• 제목/요약/키워드: Cold rolled Steel

검색결과 249건 처리시간 0.036초

냉연 공정에서의 작업단위 편성 (A Job Sequencing Model for Cold Coil Production Processes)

  • 전치혁;이승만;박철순;강상엽;장수영;최인준;강전태
    • 산업공학
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    • 제6권2호
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    • pp.117-131
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    • 1993
  • A job sequencing model is developed and its computer system is tested for processing cold-rolled coils in Tandem Cold Mills(TCM) at the Pohang Iron and Steel Company. Given coils waiting to be processed, this system generates a sequence of jobs satisfying operational constraints for the TCM process. We formulate the problem as a constraint satisfaction problem and employ the backtracking technique combined with looking ahead features in order to generate a feasible solution within a reasonable time. Our system is implemented in C language on 80486-based IBM PC. Some tests based on the real data show that our system is adequate with respect to search time and that it consistantly generates a good feasible solution.

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전기로재 BAF 냉연강판의 자동차 인산염처리성 개선 연구 (Improving Phosphatability of BAF Cold Rolled Steel Sheet from Electric Furnace)

  • 박상진;김종기;문만빈;박재선;안재천
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2007년도 춘계학술발표회 초록집
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    • pp.31-32
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    • 2007
  • 자동차 도장 전처리 공정 중 인산염처리는 소지와 도장층 사이의 밀착성을 향상시키고, 강판의 내식성을 향상시키는 목적으로 행하여진다. 인산염 조직이 치밀하게 형성되지 못하면 도장층 박리 등의 불량이 발생할 수 있다. 본 연구에서는 전기로재 BAF(Batch Annealing Furnace) 냉연강판의 인산염처리 특성에 대한 분석 및 개선안 도출 과정을 서술하였다.

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초기 소성변형이 초미세 결정립 페라이트-마르텐사이트 이상조직 탄소강의 건식 미끄럼마멸 특성에 미치는 영향 (Effect of Prior Deformation on the Sliding Wear of Ultra-fine Grained Ferrite-Martensite Dual Phase Steel)

  • 박준기;이슬기;신동혁;김용석
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 춘계학술대회 논문집
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    • pp.521-524
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    • 2008
  • Effect of prior deformation on the sliding wear of the ultra-fine grained (UFG) ferrite-martensite dual phase (DP) steel was investigated. The UFG DP steel was fabricated by the ECAP and subsequent intercritical annealing. The steel was cold rolled before the wear test, and the effect of the prior deformation on the wear was examined. The wear tests were carried out at various loads against a bearing steel ball. The wear rate of the UFG DP steel that did not experience the prior deformation was higher than that of the coarse-grained (CG) DP steel, because of more severe surface shear deformation. The wear rate of the specimens with prior deformation was much higher than that of the specimen without prior deformation. The deformed CG DP specimen showed higher rate than the deformed UFG DP specimen, and the rate-variation of the CG DP steel was much bigger under the same test condition.

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우리나라 주요 FTA의 철강재 원산지 규정 협상에 대한 비교 분석 (A Comparative Analysis on the Arrangement of Rules of the Origin of Steel Products in Korea's Major FTAs)

  • 이승택
    • 무역학회지
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    • 제44권5호
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    • pp.127-142
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    • 2019
  • As Korea's steel industry exports 38 percent of its total steel production, the future management environment of the steel industry will change depending on the outcome of the FTA negotiations. The overall industrial structure of the domestic steel industry depends on the rules of origin, which are directly linked to the effect of concessionary tariffs. Therefore, negotiations on rules of origin are as important as tariff liberalization for Korea's steel industry. Korea's cold-rolled and plated companies are expected to be negatively affected as the country of origin standards of steel products have not considered the steel production processes in Korea. In future FTA talks, the country of origin rules should be agreed on a change of tariff classification basis. This result would secure a stable export market through increased predictability of steelmakers and reduce the risk of increased costs of oil and intangible products. In addition, the government should consider the structure of domestic supply and demand so that it does not impose constraints on the change of tariff classification. Finally, participants in the negotiations should consider the opinions of the domestic steel industry.

