• Title/Summary/Keyword: rolled sheet

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CATALYTIC MEMBRANE REACTOR FOR DEYDROGENATION OF WATER VIA GAS-SHIFT

  • Tosti, Silvano;Castelli, Stefano;Violante, Vittorio
    • Proceedings of the Membrane Society of Korea Conference
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    • 1999.07a
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    • pp.43-47
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    • 1999
  • Pd-ceramic composite membranes and catalytic membrane reactors(CMR) have been studied for hydrogen purification and recovery in th fusion reactor fuel cycle. The development of techniques for coating microporous ceramic tubes with Pd and Pd/Ag layers is described: composite membranes have been produced by electroless deposition (Pd/Ag film of 10-20${\mu}{\textrm}{m}$) and rolling of thin metal sheet (Pd and Pd/ Ag membranes of 50-70 ${\mu}{\textrm}{m}$). Experimental results on electroless membranes showed that the metallic film presented some defects and the membranes had not complete hydrogen selectivity . Then the catalytic membrane reactors with electroless membranes can be applied for some industrial processes that do not require a complete separation of the hydrogen (i.e. in the dehydrogenation of hydrocarbons). The rolled thin Pd/Ag membranes separated the hydrogen from the other gas with a complete selectivity and exhibited a slightly larger (about a factor 1.7) mass transfer resistance with respect to the electroless membranes. Experimental tests confirmed the good performances in terms of durability.

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A Study on the Effects of Products Section by Cutting Punch's Edge Angle during Roll Forming Process (롤 포밍 공정에서 컷팅 펀치 인선 각도가 제품 절단에 미치는 영향에 관한 연구)

  • Cheong, Mun-Su;Kim, Sei-Whan;Lee, Chun-Kyu
    • Design & Manufacturing
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    • v.10 no.2
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    • pp.44-49
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    • 2016
  • The roll forming produces mass products using the continuous production process. Also we need the process that continuous long material or goods cutting into a desired length. Our study uses 3-D driving cutter and roll forming material as SPCC to investigate this. When we cut the material using the process of roll forming, the shear resistance is raised at the cutting punch's edge. The result is remained the trouble about burr and progressive deformation on the material. This study shows the method minimizing the above trouble. The material of punch was considering heat generated on the continuous production process. So we used the type of STD 61 for the material of punch and had the vacuum heat treatment for the surface hardness of HRC 53. The structure of the mold is designed with forming a double cam die at the upper punch and the both sides of central core. We conducted the experiment three times. In the result when had to make V-groove within the angle between 105 and 110 on the punch front end, we could get the minimum shear resistance on the punch front end. Also with the same condition we minimizes the material jams in the continuous production process.

Annealing Textures and Grain Size of Tantalum Sheet (탄탈륨 판재의 어닐링 집합조직과 결정립 크기)

  • Kang, J.Y.;Park, S.;Park, J.Y.;Park, S.J.;Song, Y.H.;Park, S.T.;Kim, G.L.;Oh, K.W.
    • Transactions of Materials Processing
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    • v.28 no.5
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    • pp.247-256
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    • 2019
  • In this study, the development of annealing textures in cold rolled and annealed tantalum sheets was analyzed using electron backscatter diffraction. At $900^{\circ}C$, the textures of the recrystallized grains in the partially and completely recrystallized microstructures displayed significant similarities. The average diameter of the recrystallized grains with ${\gamma}-fiber$ orientations exceeded that of grains with different orientations, and the average growth rates were unrelated to the orientations after an initial stage of recrystallization. Additional cold rolling and annealing was done for controlled initial microstructures and textures inherited from various processes of prior cold rolling and annealing. This second cycle of the process resulted in stronger textures with major ${\gamma}-fiber$ orientations as a result of the enhanced ${\gamma}-fiber$ orientations in the preceding textures. A coarse-grained prior microstructure resulted in a weaker annealing texture than a fine grained one regardless of the stronger previous texture, which was occasioned by the sub-structures of the minor orientations at local deformation inhomogeneities such as sharp in-grain shear bands.

A Study on Characteristics of Automatic Flatness Control System of Contact Type (접촉식 자동 형상제어 장치의 특성에 관한 연구)

  • Kim, Moon-kyung;Jeon, Eon-chan;Kim, Soon-kyung
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.5
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    • pp.67-73
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    • 1996
  • The necessity for more accurate automatic flatness control(AFC) system has increased of customers' requirement for cold rolled steel sheet. Therefore, many cold rolling mills replaced its AFC system with a measuring roll of the contact type form the non-contact type. In this paper. The performance of AFC system of contact type has been investigated under industrial conditions. It has two kinds of actuator: roll bender, spot cooling system. The test results are as follows: The more strip thickness is thick, the smaller the I value, and the more it is thin, the bigger the I value. And a complex distribution of strip tension was controlled, for example, not only a pocket wave but also a simple center wave and edge wave. Because the tension deviation is larger at acceler- ation speed and decelerationspeed than steady speed, AFC system of contact type is better to adopt over 50m/mim. AFC system reduces rapidly large flatness deviation. The maximum I value of strip has been decreased to 13 I, and sticker, defects caused by poor flatness, have been decreased about 60%.

