• The korean journal of orthodontics
• /
• v.28 no.3 s.68
• /
• pp.371-377
• /
• 1998

To estimate the possibility of clinical application of TiN ion-Plated Elgiloy(Co-Cr wire), measurements of tensile strength and hardness were made on the four tempers on each of the manufactured Elgiloy, the (heat-treated) Elgiloy for 30 minutes at $250^{\circ}C$ and the TiN ion-plated Elgiloy. For comparison, the tensile strength and hardness of Stainless Steel wires were also measured. The following are the results of the study: $\cdot$In the 4 tempers, tensile strength was the greatest in the TiN ion-plated group, followed by the heat-treated Elgiloy group and the manufactured Elgiloy group, but no statistical difference was noticed between heat-treated and manufactured Elgiloy groups(p>0.05). $\cdot$In each temper, tensile strength of ion-plated Elgiloy increased about $10kgf/mm^2$ in comparison with the values of the manufactured Elgiloy $\cdot$In yellow, green and red tempers except the blue, hardness was the greatest in ion-plated group. In the blue temper, there was no statistical difference between heat-treated and manufactured Elgiloy groups(p>0.05). $\cdot$In each temper, hardness of ion-plated Elgiloy increased about 50-90VHN in comparison with the values of the manufactured Elgiloy. $\cdot$The tensile strength of Stainless Steel wire was similar to that of the red temper of manufactured Elgiloy and the green temper of ion-plated Elgiloy.

• The Journal of Korean Philosophical History
• /
• no.35
• /
• pp.7-42
• /
• 2012

The Ho-Rak controversy is an internal dispute in the Kiho School. Both Ho and Rak adopt the theories of Yulgok(栗谷) as their common standard of right arguments. The controversy continues almost two hundred years after the dispute between LEE Gan(李柬) and HAN Wonjin(韓元震). However, it does not develop rich theoretical resources. The fundamental issue of Ho-Rak controversy is how to define the relation of mind(心) and temper(氣質). Ho School regard temper as material of the mind, and so they insist that mind and temper are ultimately the same. But Rak School regard temper as desire of the body, and so they insist that mind and temper are the another one. The viewpoint of Rak School does not correspond to the view of the traditional Neo-confucianism. So we should understand that mind and temper are ultimately the same. However if we define that mind and temper are the same, and they act at the same time, then we can not insure the foundation of pure goodness in human mind. LEE Chulyoung(李喆榮) defines that mind and temper are ultimately the same, but they act alternately. It is the exact definition about the relation of mind and temper.

• Journal of Mechanical Science and Technology
• /
• v.16 no.10
• /
• pp.1296-1302
• /
• 2002

A mathematical model for cold rolling and temper rolling process of thin steel strip has been developed using the influence function method. By solving the equations describing roll gap phenomena in a unique procedure and considering more influence factors, the model offers significant improvements in accuracy, robustness and generality of the solution for the thin strip cold and temper rolling conditions. The relationship between the shape of the roll profile and the roll force is also discussed. Calculation results show that any change increasing the roll force may result in or enlarge the central flat region in the deformation zone. Applied to the temper rolling process, the model can well predict not only the rolling load but also the large forward slip. Therefore, the measured forward slip, together with the measured roll force, was used to calibrate the model. The model was installed in tile setup computer of a temper rolling mill to make parallel setup calculations. The calculation results show good agreement with the measured data and the validity and precision of the model are proven.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.2
• /
• pp.408-417
• /
• 1995

A study on the surface roughness variation of work roll and strip at the temper rolling was performed. The results were obtained with changes according to the surface roughness of work roll and method to make the peak count on the roll in the temper rolling, and factors to affect to the work roll surface in actual rolling machine (ie. Temper mill). The results suggests that the electro-discharge textured roll has mere uniform roughness distribution than shot blasted roll and its life time is two times longer than shot blasted because it has more sine wave roughness, and it is possible to control the Rmax. In shot blasting method, Surface roughness is related to the impeller speed, But it can't control the peak count.

