Challenges in hot-dip galvanizing of high strength dual phase steel: Surface selective oxidation and mechanical property degradation

Liu, Huachu; Li, Fang; Wen, Shu Wen; Swaminathan, Srinivasan; He, Yanlin; Rohwerder, Michael; Li, Lin

doi:10.1016/j.surfcoat.2012.02.001

Cited by 61 publications

(22 citation statements)

References 23 publications

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“…The internal oxide particles are distributed in a region about 150 nm below the surface. The internal oxides were observed previously in high strength steels [7,11,12,13,14]. At a higher magnification, right between the inhibition layer and the surface of the steel substrate is another thin layer, which is evident by the different contrast, as shown in Figure 4b (indicated by the pairs of arrows).…”

Section: Resultssupporting

confidence: 70%

“…Oxidation may occur both externally and internally depending upon the oxidizing potential inside the annealing furnace [11,12,13,14]. Thus, understanding the structure of the interface of galvanized high strength steels is crucially important.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, understanding the structure of the interface of galvanized high strength steels is crucially important. How these oxides affect galvanizing of AHSSs has been the subject of extensive discussions [7,8,9,10,11,12,13,14] most recently.…”

Section: Introductionmentioning

confidence: 99%

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Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

Aslam

Martens

et al. 2016

Materials Characterization

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Site-specific studies were carried out to characterize the interface of a galvanized dual-phase (DP) steel. Focused ion beam (FIB) was used to prepare specimens the interface region (~100 nm thick) between the coating and the substrate. Transmission electron microscopy (TEM), scanning TEM (STEM) and high resolution TEM (HRTEM) were performed to resolve the phases and the structures at the interface between the zinc (Zn) coating and the steel substrate. The STEM and TEM results showed that a continuous manganese oxide (MnO) film with a thickness of ~20 nm was present on the surface of the substrate while no silicon (Si) oxides were resolved. Internal oxide particles were observed as well in the sub-surface region. Despite the presence of the continuous oxide film, a well-developed inhibition layer was observed right on top of the oxide film. The inhibition layer has a thickness of ~100 nm. Possible mechanisms for the growth of the inhibition layer were discussed.

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Section: Resultssupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

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Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

Aslam

Martens

et al. 2016

Materials Characterization

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“…1,2) The superior corrosion resistance provided by the hot-dip Zn galvanizing process is being applied to high strength multi-phase steels such as dual-phase (DP) steels with two microstructural constituents of martensite and ferrite. [2][3][4][5][6][7] One of the important issues in the application of the hot-dip galvanizing process to high strength steels is a sufficient adhesiveness of the Zn coating layer on the steel sheet. It is generally known that the Fe-Zn intermetallic phases [8][9][10] are formed at the interface between the Zn coating and the steel sheet 1) and that they are often brittle due to the difficulty of slip deformation at ambient temperature, 11,12) whereby it is essential to control the formation of the Fe-Zn intermetallic phase layers.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Interfacial Reaction of Fe–Si Alloy Sheets Hot-Dipped in Zn Melt at 460°C

et al. 2018

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In order to understand the effect of solute Si (in the steel sheet) on the interfacial reaction between liquid Zn and solid Fe (α-Fe phase) during the hot-dip galvanizing process, a change in the interfacial microstructure between Zn coating and Fe substrate in Fe-Si alloy sheets hot-dipped in Zn melt with dipping time at 460°C was examined. In pure Fe sheet, the Fe-Zn intermetallic layers form at the interface between solid Fe and liquid Zn at an early stage of dipping and subsequently grow to approximately 60 μm in thickness after 600 s. In Fe-1Si (wt%) alloy, the thickness of Zn coating substantially increases to beyond 500 μm after 600 s and the coarse ζ-FeZn 13 phase with several facet planes was often observed in the Zn coating. The thickness of the Fe-1Si alloy sheets continuously decreases till 60 s and then is reduced significantly after 600 s. The thickness loss in the later stage of dipping is more significant in the Fe-Si alloy with higher Si content. These results indicate a significant Fe dissolution into liquid Zn could occur at the later stage of dipping the Fe-1Si alloy in Zn melt, which is distinguished from the interfacial reaction between pure Fe and liquid Zn. The enhanced interfacial reaction would be responsible for the decomposition of the initially formed ζ-FeZn 13 phase layer to liquid and FeSi phases, which can be proposed based on thermodynamic calculations of the Fe-Zn-Si ternary system.

