• Title/Summary/Keyword: Galvannealed Steel Sheet

Search Result 33, Processing Time 0.023 seconds

Effects of Steel Chemistry, Annealing and Galvannealing Conditions on Bake Hardenability of Hot-Dip Galvannealed Sheet Steels (합금화 용융아연 도금강판의 강성분, 소둔 및 합금화 열처리가 소부경화성에 미치는 영향)

  • 이호종;김종상
    • Journal of the Korean institute of surface engineering
    • /
    • v.34 no.3
    • /
    • pp.247-257
    • /
    • 2001
  • In an effort to improve the dent resistance of exterior body panels at a reduced steel thickness, the bake hardenable steels added Ti or Nb with tensile strength of 35Kgf/$\textrm{mm}^2$ were investigated. The bake hardenability increased with the annealing temperature and solute carbon content. Bake hardening of 3 to 5Kgf/$\textrm{mm}^2$ was obtained in steels with a controlled solute carbon concentration range from 6 to 10ppm. The galvannealing temperature and time had little influence on the bake hardenability. The Fe-Zn alloying reaction of 35Kgf/$\textrm{mm}^2$ BH steel was remarkably retarded due to a 0.07%P addition. The optimum galvannealing temperatures of 35Kgf/$\textrm{mm}^2$ BH steel were ranged from 520 to 56$0^{\circ}C$ in view of the Fe content and powdering resistance. The cross-section and planar views of the galvannealed coatings to characterize morphology development were discussed.

  • PDF

Effects of Substrate Texture on Galvannealing Behavior of High Tensile GA Sheet Steel (고장력 합금화용융아연도금 강판의 합금화 거동에 미치는 집합조직의 영향)

  • 문만빈;신철수;오현운;남궁성;박용범
    • Proceedings of the Korean Institute of Surface Engineering Conference
    • /
    • 2003.05a
    • /
    • pp.31-32
    • /
    • 2003
  • In the Present study, the effect of galvannealing conditions on the phase distribution of the Zn-Fe intermetallic phases in the coating layer of the galvannealed steel sheets(GA) was investigated in an interstitial free steel and two kinds of high strength steels. The composition profiles of the coating layers were analyzed using AA and EDS analysis, and the distribution of the intermetallic phases was examined with the aids of X-ray diffraction. On the basis of the pole figure and OIM analyses, it was clarified that the preferred orientation of the $\zeta$ phase depended on the development of the $\gamma$-fibre texture in the substrate.

  • PDF

Effect of Silicon in Steels and Galvannealing Heat Cycles on Powdering Behavior of High Strength Galvannealed Steels (고강도 용융아연 도금강판의 파우더링 특성에 미치는 실리콘 및 합금화 열처리의 영향)

  • 이호종;오용택;김종상
    • Journal of the Korean institute of surface engineering
    • /
    • v.33 no.2
    • /
    • pp.135-144
    • /
    • 2000
  • Hot-dip galvannealed sheet (GA) with high strength of $45kg/mm^2$ in tensile strength, has developed for automotive applications. However, for a successful application, the powdering behaviour of GA must be minimized. The powdering of galvannealed coatings was reduced as the silicon content in the steel increased. Rapid heating and rapid cooling rate during the galvannealing process improved the powdering resistance due to the suppression of not only the ξ phase, but also the $ \Gamma _1$, phase. An analysis of the Fe-Zn alloy phases and its relation to the powdering behaviour are discussed with SEM micrographs.

