• Title, Summary, Keyword: Wear

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Sliding Wear Behavior of AISI 52100 Steel with Pearlitic and Bainitic Microstructures (미세조직 변화에 따른 AISI 52100 강의 미끄럼마멸 특성)

  • Yoon, N.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.20 no.7
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    • pp.479-484
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    • 2011
  • Dry sliding wear behavior of AISI 52100 steel that has a pearlite or bainite microstructure was characterized to explore the effect of microstructure on the wear of the steel. Isothermal heat treatments were employed to obtain the different microstructures. Pin-on-disk type wear tests of the steel disk were performed at loads of 25~125N in air against an alumina ball. Sliding speed and wear distance used were 0.1m/sec and 300m, respectively. Worn surfaces, wear debris and cross-sections of the worn surfaces were examined with SEM to investigate the wear mechanism of the steel. Hardness of the steel was also evaluated. Wear rate of the steel was correlated with the hardness and the microstructure. On the whole, wear resistance increased with an increase in hardness. However, the pearlite microstructure showed superior wear resistance as compared to the bainite microstructure with a similar hardness. The effect of the microstructure on the wear rate was attributed to the morphological differences of the carbide in the microstructure, which was found to have a significant effect on strain hardening during the wear.

A Study on the Development of Pattern and Design for Pet Dog's Wear (애완견 의상의 패턴과 디자인 개발 연구)

  • Lee, Joo Eun
    • Fashion & Textile Research Journal
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    • v.14 no.5
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    • pp.846-852
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    • 2012
  • Pets (such as dogs) are considered as important as family members, this perspective is due to an aging population and the decreased size of the traditional nuclear family. The pet industry has been growing every year; subsequently, is useful to develop practical patterns and designs appropriate for the body structure and movement of pet dogs. However, studies to develop a new form of pet dog's wear patterns and designs are limited. This study develops a basic pattern that is easily used based on a pet dog's size, designs popular clothing items for pet dogs, and helps in the manufactures of pet dog's wear. The results are as follow: 1) Analyzed categories and popular items of pet dog's wear from the research of the prior studies and on-line pet dog shopping malls; three categories (everyday wear, street wear, and special wear) and six items (T-shirt, one-piece, coat, jumper, and dress, tuxedo). 2) Developed the basic bodice pattern and sleeve pattern after test-wearing and revising the experimental patterns referenced from prior studies. 3) Developed patterns and designs for six popular items based on situation and gender: one-piece (everyday wear), coat (street wear), wedding dress (special wear) for female dogs/T-shirt (everyday wear), hood jumper (street wear), tuxedo (special wear) for male dogs. 4) Developed the previous six items to illustrate the research results of the study.

Study on the Analysis of Wear Phenomena of Ion-Nitrided Steel (이온질화 처리강의 마모현상 분석에 관한 연구)

  • Cho, Kyu-Sik
    • Tribology and Lubricants
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    • v.13 no.1
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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.

Post-purchase Evaluation on the Maternity Wear on the Current Korean Market by Survey and Wear test

  • Park, Soon-Jee;Lee, Hee-Jung;Suh, Chu-Yeon
    • Journal of Fashion Business
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    • v.11 no.3
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    • pp.15-34
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    • 2007
  • This study was designed to collect a precise information concerning to the preference and evaluations after usage of pregnant Korean woman for the maternity wear bysurvey and wear tests. Through the survey, 212 respondents were asked to answer what type of maternity wear they prefer and what requirements for maternity wear design are important. According to the results of survey, the mostly preferred maternity wear items were pants and one-piece dress. Korean customers for maternity wear usually pay more for the one-piece dress than other items and they also usually put on medium price pants and low-price blouse. Concerning to the purchase criteria, it may be said that design and movability, fit factors are the buying decision criteria of great weight for Korean pregnant women. Special function most desired was thermal insulation, followed by buffer action, electromagnetic shield and quickly water-absorbent and dry property. Preferred maternity wear design details were flat collar, slightly fitted waist and empire style, gather skirt, rubber band waist. Wear test was performed for two kinds of blouse (BL) and one-piece dress (OP), and threekinds of pants (PT), which have different design details respectively. According to the wear test for ready-to-wear maternity garments, the garment which considers well the characteristics of Korean pregnant women body shape earned much higher score no matter of brands or prices. Generally, high-priced national brands received an excellent evaluation in design aspect, but not satisfied with comfort to move.

Analysis of the Sliding Wear Mechanism of Pure Iron Tested Against Different Counterparts in Various Atmospheres (상대재와 분위기에 따른 순철의 미끄럼 마멸 기구 분석)

  • Koo, B.W.;Gwon, H.W.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.26 no.6
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    • pp.365-371
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    • 2017
  • During sling wear of a ferrous metal, a surface layer is formed. Its microstructure, constituting phases, and mechanical property are different from those of the original wearing material. Since wear occurs at the layer, it is important to characterize the layer and understand how wear rate changes with different layers. Various layers are formed depending on external wear conditions such as load, sliding speed, counterpart material, and environmental conditions. In this research, sliding wear tests of pure iron were carried out against two different counterparts (AISI 52100 bearing steel and $Al_2O_3$) in the air and in an inert Ar gas atmosphere. Pure iron was employed to exclude other effects from secondary phases in steel on the wear. Wear tests were performed at room temperature. Worn surfaces, wear debris, and cross-sections were analyzed after the test. It was found that these two different counterparts and environments produced diverse layers, resulting in significant changes in wear rate. Against the bearing steel, pure iron showed higher wear rate in an Ar atmosphere due to severe adhesion than that in the air. On the contrary, the iron showed much higher wear rate in the air against $Al_2O_3$. Different layers and wear rates were analyzed and discussed by oxidation, severe plastic deformation, and adhesion at wearing surfaces.

