• Title, Summary, Keyword: Wear

Search Result 6,856, Processing Time 0.043 seconds

Wear Behavior of SUS304 Stainless Steels in Corrosive Environment (부식 환경에서 SUS304 스테인레스 강의 마모 거동)

  • Lee Kwang-Jin;Yoon Sang-Don;Koo Young-Pil;Kim Hyung-Ja
    • Tribology and Lubricants
    • /
    • v.20 no.2
    • /
    • pp.91-96
    • /
    • 2004
  • Wear behavior of self-mated stainless steels in NaCl solution has been investigated. The experiment was done in the corrosive liquid of which NaCl concentration of $0\~3\%$ and temperature of $15\~90^{\circ}C$. Two kinds of wear type were observed: one is 'severe wear' type which shows gradually increasing wear volume with increasing sliding distances, the other is 'mild wear' type which shows change of wear rate from high value to low at transition distance. The specific wear rate in severe wear type was not sensitive to the liquid temperature and concentration of NaCl but stable at value of $1\times10^{-3}\;mm^3$ approximately.

A Study of Unlubricated Sliding wear of materials as hardness difference (경도의 차이에 따른 재료들의 비윤활 미끄럼 마모에 대한 연구)

  • Kim, Jung-Hyun
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.7 no.4
    • /
    • pp.369-376
    • /
    • 2004
  • It is shown that the rate of wear can be related to on 'index of wear intensity'. Since both upper and lower specimens have used the same hardness values, equivalent hardness of 'index of wear intensity' used the mean hardness value of specimens. This index is derived from the external variables of load, sliding speed and the hardness of the sliding pairs. The wear behavior as the hardness of the sliding elements on the dry wear has been investigated using a disc on disc configuration. The materials of the specimens are used as ten kinds along their hardness. Using experimental data, we figured the relationship between wea rate and index of wear intensity. The result had been derived a newly wear equation in disc on disc wear system.

  • PDF

A dry wear behavior as hardness difffrence in a dual disc on disc sliding wear tests (디스크 언 디스크 시스템에서 경도에 따른 건식 마모거동)

  • Kim Junghyun
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.13 no.5
    • /
    • pp.16-23
    • /
    • 2004
  • The wear behavior as the hardness of the sliding elements on the dry wear has been investigated using a disc on disc configuration. The materials of the specimens are used as ten kinds along their hardness. In this study, both upper and lower specimens have been used the same materials. Using experimental data, we figured the relationship between wear coefficient and friction coefficient, and the relationship between wear coefficient and friction temperature. Also we combined friction temperature and friction coefficient instead of wear coefficient. We substituted this into wear equation of Archard. The result had been derived a newly wear equation in disc on disc wear system.

The Effects of Meteorological factors on Sales of Apparel Products - focused on apparel sales in the department store- (기상 요인이 의류제품 매출에 미치는 영향분석 -백화점의 의류매출을 중심으로-)

  • 장은영;이선재
    • Journal of the Korean Society of Costume
    • /
    • v.52 no.2
    • /
    • pp.139-150
    • /
    • 2002
  • The purpose of this study was to explore the effects of meteorological factors on sales of apparel products. Basic fiat came out daily meteorological data and sales data of apparel products in department store from 1998 to 2000. Four factors(the average temperature, rainfall, wind velocity, sunshine duration) from the nine meteorological factors were selected and were collected with Korea Meteorological Administration. Sales data were collected with business strategy department of H (department store in Seoul. The sales data were divided into six classifications, which are woman's wear, men's wear, children's wear, golf wear, sports wear, and inner wear. The results of this study were as follows: 1) Sales of apparel products were significantly correlated with the average temperature, rainfall, wind velocity, sunshine duration. Among the meteorological factors, temperature turned out to be the most influential in apparel sales and then the amount of rainfall, sunshine duration affected sales according to apparel classifications differently. 2) There were some differences among the apparel classifications in the effect of meteorological factors on the sales of apparel. In the spring. the higher the temperature was, the higher the sales of women's wear and golf wear were, but the lower the sales of children's wear, sports wear and inner wear were. In the summer, The higher the amount of rainfall was, the lower the sales of all the apparel classification were. The higher the temperature was, the higher the sales of sports wear were. In the fall, the lower the temperature was, the higher the sales of all the apparel classification except snorts wear were. In the winter, the meteorological factors had little effect on the sales of women's wear, men's wear and children's wear. The higher the temperature was, the higher the sales of golf wear were. The lower the temperature was, the higher the sales of sports wear were.

