Increased performance of the annealing and pickling line furnace for stainless steel strip by oxy-fuel combustion

The No. 10 horizontal annealing and pickling line for ferritic and austenit ic stainless steels at Gueugnon has a nominal production capacity of 170 00 0 try. The strip thickness ranges from 0.4 to 4 mm with an average of 1.3 m m; the strip width varies from 600 to 1500 mm and the maximum line speed in July 1998 was 48 m/min. In order to process the same annual tonnage with an evolution of the produc t mix towards a fewer average thickness, an increase of the treatment speed from 48 m/min to 65 m/min. is required. This is achieved in two steps: in August 1998, increase of the entry and exit accumulators and revamping o f the entry and middle section drives; in August 1999, revamping of the exit section drive. In addition to that an increase of the furnace capacity is necessary to acc ommodate art increase of the? treatment speed. The technological choice mad e was to convert same burners into oxy-fuel burners. The treatment capacity results from a combination of line speed and product thickness. The maximum speed, 48 m/min, is achieved for a thickness of les s than 1 mm. For thinner gauges, thee limitation comes from the welding mac hine and the entry accumulator Above 1.3 mm, the limitation comes from the heating capacity of the furnace, and the treatement speed decreases as the thickness increases.