Method for producing strips made of steel, in particular for producing cutting and machining tools having improved service life

Abstract

In a method for producing strips made of steel, in particular for producing cutting and machining tools having improved service life, a preliminary strip is produced from a melt of a hardenable steel in a casting process and then rolled out into a hot-rolled strip and then, if necessary, annealed and cold rolled. The preliminary strip is produced in a horizontal strip casting system, wherein the melt is discharged from a feed vessel onto a cooled conveyor belt circulating over two deflecting rollers and is cast, with a killed flow and without bending, into a preliminary strip in the range between 6 and 40 mm, then rolled into hot-rolled strip having a degree of deformation of at least 50%, wherein the cooling rate on the top side and the bottom side of the preliminary strip is set differently for the purpose of residual solidification outside of the centre of the strip.

What is claimed is: 
     
         1 .- 13 . (canceled) 
     
     
         14 . A Method for producing strips of steel, in particular for producing cutting or machining tool with improved service life, comprising:
 producing a pre-strip having a thickness between 6 and 40 mm under calm flow conditions and without bending in a horizontal strip casting facility by casting a melt of a hardenable steel from a feed vessel onto a cooled conveyor belt circulating about two deflection rollers;   cooling a topside and a bottom side of the pre-strip at different cooling rates so that a residual solidification of the pre-strip is situated outside of a center of the pre-strip; and   rolling the pre-strip into a hot strip with a deformation degree of at least 50%.   
     
     
         15 . The method of  claim 14 , wherein the bottom side of the pre-strip is cooled at a higher rate than the topside of the pre-strip. 
     
     
         16 . The method of  claim 15 , wherein the bottom side of the pre-strip is cooled indirectly by cooling a bottom side of the conveyor belt. 
     
     
         17 . The method of  claim 16 , wherein the bottom side of the conveyor belt is cooled with water and the topside of the pre-strip is cooled at resting air or in a protective gas atmosphere. 
     
     
         18 . The method of  claim 14 , further comprising after a complete solidification of the pre-strip and prior to a further processing of the pre-strip, passing the pre-strip through a homogenization zone. 
     
     
         19 . The method of  claim 18 , wherein the further processing is a cutting of the pre-strip into plates. 
     
     
         20 . The method of  claim 19 , further comprising after the cutting into plates, heating the plates to rolling temperature and rolling the plates. 
     
     
         21 . The method of  claim 18 , wherein the further processing is a coiling of the pre-strip. 
     
     
         22 . The method of  claim 21 , further comprising after the coiling, de-coiling the pre-strip, heating the pre-strip to rolling temperature and rolling the pre-strip. 
     
     
         23 . The method of  claim 21 , further comprising re-heating the pre-strip prior to the de-coiling. 
     
     
         24 . The method of  claim 14 , further comprising after the rolling, coiling the pre-strip, wherein the pre-strip is subjected to the rolling in-line. 
     
     
         25 . The method of  claim 14 , wherein the deformation degree is >70%. 
     
     
         26 . The method of  claim 14 , further comprising after the cooling, cold rolling the pre-strip.