Affiliation:
1. The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology Wuhan Hubei 430081 China
2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and Technology Wuhan Hubei 430081 China
3. Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and Technology Wuhan 430081 China
4. School of Resource and Safety Engineering Wuhan Institute of Technology Wuhan 430205 China
Abstract
The effects of rare‐earth treatment on cleanliness, corrosion resistance, microstructure, and mechanical properties of 75Cr1 steel are investigated by industrial trial. In the results, it is shown that the appropriate La–Ce addition can effectively remove oxygen and sulfur elements in steel, and total oxygen (T.O) and S contents decrease by 45% and 33%, respectively. After La–Ce treatment, the typical inclusions in steel are transformed from (Mg–Al–O)–CaS composite inclusions to RExSy–CaS inclusion with a small amount of Al2O3. The number and average size of inclusions in steel are significantly reduced, and the morphology of inclusions changes from irregular shape to spherical shape, which contributes to the improvement of the corrosion resistance of 75Cr1 steel. Furthermore, the pearlite spacing and the grain size are refined, the tensile and yield strengths are significantly enhanced in the test of La–Ce‐treated steel. The 75Cr1 steels are fabricated in small batches, which avoids the nozzle clogging resulted by rare‐earth treatment during continuous casting. It implies that rare‐earth treatment to improve the quality of 75Cr1 steel shows the strong industrial applicability.
Funder
National Natural Science Foundation of China
China Postdoctoral Science Foundation