A new criterion for internal crack formation in continuously cast steels

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Vol. 31; no. 4; pp. 779 - 794
• Main Authors: YOUNG MOK WON, YEO, T.-J, DONG JIN SEOL, KYU HWAN OH
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.08.2000; Springer Nature B.V
• Subjects: Applied sciences; Exact sciences and technology; Gravity die casting and continuous casting; Iron and steel making; Metals. Metallurgy; Production of metals; Internal crack; Iron steel industry; Theoretical study; Cracking; Continuous casting; Steel; Solidification cracking; Solidification; Strain rate
• DOI: 10.1007/s11663-000-0115-y
• ISSN: 1073-5615

To estimate the cracking condition in continuously cast steels, a new model for critical fracture stress given from the measured critical strain has been proposed, which can take into account the brittle temperature range and strain rate. The effects of brittle temperature range and strain rate on critical strain for internal crack formation were analyzed. When the brittle temperature range and strain rate were increased, the possibility of internal crack formation increased due to the decreasing critical strain. To describe the thermomechanical property model of the mushy zone between zero strength temperature (ZST) and zero ductility temperature (ZDT), the yield criterion for porous metals, which can take into account delta / gamma transformation, was used. Using the fitting equation for the measured critical strain and the microsegregation analysis, the thermomechanical behavior of the mushy zone could be successfully described by the proposed model, which incorporates the effects of microsegregation of solute elements and delta / gamma transformation on hot tear during solidification at the given range of steel compositions and strain rates. A cracking criterion based on the difference of deformation energy in the brittle temperature range is proposed to explain the cracking phenomenon of whole carbon range.