• Journal of Mechanical Science and Technology
• /
• v.15 no.2
• /
• pp.225-231
• /
• 2001

A mathematical model for the analysis of roll gap phenomena in the strip temper rolling process is described. A new approach to solve the roll indentation and diverging problem in modeling of severe temper rolling cases is obtained by adopting the preliminary displacement principle of two contacted rough bodies to describe the friction behavior in the roll gap. The mechanical peculiarities of the temper rolling process, such as a high friction value with high roughness rolls and a non-circular contact arc, low reduction and non-negligible entry and exit elastic zones as well as central preliminary displacement zone etc., are all taken into account. The deformation of work rolls is calculated with the influence function method and an arbitrary contact are shape is permitted. The strip deformation is modeled by the slab method and the entry and exit elastic deformation zones are included. The preliminary displacement principle is used to determine the boundaries and to calculate the friction of the central preliminary displacement zone. The model is calibrated against the production mill data and installed in the setup computer of a temper rolling mill in POSCO. The validity and precision of the model have been proven through a comparison of the measured roll forces and the predicted ones.

• Proceedings of the KWS Conference
• /
• 1992.04a
• /
• pp.45-47
• /
• 1992

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.505-511
• /
• 1993

The results were obtained with changes according to the surface roughness of work roll and method to make the peak count on the roll in the temper rolling, and factors to affect to the work roll surface in actual rolling machine(ie. Temper mill). Conclusions are as follows. 1. E.D.T(Electro-discharge texturing)roll is more uniform roughness distribution than shot blasted roll and it's life time is two timees longer than that of shot blasted because it has more sine wave roughness. 2. The higher peak count of surface roughness, the more time is necessary to work roll texturing In shot blasting method, Surface roughness is relating to the grit size,impeller speed and hardness of roll material, But is can't control the peak count. 3. In shot blast texturing, Surface roughness of temper rolled strip which is transfered surface roughness of work roll is more ununiform than that of E.D.T roll 4. E.D.T roll has more uniform than the shot blasted roll and has more peak count than that of shot blasted roll. The surface of painted strip to image clarity is superior to that of shot blasted roll because E.D.T roll has more peak count and smooth surface.

• KSTLE International Journal
• /
• v.2 no.1
• /
• pp.80-84
• /
• 2001

The purpose of this paper is to show the result from the study to improve the formability and appearance which is important in the cold rolled strip, the coated strip and prepainted strip. Furthermore, to give appropriate surface roughness, shape of work roll for temper mill is also important. The strip has a greater peak counts and homogeneous roughness. This makes the prepainted surface smooth and consistent in appearance with good image clarity. Therefore, the surface roughness of the work roll is very important. The reason that surface roughness of the work roll is transferred to the strip surface is the rolling farce and tension at the temper rolling or cold rolling. This study is classified in order to get an accurate and homogeneous roughness. There are few papers published in this field, because its importance is not known and the proper operation of the machine is not generally well known. This paper investigates the correlation between strip surface roughness and the surface of the work roll. After studying the surface roughness and shape according to the texturing method for roll surfaces at temper rolling, the findings were as follows. Irregular surface roughness can be compensated with several paint coatings, but this also makes the quality deteriorate and manufacturing costs go up.

• Journal of the Korean Society for Heat Treatment
• /
• v.34 no.1
• /
• pp.1-9
• /
• 2021

The martensitic stainless steel has excellent corrosion resistance and higher strength by quenching and tempering heat treatment. It has been widely used as blade material due to these properties. The hardness and impact toughness of martensitic stainless steel depended strongly on tempering temperatures. The 12Cr martensite stainless steel (SS 410) tempered about 540℃ showed temper embrittlement. To know cause of temper embrittlement in terms of phase identification, a detailed analysis of electron diffraction patterns during TEM observations has been carried out on the <110>α-Fe and <113>α-Fe zone axes for temper embrittlement specimen. The double electron diffraction spots at 1/3(211) and 2/3(211) positions were observed. The lattice space between individual diffraction spots was about 3.5 Å and this value coincide with three times to α-bcc lattice space (1.17 Å). The area which found double diffraction spots was judged metastable "zone" similar to the omega phase and induced embrittlement of SS410 material.

• KSTLE International Journal
• /
• v.2 no.2
• /
• pp.133-137
• /
• 2001

This paper investigates the correlation between strip surface roughness and the surface of the work roll. As the actual temper mill(TM) is used, this data will be adopted to another actual temper mill for the application and operation of this experiment. Conclusions are as follows: Electro-discharge texturing(EDT) roll has homogeneous roughness distribution and shape, and also a sinuous peak surface and the life is 2 times longer than that of shot blast texturing(SBT) method. And the higher surface roughness of work roll, the more time is necessary at the EDT method. In the SBT method without the correlation of roughness, but impeller rotation speed with an uncontrollable peak count. The roughness of SBT roll is irregularity compared to that of EDT roll because the work roll roughness is transferred to the strip which was temper rolled, and produces a more desirable image and greater clarity to the color painted steel sheet.