Technical Characteristics of Roller Hearth Reheating Furnace
The roller hearth reheating furnace was first designed by Bricmont Company of the United States and put into use in Nucor Company of the United States, and achieved ideal results. Since then, the company has 17 production lines in the world, accounting for 70% of the world’s total roller hearth furnace at that time. Bricmont’s technology is concise and practical, and its production and operation cost is low. It is embodied in the following aspects:
Roller: Bricmont uses low carbon Co alloy rollers, which have excellent high-temperature properties. Compared with other suppliers’Cr28Ni48W5, Bricmont is not easy to crack and has several times a longer service life. The practice has proved that the service life of furnace rollers supplied by Bricmont Company is about 2 years, which is twice the guaranteed value.
Anti-deviation correction function.The slab must run at least 200 m in the furnace, which is very easy to deviate, and the slab will impact the furnace wall and other phenomena. Bricmont has skillfully utilized the deflection of the furnace roll itself in the design of the furnace roll, so that the billet can be automatically aligned in the operation process, thus thoroughly solving the problem and effectively reducing the cost of production and operation.
Installation method of furnace rollers. Bricmont’s furnace rollers are installed on the basis of civil engineering. The reducer and the furnace rollers are connected by rubber handles, which simplifies the equipment manufacturing process and reduces the project investment. Moreover, in actual production, the operation cost will be reduced accordingly.
Selection of refractories for furnace rolls. Because the roller of roller hearth furnace is in operation for a long time, the insulation of the roller is a very difficult problem. Bricmont has adopted a non-baking castable between light and heavy castables and designed M series of roller anchor hooks, which effectively solves the insulation of the roller. The actual cost of roller maintenance is only 1/3 of that of other companies.
Advanced combustion control methods. Bricmont has adopted the conventional double-crossing limit control. It has carefully designed the structure, capacity, and layout of the burner, which can meet the technological requirements, while the investment and operation costs are low.
Transverse moving vehicles and blank-picking rollers are used. Bricmont Company has proposed the transition mode of slab transverse movement for the thin slab continuous casting and rolling process plan to be adopted by Tangshan Iron and Steel Co. In order to prolong the buffer time of heating furnace and eliminate defective slab, Tangshan Iron and Steel Co.
Reformation of the regenerative burner of roller hearth heating furnace for thin plate continuous casting and rolling in Tangshan Iron and Steel Co.
After modification, the temperature in the furnace is obviously increased and the gas usage is also decreased, but the heat dissipation of the furnace wall is faster and the insulation effect is still not ideal. In 2012, Tangshan Iron and Steel Company reconstructed the 1810 line reheating furnace, replaced the furnace wall with the form of supporting mold casting, achieved a good thermal insulation effect, and provided a solid foundation for thin slab continuous casting and rolling below 1.6.
Concluding remarks
In summary, in the design of the mechanical equipment of the roller hearth furnace, there are many characteristics and improvements in its structure. These new technologies need to be further developed and perfected in practical application to further improve the utilization ratio of the roller hearth furnace equipment.
