Energy-efficient production of a ferritic hot-rolled strip in an integrated casting-rolling plant
Energy-efficient production of a ferritic hot-rolled strip ( 6 ) in an integrated casting-rolling plant ( 1 ), which modifies the known processes for producing a ferritic hot-rolled strip ( 6 ) in an integrated casting-rolling plant ( 1 ) so that the ferritic hot-rolled strip ( 6 ) can be produced significantly more energy-efficiently but nevertheless has good metallurgical properties and a good surface quality.
1 . An integrated casting-rolling plant for producing a ferritic hot-rolled strip by carrying out a process comprising:
a continuous caster for continuously casting a liquid steel to give a first strip having a slab or thin slab cross section;
a multipart roughing stand for prerolling the first strip to give an intermediate strip;
at least one inductive surface heating module being configured for heating broad sides of the intermediate strip to a surface temperature of ≥1000° C., wherein the at least one surface heating module is heated by an alternating current having a first frequency f 1 ;
a descaling apparatus configured for descaling the broad sides of the heated intermediate strip;
a multipart finishing stand configured for final rolling of the descaled intermediate strip to give a hot-rolled strip, wherein the descaled intermediate strip after descaling and without further cooling enters a first set of the finishing stand with an average temperature of 775-900° C. and at least a last rolling pass in the finishing stand takes place in a ferritic temperature range of ferritic steel;
a cooling section configured for bringing the hot-rolled strip to coiler temperature, the cooling section having insulation panels between which the hot-rolled strip passes to thermally insulate the hot-rolled strip;
a cutter downstream of the cooling section; and
a coiler downstream of the cutter and configured for winding up the hot-rolled strip.
2 . The integrated casting-rolling plant as claimed in claim 1 , wherein an induction furnace (IH) having a plurality of inductive volume-heating modules is arranged in the flow direction of the material between the multipart roughing stand and the at least one inductive surface heating module wherein the induction furnace (IH) increases temperature of the intermediate strip.
3 . The integrated casting-rolling plant as claimed in claim 1 , wherein a pyrometer for measuring a surface temperature Tact of the partially finished intermediate strip is arranged between the first stand of the finishing mill and a second stand of the finishing mill or between the second stand and a third stand of the finishing mill, the pyrometer is connected so as to be able to transmit a signal to a temperature regulator and the temperature regulator is connected so as to be able to transmit a signal to the at least one inductive volume-heating module, the temperature regulator can transmit an actuating variable as a function of an intended surface temperature Tint and taking into account the surface temperature Tact to at least one inductive volume-heating module, wherein the volume-heating modules can heat the intermediate strip to such a degree that the surface temperature Tact corresponds closely to the intended surface temperature Tint.