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“…Como principais características, eles apresentam elevada resistência mecânica, baixa razão elástica e bons níveis de alongamento uniforme e total, habilitando-os à confecção de peças estruturais mais leves. Contudo, para fabricação destes aços com alto nível de qualidade é necessário compreender precisamente o comportamento das transformações de fases, com ênfase na composição química e nos tratamentos térmicos, em especial na taxa de resfriamento, visando a obtenção de microestrutura adequada à aplicação do produto final [1]. Neste trabalho avaliou-se o efeito de diferentes ciclos térmicos na microestrutura e propriedades mecânicas de um aço Dual Phase revestido por imersão a quente, da classe de resistência de 800 MPa, a partir de simulações em escala piloto no equipamento HDPS (Hot Dip Process Simulator) e ensaios dilatométricos, objetivando investigar quais parâmetros de processo terão maior probabilidade de êxito em escala industrial, baseando-se na caracterização microestrutural e nos resultados de tração à temperatura ambiente e flangeamento.…”

Section: Introductionunclassified

EFEITO DOS PARÂMETROS DE RECOZIMENTO CONTÍNUO NA MICROESTRUTURA E PROPRIEDADES MECÂNICAS DE UM AÇO REVESTIDO POR IMERSÃO A QUENTE DA CLASSE DE RESISTÊNCIA DE 800 Mpa

Guimarães¹,

Cetlin²,

Rocha³

et al. 2017

Anais Do Seminário De Laminação E Conformação

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ResumoNeste trabalho avaliou-se o efeito de diferentes ciclos térmicos na microestrutura e propriedades mecânicas de um aço Dual Phase revestido por imersão a quente, da classe de resistência de 800 MPa, a partir de simulações em escala piloto no equipamento HDPS (Hot Dip Process Simulator), ensaios dilatométricos, tração à temperatura ambiente e flangeamento. Nas simulações de recozimento contínuo foram experimentadas duas temperaturas de encharque no recozimento intercrítico (740°C e 780°C) e três temperaturas de patamar isotérmico no resfriamento rápido (610°C, 560°C e 510°C). A caracterização microestrutural evidenciou que a temperatura de encharque de 740°C não foi suficiente para dissolução completa dos carbonetos formados na laminação a quente, resultando em frações reduzidas de segundo constituinte. Com isso, o limite de resistência mínimo de 800 MPa não foi alcançado. Além disso, os resultados de ductilidade e flangeamento se mostraram aquém dos obtidos nas simulações com encharque a 780°C. Nas simulações com temperatura de encharque a 780°C e isotérmicas de 510°C e 560°C no resfriamento rápido foi atendido o limite de resistência mínimo, com capacidade de expansão de furo ligeiramente superior à obtida nas simulações com encharque a 740°C. Palavras-chave: Aços avançados de alta resistência; Dual phase; Recozimento contínuo. EFFECT OF CONTINUOUS ANNEALING PARAMETERS ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A HOT DIP GALVANIZED STEEL OF THE 800 MPa STRENGTH CLASS AbstractIn this work was evaluated the effect of different thermal cycles on the microstructures and mechanical properties of a hot dip galvanized Dual Phase steel, class 800 MPa, from simulations in laboratory scale with the equipment HDPS (Hot Dip Process Simulator), dilatometric test, tensile test and flanging test. In the continuous annealing simulations were tested two soaking temperature (740°C and 780°C) and three isothermal temperatures in the rapid cooling (610°C, 560°C and 510°C). Microstructural characterization showed that the soaking temperature at 740°C was not enough for the complete dissolution of carbides, resulting in lower fractions of the second constituent. Thus, the minimum tensile strength was not reached. Furthermore, the ductility and flanging were lower compared to soaking temperature at 780°C. In the thermal cycles at 780°C and isothermal temperature at 510°C and 560°C in the rapid cooling the minimum tensile strength was reached, hole expansion was slightly higher compared to soaking temperature at 740°C.

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Challenges in hot-dip galvanizing of high strength dual phase steel: Surface selective oxidation and mechanical property degradation

Cited by 61 publications

References 23 publications

Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

Enhanced Interfacial Reaction of Fe–Si Alloy Sheets Hot-Dipped in Zn Melt at 460°C

EFEITO DOS PARÂMETROS DE RECOZIMENTO CONTÍNUO NA MICROESTRUTURA E PROPRIEDADES MECÂNICAS DE UM AÇO REVESTIDO POR IMERSÃO A QUENTE DA CLASSE DE RESISTÊNCIA DE 800 Mpa

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