Method of operating a reheating furnace in a hot rolling line and a reheating furnace employed therefor

A method for heating workpieces in a reheating furnace in a hot rolling line of the type including a casting system for continuously casting workpieces to be rolled, a heating system to receive said workpieces from said casting system and to heat said workpieces and a rolling system to receive heated workpieces from said heating system and to roll said workpieces at a rolling speed greater than the casting speed of said casting system, said heating method comprising:

• (1) providing said heating system as a single reheating furnace having a longitudinal direction extending between a charging end adjacent said casting system and a discharging end adjacent said rolling system, and moving means for moving said workpieces through said furnace from said charging end thereof to said discharging end thereof, said moving means divided in said longitudinal direction into at least three walking beams each being independently movable in vertical and horizontal directions;
• (2) successively charging a first plurality, equal to a rolling quantity of workpieces to be rolled by said rolling system in a single rolling cycle, of cast workpieces from said casting system into said charging end of said furnace at said casting speed;
• (3) operating said walking beams to transport at a predetermined speed said first plurality of workpieces in said longitudinal direction through said furnace while therein heating said workpieces;
• (4) upon the arrival of the leading of said first plurality of workpieces at said discharging end, operating said walking beams to interrupt said transport, and maintaining said first plurality of workpieces within said furnace while continuing said heating thereof;
• (5) while said first plurality of workpieces are maintained and heated within said furnace, initiating the successive charging of a second plurality of cast workpieces from said casting system into said charging end of said furnace at said casting speed;
• (6 ) during the charging of said second plurality of workpieces, and after said first plurality of workpieces have been heated for a predetermined period of time, operating said walking beams to discharge said first plurality of workpieces from said discharging end of said furnace to said rolling system at a discharge speed greater than said predetermined speed and in synchronization with said rolling speed;
• (7) during said discharging, continuing to charge said second plurality of workpieces into said charging end of said furnace, until said second plurality equals said first plurality;
• (8) operating said walking beams to transport at said predetermined speed said second plurality of workpieces in said longitudinal direction through said furnace while therein heating said workpieces;
• (9) upon the arrival of the leading of said second plurality of workpieces at said discharging end, operating said walking beams to interrupt said transport, and maintaining said second plurality of workpieces within said furnace while continuing said heating thereof;
• and
• (10) subsequently sequentially repeating said steps (5), (6), (7), (8) and (9) for successive further pluralities of cast workpieces.