• Title/Summary/Keyword: Continuous annealing process

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Strip temperature control for the heating furnace in the continuous-annealing line (냉연 연속 소둔로 가열대 판온제어)

  • 정호성;유석환;백기남
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.779-782
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    • 1990
  • Recently batch type cold rolling processes have been replaced by continuous annealing type processes for cold rolled sheets of mild steel and high strength steel in order to obtain higher productivity, labor saving. In the continuous annealing line, it is very important to maintain the target steel strip temperature at the exit side of each furnace. The automation system of continuous annealing line is based on a hierachical composition. This paper shows how to preset the set value of furnace temperature control for the heating section in a continuous annealing line. Saying in other words, this paper presents the development of an adaptive control approach to control the exit strip temperature in the continuous annealing line. There are three parts in this approach; one is a process modelling and another is recursive parameter estimation and the other is a design of temperature controller.

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Effect of Productivity on the Hydrogen Content of Atmospheric gas in the BAF (BAF에서 분위기 가스의 수소 성분이 생산성에 미치는 영향)

  • 김순경;전언찬;김문경
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.560-564
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    • 1996
  • In recently, annealing process of cold rolled sheet tend to change to continuous annealing process for improving qualify, saving yield. In the meantime as demand for various kind and small lot of products has been increasing, batch annealing has been appreciated for its small restriction for the operation. So, we tested on the effect for a hydrogen contents of atmospheric gas at annealing furnace. As a result of several investigation. We confirmed for the following characteristics ; improved productivity, uniform heating, improved surface quality, saving energy. Therefore, the use of hydrogen instead of nitrogen as the protective gas, combined with high convection in batch annealing furnaces, has shown that considerable increases in furnace output and material quality are attainable. Owing to the low density, high diffusion and reducing character of hydrogen, a better transfer resulting in uniform material temperatures and improved coil surfaces can be achieved.

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The Effect of Isothermal Annealing on Microstructure of Forged Parts (단조품의 등온 어닐링에 따른 미세조직 변화)

  • Kim, D.B.;Lee, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.5
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    • pp.303-308
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    • 2000
  • The ring gears of automobile parts are manufactured generally process chart of which is as follows : forging ${\rightarrow}$ annealing or normalizing ${\rightarrow}$ rough machining ${\rightarrow}$ hardening(Quenching-Tempering or carburizing process) ${\rightarrow}$ finish machining. Isothermal annealing process after forging is most effective in the side of improvment of machinability. On this study we selected two kinds of steel;SCM415, SCM435 of most universal and investigated microstructures to find out most suitable condition of heat treatment in proportion continuous cooling and isothermal annealing. As the cooling rate is $5^{\circ}C$ per minute in continuous cooling process, martensite and bainite are coexisted with ferrite and pearlite in SCM435 steel. If the cooling rate is slower than $5^{\circ}C$ per minute, microstructure were only ferrite and pearlite but formation of band structure can't be avoid. On the other hand, microstructure is only ferrite and pearlite regardless of cooling rate because carbon content of SCM415 steel is low. Moreover formation of band structure isn't exposed by faster cooling rate. Most optimal temperature of the isothermal annealing is from $650^{\circ}C$ to $680^{\circ}C$ in SCM435 steel. When holding time is 60 minute with $650^{\circ}C$, the identical ferrite and pearlite microstructures can be obtained.

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A Study on the Annealing of High Tensile Strength Steel for Automobile (자동차용 고장력 강판의 열처리에 관한 연구)

  • 박범식
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1999.10a
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    • pp.530-535
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    • 1999
  • In recently, annealing process of cold rolled sheet tend to change to continuous annealing process for improving quality, saving yield. In the meantime as demand for various kind and small lot of products has been increasing, batch annealing has been appreciated for its small restriction for the operation. So, we tested on the effect for the proper heating temperatures, heating time of cycle, cooling time and total cycle time in this annealing process of hi tensile strength steel for automobile. As a result of several investigation. we confirmed for the following characteristics; In this process, we knew that 68$0^{\circ}C$ is suitable for this heating temp. cycle heating time of 38 Hr, cooling time of 31 Hr and total cycle time of 70 Hr. Still more, we could know that it is proper for cold rolling before annealing to be managed by 7 pass because of the act on high pressure.

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Configuration methodology and performance evaluation of distributed control systems (분산제어 시스템의 구성 방법 및 성능 평가)

  • 김평수;권욱현
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.616-619
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    • 1996
  • This paper presents the configuration methodology of Distributed Control System(DCS)s for process plant and their performance evaluation. Performance evaluation is specified both in terms of operational and installation aspects of system. In order to evaluate performance criteria of operational aspect, a simulation method is proposed. Modeling of system components including process computer, database, process controllers and LANs, etc, is implemented for simulation. Based on these characteristics, different system configurations are evaluated and compared through results about evaluation criteria in order to select the best DCS for particular process. The results, in abbreviated form, of the performance evaluation of DCS controlling a CAL(Continuous Annealing Line) plant of iron process are presented.

