Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
On Liquid Metal Wetting of Casting Rings for DC Casting
Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. (Teknisk fysik)
Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences. (Teknisk fysik)ORCID iD: 0000-0002-3622-4247
2015 (English)In: TMS Light Metals / [ed] Margaret Hyland, Warrendale: Minerals, Metals & Materials Society, 2015, Vol. 2015-January, 859-864 p.Conference paper, Published paper (Refereed)
Abstract [en]

During air–slip direct chill casting of aluminum alloys, uneven or low air pressure areas at the surface of the porous graphite ring mold, can cause the metal to stick to the graphite ring and produce traces along the billets called vertical drags (VD). To prevent this type of defect, it would be an advantage to decrease the wettability of the graphite ring.  It has been shown that nanostructured surfaces can have hydrophobic properties, and a question is weather the same effect can be achieved for molten metals. A TiO2 nanowire structure is proposed to cover the casting ring, and the wetting behavior of such a structure has been studied, and compared to the wetting at a regular graphite ring surface by the dispensed sessile drop method. The results showed that the nanostructured surface very strongly dewetting metal droplets.

Place, publisher, year, edition, pages
Warrendale: Minerals, Metals & Materials Society, 2015. Vol. 2015-January, 859-864 p.
Series
TMS Light Metals, ISSN 0147-0809
Keyword [en]
DC Casting, Wetting, Casting ring, Aluminium
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:miun:diva-26338Scopus ID: 2-s2.0-84942925150ISBN: 9781119082446 (print)OAI: oai:DiVA.org:miun-26338DiVA: diva2:875537
Conference
Light Metals 2015 - TMS 2015 Annual Meeting and Exhibition; Walt Disney WorldOrlando; United States; 15 March 2015 through 19 March 2015; Code 113955
Funder
Knowledge Foundation
Available from: 2015-12-01 Created: 2015-12-01 Last updated: 2017-02-08Bibliographically approved
In thesis
1. Investigation of Surface Formation in As-Cast and Homogenized 6xxx Aluminium Billets
Open this publication in new window or tab >>Investigation of Surface Formation in As-Cast and Homogenized 6xxx Aluminium Billets
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The direct chill (DC) casting technique to produce billets for extrusion and ingots for rollingwas developed in the 1930s. The principle, which is still valid, is a two-stage cooling with a primary cooling at a mould surface followed by water spraying directly on the surface. Improvements of this technique have mainly focused on changes to the primary cooling, where a water-cooled metal mould has been replaced by different techniques to minimize cooling at this stage. The drive for development comes from the extrusion industry, which can increase the productivity and quality of extruded profiles by improving the billet surface appearance and structure. Hot top casting supported by airflow against the casting surface during the primary cooling is currently the standard procedure to achieve acceptable billet surfaces. The goal is to minimize the depth of the surface segregation zone, which is the governing factor for the appearance of different phases in the surface region. Billet surface quality is evaluated by quantifying surface appearance, segregation zone thickness, and  occurrence of large Mg2Si and β-particles near the surface. The β-Al5FeSi intermetallic phase and coarse Mg2Si particles have negative effects on extrudability and workability of 6xxx Al alloys billets. To achieve extruded products with a high surface quality the as-cast billets are  heat-treated before extrusion. During heat treatment the undesired intermetallic particles, i.e., β-AlFeSi platelets are transformed to rounded α-Al(FeMn)Si intermetallic phases.

In this  research the formation of the surface segregation for smooth defect-free surfaces in both as-cast and homogenized billets was studied. In addition, the surfaces with defects such as wavy, spot and vertical drag defects were investigated and possible mechanisms for initiation of those defects were explained. Moreover, for a better understanding of the homogenization process in-situ studies of the heat treatment of 6082, 6005, 6060 and 6063 Al alloys were carried out by using a transmission electron microscope (TEM). Based on the observations, an explanation of the probable mechanisms taking place during transformation from β-to α-phase was presented.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University, 2017. 52 p.
Series
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 259
Keyword
DC casting, surface segregation, surface defects, intermetallic phase, phase transformation, homogenization
National Category
Engineering and Technology
Identifiers
urn:nbn:se:miun:diva-30007 (URN)978-91-88527-08-0 (ISBN)
Public defence
2017-03-14, O102, Holmgatan 10, 851 70, Sundsvall, 13:15 (English)
Opponent
Supervisors
Note

Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 5 manuskript, delarbete 6 inskickat och delarbete 7 inskickat.

At the time of the doctoral defence the following papers were unpublished: paper 5 manuscript, paper 6 submitted, paper 7 submitted.

Available from: 2017-02-08 Created: 2017-02-08 Last updated: 2017-02-09Bibliographically approved

Open Access in DiVA

fulltext(2170 kB)280 downloads
File information
File name FULLTEXT01.pdfFile size 2170 kBChecksum SHA-512
d28918b5dd55e7d281be60f310561e00194b25ff6c26f3a8fe3314418c65e0d9d1b7ad36f92bad496db47efdb8517956e33f376214e7709aa91c2e7c9124ebb8
Type fulltextMimetype application/pdf

Scopus

Search in DiVA

By author/editor
Bayat, NazlinCarlberg, Torbjörn
By organisation
Department of Natural Sciences
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 280 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 202 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf