Formation of fine ferrite grains during hot deformation of Cu bearing steel

Kazukuni Hase, Yasumasa Hirai, Toshiyuki Hoshino, Akihiro Matsuzaki, Keniti Amano, Setsuo Takaki

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In order to refine the microstructure of low carbon steels, effect of copper addition was investigated in terms of super-cooling of austenite, dynamic austenite to ferrite transformation, and dynamic recrystallization of ferrite. Large decrease in transformation starting temperature was observed by copper addition. This is caused by the segregation of copper to austenite grain boundaries during prolonged austenitizing treatment. Fine ferrite grain structure in size of 2.1 μm was obtained by the deformation of super-cooled austenite at the reduction of 50% at 1043K in 2 mass% Cu bearing steel whose Ar3 temperature was decreased to 1008K by austenitizing for 14.4 ks at 1223K. This grain refining process has two stages. In the first stage, the austenite was transformed to ferrite through a deformation induced dynamic transformation (DIDT). The DIDT ferrite was characterized by fine cementite particles which cannot be observed in usual ferrite formed by thermal transformation. Volume fraction of the DIDT ferrite increases with increasing the degree of deformation. In the next stage, the ferrite grains were further refined and equiaxed with increasing the degree of deformation. A possibility that a dynamic recrystallization of DIDT ferrite occurs during the deformation was shown and this results in the marked grain refinement of ferrite.

Original languageEnglish
Pages (from-to)554-561
Number of pages8
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Volume90
Issue number8
DOIs
Publication statusPublished - Jan 1 2004

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Bearings (structural)
Hot working
Steel
Ferrite
ferrites
steels
austenite
Austenite
Copper
Dynamic recrystallization
copper
cementite
low carbon steels
Grain refinement
Crystal microstructure
refining
Low carbon steel
Refining
Volume fraction
Grain boundaries

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Metals and Alloys
  • Materials Chemistry

Cite this

Formation of fine ferrite grains during hot deformation of Cu bearing steel. / Hase, Kazukuni; Hirai, Yasumasa; Hoshino, Toshiyuki; Matsuzaki, Akihiro; Amano, Keniti; Takaki, Setsuo.

In: Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan, Vol. 90, No. 8, 01.01.2004, p. 554-561.

Research output: Contribution to journalArticle

Hase, Kazukuni ; Hirai, Yasumasa ; Hoshino, Toshiyuki ; Matsuzaki, Akihiro ; Amano, Keniti ; Takaki, Setsuo. / Formation of fine ferrite grains during hot deformation of Cu bearing steel. In: Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan. 2004 ; Vol. 90, No. 8. pp. 554-561.
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