• 제목/요약/키워드: Wear

검색결과 7,437건 처리시간 0.04초

구상흑연주철의 고압하 마멸특성에 미치는 합금원소의 영향 I-Cu, Mn (Effects of Alloying Elements on the High Pressure Wear Characteristics of Ductile Cast Iron I-Cu, Mn)

  • 방웅호;강춘식;박재현;권영각
    • 한국주조공학회지
    • /
    • 제20권4호
    • /
    • pp.230-239
    • /
    • 2000
  • High pressure wear characteristics of DCI(Ductile Cast Iron) were investigated through unlubricated pin-on-disc wear test. Wear test were carried out at speed of 23m/min, under pressure of 3MPa and 3.3 MPa. Cu and/or Mn were added to examine the effect of alloying elements on the high pressure wear characteristics of DCI. To investigate the relationship between wear characteristics and mechanical properties of DCI, Brinell hardness and V-notched Charpy impact energy were tested. Wear surface of each specimen was observed by SEM to determine the wear mechanism of DCI under high pressure wear condition. In the mild wear region, wear characteristics of alloyed DCI specimens were very similar to that of unalloyed DCI. But mild-severe wear transition was occurred at different wear distance and wear rate of DCI specimens were changed by alloying elements. In severe wear condition, wear rate of DCI was dramatically increased by the addition of Mn. Although the addition of Cu 0.46wt% did not decrease the wear rate of DCI in the severe wear region, but it delayed the mild-severe wear transition. Under high pressure wear condition, wear rate and mild-severe wear transition were not concerned with hardness of DCI specimens, but they were deeply associated with impact energy changed by alloying elements.

  • PDF

이온 주입한 강의 미시적 마모 튼성의 평가 (Development of methodology for evaluating tribological properities of Ion-implanted steel)

  • 문봉호;최병영
    • 한국정밀공학회지
    • /
    • 제14권9호
    • /
    • pp.146-154
    • /
    • 1997
  • Ion implantation has been used successfully as a surface treatment technology to improve the wear. fatigue and corrosion resistances of materials. A modified surface layer by ion implantation is very thin(under 1 m), but it has different mechanical properties from the substrate. It has also different wear characteristics. Since wear is a dynamic phenomenon on interacting surfaces with relative motion, an effective method for investigtating the wear of a thin layer is the observation of wear process in microscopic detail using in-situ system. The change of wear properties produces the transition of wear mode. To know the microscopic wear mechanism of this thin layer, it is very important to clarify its microscopic wear mode. In this paper, using the SEM and AFM Rribosystems as in-situ system, the microscopic wear of Ti ion-implanted 1C-3Cr steel, a material for roller in the cold working process, was investigated in repeated sliding. The depth of wear groove and the speciffc wear amount were changed with transition of microscopic wear mode. The depth of wear groove with friction cycles in AFM tribosystem and specific wear amount of Ti ion-implanted 1C-3Cr steel were less about 2-3 times than those of non-implanted 1C-3Cr steel. The microscopic wear mechansim of Ti ion-implanted 1C-3Cr steel was also clarified. The microscopic wear property was quantitatively evaluated in terms of microscopic wear mode and specific wear amount.

  • PDF

측정된 마모 깊이와 시간에 의해 역으로 계산된 마모상수를 이용한 마모 깊이 예측 (A Method to Predict Wear Depth Using Inversely Calculated Wear Constants from Known Wear Depth and Time)

  • 이용선;김태순;박치용;부명환;이창섭
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2003년도 춘계학술대회
    • /
    • pp.178-188
    • /
    • 2003
  • The wear of steam generator tubes is due to the vibration occurred between tubes and tube supporters. To predict the future wear depth, the wear constants of the impact and the sliding model is used. The wear constants, 3C/2 and K/3H, are found inversely from known wear depth and time. Using these constants, the future wear depths are found from two bodies that deform the elliptical shape. The results are compared with the measured wear depth of steam generator tubes in a nuclear power plant. The results show that the predicted wear depth envelopes the measured wear depth.

  • PDF

Ferrography에 의한 마멸분 정량분석

  • 오성모;이봉구
    • 대한기계학회논문집A
    • /
    • 제24권10호
    • /
    • pp.2420-2427
    • /
    • 2000
  • In contacting between surface, there is wear and the generation of wear particles. The particles contained in the lubricating oil carry detailed and important information about the condition monitoring of the machine. Therefore, This paper was undertaken for Ferrography system of wear debris generated from lubricated moving machine surface. The lubricating wear test was performed under different experimental conditions using the Falex wear test of Pin and V-Block type by Ti(C,N) coated. It was shown from the test results that wear particle concentration(WPC) ; wear severity Index(IS) and size\distribution have come out all the higher value by increases sliding friction time. By the Ferrogram a thin leaf wear debris as well as ball and plate type wear particles was observed.

급속응고법으로 제조한 과공정 Al-Si합금분말 압출재의 마멸특성 (Wear Characteristics of the Extruded Bars of Hypereutectic Al-Si Alloy Powders produced by Rapid Solidification Process)

  • 안영남;조규섭;나형용
    • 한국주조공학회지
    • /
    • 제14권5호
    • /
    • pp.447-454
    • /
    • 1994
  • Wear resistance and wear mechanism of hypereutectic Al-($15{\sim}40$)wt%Si alloys were investigated. Primary Si particles under $20{\mu}m$ size were formed in hypereutectic Al-Si alloy powders due to rapid solidification. But the Si particles of extruded bars were finely distributed in smaller size than that of atomized powders. The wear mechanism of hypereutectic Al-Si alloys was divided into three types of wear phenomena, which were abrasive wear, delamination wear and severe adhesive wear according to sliding speed and load. At low sliding speed and load, wear mechanism was abrasive wear, so Al-15wt%Si alloy showed the best wear resistance. At high sliding speed and load, wear mechanism was adhesive wear, and Al-40wt%Si alloy showed the best wear resistance.

