| Cover annealing furnace has been developed quickly in the world since1960s. Compared with the traditional annealing furnace, productivity of strong convectional and full hydrogen protected cover annealing furnace increased from 40% to 60%, and the quality of steel products has also increased. With the development of computer controlling technology and structure of the furnace, the research on mathematical modeling of the furnace has been widely carried out, such as temperature field modeling, stress modeling, but there is no any study concerned with analysis of annealing process of wire rolls. To solve the practice problems existed in 400/390 cover furnace processing, the basic heat transfer status in annealing process of wire rolls has been deeply analyzed, the mathematical model of heat transfer of wire rolls during annealing has been established with Fourier heat transfer differential equation and practical processing parameters. The temperature distribution, heating processing of wire rolls, and the relationship between nitrogen, inter cover and quality of heat treatment has been obtained. The calculated data is basically agreed with measured data, the difference between data was also analyzed, the critical factors affecting the accuracy of the mathematical model was found out, the solving methods have been proposed. Through the analysis made above, the processing factors for guiding annealing have been designed. The model has also established the good base for further study of the cover annealing furnace processing. In addition, some important parameters and equivalent heat transfer coefficient were analyzed in detail, which established theory foundation for analyzing of wire rolls heat treatment and reforming of controlling system of 400/390 cover annealing furnace in Changcheng Special Steel. |