Cold Data Identification using Raw Bit Error Rate in Wear Leveling for NAND Flash Memory

  • Hwang, Sang-Ho;Kwak, Jong Wook;Park, Chang-Hyeon
    • Journal of the Korea Society of Computer and Information
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    • v.20 no.12
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    • pp.1-8
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    • 2015
  • Wear leveling techniques have been studied to prolong the lifetime of NAND flash memory. Most of studies have used Program/Erase(P/E) cycles as wear index for wear leveling. Unfortunately, P/E cycles could not predict the real lifetime of NAND flash blocks. Therefore, these algorithms have the limited performance from prolonging the lifetime when applied to the SSD. In order to apply the real lifetime, wear leveling algorithms, which use raw Bit Error Rate(rBER) as wear index, have been studied in recent years. In this paper, we propose CrEWL(Cold data identification using raw Bit error rate in Wear Leveling), which uses rBER as wear index to apply to the real lifetime. The proposed wear leveling reduces an overhead of garbage collections by using HBSQ(Hot Block Sequence Queue) which identifies hot data. In order to reduce overhead of wear leveling, CrEWL does not perform wear leveling until rBER of the some blocks reaches a threshold value. We evaluate CrEWL in comparison with the previous studies under the traces having the different Hot/Cold rate, and the experimental results show that our wear leveling technique can reduce the overhead up to 41% and prolong the lifetime up to 72% compared with previous wear leveling techniques.

Analysis of Sliding Wear Behavior of Mild Steel According to Hardness of Dissimilar Mating Materials (이종 상대재 경도에 따른 철강재료의 미끄럼 마모 특성 해석)

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.32 no.6
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    • pp.195-200
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    • 2016
  • This study examines the wear behavior of mild steel pins mated against alloyed tool steel discs in a pin-on-disc type sliding test machine and provides specific clarification regarding the effects of disc hardness on the wear behavior of a mating mild steel pin. The analysis confirms these effects through the observation of differences in the wear rates of the mild steel pins at low sliding speed ranges. These differences occur even though the hardness of the mating disc does not affect the wear characteristic curve patterns for the sliding speeds, regardless of the wear regime. In the running-in wear regime, increasing the hardness of the mating disc results in a decrease in the wear rates of the mild steel pins at low sliding speed ranges. However, in the steady-state wear region, the wear rate of a pin mated against the 42DISC is greater than the wear rate of a pin mated against the 30DISC, which has a lower hardness value. This means that the tribochemical reactivity of the mating disc, which is based on hardness value, influences the wear behavior of mild steel at low sliding speed ranges. In particular, oxides with higher oxygen contents, such as $Fe_2O_3$ oxides, form predominantly on the worn surface of the 42DISC. On the contrary, the wear behavior of mild steel pins at high sliding speed ranges is nearly unaffected by the hardness of the mating disc.

A Fundamental Study for the Sliding Wear Characteristics of the Crane Sheave Against a Rope Wire (크레인시브와 로프소선간의 미끄럼 마멸특성에 관한 기초연구)

  • Ryu, Jung-Buk;Chae, Young-Hun;Kim, Seock-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.11
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    • pp.1873-1880
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    • 2003
  • The sliding wear characteristics of the crane sheave were investigated using a pin on disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

The Sliding Wear Characteristics of the Carbon Steel Castings against High Carbon Steel Wire Rods (탄소주강품과 경강선재간의 미끄럼 마멸특성)

  • 류중북;채영훈;김석삼
    • Tribology and Lubricants
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    • v.19 no.4
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    • pp.223-229
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    • 2003
  • The sliding wear characteristics of the crane sheave were investigated using a pin-on-disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

Wear Mechanism of Tube Fretting Affected by Support Shapes

  • Kim, Hyung-Kyu;Lee, Young-Ho;Yoon, Kyung-Ho;Kang, Heung-Seok;Song, Kee-Nam;Ha, Jae-Wook
    • KSTLE International Journal
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    • v.3 no.1
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    • pp.68-73
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    • 2002
  • A fretting wear experiment in roam temperature air was performed to evaluate the wear mechanism of fuel rod using a fretting wear tester, which has been developed for experimental study, The main focus was to compare the wear behaviors of fuel rod against support springs with different contact contours (i.e. concave and convex). Wear volume, degree or surface hardening and adhesion tendency of wear particle were examined by the surface roughness tester. The result indicated that with a change of contact condition from contact force of 5 N to 0.1 mm gap, the wear volume of tube increased in the condition of concave spring, but slowly decreased in convex spring. From the results of SEM observation, wear mechanism of each test condition was also dependent on the spring shapes. The wear mechanism of each test condition in room temperature air is discussed.