A Study on Use and Purchase Behavior of Sleeping wear for Summer in Chungchong area. (여름용 잠옷착용실태와 구매행동에 관한 연구-충청지역 도시를 중심으로-)

  • 권수애;김은영;최종명;이은경
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.24 no.6
    • /
    • pp.838-849
    • /
    • 2000
  • The purpose of this study was to investigate use and purchase behavior of sleeping wear for summer. Subjects in this study were composed of 591 males and females aged from twenties to fifties, living in Taejon and Chongju. For data analysis, descriptive analysis, $\chi$$^2$-test, t-test, ANOVA, and factor analysis were used. The results are as follows. First, subjects used sleeping wear(a night gown and pajamas), and home wear(T-shirts and sweat suit with zippered top) with similar rates. The subjects, who are females, married, older and have professional jobs, owned sleeping wear such as a night gown and pajamas more than home wear. Also, the mean of using pajamas was the highest, and they were satisfied with them more than others who didn't wear them. Second, one-third of consumers purchased sleeping wear once a year in a specialty store. Consumers mainly searched for information regarding sleeping wear in the display section. Most consumers weren't influenced by others when they made their purchases. When consumers decided to purchase a product, they considered six criteria such as fabric/management, wearing/fitness, esthetic, service, symbolic status, and economic for evaluating. Among them, the factor wearing/fitness was considered the most important. These results imply that consumers would be conscious of sleeping wear even though sleeping wear and home wear are used interchangeably. In addition, consumer behavior concerning sleeping wear is different from their characteristics such as sex, age, occupation, the level of education, and marital state. Therefore, the markets with sleeping wear would be able to be segmented based on consumers’characteristics. Also, marketers should focus on distribution channels to reform the markets of sleeping wear, that is, they may offer products in specialty stores. Additionally, market managers would be able to concentrate on visual merchandising in stores in order to increase brand awareness and market share.

  • PDF

A Study on Wear and Wear Mechanism of Exhaust Valve and Seat Insert Depending on Different Speeds Using a Simulator

  • Hong, Jae-Soo;Chun, Keyoung-Jin;Youn, Young-Han
    • Journal of Mechanical Science and Technology
    • /
    • v.20 no.12
    • /
    • pp.2052-2060
    • /
    • 2006
  • The wear of engine valve and seat insert is one of the most important factors which affect engine performance. Because of higher demands on performance and the increasing use of alternative fuel, engine valve and seat insert are challenged with greater wear problems than in the past. In order to solve the above problems, a simulator was developed to be able to generate and control high temperatures and various speeds during motion. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. This work focuses on the different degrees of wear at three different singular test speeds (10 Hz, 25 Hz & multi-Hz). For this study, the temperature of the outer surface of the seat insert was controlled at 350$^{\circ}C$, and the test load was 1960 N. The test cycle number was $6.0{\times}10^6$. The mean ($\pm$standard error) wear depth of the valve at 10 Hz and 25 Hz was 45.1 ($\pm$3.7)$\mu$m and 81.7 ($\pm$2.5)$\mu$m, respectively. The mean wear depth of the seat insert at 10 Hz and 25 Hz was 52.7 ($\pm$3.9)$\mu$m and 91.2 ($\pm$2.7)$\mu$m, respectively. In the case of multi-Hz it was 70.7 ($\pm$2.4)$\mu$m and 77.4 ($\pm$3.8)$\mu$m, respectively. It was found that higher speed (25 Hz) cause a greater degree of wear than lower speed (10 Hz) under identical test condition (temperature, valve displacement, cycle number and test load). In the wear mechanisms of valves, adhesive wear, shear strain and abrasive wear could be observed. Also, in the wear mechanisms of seat inserts, adhesive wear, surface fatigue wear and abrasive wear could be observed.

