• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.5
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• pp.924-931
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• 2002

Vacuum interrupters in order to be used in various switch-gear components such as circuit breakers, distribution switches, contactors, etc. spread the arc uniformly over the surface of the contacts. The electrodes of vacuum interrupters are made of sinter-forged Cu-Cr materials for good electrical and mechanical characteristics. Since the closing velocity is 1-2m/s and impact deformation of the electrode depends on the strain rate at that velocity, the dynamic behavior of the sinter-forged Cu-Cr is a key to investigate the impact characteristics of the electrodes. The dynamic response of the material at the high strain rate is obtained from the split Hopkinson pressure bar test using disc-type specimens. Experimental results from both quasi-static and dynamic compressive tests are Interpolated to construct the Johnson-Cook model as the constitutive relation that should be applied to simulation of the dynamic behavior of the electrodes. The impact characteristics of a vacuum interrupter are investigated with computer simulations by changing the value of five parameters such as the initial velocity of a movable electrode, the added mass of a movable electrode, the wipe spring constant, initial offset of a wipe spring and the virtual fixed spring constant.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.563-564
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• 2006

The effect of different cooling rate on the structure and mechanical properties of Fe-3%Mn-(Cr)-(Mo)-0.3%C steels is described. Pre-alloyed Astaloy CrM and CrL, ferromanganese and graphite were used as the starting powders. Following pressing in a rigid die, compacts were sintered at $1120^{\circ}C$ and $1250^{\circ}C$ in $H_2/N_2$ atmospheres and cooled with cooling rates $1.4^{\circ}C/min$ and $6.5^{\circ}C/min$. Convective cooled specimens were subsequently tempered at $200^{\circ}C$ for 60 and 240 minutes.

• Resources Recycling
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• v.17 no.6
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• pp.57-61
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• 2008

The aim of this study is to produce the coke which can be used for the production of ferroalloy, by mixing phenolic resin and anthracite and sintering it. The influence of factors on the strength of coke were investigated. The results of this study are as follows: It is found that the anthracite coke of $100{\sim}150\;kgf/cm^2$ strength for ferroalloy can be made by a series of process as follows; Mixing homogeneously 6% liquefied phenolic resin and 6% water with $35{\sim}325$ mesh anthracite of low ash content. Making pellet by press the mixture in $10-50\;kgf/cm^2$ pressure. Dehydrating the pellet for 6 hrs at $50^{\circ}C$, and hardening it for 180 min at $200^{\circ}C$. Sinter the mixture for 6 hrs at $1,200^{\circ}C$.