  • PDF

An Evaluation of the Weldability Characteristics on the 4 Lap Spot Welded Joint of Structural Steel Sheets in Automobile (자동차용 강판의 4겹 다층 점용접물의 용접특성 평가)

  • Kim, Hoi-Hyun;Kim, Seong-Su;Baek, Seung-Se;Kwon, Il-Hyun;Yang, Seong-Mo;Yu, Hyo-Sun
    • Proceedings of the KSME Conference
    • /
    • 2004.11a
    • /
    • pp.314-318
    • /
    • 2004
  • This research is conducted to investigate weldability characteristics with various welding conditions on the 4 lap spot welded joint of structural steel sheets in automobile. The relationship between the tensile-shear strength and the indentation depth has been investigated to evaluate the weldability and the optimum welding conditions. The welding current and the welding time have a greatly affect to the tensile-shear strength compared to the electrode force. It was found that the indentation depth has a relatively close relationship with the expulsion occurrence. The optimum welding conditions were proposed for the 4 lap spot welded joint.

  • PDF

The corrosion behavior of galvanized steel sheets at the cut edges (용융아연도금강판의 단면부 부식특성)

  • 남궁성;허보영
    • Journal of the Korean institute of surface engineering
    • /
    • v.34 no.4
    • /
    • pp.297-302
    • /
    • 2001
  • As GA (Hot dip galvannealed steel sheet) has good corrosion resistance, weldability and paintability as well as excellent formability, it's demand is rapidly increasing for automotive panels. The GA coated layers are composed of several kinds of brittle Fe-Zn Metallic compounds which are susceptible to powdering during the press forming, however, very careful controls of manufacturing conditions such as galvannealing heat-treatment or bath composition are essential to meet with the required quality of automotive use. In this study the required characteristics of automotive panel are practically surveyed in detail and the appropriate manufacturing conditions of galvannealing or bath composition have experimentally investigated by using the various analyzing and simulating equipments. The result in this study indicated that the corrosion resistance at the cut edges was improved by increasing of coating weight and decreasing of thickness of sheet steels.

  • PDF

저탄소 2상조직강의 열처리공정 조건에 따른 기계적특성 변화

  • Kim, Hun-Dong;Park, Jin-Seong;Mun, Man-Bin
    • Proceedings of the Materials Research Society of Korea Conference
    • /
    • 2010.05a
    • /
    • pp.40.1-40.1
    • /
    • 2010
  • Recently high strength steel sheets with high formability for automotive parts have been being developed to meet the demands for passenger safety and weight reduction of car body. Among these high strength steels, dual-phase steels are regarded as one of the attractive steels due to their excellent mechanical properties including high strength and ductility. However, to be successfully applied to automotive parts they should be corrosion resistant enough to satisfy the required quality of car maker. This also requires their feasibility for galvannealed production including hot dip galvanizability. In this study has been placed on understanding the effects of heat-treatment(austenizing and isothermal treatment) on the microstructures and mechanical properties of a 0.06C-0.03Si-2.0Mn high strength steel for cold forming. The microstructure and phase distribution were examined with eth aids of SEM, EBSD, TEM etc.. Through the study the production of 590MPa grade DP GA steels with good formability and galvaniability were shown to be possible.

  • PDF

Characteristics of Zn-Ni Electrodeposition of 60 kgf/$\textrm{mm}^2$ Grade Transformation Induced Plastic Steel Sheets for Automotive Body (60 kgf/$\textrm{mm}^2$급 자동차용 변태유기소성강화강 Zn-Ni 전기도금 특성 연구)

  • Kim D. H.;Kim B. I.;Jeon Y. T.;Jeong Y. S.
    • Journal of the Korean institute of surface engineering
    • /
    • v.37 no.5
    • /
    • pp.263-272
    • /
    • 2004
  • High strength steels such as transformation induced plastic steel, dual phase and solid solution Hardening have been developed and continuously improved due to the intensified needs in the automotive industry. But silicon and manganese in transformation induced plastic steels were known to exhibit harmful effects on galvannealing reaction by oxide film formed during heat treatment. Therefore, in this work, the applicability of Zn-Ni electrodeposition instead of hot dip galvannealed coating to transformation induced plastic steels was evaluated and optimum electroplating condition was investigated. Based on these investigations optimized electroplating conditions were proposed and Zn-Ni electrogalvanized steel sheet was produced by EGL (electrogalvanized line). Its perfomance properties for automotive steel was evaluated.