• Title/Summary/Keyword: die wear

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Endurance in Al Alloy Melts and Wear Resistance of Titanium Matrix Composite Shot-Sleeve for Aluminum Alloy Die-casting (Al 합금 다이캐스팅 용 타이타늄 기지 복합재료 슬리브의 내용손성 및 내마모성 평가)

  • Choi, Bong-Jae;Sung, Si-Young;Kim, Young-Jig
    • Korean Journal of Metals and Materials
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    • v.50 no.2
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    • pp.176-182
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    • 2012
  • The main purpose of this study was to evaluate the endurance against Al alloy melts and wear resistance of an in-situ synthesized titanium matrix composite (TMC) sleeve for aluminum alloy die-casting. The conventional die-casting shot sleeve material was STD61 tool steel. TMCs have great thermal stability, wear and oxidation resistance. The in-situ reaction between Ti and $B_4C$ leads to two kinds of thermodynamically stable reinforcements, such as TiBw and TiCp. To evaluate the feasibility of the application to a TMCs diecasting shot sleeve, the interfacial reaction behavior was examined between Al alloys melts with TMCs and STD61 tool steel. The pin-on-disk type dry sliding wear test was also investigated for TMCs and STD61 tool steel.

Die Life Estimation of Hot Forging for Surface Treatment and Lubricants (표면처리 및 윤활제에 따른 열간 단조 금형의 수명 평가)

  • 이현철;김병민;김광호
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.26-35
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    • 2003
  • This study explains the effects of lubricant and surface treatment on hot forging die life. The mechanical and thermal load, and thermal softening which is happened by the high temperature of die, in hot and warm forging, cause die wear, heat checking and plastic deformation, etc. This study is fur the effects of solid lubricants and surface treatment condition for hot forging die. Because cooling effect and low friction are essential to the long life of dies, optimal surface treatment and lubricant are very important to improve die life for hot forging process. The main factors, which affect die hardness and heat transfer, are surface treatments and lubricants, which are related to thermal diffusion coefficient and heat transfer coefficient, etc. For verifying these effects, experiments are performed for hot ring compression test and heat transfer coefficient in various conditions as like different initial billet temperatures and different loads. The effects of lubricant and surface treatment for hot forging die life are explained by their thermal characteristics. The new developed technique in this study for predicting tool life can give more feasible means to improve the tool life in hot forging process.

A Study on the Performance of CBN Tools in the Machining of Hardened Die-Materials by High-Speed face Milling (금형용 고경도재의 고속정면밀링 가공시 CBN 공구의 성능에 관한 연구)

  • 조성실;임근영;김태영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.26-30
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    • 1996
  • This paper presents the performance of CBN tools in the machining of hardened die-materials, SKD11 and SKD61 steel with HRC 50, by high-speed face milling. Generally, grinding or EDM is being used in machining of hardened materials but the cost is very high. If those can be replaced by cutting, it will be a greatly economical advantage. CBN tool has been recognized as an effective tool in turning, but it has not been in milling. So wear and surface roughness mode of CBN tool for hardened SKD11 and SKD61 steel were investigated by high-speed face milling in this study Also the relation between cutting force and wear mode of CBN tools was investigated.

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Adjustment of Roll Gap for the Dimension Accuracy of Bar in Hot Bar Rolling Process

  • Kim, Dong-Hwan;Kim, Byung-Min;Lee, Youngseog
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.1
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    • pp.56-62
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    • 2003
  • The objective of this study is to adjust the roll gap for the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes for round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

The Study on the Wear Corrosion Behavior of Induction Hardening High Strength Cast Iron in the pH Environments (고주파 열처리한 강인주철재의 마멸부식거동에 관한 연구)

  • Park, Yun-Sik;Lim, Uh-Joh;Park, Dong-Gi
    • Journal of the Korean Institute of Gas
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    • v.12 no.4
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    • pp.52-57
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    • 2008
  • This paper studies on the wear corrosion behavior of induction hardening high strength cast iron in the acidic environments. In a variety of pH solutions, wear corrosion behavior of GC 300 with a variety of contact pressures was investigated, and corrosion wear behavior after immersion test was considered. Also, electrochemical polarization test for GC 300 was carried out in various pH solutions. The main results are as following: In the strong acidic environment, wear corrosion rate of GC 300 appears highly and in the neutral environment is stable. Also, graphitic corrosion in the strong acidic environment occurs. The corrosion current density of GC 300 becomes high in a order of pH 1 > pH 2 > pH 4 > pH 6.5.