오스테나이트계 고망간강에서 인장 특성과 피로거동에 미치는 변형유기상의 영향 (The Effect of Deformation Induced Phase on Tensile Properties and Fatigue Behavior of Austenitic High Mn steel)

  • 최상민;권숙인
    • 열처리공학회지
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    • 제7권4호
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    • pp.277-287
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    • 1994
  • The effect of grain size on the tensile properties and fatigue behavior of austenitic high Mn steel has been investigated. The recrystallized austenite grain size of the cold rolled high Mn steel was increased as the annealing temperature increased from $600^{\circ}C$ to $1000^{\circ}C$. Larger austenite grain size decreased the yield strength and the tensile strength, and increased the uniform elongation due to transformation of some austenite into twins or E-martensite phase during deformation. Austenite grain refinement increased the tendency to form dislocation cells, instead. The specimen annealed at $1000^{\circ}C$ with large grain size showed lower fatigue crack propagation rate in low ${\Delta}K$ region due to rougher fracture surface caused by formation of deformation twins during fatigue at the crack tip region.

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Hardening of Steel Sheets with Orthotropy Axes Rotations and Kinematic Hardening

  • Hahm, Ju-Hee;Kim, Kwon-Hee;Yin, Jung-Je
    • International Journal of Precision Engineering and Manufacturing
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    • 제1권1호
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    • pp.91-97
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    • 2000
  • Anisotropic work hardening of cold rolled low carbon steel sheets is studied. The experiments consist of two stage tensile prestraining and tensile tests. At the first prestraining, steel sheets are streteched along the rolling direction by 3% and 6% tensile strains. The second prestrains are at 0${\cric}$, 30${\cric}$, 60${\cric}$to the rolling directions by varying degrees. Tensile tests are performed on the specimens cut from the sheets after the two stage prestraining. A theoretical framework on anisotropic hardening is proposed which includes Hill's quadratic yield function, ziegler's kinematic hardening rule, and Kim and Yin's assumption on the rotation of orthotropy axes. The predicted variations of R-values with second stage tensile strain are compared with the experimental data.

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자동차용 강판의 소둔방법에 따른 성형성의 변화에 관한 연구 (A Study on the Formability of Autonobile Panel on the Heat Treatment Method)

  • 김순경;이승수;전언찬
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1995년도 추계학술대회 논문집
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    • pp.629-632
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    • 1995
  • The formability of an automobile body panel is very important. So, we performed an annealing condition change for the development of annealing condition with temperature, atmospheric gas and the annealing cycle. Formability was changed under the influenced of the mechanical properties of steel sheet for the automobile body panel. Therefore, ot os important in the BAF(Batch annealing furnace) annealing process. Because mechanical properties were decided on the heat treatment method of the coil. So, we tested the development of mechanical properties according to the heat treatment method at the annealing furnace using the Ax atmospheric gas and the HNx atmospheric gas. As a result of several investigations, we confirmed the following characteristics ; mechanical properties change under the influence of the annealing cycle and atmospheric gas.

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자동차용 강판의 성형성 개선에 관한 연구 (A Study on the Improvement of Formability of Automobile Body Sheet)

  • 김순경
    • 한국생산제조학회지
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    • 제7권2호
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    • pp.108-114
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    • 1998
  • Development on the mechanical properties of steel sheet for the automobile body panel is very important in the BAF(Batch annealing furnace) annealing process. Because of the heat treatment method in the BAF, mechanical properties was decided on the heat treatment method of the coil. So, we tested on the development of mechanical properties according to heat treatment method at the annealing furnace using the Ax(H$_2$75%, $N_2$25%) atmospheric gas and the HNx(H$_2$4%, $N_2$96%) atmospheric gas. As a result of several investigations. We confirmed the following characteristics ; mechanical properties was changed under the influence of the annealing cycle, the heat treatment method and the atmospheric gas. And, elongation in the HNx BAF was better than the Ax BAF. Finally, most important thing in the BAF is using of proper annealing cycle in order to get a good quality.

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인삼염처리성에 미치는 소재 제조조건 영향 (Effect of Maunfacturing Conditions of Substrate on Phosphatability)

  • 김형준
    • 한국표면공학회지
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    • 제30권5호
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    • pp.310-319
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    • 1997
  • The purpose of this study is to investigate the effect of the specific alloying elements in steel such as Cr, Ni and Cu, and surface roughness of substrate with two different FCS temperature zones in the CAL process on the phosphatability of the cold-rolled sheet used for the drum in order to improve the zinec phosphating property. Phosphatability is dependent of the surface oxide and roughness on the substrate and can be indirectly improved by increasing surface roughness of the steel sheet. Basically, in order to obtain the good phosphatability, the low concentration of the retained elements such as Cr, Ni and Cu among the steel alloy elements should be required. Phosphatability of substrate with high concentration instead of the retained elements and surface roughness, however, can be effectively improved instead of low FSC temperature.

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