Thermal-fluid-structure Coupling FAEM Analysis Of Oxygen Top-blown Converter

Oxygen top-blown steelmaking is one of the major steel-making methods in iron and steelindustries in China. Because of the high cost of converter kits and complicated smelting process,the life of converter has an important influence on product quality and economic efficiency, soextending the life of the converter has become the core of technological innovation work of steelenterprises. During the process of blowing, the lining suffers from melting fail because ofchronically erosion, splashing and oxidation from the molten steel. High thermal stress caused bythermal expansion and temperature unevenness will lead the structural deformation or fracture ofthe converter. Meanwhile, during the tilting process, the thermal stress varies greatly which willlead repeated contraction, pansion of the furnace structure and cause fatigue crack on the furnace.These factors may cause the converter deformation, cracks, overheating and burn and otherdamage, which will shorten the life of the converter directly and reduce economic efficiency.Based on the use of sequential coupling approach, this thesis has completed theheat-flow-solid coupling analysis and calculation of the converter system by using CFD andANSYS software. Then the converter flow field, temperature field and integrated stress fieldhave been established. The reasonable research methods and basic steps of this thesis haveprovided a fessible solution for other areas of research for its certain value. In addition, thisthesis has analyzed the heat-solid coupling stress field of converter system with different tiltingangle and examined the maximum stress-tilting angle variation and dynamic load shocks of thewhole of the converter. This thesis focuses on the analysis of carrying capacity of the converterring both before and after pitting, and put forward reasonable proposals.Researches show that the oxygen blowing can cause a greater level disturbance and thesplash of molten steel. A small amount of liquid steel adhered to the inner wall of the pool andthe high position of the oxygen lance. The liquid steel’s strong splashing will erode refractorylining. In a pure top-blown condition, the liquid steel at the bottom of the molten pool flowsslowly and its flow rate is less than0.06m/s. This dead zone is not conducive for stirring of themolten pool and decarbonization capacity is poor. The heat-flow-solid coupling maximum stressof the furnace shell is at the connection of next block and the furnace shell clamp. The maximumstress is198MPa which is close to the furnace shell material yield limit. It is necessary toimprove its local structure to reduce stress concentration. Most components of the convertersystem reach a large value of stress when tilt angle is60°, so this position is the most dangerouspostion. Under no damage condition, the maximum stress of the inner web is72.4MPa. In caseof damage, the maximum stress of pitting area is111.1MPa. By comparisons, the rising rate is53%. The maximum stress value will increase when dynamic load is considered. Thus, the innerwebs pitting area has great impact on the structural strength of the converter ring. It is nessary toreinforce and maintain timely to improve the carrying capacity of the converter ring.