• International Journal of Automotive Technology
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• v.6 no.3
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• pp.259-268
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• 2005

In order to analyze the sheet drawability, the measurement of the plastic strain ratio was carried out for the 5182 aluminum alloy sheets in which were cold rolled without lubrication and subsequent recrystallization annealing. The average plastic strain ratio of the 5182 aluminum sheets was 1.50. It was considered that the higher plastic strain ratio was resulted from the ND//<111> component evolved during rolling and maintained during annealing. The AA5182/polypropylene/AA5182 (AA/PP/AA) sandwich sheets of the 5182 aluminum alloy skin sheet and the polypropylene core sheet with high formability have been developed for application for automotive body panels in future light weight vehicles with significant weight reduction. The AA/PP/AA sandwich sheets were fabricated by the adhesion of the core sheet and the upper and lower skin sheets. The AA/PP/AA sandwich sheet had high plastic strain ratio (1.58), however, the planar anisotropy of the sandwich sheet was little changed after fabrication. The optimum combination of directionality of the upper and lower skin sheets having high plastic strain ratio and low planar anisotropy was calculated theoretically and an advanced process for producing the sandwich sheets with high plastic strain ratio was proposed. The developed sandwich sheets have a high average plastic strain ratio of 1.55 and a low planar anisotropy of 0.17, which was improved more by 3.2 times than that of 5182 aluminum single sheet.

• Transactions of Materials Processing
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• v.28 no.5
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• pp.281-286
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• 2019

The plastic strain ratio is one of the factors of the deep drawability of metal sheets. The plastic strain ratio of Al sheet is low value. Therefore, it is necessary to increase the plastic strain ratio in order to improve the deep draw ability of the Al sheet. This study investigated the increase of the plastic strain ratio and the texture change of AA3003 sheet after the hot asymmetric rolling. The average plastic strain ratio of the initial AA3003 sheets was 0.69. After 83% hot asymmetric rolling at $200^{\circ}C$, the average plastic strain ratio was 0.83. The average plastic strain ratio of the 83% hot asymmetrically rolled AA3003 sheet at $200^{\circ}C$ is 1.2 times higher than that of the initial AA3003 sheet. The ${\mid}{\Delta}R{\mid}$ of 83% hot asymmetrically rolled AA3003 sheet at $200^{\circ}C$ is 0.83 times lower than that of the initial AA3003 sheet. This result is due to the development of the intensity of ${\gamma}-fiber$ texture and reduces the intensity of {001}<110> and {001}<100> textures after hot asymmetric rolling of AA3003 sheet.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.92-95
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• 2003

Asymmetric rolling of AA1050 Al alloy sheets was performed to obtain the shear textures for improving the deep drawability and the grain refinement. The effect of roll velocity ratio on the texture and the grain refinement of 50％ asymmetrically rolled sheets was studied. The textures of the asymmetrically rolled sheets after annealing at 400$^{\circ}C$ for 1 h was also investigated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.112-115
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• 1999

The effect of intermediate annealing on the texture evolution in I.f steel was investigated by using X-ray texture measurement. After The sample was cold rolled to 80% reduction intermediate annealing was introduced to preform ${\gamma}$-fiber orientation grains in deformed matrix. The annealing time was varied between 30 and 3600 sec, These samples were cold rolled to 90% reduction and full annealed. By intermediate annealing final full annealed samples had very homogeneous ${\gamma}$-fiber orientation resulting in good deep drawability.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.252-255
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• 1998

PVA(Poly Vinyl Alcohol)는 폴리에틸렌과 함께 최고 수준의 결정 탄성율(250~300 GPa)을 보유하고 있고, 이론적으로 높은 기계적 특성을 지녔기 때문에 초연신에 의한 고강도 고탄성율 섬유를 얻을 가능성이 매우 크다. 그러나 분자에 많이 존재하는 -OH기에 의한 강력한 분자내 및 분자간 수소결합 때문에 융점이 228~25$0^{\circ}C$ 정도로 높은 편이라는 장점이 있는 반면, 연신이나 열처리동안 분자 사슬의 alRMfj짐이나 재배열이 입체장애로 방해를 받아서 충분히 배향시키는데 상당한 어려움이 있다. (중략)

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.71-74
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• 2008

The clad sheet is the sheet metal that joined the one or more material with the different property by rolling process. In this study, it is investigated about the mechanical property or formability of SUS-Al-Mg clad sheet. The clad sheet was formed at elevated temperature because of their poor formability at room temperature. The tensile test was confirmed at various temperature and the reduction of strain rate above $250^{\circ}C$. LDR(Limited Drawing Ratio) was obtained through deep drawing test to confirm the formability of the clad sheet. The FE analysis is performed to compare prototype products.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.348-349
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• 2003

PVA는 열가소성 고분자임에도 불구하고 융점(230~25$0^{\circ}C$)에 이어 바로 측쇄의 분해(270 $^{\circ}C$)가 시작되므로 공정상 많은 어려움을 가지고 있다. 그러나 요드와 같은 극성의 가소제를 사용하면 결정영역 까지도 가소화 시킬 수 있는 이점이 있어 PVA 유연성, 가공성 둥의 성질을 개선시킬 수 있다. [1-3] 특히 본 연구에서 성형 전 요드화된 폴리비닐알코올 필름을 제작하여 구조를 살펴본 결과, 결정성이 많이 감소하다가 요드흡착량이 150%의 경우에서는 무정형상태까지 나타났다. (중략)

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.117-120
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• 2003

Warm deep drawing which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical cup drawing of Mg-alloy sheet metal. In experiments the temperature of die and blank holder is varied from room temperature to $300^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch corner area. Test material chosen for experiments is AZ31 magnesium sheet metal. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio as well as thickness distributions of drawn cups are investigated and validity of warm deep drawing process is also discussed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.4
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• pp.6-11
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• 2002

Formability in deep drawing process depends not only on a drawability of workpiece material but also on process conditions such as die punch comer radius, lubricant conditions, punch-die clearance etc. For instance, bending resistance should be reduced by increasing die round appropriately, drawing load should be minimized by improving the lubricant condition between die and material, and blanking load should be increased by selecting a pertinent punch round and by augmenting the friction resistance in punch. In this study, a multi-stage deep drawing process is analyzed using ABAQUS. The effects of formability factors, such as die shoulder radius, punch-die clearance and friction coefficient are investigated, and the results are also discussed in detail.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1410-1413
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• 2004

Finite element method is very effective method to simulate the forming processes with good prediction of the deformation behaviour. For the finite element modeling of sheet mental forming the accurate tool model is required. Due to the geometrical complexity of real-size part stamping tools it is hard to make FE model for real-size auto-body stamping parts. In this paper, it was focussed on the drawability factors on auto-body panel stamping by AUTOFORM with using tool planning alloy to reduce law price as well as high precision from Design Optimization of die. According to this study, the results of simulation will give engineers good information to access the Design Optimization of die.