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The Crystallographic and Magnetic Properties of $Fe_{1-x}Co_x$System ($Fe_{1-x}Co_x$계의 결정구조와 자기적인 성질)

  • 김정기;한경훈;서정철
    • Journal of the Korean Magnetics Society
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    • v.9 no.4
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    • pp.190-195
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    • 1999
  • The crystallographic and magnetic properties of the system of $Fe_{1-x}Co_x$(x=0.2 and 0.4) prepared by microwave arc-melting with the maximum power of 3.5 kW and a iron-foil with thickness of 25 ${\mu}{\textrm}{m}$ have been studied by the methods of X-ray diffraction and the measurement of the magnetic hysteresis using the vibrating sample magnetometer at room temperature. The samples were prepared in three different ways: First, pellet form pressed under the pressure of 9,000 N/$\textrm{cm}^2$. Second, the sheet cold rolled. Third, thin sheet treated with the temperature of 90$0^{\circ}C$. The X-ray diffraction pattern of the sample prepared by the first method shows that the crystal structure of the sample is bcc as same as that of Fe with a good uniformity. The iron-foil has the coercivity of 43 Oe and the initial slope of magnetization of 0.328 emu/gOe. The coervicity and magnetization of the sample prepared by the second method increased as the Co content increased. But the initial slop of the magnetization decreased as the Co content increased. This means that the displacement of domain wall is suppressed by the increases of coercivity as the Co content increased. The saturation magnetization of the samples made by the third method increased. On the other hand, the coercivity of these samples decreased. The increase of saturation magnetization of the samples seems to be related to the changes in X-ray intensity after heat treatment. Also some magnetic parameters of the samples were calculated by using a simple model and compared with other values.

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A Prediction of the Penetration Depth on CO2 Arc Welding of Steel Sheet Lap Joint with Fillet for Car Body using Multiple Regression Analysis Technique (자동차용 박강판 겹치기 이음부의 CO2 아크 용접에서 다중회귀분석기법을 이용한 용입깊이 예측에 대한 연구)

  • Lee, Kyung-Min;Sim, Hyun-Woo;Kwon, Jae-Hyung;Yoon, Buk-Dong;Jeong, Min-Ki;Park, Moon-Soo;Lee, Bo-Young
    • Journal of Welding and Joining
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    • v.30 no.2
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    • pp.59-64
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    • 2012
  • Welding is an essential process in the automotive industry. Most welding processes that are used for auto body are spot welding and $CO_2$ welding are used in a small part. In production field, $CO_2$ welding process is decreased and spot welding process is increased due to welding quality is poor and defects are occurred in $CO_2$ welding process frequently. But $CO_2$ welding process should be used at robot interference parts and closed parts where spot welding couldn't. Because of the 0.65mm ~ 2.0mm thickness steel sheet were used in the automotive industry, poor quality of welding area such as burn through and under fill were happened frequently in $CO_2$ process. In this paper, we will study about the penetration depth which gives a huge impact on burn through changing a degree of base metal, welding position and torch angle. Voltage, current and welding speed were fixed but degree of base metal, welding position and torch angle were changed. And Cold- Rolled(CR) steel sheet was used. Penetration depth was analysed by multiple regression analysis to derive approximate calculations. And reliability of approximate calculations were confirmed through additional experiments. As the results of this research, we confirmed the effect of torch and plate angle to bead shape. And we present a possibility that can simulate more accurate to weld geometry, as deduced the verification equations that has tolerance of less than 21.69%.

The formability of high strength steel plate applied TRB for stamping (스탬핑용 고강도강 TRB 판재의 성형 특성)

  • Park, Hyun-kyung;Jeong, Ji-Won;Lee, Gyung-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.184-189
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    • 2018
  • Recently, research on lightweight automobiles is increasing continuously to respond to the high safety standards and environmental regulations. The application of high strength steel is one of the effective methods for developing lightweight car bodies. A TWB (Tailor Welded Blank) is major method that allows partial high strength with light weighting using a multi-thickness and multi-material welded blank. On the other hand, additional welding process is required to prepare the blank and quality control for the welding process also required. To secure this point, the TRB (Tailor Rolled Blank) method was suggested. In the TRB method, the thickness of sheet is controlled by the rolling presses and the production efficiency is much higher than welding in TWB methods. In this study, the formability of high strength TRB steel plate was analyzed to examine the rolling effect of the blank. The formability of the specimen was tested using 0.8 and 1 mm thick steel sheets for the TRB plate. The strain was analyzed by the digital image sensing of grid markings on the specimen and the forming limit diagram was calculated. An Erichsen test for the 0.8 and 1 mm thick TRB specimens was carried out and the formability was investigated by comparing with FE analysis.

