Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process

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Abstract

In hot-stamping processes, Al-Si coating is generally applied on the steel substrate to avoid decarburization and to enhance corrosion resistance of the hot-stamped parts. However, during hot stamping, the AlSi coating fractures due to thermal and mechanical loads. This deteriorates the surface quality of the stamped parts, increasing tool wear and friction between the stamping tool and coated sheet metal. These cracks are generally initiated during the heating and/or quenching phase due to phase transformations and thermal loads. The initiation of the cracks in the coating can be largely influenced by the evolution of coating microstructure, i.e. intermetallic compounds- FexAly, each of which has different thermal and mechanical properties. These intermetallic compounds are formed during the heating phase and grow in a natural order of increasing iron content in the layers close to the substrate-coating interface.

The goal of this study is to investigate the initiation of cracks in the coating during quenching stage due to thermal loads only. Heat treatment experiments are conducted on the Al-Si coated hot-stamping steel at different austenitization temperatures, dwell times and cooling rates. The distribution of voids/micro-cracks and intermetallic compounds in the coating are examined via digital microscopy and SEM/EDX measurements, respectively. A thermal-structural finite-element model is built to predict the crack initiation in Al-Si coating during quenching; the model accounts for the spatial distribution and mechanical properties of different intermetallic compounds. The results show large strain localization around the voids due to thermal loads during quenching, leading to micro-cracks towards the surface.
Original languageEnglish
Title of host publication11th Forming Technology Forum Zurich 2018
Subtitle of host publicationExperimental and numerical methods in the FEM based crack prediction
EditorsPavel Hora
Place of PublicationETH Zurich, Switzerland
Pages87-92
Number of pages6
Publication statusPublished - 3 Jul 2018
Event11th Forming Technology Forum 2018: Experimental and numerical methods in the FEM based crack prediction - Technopark Zürich, Zurich, Switzerland
Duration: 2 Jul 20183 Jul 2018
Conference number: 11
http://www.ivp.ethz.ch/en/news-and-events/ftf18.html

Conference

Conference11th Forming Technology Forum 2018
Abbreviated titleFTF 2018
CountrySwitzerland
CityZurich
Period2/07/183/07/18
Internet address

Fingerprint

Stamping
Crack initiation
Quenching
Heating
Coatings
Intermetallics
Cracks
Thermal load
Decarburization
Mechanical properties
Steel
Substrates
Sheet metal
Spatial distribution
Surface properties
Corrosion resistance
Energy dispersive spectroscopy
Microscopic examination
Thermodynamic properties
Phase transitions

Keywords

  • austenitization temperature
  • coating fracture
  • dwell time
  • voids
  • micro-cracks

Cite this

Zaman, S. B., Hazrati Marangalou, J., de Rooij, M. B., Matthews, D. T. A., Venema, J., & van den Boogaard, A. H. (2018). Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process. In P. Hora (Ed.), 11th Forming Technology Forum Zurich 2018: Experimental and numerical methods in the FEM based crack prediction (pp. 87-92). ETH Zurich, Switzerland.
Zaman, Shakil Bin ; Hazrati Marangalou, Javad ; de Rooij, M.B. ; Matthews, David Thomas Allan ; Venema, Jenny ; van den Boogaard, Antonius H. / Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process. 11th Forming Technology Forum Zurich 2018: Experimental and numerical methods in the FEM based crack prediction. editor / Pavel Hora. ETH Zurich, Switzerland, 2018. pp. 87-92
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title = "Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process",
abstract = "In hot-stamping processes, Al-Si coating is generally applied on the steel substrate to avoid decarburization and to enhance corrosion resistance of the hot-stamped parts. However, during hot stamping, the AlSi coating fractures due to thermal and mechanical loads. This deteriorates the surface quality of the stamped parts, increasing tool wear and friction between the stamping tool and coated sheet metal. These cracks are generally initiated during the heating and/or quenching phase due to phase transformations and thermal loads. The initiation of the cracks in the coating can be largely influenced by the evolution of coating microstructure, i.e. intermetallic compounds- FexAly, each of which has different thermal and mechanical properties. These intermetallic compounds are formed during the heating phase and grow in a natural order of increasing iron content in the layers close to the substrate-coating interface.The goal of this study is to investigate the initiation of cracks in the coating during quenching stage due to thermal loads only. Heat treatment experiments are conducted on the Al-Si coated hot-stamping steel at different austenitization temperatures, dwell times and cooling rates. The distribution of voids/micro-cracks and intermetallic compounds in the coating are examined via digital microscopy and SEM/EDX measurements, respectively. A thermal-structural finite-element model is built to predict the crack initiation in Al-Si coating during quenching; the model accounts for the spatial distribution and mechanical properties of different intermetallic compounds. The results show large strain localization around the voids due to thermal loads during quenching, leading to micro-cracks towards the surface.",
keywords = "austenitization temperature, coating fracture, dwell time, voids, micro-cracks",
author = "Zaman, {Shakil Bin} and {Hazrati Marangalou}, Javad and {de Rooij}, M.B. and Matthews, {David Thomas Allan} and Jenny Venema and {van den Boogaard}, {Antonius H.}",
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editor = "Pavel Hora",
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Zaman, SB, Hazrati Marangalou, J, de Rooij, MB, Matthews, DTA, Venema, J & van den Boogaard, AH 2018, Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process. in P Hora (ed.), 11th Forming Technology Forum Zurich 2018: Experimental and numerical methods in the FEM based crack prediction. ETH Zurich, Switzerland, pp. 87-92, 11th Forming Technology Forum 2018, Zurich, Switzerland, 2/07/18.

Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process. / Zaman, Shakil Bin; Hazrati Marangalou, Javad ; de Rooij, M.B.; Matthews, David Thomas Allan; Venema, Jenny ; van den Boogaard, Antonius H.

11th Forming Technology Forum Zurich 2018: Experimental and numerical methods in the FEM based crack prediction. ed. / Pavel Hora. ETH Zurich, Switzerland, 2018. p. 87-92.

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

TY - GEN

T1 - Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process

AU - Zaman, Shakil Bin

AU - Hazrati Marangalou, Javad

AU - de Rooij, M.B.

AU - Matthews, David Thomas Allan

AU - Venema, Jenny

AU - van den Boogaard, Antonius H.

PY - 2018/7/3

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N2 - In hot-stamping processes, Al-Si coating is generally applied on the steel substrate to avoid decarburization and to enhance corrosion resistance of the hot-stamped parts. However, during hot stamping, the AlSi coating fractures due to thermal and mechanical loads. This deteriorates the surface quality of the stamped parts, increasing tool wear and friction between the stamping tool and coated sheet metal. These cracks are generally initiated during the heating and/or quenching phase due to phase transformations and thermal loads. The initiation of the cracks in the coating can be largely influenced by the evolution of coating microstructure, i.e. intermetallic compounds- FexAly, each of which has different thermal and mechanical properties. These intermetallic compounds are formed during the heating phase and grow in a natural order of increasing iron content in the layers close to the substrate-coating interface.The goal of this study is to investigate the initiation of cracks in the coating during quenching stage due to thermal loads only. Heat treatment experiments are conducted on the Al-Si coated hot-stamping steel at different austenitization temperatures, dwell times and cooling rates. The distribution of voids/micro-cracks and intermetallic compounds in the coating are examined via digital microscopy and SEM/EDX measurements, respectively. A thermal-structural finite-element model is built to predict the crack initiation in Al-Si coating during quenching; the model accounts for the spatial distribution and mechanical properties of different intermetallic compounds. The results show large strain localization around the voids due to thermal loads during quenching, leading to micro-cracks towards the surface.

AB - In hot-stamping processes, Al-Si coating is generally applied on the steel substrate to avoid decarburization and to enhance corrosion resistance of the hot-stamped parts. However, during hot stamping, the AlSi coating fractures due to thermal and mechanical loads. This deteriorates the surface quality of the stamped parts, increasing tool wear and friction between the stamping tool and coated sheet metal. These cracks are generally initiated during the heating and/or quenching phase due to phase transformations and thermal loads. The initiation of the cracks in the coating can be largely influenced by the evolution of coating microstructure, i.e. intermetallic compounds- FexAly, each of which has different thermal and mechanical properties. These intermetallic compounds are formed during the heating phase and grow in a natural order of increasing iron content in the layers close to the substrate-coating interface.The goal of this study is to investigate the initiation of cracks in the coating during quenching stage due to thermal loads only. Heat treatment experiments are conducted on the Al-Si coated hot-stamping steel at different austenitization temperatures, dwell times and cooling rates. The distribution of voids/micro-cracks and intermetallic compounds in the coating are examined via digital microscopy and SEM/EDX measurements, respectively. A thermal-structural finite-element model is built to predict the crack initiation in Al-Si coating during quenching; the model accounts for the spatial distribution and mechanical properties of different intermetallic compounds. The results show large strain localization around the voids due to thermal loads during quenching, leading to micro-cracks towards the surface.

KW - austenitization temperature

KW - coating fracture

KW - dwell time

KW - voids

KW - micro-cracks

UR - https://www.ethz.ch/content/dam/ethz/special-interest/mavt/virtual-manufacturing/ivp-dam/News_Events/ftf2018/FTF2018_Proceedings_digital_release_2018-10-23.pdf

M3 - Conference contribution

SP - 87

EP - 92

BT - 11th Forming Technology Forum Zurich 2018

A2 - Hora, Pavel

CY - ETH Zurich, Switzerland

ER -

Zaman SB, Hazrati Marangalou J, de Rooij MB, Matthews DTA, Venema J, van den Boogaard AH. Modeling crack initiation in Al-Si coating during heating/quenching phase of hot stamping process. In Hora P, editor, 11th Forming Technology Forum Zurich 2018: Experimental and numerical methods in the FEM based crack prediction. ETH Zurich, Switzerland. 2018. p. 87-92