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
Study and empirical modelling of recrystallisation annealing of martensitic chromium steel strip by means of EBSD
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
2009 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Recrystallisation annealing, a repeated heat treatment between different stages of cold rolling of martensitic chromium steel strip, is successful when neither high rolling forces nor wear of the working rolls occur during the subsequent cold rolling. Mechanical properties as tensile strength, yield, elongation or hardness have been, by tradition, the criteria that described the quality of the annealing process. In recent years, the development of the measurement equipment in the rolling mills and of the instruments for material investigations has accentuated more and more the role played by the microstructural properties in the evaluation of the heat treatment. Two microstructural characteristics of the degree of annealing are, firstly and most important, the recrystallisation degree, and, secondly, the secondary carbide density.

The sample manufacturing and heat treatment, modelling and microstructure investigations by light optical- (LOM) and scanning electron microscopy (SEM) described in this article were carried out at Sandvik Materials Technology’s R&D Department and Bell Furnace Line in Sandviken, Sweden, while microstructure investigations and evaluation by scanning electron microscopy with field emission gun (FEG-SEM) and electron back scatter diffraction (EBSD) were done at the Corrosion and Metals Research Institute (KIMAB) in Stockholm, Sweden.

The first part of this work shows that, in contrast to the traditional methods LOM and SEM, that use chemical etching for the preparation of the samples, EBSD can successfully characterise recrystallised structures in annealed martensitic chromium steels. Unlike conventional microscopy with LOM and SEM, EBSD is able to reveal the grain geometry, as well as to separate and identify the different phases in this kind of steels (ferrite, M23-, M6-carbides). Important parameters such as grain size, particle size and recrystallised fraction can be measured with high accuracy. This information can be used to understand, evaluate, control and even predict the recrystallisation annealing of martensitic chromium steel.

The second part of this work presents how the results from microstructure description by EBSD can be directly used in relatively simple empirical models for determination of recrystallisation degree as function of the annealing parameters and the deformation history. EBSD was applied to evaluate the degree of recrystallisation in a series of annealing tests, with the purpose to model recrystallisation temperature in two types of martensitic chromium steel strip, a traditional one and one alloyed with molybdenum, cold rolled with different amounts of reduction and annealed with different temperatures, soaking times and heating rates. The empirical quadratic models were built with Umetrics’ software for experimental design, MODDEÒ 8.0 and they defined the recrystallisation degree (limits for LAGB and HAGB were set to 1.5° and 7.5° for the first grade and 2.5° and 10° for second one) and the secondary carbides density as functions of annealing temperature, soaking time and cold reduction (the factor heating rate was removed as nonsignificant). To be observed that these empirical models were fit much better for the recrystallisation degree than for the secondary carbides density.

The modelling work described above, together with the implementation of online physical temperature models in the bell annealers may lead to an increased productivity in the production plant by shortening the annealing cycle and minimising scrap and thus to an economical gain of ca 1,5 MSEK per year at Sandvik Materials Technology.

 

Place, publisher, year, edition, pages
Stockholm: KTH , 2009. , 72 p.
Keyword [en]
EBSD, Etching, Metallography, Cold Rolling, Recrystallisation annealing
Identifiers
URN: urn:nbn:se:kth:diva-10539ISBN: 978-91-7415-253-1 (print)OAI: oai:DiVA.org:kth-10539DiVA: diva2:218924
Presentation
(English)
Available from: 2009-05-25 Created: 2009-05-25 Last updated: 2010-10-21Bibliographically approved
List of papers
1. Manufacturing of cold rolled strip in hardenable martensitic chromium steel
Open this publication in new window or tab >>Manufacturing of cold rolled strip in hardenable martensitic chromium steel
2006 (English)Report (Other academic)
Series
4H5915 Steel Production Technology, Project reports from the participants in the course
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25433 (URN)
Note
QC 20101021Available from: 2010-10-21 Created: 2010-10-21 Last updated: 2010-10-21Bibliographically approved
2. EBSD versus conventional microscopy and empirical modelling of recrystallised fraction by means of EBSD in annealed martensitic chromium steel strip
Open this publication in new window or tab >>EBSD versus conventional microscopy and empirical modelling of recrystallised fraction by means of EBSD in annealed martensitic chromium steel strip
2009 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774Article in journal (Refereed) Submitted
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25434 (URN)
Note
QS 20120315Available from: 2010-10-21 Created: 2010-10-21 Last updated: 2017-12-12Bibliographically approved
3. An experimental study of recrystallisation annealing in martensitic stainless steel strip by means of EBSD and empirical modeling
Open this publication in new window or tab >>An experimental study of recrystallisation annealing in martensitic stainless steel strip by means of EBSD and empirical modeling
2008 (English)In: proceedings of 6th European Stainless Steel Conference, Helsinki, Finland, June 10-13, 2008, 2008Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-25435 (URN)
Conference
6th European Stainless Steel Conference, Helsinki, Finland, June 10-13, 2008
Note
QC 20101021Available from: 2010-10-21 Created: 2010-10-21 Last updated: 2010-10-21Bibliographically approved

Open Access in DiVA

fulltext(21707 kB)825 downloads
File information
File name FULLTEXT01.pdfFile size 21707 kBChecksum SHA-512
571b00315554d5e21f2240d833cab2fc41be3dcdca8abdeab1c68a0e2f55778d8a15957488a5666fe188c0ca3ffe231b45caf8041541d589b9cb19fc511a68ae
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Ionescu-Gabor, Sorin
By organisation
Materials Science and Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 825 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: 352 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