• 한국자동차공학회논문집
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• 제2권2호
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• pp.95-102
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• 1994

Aluminum sheet application to automobile body panels has now become an important objective to meet the requirements of automobile weight reduction. As the Mg content in Al-Mg based alloys increased up to 7.19%, the strength and elongation increased. For instance. Al-7.19Mg alloy had a high strength of 305MPa and a high elongation of 35%. A study was also made to investigate the interrelation between grain size and tensile properties with varying the contents of Mg, Ti and Zr elements and annealing conditions. The yield stress decreased as the grain size increased, which increased the uniform elongation. The strain hardening exponents n increased as the Mg content increased, which depended on the increasing difficulties of the cross slip of dislocation.

• 한국식품과학회지
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• 제34권6호
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• pp.1023-1029
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• 2002

본 연구는 천연전분과 hydroxypropyl화 전분에 가소제를 0, 16, 33, 50, 66% 비율로 첨가하여 RVA점도를 측정하고 필름을 제조한 후 물성을 측정하여 두 물성 사이의 상관관계를 알아보고자 행하였다. 필름의 인장강도는 가소제의 함량이 높아질수록 감소하였고 신장율과 수증기투과도는 증가하였으며 glycerol이 sorbitol보다 큰 변화를 보이는 것으로 나타났다. Hydroxypropyl화 전분이 천연전분에 비해 강도는 떨어지나 신장율은 높아지는 것으로 나타났고 수증기투과도는 2배 큰 것으로 나타났다. 가소제를 혼합하여 필름의 물성을 측정한 결과 sorbitol은 유연성보다는 필름의 강도를 유지하는 역할을 그리고 glycerol은 필름의 신장율을 증가시키는 역할을 하는 것으로 나타났다. RVA물성과 필름 물성의 관계에서 가장 연관성이 높은 것은 peak viscosity, 인장강도, 수증기투과도인 것으로 판명되었고 peak viscosity와 인장강도, peak viscosity와 수증기투과도의 관계는 각각 직선적인 것으로 나타났다. 따라서 RVA 물성 중 peak viscosity를 활용하여 필름의 인장강도, 수증기투과도를 예측할 수 있다고 판단되었다.

• 동력기계공학회지
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• 제12권3호
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• pp.72-77
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• 2008

This study was investigated to know the effect of Cu addition on austempered ductile cast iron at various temperatures and times. Test results showed that the volume fraction of retained austenite and the carbon contents of retained austenite showed the greatest value at $400^{\circ}C$. Also, in case of specimens having more Cu contents, the volume fraction of retained austenite and the carbon contents of retained austenite showed the lower value. After austempering treatment, tensile strength and Impact value increased, but elongation decreased. With increasing austempering treatment temperature, tensile strength, elongation, and impact value decreased. In case of specimen having more Cu contents, tensile strength showed the higher value, but elongation showed the lower value. Damping capacity was decreased by austempering treatment and was not affected on austempering temperature and time. In case of specimen having more Cu contents, damping capacity showed the higher value.

• 한국응용과학기술학회지
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• 제37권5호
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• pp.1248-1256
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• 2020

In this study, the polyurethane resin was synthesized by applying PTMG and DMBA of different composition ratios for the synthesis of water-dispersible polyurethane used in wound coating resin. The varying properties of the synthesized water-dispersible polyurethane were measured through tensile strength, elongation, and abrasion resistance analysis. As for the tensile strength measurement result according to the PTMG content, the sample with the highest reaction molar ratio was measured as 1.08 kgf/mm2 and the elongation was measured as 520%. As for the tensile strength result according to the DMBA content, the sample with the highest reaction molar ratio was measured as 0.51 kgf/mm2, and the elongation was measured as 435%. The degree of surface destruction by the abrasion resistance measurement was visually confirmed through SEM.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 제2회 박판성형심포지엄 논문집 박판성형기술의 현재와 미래
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• pp.121-130
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• 1998

In order to analyze the forming characteristics of laser welded tailored blanks, laser welded blanks of different thickness and strength combinations were prepared and tensile, stretching, stretch flanging and deep drawing tests were done. The tensile elongation perpendicular to the weld line, stretching and stretch flanging formability decreased with increasing the deformation restraining force (strength ${\times}$ thickness) ratio between two welded sheets. The tensile elongation along weld line reached a value above 90% of the single sheet's elongation. Stretch flanging formability was reduced to approximately 10% of the single sheet value when the deformation restraining force ratio between two welded sheets was increased to two. Weld line movement of deep drawing test specimens was also affected by the strength ratio of the combined sheets, the weld line location and forming conditions. In all forming modes of tailored blanks, excessive weld line movement resulted from strain concentrations at the weaker sheet and resulted in fracture of the weaker side.

