Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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
Determination of the columnar to equiaxed transition in hypoeutectic lamellar cast iron
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Jönköping University.ORCID iD: 0000-0001-7012-9342
Jönköping University.ORCID iD: 0000-0002-3024-9005
2014 (English)In: ISIJ International, ISSN 0915-1559, E-ISSN 1347-5460, Vol. 54, no 2, p. 460-465Article in journal (Refereed) Published
Abstract [en]

Shrinkage porosity as a volume change related casting defect in lamellar cast iron was reported in theliterature to form during solidification in connection to the dendrite coherency. The present work includesan experimental study on dendrite coherency – also called columnar-to-equiaxed transition in lamellar castiron using thermal analysis and expansion force measurements. Investigation was carried out in order tostudy the mechanism of dendrite coherency formation. Cylindrical test bars were cast from the same alloywith different pouring temperature, amount of inoculant and time between the addition of inoculant andstart of pouring the samples. Cooling rate and expansion force was recorded as a function of time. Anumerical algorithm based on temperature differences measured under solidification was used to inter-pret the solidification process. Three different methods have been compared to determine the columnarto equiaxed transition. The compared methods were based on registered temperature differences, basedon registered expansion forces during the volume change of the solidifying samples and based on the cal-culated released latent heat of crystallization. The obtained results indicate a considerable influence on theformation and progress of coherency due to variation of casting parameters. It has been shown that thecoherency is not a single event at a defined time moment rather a process progressing during a timeinterval.

Place, publisher, year, edition, pages
2014. Vol. 54, no 2, p. 460-465
Keywords [en]
columnar to equiaxed transition, dendrite coherency, lamellar cast iron, inoculation
National Category
Metallurgy and Metallic Materials
Research subject
Materials Science and Engineering
Identifiers
URN: urn:nbn:se:kth:diva-136982DOI: 10.2355/isijinternational.54.460ISI: 000332682800030Scopus ID: 2-s2.0-84897080403OAI: oai:DiVA.org:kth-136982DiVA, id: diva2:677637
Note

QC 20180404

Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2018-05-15Bibliographically approved
In thesis
1. Study of solidification and volume change in lamellar cast iron with respect to defect formation mechanisms
Open this publication in new window or tab >>Study of solidification and volume change in lamellar cast iron with respect to defect formation mechanisms
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Lamellar cast iron is a very important technical alloy and the most used material in the casting production, and especially in the automotive industry which is the major consumer. Beside the many great properties, it is inclined to form casting defects of which some can be prevented, and some may be repaired subsequently. Shrinkage porosity is a randomly returning problem, which is difficult to understand and to avoid. This defect is a volumetric deficiency which appear as cavities inside the casting in connection to the casting surface. Another frequent defect is the metal expansion penetration. This defect is a material surplus squeezed to the casting surface containing sand inclusion from the mold material. Shrinkage porosity is usually mentioned together with metal expansion penetration as the formation mechanism of both defects have common roots. It is also generally agreed, that these type of defects are related to the volumetric changes occurring during solidification. Additionally, the formation of these defects are in connection with the coherency of the primary austenite dendrites.

The purpose of this work was to develop knowledge on factors affecting a volume-change related casting defect formation in order to minimize the presence of these defects in engine component production. This was done by extending the existing solidification investigation methods with novel solutions. Introduction of expansion force measurement in the determination of dendrite coherency combined with multi axial volume change measurement refine the interpretation of the solidification. Comparison of registered axial and radial linear deformation in cylindrical samples indicated an anisotropic volume change. Different methods for dendrite coherency determination have been compared. It was shown that the coherency develops over an interval. Dependent on the added inoculant the coherency is reached at different levels of fractions of a solidified primary phase. It is also shown, that inoculation has an effect on the nucleation and growth of the primary phase. Quantitative image analysis has been performed on the primary phase in special designed samples designed to provoke shrinkage porosity and metal expansion penetration. It was found, that the inter-dendritic space varies within a casting. This was explained by the coarsening of the primary dendrites which originates from differences in the local time of solidification.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. p. x, 29
Keywords
lamellar cast iron, shrinkage porosity, solidification, volumetric change, dendrite coherency, inter-dendritic space
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-136985 (URN)978-91-7501-938-3 (ISBN)
Presentation
2013-12-05, Sal M131 Sefström, Brinellvägen 23, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 20131210

Available from: 2013-12-10 Created: 2013-12-10 Last updated: 2013-12-10Bibliographically approved

Open Access in DiVA

fulltext(600 kB)2 downloads
File information
File name FULLTEXT01.pdfFile size 600 kBChecksum SHA-512
e8cbffbd56403087974b25ef450ded365272bf067a5dc3bc7528acc52204c59011bca48f4562c688d22a8b78a5b6506f039b9ac44ae0963cb6cbe0cc9bc69056
Type fulltextMimetype application/pdf

Other links

Publisher's full textScopushttps://www.jstage.jst.go.jp/article/isijinternational/54/2/54_460/_article

Search in DiVA

By author/editor
Svidró, PéterDiószegi, Attila
By organisation
Materials Science and Engineering
In the same journal
ISIJ International
Metallurgy and Metallic Materials

Search outside of DiVA

GoogleGoogle Scholar
Total: 2 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

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 49 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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