Abstract: Aiming at the problems such as the fracture of the supporting bolts during the operation of the converter in a steelmaking plant with variable working conditions, the fracture mechanism of the supporting bolts in the steelmaking converter under different working conditions was studied with a 130t converter being taken as an example. Firstly, the converter tilting moment equation was derived, the MTALAB was used to analyse and calculate the converter tilting moment at different tilting angles, and the tilting moment curve was obtained so that the load of the supporting bolt under variable working conditions could be accurately calculated. Then, the finite element method was used to model the support bolts, and the mechanical analysis of the support bolts and their pins under the condition of maximum force was carried out. Finally,the support bolt structure was optimized and improved,and the performance of the optimized supporting bolt was checked. The results show that the supporting bolts are the most loaded when the converter rotates to 65°. The maximum equivalent stress value at the excessive arc of the bolts on the opposite side of the tap hole is close to the yield strength limit of the material. The adopted analysis method provides the basis for the subsequent quantitative increase of the safety factor of the supporting bolts, so as to ensure the safe operation of the converter without major structural modifications.
Key words:  support bolt tilting moment; fracture mechanism; stress analysis; finite element; variable working conditions