• 열처리공학회지
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• 제10권2호
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• pp.109-120
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• 1997

Microstructure and mechanical properties of Fe-Si-Mn-P high strength steel sheet have been investigated by controlling the cooling rate. Bainite and ferrite were obtatined by annealing in the ferrite pluse austenite region, and ferrite and austenite were obtatined after annealing in the fully austenite region. Ferrite and pearlite were obtained when the cooling rate was controlled from the annealing temperature above $760^{\circ}C$ and bainite showed with increasing cooling rate, however below $760^{\circ}C$ ferrite and bainite were obtained. Tensile strengths and hardness nearly unchanged with increasing cooling rate after control the cooling rate from the temperature above $760^{\circ}C$, while tensile strengths increased and elongation decreased with increasing cooling rate when the cooling rate was controlled from the tempeature below $760^{\circ}C$. Without regard to annealing temperature, tensile strength increased and elongation decreased with increasing cooling rate. Tensile strengths and elongation values heat treated in the ferrite plus austenite region were higher than those in the fully austenite region. Retained austenite and strength-elongation balance showed the maximum value at $780^{\circ}C$ and decreased with increasing annealing temperature. Strength-elongation balance value was controlled by the retained austenite.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.410-413
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• 2008

In this study, we compare the mechanical properties of forged and machined bushings for an excavator track chain. The manufacturing process is explained in detail together with the procedure of making the specimens. The longitudinal tensile strength and elongation and the radial ring compression strength are measured for this comparison. It has been shown that the forged is much better than the machined with regard to both longitudinal tensile strength and radial ring compression strength but that both are the same in terms of longitudinal elongation.

• 대한금속재료학회지
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• 제48권7호
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• pp.598-604
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• 2010

Tensile tests are widely used for evaluating mechanical properties of materials including flow curves as well as Young's modulus, yield strength, tensile strength, and yield point elongation. This research aims at analyzing the plastic flow behavior of high strength steels for automotive bodies using the finite element method in conjunction with the viscoplastic model considering the yield point elongation phenomenon. The plastic flow behavior of the high strength steel was successfully predicted, by considering an operating deformation mechanism, in terms of normalization dislocation density, and strain hardening and accumulative damage of high strength steel using the modified constitutive model. In addition, the finite element method is employed to track the properties of the high strength steel pertaining to the deformation histories in a skin pass mill process.

• 한국의상디자인학회지
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• 제15권3호
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• pp.33-40
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• 2013

This paper focused on investigating the seam strength by cutting direction depending on the fabrics and weave by comparing the tensile strength and elongation of bias, warp and weft of 4 kinds of find cotton fabrics and combining 6 kinds of seam cutting directions. The cutting directions are selected the warp direction, weft direction and 45-degree bias direction. Then, three kinds of directions, the warp/warp direction, the weft/weft direction and the bias/bias directions, and the three different kinds of directions, the warp/weft direction, the warp/bias direction and the weft/bias directions, were finally selected. The results are as follows: The tensile strength of all fabrics was higher in the order of warp, bias and weft direction and tensile elongation was higher in the order of bias, warp and weft direction in almost all fabrics. 100's and 150's cotton fabrics showed the highest seam strength when they were cut in the bias/bias direction. The seam strength of the fabrics cut in the same direction was the highest in the fabrics cut in the bias/bias direction. Four kinds of fabrics demonstrated the similar seam strength. However, for the seam strength of fabrics cut in the different directions, 100's cotton fabrics had the difference of seam strength by direction and weave, but 150's cotton fabrics didn't have any difference in seam strength by direction and weave. As described above, the seam strength was influenced by the cutting direction of fabrics. Accordingly, the seam strength can be improved by changing the cutting direction of seam when making the clothing.

• 열처리공학회지
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• 제11권4호
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• pp.295-304
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• 1998

The effects of retained austenite and carbon content in the retained austenite on the tensile strength-elongation balance and spot weldability of TRIP high strength steel sheet have been investigated. The retained austenite of granular type increased with increasing intercritical annealing and austempering temperature, and film type was increased with the increase of austempering time. The volume fraction of retained austenite increased with decreasing intereritical annealing temperature, and the maximum value was obtained at austempering temperature of $400^{\circ}C$. The values of tensile strength-elongation balance increased with decreasing intercritical annealing temperature and maximum value was obtained at austempering temperature of $400^{\circ}C$. The maximum value of tensile strength-elongation balance was obtained at a retained austenite content of about 12%. Tensile shear strength of the specimens with retained austenite was higher than that of the normalizing specimens. With increasing welding current and time, the tensile shear strengh and nugget diameter increased, while nugget thickness showed the peak value and then decreased. The optimum range of welding condition at the given welding pressure of 350kgf was 7~11kA and 10~15 cycles.