Effect of thermal cycle and nitrogen content on the gor ductility of boron-bearing steel
SCIE
SCOPUS
- Title
- Effect of thermal cycle and nitrogen content on the gor ductility of boron-bearing steel
- Authors
- Cho Kyung Chul; Mun Dong Jun; Kang Myeong Hun; Lee Jae Sang; Park Joong Kil; Koo, YM
- Date Issued
- 2010-06
- Publisher
- ISIJ
- Abstract
- Hot ductility of Boron (B)-bearing steel has been examined in view of slab corner cracking problem. Addition of B to the low carbon steel reduced its hot ductility under a thermal cycle in which samples were cooled directly to the test temperature before straining. The change in hot ductility of B-bearing steel with deformation temperature showed one trough in the temperature range of 800-1 000 degrees C, which covered the lower temperature region of austenite single phase (region (I)), and near the austenite/ferrite transformation temperature (Ae(3)) (region (II)). An abrupt temperature decrease and reheating before straining heavily deteriorated the hot ductility of B-bearing steel in the region (I). In all steels, the strain concentration in the film-like ferrite primarily reduced hot ductility in region (II) regardless of the addition of B and the thermal cycles before straining. The ductility reduction of B-bearing steel is caused by the distribution and amount of BN precipitation, which is determined by the thermal cycles and the N content. Increase in the N content remarkably reduced hot ductility of B-bearing steel in region (I), where the behavior of BN precipitates controlled hot ductility. The results shows that the improvement of hot ductility in B-bearing steel can be attained by decreasing the N content and by avoiding an abrupt temperature decrease in the secondary cooling stage of the slab after solidification.
- Keywords
- corner crack; hot ductility; Boron-bearing steel; BN precipitation; N content; thermal cycle; TRANSVERSE CRACKING; MICROALLOYED STEELS; GRAIN-SIZE; RECRYSTALLIZATION; MECHANISM; STRENGTH; ALUMINUM; BEHAVIOR; SLABS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/25803
- DOI
- 10.2355/isijinternational.50.839
- ISSN
- 0915-1559
- Article Type
- Article
- Citation
- ISIJ INTERNATIONAL, vol. 50, no. 6, page. 839 - 846, 2010-06
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