• 한국공작기계학회논문집
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• 제14권3호
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• pp.122-127
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• 2005

The styling of automobile wheels and their effect on vehicle appearance has increased in importance in recent years. The wheel designer has been given the task of insuring that a wheel design meets its engineering objectives without affecting the styling theme. The wheel and tire system is considered as a vehicle component whose dynamic modal information of the tire/wheel system are employed in the modal synthesis model of the vehicle. The vibration characteristics of a automobile wheel play an important role to judge a ride comfort and quality for a automobile. In this paper, the vibration characteristics of a Al-alloy and steel wheel for automobile are studied. Natural frequency, damping and mode shape are determined experimentally by frequency response function method. Results show that wheel material property, size and design are parameter for shift of natural frequency and damping.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.47-50
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• 2003

Hot-forging Process and die design was made for a large-scale compressor wheel of Ti-6Al-4V alloy with 2-D FE analysis. The design integrated the geometry-controlled approach and dynamic materials modelling(DMM). In order to obtain the processing contour map of Ti-6Al-4V alloy based on DMM, compression tests were carried out in the temperature range of 915$^{\circ}C$ to 1015$^{\circ}C$ and the strain range of 10$\^$-3/s$\^$-1/ to 10s$\^$-1/. In the die design of the compressor wheel using the rigid-plastic FE analysis, forging dimensional accuracy, the capacity of the forging machine and defect-free forging were considered as main design factors. The microstructure of hot forged wheel using the designed die showed a typical alpha-beta structure without forging-defects.

• 한국주조공학회지
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• 제41권2호
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• pp.127-131
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• 2021

고온 환경에 대한 우수한 특성을 바탕으로 산업 장비의 고온 재료에 Ti-48Al-2Cr-2Nb 합금이 사용된다. 본 연구에서는 Ti-48Al-2Cr-2Nb 합금 터보 차저 터빈 휠을 진공 원심 주조 방법으로 제작했다. 알루미나 몰드를 이용한 원심 주조시 터보 차저 터빈 휠 블레이드의 미스런 불량을 방지하기 위한 조건을 조사하였다. 진공 원심 주조로 제조된 합금의 미세 구조는 광학 현미경 (OM), 마이크로 비커스 경도 분석기 (HV), X- 선 회절 (XRD) 및 SEM-EDS로 연구하였다. 주조된 Ti-48Al-2Cr-2Nb 합금의 경도 및 SEM-EDS 결과는 산화층 (α- 케이스)의 두께가 일반적으로 50㎛ 미만임을 보여주었다. 예열 온도 1,100oC, RPM 260, 게이트 크기가 큰 알루미나 몰드의 경우 미스런 불량이 거의 없었다. 따라서 높은 예열 온도, 중간 RPM, 큰 게이트 크기 및 알파 케이스 형성 억제를 위한 알루미나 몰드를 통해 미스런이 적은 Ti-48Al-2Cr-2Nb 합금 터보 차저 터빈 휠을 얻을 수 있음을 확인했다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.623-628
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• 2001

The styling of passenger car wheels and their effect on vehicle appearance has increased in importance in recent years. The wheel designer has been given the task of insuring that a wheel design meets its engineering objectives without affecting the styling theme. The wheel and tire system is considered as a vehicle component whose dynamic modal information of the tire/wheel system are employed in the modal synthesis model of the vehicle. The Vibration characteristics of a passenger car wheel play an important role to judge a ride comfortability and quality for a passenger car. In this paper, the vibration characteristics of a AI-alloy and steel wheel for passenger car are studied. Natural frequency, damping and mode shape are determined experimentally by frequency response function method. Results show that wheel material property, size and design are parameter for shift of natural frequency and damping.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1076-1079
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• 2001

This investigation reports the grinding characteristics of titanium alloy(Ti-6Al-4V). Grinding experiments were performed at various grinding conditions. The grinding forces and grinding force ratio were measured to investigate the grindability of titanium alloy with the Diamond and CBN wheel. To investigate the grinding characteristics of titanium alloy grinding force ratio and grinding ratio were measured. Surface profile of wheel was also measured with tracer and the ground surfaces and chip were observed with SEM. Grinding-ratio of titanium alloy was much lower than that of other materials. Grinding-ratio of titanium alloy with Diamond wheel was almost six times larger than that with CBN wheel.