Fracture Mechanics Approach to X-Ray Diffraction Method for Spot Welded Lap Joint Structure of Rolled Steel Considered Residual Stress (잔류응력을 고려한 압연강 용접구조물의 X-ray 회절법에 의한 파괴 역학적 고찰)

  • Baek, Seung-Yeb;Bae, Dong-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.10
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    • pp.1179-1185
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    • 2011
  • Cold and hot-rolled carbon steel sheets are commonly used in railroad cars or commercial vehicles such as the automobile. The sheets used in these applications are mainly fabricated by spot welding, which is a type of electric resistance welding. However, the fatigue strength of a spot-welded joint is lower than that of the base metal because of high stress concentration at the nugget edge of the spot-welded part. In particular, the fatigue strength of the joint is influenced by not only geometrical and mechanical factors but also the welding conditions for the spot-welded joint. Therefore, there is a need for establishing a reasonable criterion for a long-life design for spot-welded structures. In this thesis, ${\Delta}P-N_f$ relation curves have been used to determine a long-life fatigue-design criterion for thin-sheet structures. However, as these curves vary under the influence of welding conditions, mechanical conditions, geometrical factors, etc. It is very difficult to systematically determine a fatigue-design criterion on the basis of these curves. Therefore, in order to eliminate such problems, the welding residual stresses generated during welding and the stress distributions around the weld generated by external forces were numerically and experimentally analyzed on the basis of the results, reassessed fatigue strength of gas welded joints.

Stress Modeling of the Laser Drilling Process in Carbon Steel (레이저 드릴링을 통한 강판 가공 시 응력 모델링)

  • Lee, Wooram;Kim, Joohan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.7
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    • pp.857-864
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    • 2013
  • A laser machining process has been applied in many manufacturing fields and it provides an excellent energy control for treating materials. However, a heat effect during laser machining can deteriorate material properties. Specifically, a thermally induced stress can be a problem in laser-machined structures on a metal surface. In this study, temperature and stress on cold-rolled carbon steel sheet machined with laser hole drilling were explored in an experimental approach and a numerical method. Stresses by temperature gradients inside the materials were generated in fast cooling. The stresses were measured by using a hole-drilling method and the material properties of carbon steel (SCP1-S) were obtained in the experiment. It was found that the stress predicted from the numerical analysis was in agreement with the stresses measured by using the hole-drilling method. The analysis can be applied for evaluating structure characteristics machined with a laser.

Texture Evolution during Primary Recrystallization and Effect of Number of Cold Rolling Passes, Heating Rate, and Si Contents in Grain-Oriented Electrical Steel (방향성 전기강판에서 1차 재결정시 Si 함량과 냉간압연 횟수, 승온 속도에 따른 집합조직 발달)

  • Jeon, Soeng-Ho;Park, No Jin
    • Journal of the Korean Society for Heat Treatment
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    • v.31 no.6
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    • pp.269-274
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    • 2018
  • Grain-oriented electrical steel sheets are mainly used as core materials for transformers and motors. They should have excellent magnetic properties such as low core loss, high magnetic flux density and high permeability. In order to improve the magnetic properties of the electrical steel sheet, it is important to form Goss oriented grains with a very strong {110}<001> orientation. Recently, efforts have been made to develop Goss grains by controlling processes such as hot rolling, cold rolling, and primary and secondary recrystallization. In this study, the sheets containing 3.2 and 3.4wt.% Si were used, which were rolled with 1 and 10 passes with total thickness reduction of 89%. Heating was carried out for primary recrystallization with different heating rates of $25^{\circ}C/s$ and $24^{\circ}C/min$ until $720^{\circ}C$. The behavior of Goss-, {411}<148>-, and {111}<112>-oriented grains were analyzed using X-ray diffraction(XRD) and electron back-scatter diffraction(EBSD) analysis. The area fraction of Goss-oriented grains increased with the number of rolling passes during cold rolling; however, after the primary recrystallization, the area fraction of the Goss grains was higher and exact Goss grains were found in the specimens subjected to rapid heating after one rolling pass.