Control of Upstream Austenite Grain Coarsening during the Thin-Slab Cast Direct-Rolling (TSCDR) Process

Metals

卷:9

HatemS. Zurob¹  Peng Zhang²  Mani Subramanian³  Sang-Hyun Cho³  Tihe Zhou³  RonaldJ. O’Malley⁴ 

[1] Technology, 1400 N. Bishop Ave., Rolla, MO 65409-0330, USA;

[2] Algoma Inc. 105 West Street, Sault Ste. Marie, ON P6A 7B4, Canada;

[3] Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L7, Canada;

[4] Department of Materials Science and Engineering, Missouri University of Science &

关键词: thin-slab cast direct-rolling;    austenite grain coarsening;    grain growth control;    liquid core reduction;    secondary cooling;    two-phase pinning;   

DOI  :  10.3390/met9020158

来源: DOAJ

【 摘 要 】

Thin-slab cast direct-rolling (TSCDR) has become a major process for flat-rolled production. However, the elimination of slab reheating and limited number of thermomechanical deformation passes leave fewer opportunities for austenite grain refinement, resulting in some large grains persisting in the final microstructure. In order to achieve excellent ductile to brittle transition temperature (DBTT) and drop weight tear test (DWTT) properties in thicker gauge high-strength low-alloy products, it is necessary to control austenite grain coarsening prior to the onset of thermomechanical processing. This contribution proposes a suite of methods to refine the austenite grain from both theoretical and practical perspectives, including: increasing cooling rate during casting, liquid core reduction, increasing austenite nucleation sites during the delta-ferrite to austenite phase transformation, controlling holding furnace temperature and time to avoid austenite coarsening, and producing a new alloy with two-phase pinning to arrest grain coarsening. These methodologies can not only refine austenite grain size in the slab center, but also improve the slab homogeneity.

【 授权许可】

Unknown