  • PDF

마멸모델을 이용한 금형마멸 예측에 관한 연구 (A Study on the Prediction of Die Wear using Wear Model)

  • 박종남
    • 한국기계가공학회지
    • /
    • 제12권1호
    • /
    • pp.90-96
    • /
    • 2013
  • 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 which are suited to be used in the design state in order to optimize the process. In this paper, the wear experiments to obtain 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 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.

충격 프레팅에 의한 증기발생기 세관 마모손상 진행모델 (Wear Progress Model by Impact Fretting in Steam Generator Tube)

  • 이정근;박치용;김태룡;조선영
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2007년도 춘계학술대회A
    • /
    • pp.1684-1689
    • /
    • 2007
  • Fretting wear is one of the important degradation mechanisms of steam generator tubes in the nuclear power plants. Especially, impact fretting wear occurred between steam generator tubes and tube support plates or anti-vibration bar. Various tests have been carried out to investigate the wear mechanisms and to report the wear coefficients. Those are fruitful to get insight for the wear damage of steam generator tubes; however, most wear researches have concentrated on sliding wear of the steam generator tubes, which may not represent the wear loading modes in real plants. In the present work, impact fretting tests of steam generator tube were carried out. A wear progression model for impact-fretting wear has been investigated and proposed. The proposed wear progression model of impact-fretting wear is as follows; oxide film breaking step at the initial stage, and layer formation step, energy accumulation step and finally particle torn out step which is followed by layer formation in the stable impact-fretting progress. The wear coefficient according to the work-rate model has been also compared with one between tube and support.

  • PDF

마멸모델을 이용한 금형마멸 예측에 관한 연구 (A Study on the Prediction of Die Wear using Wear Model)

  • 박종남
    • Design & Manufacturing
    • /
    • 제7권1호
    • /
    • pp.28-33
    • /
    • 2013
  • 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. The mechanisms of wear are consisted of adhesion, abrasion, erosion and so on. Die wear affects the tolerances of formed parts, metal flow, and costs of process. The only way to control these failures is to develop a prediction method on die wear suitable in the design state in order to optimize the process. The wear system is used to analyse 'operating variables' and 'system structure'. In this study, with AISI D2, AISI 1020, AISI 304SS materials, a series of the wear experiments of pin-on-disk type to obtain the wear coefficients from Archard's wear model and the upsetting processes are carried out to observe the wear phenomenon during the cold forming process. The analysis of upsetting processes are performed by the rigid-plastic finite element method. The result of the analysis is used to investigate the die wear the processes, and the analysis simulated die wear profiles are compared with the experimental measured die wear profiles.

  • PDF

충격 프레팅에 의한 증기발생기 세관 마모손상 진행모델 (Wear Progress Model by Impact Fretting in Steam Generator Tube)

  • 박치용;이정근;김태룡
    • 대한기계학회논문집A
    • /
    • 제32권10호
    • /
    • pp.817-822
    • /
    • 2008
  • Fretting wear is one of the important degradation mechanisms of steam generator tubes in the nuclear power plants. Especially, impact fretting wear occurred between steam generator tubes and tube support plates or anti-vibration bar. Various tests have been carried out to investigate the wear mechanisms and to report the wear coefficients. Those are fruitful to get insight for the wear damage of steam generator tubes; however, most wear researches have concentrated on sliding wear of the steam generator tubes, which may not represent the wear loading modes in real plants. In the present work, impact fretting tests of steam generator tube were carried out. A wear progress model for impact-fretting wear has been investigated and proposed. The proposed wear progress model of impact-fretting wear is as follows; oxide film breaking step at the initial stage, and layer formation step, energy accumulation step and finally particle torn out step which is followed by layer formation in the stable impact-fretting progress. The wear coefficient according to the work-rate model has been also compared with one between tube and support.

마모해석을 위한 고유치해석과 Adaptive Meshing 알고리듬을 이용한 수치해석 비교 (A Comparative Study on Eigen-Wear Analysis and Numerical Analysis using Algorithm for Adaptive Meshing)

  • 장일광;장용훈
    • Tribology and Lubricants
    • /
    • 제36권5호
    • /
    • pp.262-266
    • /
    • 2020
  • Herein, we present a numerical investigation of wear analysis of sliding systems with a constant speed subjected to Archard's wear law. For this investigation, we compared two methods: eigen-wear analysis and adaptive meshing technique. The eigen-wear analysis is advantageous to predict the evolution of contact pressure due to wear using the initial contact pressure and contact stiffness. The adaptive meshing technique in finite element analysis is employed to obtain transient wear behavior, which needs significant computational resources. From the eigen-wear analysis, we can determine the appropriate element size required for finite element analysis and the time increment required for wear evolution by a dimensionless variable above a certain value. Since the prediction of wear depends on the maximum contact pressure, the finite element model should have a reasonable representation of the maximum contact pressure. The maximum contact pressure and wear amount according to this dimensionless variable shows that the number of fine meshes in the contact area contributes more to the accuracy of the wear analysis, and the time increment is less sensitive when the number of contact nodes is significantly larger. The results derived from a two-dimensional wear model can be applied to a three-dimensional wear model.