Abstract
Zinc coated steels for hot press forming are intended to offer active corrosion resistant ultrahigh strength steel for applications in the automotive industry. During hot-press forming, zinc can infiltrate the underlying grain boundaries during the heat and forming step, leading to intergranular cracking of the base metal. In this study, samples of coated 22MnB5 steel were heated in a furnace at temperatures of 880, 900 and 920°C for 240 to 600 s and subsequently hot-formed into U-shaped profiles. Microstructure, morphology and depth of cracks were analysed using conventional optical and scanning electron microscopy, energy dispersive spectroscopy and focused ion beam imaging. The distribution of Zn in the heated coatings and underlying substrate was measured in detail by energy dispersive spectroscopy in transmission electron microscopy with samples taken out from the coating/base metal interfaces applying an in-plane focused ion beam lift-out method. In general the heating conditions do not appear to have effect on the density and spatial distribution of cracking in the top-wall and in the side-wall, but concerning the depth of penetration into the martensite/prior austenite substrate there is clear evidence that with extended heating time and temperature the depth of the penetration into the substrate and also the amount of penetrating cracks inside the top-wall is reduced. However full understanding of the role of heating condition on microcrack formation in zinc coated 22MnB5 has not been achieved at this stage yet; further work is underway and will be published later.
| Original language | English |
|---|---|
| Title of host publication | Materials Science and Technology Conference and Exhibition 2014, MS and T 2014 |
| Publisher | Association for Iron and Steel Technology, AISTECH |
| Pages | 299-306 |
| Number of pages | 8 |
| Volume | 1 |
| ISBN (Electronic) | 9781634397230 |
| Publication status | Published - 2014 |
| Externally published | Yes |
| Event | Materials Science and Technology Conference and Exhibition 2014, MS and T 2014 - Pittsburgh, United States Duration: 12 Oct 2014 → 16 Oct 2014 |
Conference
| Conference | Materials Science and Technology Conference and Exhibition 2014, MS and T 2014 |
|---|---|
| Country | United States |
| City | Pittsburgh |
| Period | 12/10/14 → 16/10/14 |
Fingerprint
Keywords
- FIB lift-out
- Heat treatment
- Hot press forming
- TEM
- Zn coated boron steels
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Materials Science(all)
Cite this
Role of heating conditions on microcrack formation in zinc coated 22MnB5. / Janik, Vit; Beentjes, Peter; Norman, David; Hensen, Guido; Seetharaman, Sridhar.
Materials Science and Technology Conference and Exhibition 2014, MS and T 2014. Vol. 1 Association for Iron and Steel Technology, AISTECH, 2014. p. 299-306.Research output: Chapter in Book/Report/Conference proceeding › Conference proceeding
}
TY - GEN
T1 - Role of heating conditions on microcrack formation in zinc coated 22MnB5
AU - Janik, Vit
AU - Beentjes, Peter
AU - Norman, David
AU - Hensen, Guido
AU - Seetharaman, Sridhar
PY - 2014
Y1 - 2014
N2 - Zinc coated steels for hot press forming are intended to offer active corrosion resistant ultrahigh strength steel for applications in the automotive industry. During hot-press forming, zinc can infiltrate the underlying grain boundaries during the heat and forming step, leading to intergranular cracking of the base metal. In this study, samples of coated 22MnB5 steel were heated in a furnace at temperatures of 880, 900 and 920°C for 240 to 600 s and subsequently hot-formed into U-shaped profiles. Microstructure, morphology and depth of cracks were analysed using conventional optical and scanning electron microscopy, energy dispersive spectroscopy and focused ion beam imaging. The distribution of Zn in the heated coatings and underlying substrate was measured in detail by energy dispersive spectroscopy in transmission electron microscopy with samples taken out from the coating/base metal interfaces applying an in-plane focused ion beam lift-out method. In general the heating conditions do not appear to have effect on the density and spatial distribution of cracking in the top-wall and in the side-wall, but concerning the depth of penetration into the martensite/prior austenite substrate there is clear evidence that with extended heating time and temperature the depth of the penetration into the substrate and also the amount of penetrating cracks inside the top-wall is reduced. However full understanding of the role of heating condition on microcrack formation in zinc coated 22MnB5 has not been achieved at this stage yet; further work is underway and will be published later.
AB - Zinc coated steels for hot press forming are intended to offer active corrosion resistant ultrahigh strength steel for applications in the automotive industry. During hot-press forming, zinc can infiltrate the underlying grain boundaries during the heat and forming step, leading to intergranular cracking of the base metal. In this study, samples of coated 22MnB5 steel were heated in a furnace at temperatures of 880, 900 and 920°C for 240 to 600 s and subsequently hot-formed into U-shaped profiles. Microstructure, morphology and depth of cracks were analysed using conventional optical and scanning electron microscopy, energy dispersive spectroscopy and focused ion beam imaging. The distribution of Zn in the heated coatings and underlying substrate was measured in detail by energy dispersive spectroscopy in transmission electron microscopy with samples taken out from the coating/base metal interfaces applying an in-plane focused ion beam lift-out method. In general the heating conditions do not appear to have effect on the density and spatial distribution of cracking in the top-wall and in the side-wall, but concerning the depth of penetration into the martensite/prior austenite substrate there is clear evidence that with extended heating time and temperature the depth of the penetration into the substrate and also the amount of penetrating cracks inside the top-wall is reduced. However full understanding of the role of heating condition on microcrack formation in zinc coated 22MnB5 has not been achieved at this stage yet; further work is underway and will be published later.
KW - FIB lift-out
KW - Heat treatment
KW - Hot press forming
KW - TEM
KW - Zn coated boron steels
UR - http://www.scopus.com/inward/record.url?scp=84925593820&partnerID=8YFLogxK
UR - http://www.proceedings.com/24744.html
M3 - Conference proceeding
VL - 1
SP - 299
EP - 306
BT - Materials Science and Technology Conference and Exhibition 2014, MS and T 2014
PB - Association for Iron and Steel Technology, AISTECH
ER -