s wear companies was higher than that of women′s and unisex wear companies. 19.43% of stock cost reflection rate was applied, and the stack cost of men′s and women′s wear companies was higher than that of unisex wear companies. 2. Periodic bargain sale was the most frequently used way of stock clearance, and "uniform price sale"and outlet stores were the second and the third irrespectively. Unisex wear companies appeared to be more enthusiastic in stock clearance than the companies belonging to the other two categories. The main places for the stock clearance were department stores, outlet stores and enterprises specialized in the stock clearance. 3. QR production was proved to be the most commonly adjusted method of stock reduction, and the emphasis on development of new design and the utilization of stock management system through computer network were the next, While unisex wear companies had established the positive policies, men′s wear companies took lukewarm altitudes in every aspect. The companies selling on an order were 18.64%, and unisex wear companies showed the higher rate. The lead-time after QR production was 10.91 days, and it seemed to take more time for men′s wear companies than for women′s and unisex wear companies. The rate of the chance in stock was proved to decrease by 12.94%, and there was found no meaningful difference among the three categories of apparel companies.

• Tribology and Lubricants
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• 제16권5호
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• pp.357-364
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• 2000

In this study, the sliding wear in spur gears, using Archard's wear model, is analyzed. Formulas of tooth sliding wear depth along the line of action are derived. The tooth profile is modified Id make a smooth transmission of the normal loads and the cylinder profile for reducing the pressure spike is suggested. The sliding wear rate is calculated with these profiling results. We expect these modification methods to contribute to the reduction of sliding wear not only in the root, but the tip of tooth and tooth edge.

• Tribology and Lubricants
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• 제35권6호
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• pp.356-361
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• 2019

The friction and wear between machine components directly influence the energy loss and failure in various machines. Therefore, there is always a demand for finding methods to reduce friction and wear. Of the possible methods, lubrication is a widely used method for reducing friction and wear. In the case of lubrication, it is important to analyze the tribological behavior in the boundary lubrication because most of friction and wear occurs in the boundary lubrication regime. Cast iron has been regarded as a good material for industrial applications due to the excellent mechanical properties and high productivity. Especially, nodular cast iron is a material that shows better mechanical properties and wear-resistance compared with cast iron due to inclusion of spheroidal graphite. In this work, we investigated the tribological characteristics of nodular cast iron with respect to different counter parts in boundary lubrication regime. Sliding tests were conducted with SUJ2, ZrO₂, Si₃N₄ balls as counter parts using a pin-on-disk type tribotester. The results showed different friction and wear behaviors with different counter parts. The case of ZrO₂ showed the lowest wear rate in specimen and no significant ball wear. In case of SUJ2, it showed similar wear rate with ZrO₂ case in specimen and the highest friction coefficient. The case of Si₃N₄ showed the lowest friction coefficient, 33% lower than the case of SUJ2. It showed 16.9 times larger wear rate in specimen and 43% larger wear rate in ball compared to that of the SUJ2 case.

• 대한기계학회논문집
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• 제17권6호
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• pp.1404-1411
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• 1993

본 연구는 오스템퍼링 온도와 유지시간을 변화시켜 오스템퍼링 한 저합금구 상흑연주철을 실험재로 하여 증류수 및 NaCI수용액 중에서의 부식마멸특성 및 그 기구 를 규명하여 Tribology 설계에 대한 자료를 제시하는 것을 목적으로 하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.575-578
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• 2000

Die design to minimize the die wear in the cold forging process is very important as it reduce the production cost and the increase of the production rate. The quantitative estimation for the die wear is too hard because the prediction of the die wear is determined with many process variables. So, in this paper, the optimal shape of the backward extrusion punch is newly designed through the FE-analysis considering the surface expansion and Archard's wear model in order to reduce the rapid wear rate that is generated for the backward extrusion product exceeding the forming limit. The main shape variables of the backward extrusion punch are the flat, angle, and round of the punch nose part. As the flat and angle of the punch nose are larger, the surface expansion is reduced. and, the wear rate is decreased according to the reduction of the punch round. These results obtained through this study are applied to the real manufacturing process, it is implemented the reduction of the wear rate.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.125-133
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• 2011

The wear of rubber track being in contact with the road surface is an important subject because it decreases the traction performance and the operating efficiency of tracked vehicle. For the above reasons, many attempts have been made to quantitatively calculate the rubber track. However, it depends on the experimental methods which are highly time- and cost-consuming. Therefore, the numerical simulation approach is highly desirable, but it needs to model the complex geometry and the material behavior in details as well as the interaction with the road surface. In this study, the rubber track and its material behavior are elaborately modeled since these factors are very important in the prediction of the wear rate of the rubber track. Accordingly to the studies on the rubber wear by previous investigations, it has been found that the wear is greatly influenced by the frictional energy. The frictional energy of rubber track is computed by utilizing the 3D finite element analysis of the rubber track, and the wear rate is evaluated making use of the frictional energy and a wear model.

• Journal of Welding and Joining
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• 제18권5호
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• pp.105-111
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• 2000

The wear behavior of thermal sprayed AlSiMg-40TiC composite coatings were studied as a function of load and sliding velocity under unlubricated conditions. Experiments were performed using a block-on-ring(WC-6wt%/Co, Hv 1500) type. The tests were carried out a various load(30∼ 125.5N) and sliding velocity(0.5∼2.0m/s). Three wear rate regions were observed in the AlSiMg-40TiC composite coatings. The wear rate in region I at low load (less then 8N( were less than 1×{TEX}$10^{-5}${/TEX}㎣/m. Low wear rates in region I resulted from the load-bearing capacity of TiC particles. The transition from region I to II occurred when the applied load exceeded the fracture and pull-out strength of the particles. The TiC fractured particles trapped between the specimen and the counterface acted as third-body abrasive wear. The subsurface layer worn surface in region II was composed of the mechanically mixed layer (MML). The wear rate increase abruptly above a critical load (region III). The high wear rate in region III was induced by frictional temperature and involves massive surface damage.