• 한국주조공학회지
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• 제15권4호
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• pp.408-415
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• 1995

Polycrystalline Al-Cu ribbons were produced by planar flow casting(PFC). Solidification behavior and microstructual changes of the ribbons have been investigated as a function of ribbon thickness and processing parameters. The solidification front velocity, V varies within the ribbon, decreasing with increasing the distance, S from the wheel-contact surface, as $V=17.6S^{-1}$. In Al-4.5wt%Cu alloy, rapid decrease in solidification velocity toward the free surface causes a change in solidification morphology from planar to cellular, and finally, to dendritic. The length and inclination of columnar grains solidified with planar front were related to the wheel velocity. The transition from particulate degenerate eutectic structure to regular lamellar eutectic structure was observed to be caused by a difference of the relative growth velocites of ${\alpha}-Al$ and ${\theta}$ during solidification in the Al-Cu eutectic alloy.

• 소성∙가공
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• 제18권4호
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• pp.354-360
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• 2009

Hot-forging process and die design were made for a large-scale compressor wheel of Ti-6Al-4V alloy by using the results of 2-D FEM simulation. The design integrated the geometry-controlled approach and the processing contour map based on the dynamic materials model and the flow stability criteria. In order to obtain the processing contour map of Ti-6Al-4V alloy, compression tests were carried out in the temperature range of $915^{\circ}C$ to $1015^{\circ}C$ and the strain rate range of $10^{-3}s^{-1}$ to $10s^{-1}$. In the die design of the compressor wheel using the rigid-plastic FEM simulation, forging dimensional accuracy, the capacity of the forging machine and defect-free forging were considered as main design factors. The microstructure of hot forged wheel using the designed die showed a typical alpha-beta structure without forging-defects.

• 한국분말재료학회지
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• 제2권2호
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• pp.142-148
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• 1995

2219 aluminum alloy bonded diamond wheels containing intermetallic compounds were fabricated by powder metallurgy method. Nickel and titanium were added in aluminum matrix piece. The hot pressing condition was $600^{\circ}C$ and 20 Mpa in the furnace of the electric resistance type. The mechanical properties and grinding tests were carried out to confirm the wheel performance. Aluminum oxide ceramics were chosen for use in the grinding tests. The test proved that the heat resistance 2219 aluminum bonded diamond wheel containing 15 wt% nickel and 15 wt% titanium respectively showed the best performance.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1994년도 추계학술대회강연 및 발표대회 강연및 발표논문 초록집
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• pp.9-9
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• 1994

• 소성∙가공
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• 제16권5호통권95호
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• pp.354-359
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• 2007

Effects of forging and mechanical properties of 6061 aluminum alloy wheel for automobiles were investigated in the present study. Microstructural and tensile characteristics of automobile wheel after hot forging process using dynamic screw press were analyzed to evaluate effect of metal flow on mechanical properties. The results showed advanced mechanical properties of 6061 alloy wheel because of $Mg_2Si$ precipitation by T6, elongated grain by forging, and work hardening by dense metal flow, etc. Hot compression tests were conducted in order to characterize high temperature compression deformation behaviors and microstructural variation in the range of $300{\sim}450^{\circ}C$, in the strain rate range of $10^{-3}{\sim}10^1\;sec^{-1}$. As strain rate increased, maximum compression stress increased but it was shown the reverse linear relation between temperature and maximum stress irrelevant to strain rate variation. On the other hand, temperature and yield stress didn't have any linear relation and its relation showed big deviation by a function of strain rate and test temperature.