DTA study and thermodynamic prediction of the solidification interval of boron 500HB abrasion-resistant steel

Abstract

Special wear-resistant steels are essential in applications with extreme abrasion conditions. Main applications of low-alloyed, weldable abrasion-resistant steels are found in mining, agriculture, and elsewhere. They are normally produced via continuous casting process and then hot rolled into heavy plates of desired thickness and width. This paper focuses on the strand casting part where the solidification interval of boron 500HB steel is studied through DTA heating curves and compared with thermodynamic predictions using Thermo-Calc (TCFE7 and TCFE9 database) and JMatPro with internal database General steel. Liquidus temperatures measured from the second heating curve are in good agreement with the thermodynamic approach using both commercial software. Additionally, the invariant peritectic temperature was experimentally determined and a reasonable agreement is achieved with predictions. All databases revealed a similar solidus temperature if the calculation was performed without boron included. By including 23 ppm of boron into the calculation, only one commercial software predicted the solidus temperature in good agreement with the measured value determined by DTA, the other result differed significantly. This study shows that important variation of the predicted metallurgical length in the strand slab caster exists if the solidus position is estimated using thermodynamic prediction. As the studied samples were taken directly from an industrial plate, a qualitative evaluation of micro-segregation through the cross-section of the thickness was also done and taken into account with thermal analysis.