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Development of machining technology for non-continuous pattern removing plastic deformation around pattern (패턴 주변의 소성변형현상을 제거한 고품위 불연속패턴 가공기술 개발)

  • Jeon, Eun-chae;Je, Tae-Jin;Chang, Sunghwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.6
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    • pp.1-6
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    • 2010
  • Patterned optical components are widely used for optical products such as LCD and lighting. Since CCFL was used as a light source in the products, prism films having linear continuous optical patterns were widely used. However, LED which is a dot light source is popular recently, therefore, the optical products need new optical components having non-continuous optical patterns. Indentation machining method is a powerful method for machining of non-continuous pattern. When a copper mold and a brass mold were machined by this method, severe plastic deformation called pile-up was observed around the patterns. Since pile-up has negative relationship to ductility, this deformation can be eliminated by annealing treatment which makes the materials ductile. No plastic deformation occurred when machined after annealing at $600{^{\circ}C}$ and $575{^{\circ}C}$ for copper and brass, respectively. Finally, non-continuous optical patterns with high quality were machined on a copper mold and a brass mold successively.

Study on fabrication process of long length of Bi-2223/Ag MTS wires for high critical current (Bi-2223/Ag HTS 장선재의 Ic 특성 향상 공정 연구)

  • 하동우;양주생;황선역;이동훈;최정규;하홍수;오상수;권영길
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.105-108
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    • 2003
  • Long length of Bi-2223 superconducting wires were fabricated by stacking, drawing process with different precursor owders and different heat-treatment histories. The precursor powders were 2 kinds of Pb content. And a part of the tapes were experienced pre-annealing process which caused tetragonal structure of Bi-2212 phase to orthorhombic structure of it was during drawing process. We confirmed the transformation of Bi-2212 phase from tetragonal structure to orthorhombic structure and reduction of second phases. We designed and made a continuous Ic measurement system for Bi-2223/Ag HTS tape. We could achieve best Ic of 65 A at the Bi-2223/Ag tape using low Pb content of precursor powder and experienced pre-annealing process.

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Optimal Design of Truss Structures by Resealed Simulated Annealing

  • Park, Jungsun;Miran Ryu
    • Journal of Mechanical Science and Technology
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    • v.18 no.9
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    • pp.1512-1518
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    • 2004
  • Rescaled Simulated Annealing (RSA) has been adapted to solve combinatorial optimization problems in which the available computational resources are limited. Simulated Annealing (SA) is one of the most popular combinatorial optimization algorithms because of its convenience of use and because of the good asymptotic results of convergence to optimal solutions. However, SA is too slow to converge in many problems. RSA was introduced by extending the Metropolis procedure in SA. The extension rescales the state's energy candidate for a transition before applying the Metropolis criterion. The rescaling process accelerates convergence to the optimal solutions by reducing transitions from high energy local minima. In this paper, structural optimization examples using RSA are provided. Truss structures of which design variables are discrete or continuous are optimized with stress and displacement constraints. The optimization results by RSA are compared with the results from classical SA. The comparison shows that the numbers of optimization iterations can be effectively reduced using RSA.

Effect of Thermomechanical Process on Mechanical Property and Microstructure of 9Cr-1Mo Steel (열간가공이 9Cr-1Mo강의 기계적 성질과 미세조직에 미치는 영향)

  • Kim, Jun-Hwan;Baek, Jong-Hyuk;Han, Chang-Hee;Kim, Sung-Ho;Lee, Chan-Bock;Na, Kwang-Su;Kim, Seong-Ju
    • Korean Journal of Metals and Materials
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    • v.47 no.10
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    • pp.621-628
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    • 2009
  • Thermomechanical processes were carried out to evaluate their effects on the mechanical and the microstructural property of a ferritic-martensitic steel. Modified 9Cr-1Mo steels were hot-rolled at a temperature of either $780^{\circ}C$ or $850^{\circ}C$ after normalizing at $1050^{\circ}C$ and then were air-cooled. Continuous annealing at $850^{\circ}C$ for 2 hours immediately after the hot rolling was also performed and they were compared to the specimens without thermomechanical process. The result showed that there were little differences between the hot rolled specimens in terms of the precipitation density and size. However, V content inside the MX precipitates increased in the case of the specimen rolled at $850^{\circ}C$. The application of the continuous annealing induced coarsening of the Nb-rich MX precipitation as well as an increase in the amount of V-rich MX precipitation, which is expected to enhance high temperature mechanical properties of the ferritic-martensitic steel.

Texture and Microstructure in AA 3103 Sheets Deformed by Continuous Confined Strip Shearing Process (CCSS 가공에 의한 AA3103 판재의 집합조직 변화와 결정립 미세화에 관한 연구)

  • 이재필;이재철;허무영
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.176-178
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    • 2003
  • Strip samples of AA 3103 were deformed by Continuous confined strip shearing (CCSS). The CCSS process was designed to provide a repeated shear deformation in metallic sheet materials. CCSS led to the formation of characteristic shear textures comprising a pronounced{111}<uvw> orientations. The intensity of the deformation texture hardly increased with increasing number of CCSS passes. EBSD equipped in a FESEM with a high beam current revealed the formation of fine grains even after annealing for the recrystallization.

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