Evaluation of Wear Index of Toothbrushes Used by University Students and Analysis of Related Factors (대학생의 칫솔 마모도 평가 및 관련요인 분석)

  • Kim, Sun-Ju
    • The Journal of the Korea Contents Association
    • /
    • v.16 no.2
    • /
    • pp.609-617
    • /
    • 2016
  • The purpose of this study is to investigate the wear index of toothbrush and related factors in the university students. A self-reported questionnaire was completed by 573 university students from March 16 to April 10, 2015. The questionnaire consisted of general characteristics of the subjects, wear index, and wear rate of the toothbrush. The wear index of 46.9 percent was above 0.400, and the average wear index was $0.403{\pm}0.20$. Overall, the wear index of the toothbrushes was high. 2. As a result of measuring the wear rate of the toothbrushes, the wear rate of 70.4 percent stood at 1 and 2. The average wear rate stood at $1.620{\pm}0.74$. Overall, the wear rate of the toothbrushes was high. 3. As for wear index and wear rate by gender, the wear index and wear rate of the toothbrushes used by the male students were larger than those of the toothbrushes used by the female students. The wear index and wear rate were significantly higher when the toothbrush replacement period was longer. Given the findings of the study, efficient oral health education on the right toothbrush management should be provided for college students to manage their toothbrushes properly.

Experimental and Analytical Study on the Die Wear during the Upsetting Processes (업셋팅 금형의 마모 실험 및 해석)

  • 박종남;김태형;강범수;이상용;이정환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • /
    • pp.122-130
    • /
    • 1996
  • During the cold forming, due to high working pressure acting on the die surface, failure mechanics must be considered before die design. One of the main reasons of die failure in industrial application of metal forming technologies is wear. Die wear affects the tolerances of formed parts, metal flow and costs of process etc. The only way to control these failures is to develop methods which allow prediction of die wear and costs of process etc. The only way to control these failures is to develop methods which allow prediction of die wear and which are suited to be used in the design state in order to optimize the process. In this paper, the wear experiments to abtain the wear coefficients and the upsetting processes was accomplished to observe the wear phenomenon during the cold forming process. The analysis of upsetting processes was accomplished to observe the wear phenomenon during the cold forming process. The analysis of upsetting processes was accomplished by the rigid-plastic finite element method. The result from the deformation analysis was used to analyse the die wear during the processes and the predicted die wear profiles were compared with the measured die wear profiles.

  • PDF

Wear Simulation of Engine Bearings in the Beginning of Firing Start-up cycle (파이어링 시동 사이클 초기에서의 엔진 베어링 마모 시뮬레이션)

  • Chun, Sang Myung
    • Tribology and Lubricants
    • /
    • v.35 no.4
    • /
    • pp.244-266
    • /
    • 2019
  • The purpose of this study is to estimate the wear volumes of engine journal bearings operating at variable angular velocity of a shaft in the beginning of firing start-up cycle. To do this, first we find the potential region of wear scar on engine journal bearings where the applied bearing load and crank shaft velocity are variable. The potential wear regions are discovered by finding minimum oil film thickness at every crank angle existing below most oil film thickness scaring wear (MOFTSW) obtained based on the concept of the centerline average surface roughness. Then we calculate the wear volume from the wear depth and two wear angles decided by the magnitude of each film thickness lower than MOFTSW at every crank angle. The results show that the expected wear region is located at a few bearing angles after and/or behind the upper center of a big-end bearing and the lower center of a main bearing. And the real wear region is similar to the estimated wear region. Further we find that the wear scar on an engine journal bearing may occur at re-starting time after switch-off of a start motor especially under the condition of high oil temperature.

The Effect of TiN and CrN Coatings on the Fretting Wear of Tubes against Supports in a Nuclear Steam Generators

  • Park, Dong-Shin;Park, Jung-Min;Kim, Jin-Seon;Lee, Young-Ze
    • KSTLE International Journal
    • /
    • v.10 no.1_2
    • /
    • pp.33-36
    • /
    • 2009
  • The nuclear steam generator is composed of a bundle of tubes. The length of these tubes is very long, but their diameter is small. Fluid exists inside of the steam generator and its flow causes vibration, therefore these tubes are supported by anti-vibration bars. The wear damage due to the vibration is known as fretting wear, which should be minimized to ensure the safety of the plants. Research needs to be done about decreasing the amount of fretting wear. Hard coatings have proven to be very effective in reducing the amount of wear. The commercial coatings of TiN and CrN have excellent wear resistance and are used to protect the Inconel tube from fretting wear. The tube-on-flat type tester was used for conducting the fretting wear tests. It was found that the wear amounts of the coated tubes decreased depending on the coating thickness. CrN was found to be very effective in reducing the wear, while the wear amounts were dependent on the coating thickness in the case of TiN and a thick coating of TiN was very effective on wear resistance.