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Abrasive Wear Characteristics of Materials for Diesel Engine Cylinder Liner and Piston Ring (디젤엔진 실린더 라이너-피스톤 링 소재의 연삭 마멸 특성)

  • Jang, Jeong-Hwan;Kim, Jung-Hoon;Kim, Chang-Hee;Moon, Young-Hoon
    • Journal of the Korean Society for Heat Treatment
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    • v.20 no.2
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    • pp.72-77
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    • 2007
  • Abrasive wear between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. Wear by abrasion are forms of wear caused by contact between a particle and solid material. Abrasive wear is the loss of material by the passage of hard particles over a surface. From the pin-on-disk test, particle dent test and scuffing test, abrasive wear characteristics of diesel engine cylinder liner-piston ring have been investigated. Pin-on-disk test results indicate that abrasive wear resistance is not simply related to the hardness of materials, but is influenced also by the microstructure, temperature, lubricity and micro- fracture properties. In particle dent test, dent resistance stress decreases with increasing temperature. From the scuffing test by using pin-on-disk tester, scuffing mechanisms for the soft coating and hard coating were proposed and experimentally confirmed.

Characteristics of Tool Wear and Surface Roughness using for Hybrid Lubrication in Micro-Milling Process of Flexible Fine Die (플렉서블 양각금형의 마이크로 밀링가공에서 하이브리드 윤활공정에 따른 공구마멸과 표면조도 특성)

  • Kim, Min-Wook;Ryu, Ki-Teak;Kang, Myung-Chang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.6
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    • pp.30-36
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    • 2013
  • An FFD(flexible fine die) is an embossed mold that consists of a thin plate ranging from 0.6 to 3 mm in thickness. FFDs are primarily used for cutting LCD films and F-PCB sheets. In the high-speed micro-milling process of flexible fine dies, the lubrication and cooling of the cutting edges is very important from the aspect of eco machining and cutting performance. In this paper, a comparative study of tool wear and surface roughness between cutting fluid and hybrid lubrication for eco-machining of FFD was conducted for processes of high-speed machining of highly hardened material (STC5, HRC52). Especially, the incorporated fluid method for eco machining, in which the cutting performances can be simultaneously measured, was introduced. The machining results show that hybrid lubrication, instead of conventional cutting fluid, leads to excellent tool wear and surface roughness and represents the proper conditions for eco micro-machining of flexible fine dies.

A Study on the Prediction of Fatigue Life in Die (금형의 피로수명 예측에 관한 연구)

  • 여은구
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.4
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    • pp.87-92
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    • 1999
  • Generally the life of die is limited by fatigue fracture or dimensional inaccuracy originated from wear. In this paper to predict the fatigue life of die the stress and strain histories of die can be predicted by the analysis of elastic-plastic finite element method and the elastic analysis of die during the process analysis of workpiece. Also the stress-life curve of die material can be obtained through experiment. With the above to재 facts we propose the analysis method of prediction fatigue life in die,. In the proposed model the analysis of elastic-plastic finite element method for material is carried out by using ABAQUS. Surface force resulted from the contacting border of the die and workpiece is transformed into the nodal force of die to implement elastic analysis. besides the proposed analysis model of die is applied to extrusion die and forging. die.

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A Study of Electrode Wear Estimation and Compensation for EDM Drill (방전 드릴링에서 전극 소모량 예측 및 보정)

  • Lee, Cheol-Soo;Choi, In-Hugh;Choi, Young-Chan;Kim, Jong-Min;Heo, Eun-Young
    • Journal of Korean Institute of Industrial Engineers
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    • v.39 no.3
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    • pp.149-155
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    • 2013
  • Electric discharging machining (EDM) is commonly adopted to machine the precise and tiny part when it is difficult to meet the productivity and the tolerance by the conventional cutting method. The die-sinking EDM method works well to machine the micro-parts and the perpendicular wall of die and mould, whereas EDM drilling, called super drill, is excellent to machine the deep and narrow hole regardless the material hardness and the hole location. However, the electrode wear is rapid compared to the conventional cutting tool and makes it difficult to control the electrode feeding and to machine precisely. This paper presents an efficient method to estimate the electrode wear using hole pass-through experiment while the stochastic method is used to compensate for the estimation model. To validate the proposed method, the commercial EDM drill machine is used. The experiment result shows that the electrode wear amount can be predicted very precisely.