Original Article

A lead tracer method for accurate determination of the solidification end in billet continuous casting

¹ State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, PR China
² WISDRI CCTEC ENGINEERING CO., LTD, Wuhan 430073, PR China
³ Technical Research Institute, MCC Capital Engineering and Research Incorporation Limited, Beijing 100088, PR China
⁴ Handan Iron and Steel Company Hegang Group, Handan 056015, PR China

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Received: 9 March 2026
Accepted: 22 June 2026

Abstract

The accurate determination of the solidification end point position in the continuous casting process is crucial for the implementation of solidification end reduction technology, which can significantly improve internal defects such as center segregation and porosity in long product billets. This study proposes a lead tracer method that combines lead tracer experiments with a VOF multiphase flow mathematical model to accurately determine the solidification end point position under different casting conditions. Experiments were conducted on billets of various steel grades and operating conditions. The results show that the lead tracer method can clearly reveal the liquid core morphology and accurately determine the solidification end point position. Additionally, the influence of process parameters on the lead trace length was investigated. Experimental results indicate that under mold electromagnetic stirring (M-EMS, 350 A, 4 Hz), the lead trace length is shortened by 0.70 m, while an increase in superheat by 20 °C prolongs it by 0.30 m. The corrected lead trace length lays the foundation for implementing solidification end reduction technology. Compared with the traditional nail shooting method, this method offers significant advantages in accuracy and visualization, contributing to improved internal quality control of continuous casting billets.