Edge-provided tool and method for the manufacture thereof

Abstract

The invention relates to an edge-provided tool, such as a doctor blade, for use as wiping tool in the production of pulp and/or paper in different stages of the production process. It consists of an edge-provided strip of steel, the edge portion of which has been provided with a wear-resistant coating applied by means of laser technique, so that metallurgical binding is present between said coating and the steel strip, whereby a level of surface hardness of more than 850 UV being attained. Thereby, wear-resistant doctor blades having a long service life have been obtained.

1 . Doctor or coater blade, in particular for use as wiping, scraper and/or cleaning tool in production of paper pulp and/or paper in different stages of the production process, comprising an edge-provided strip of steel, the edge portion of which has been provided with a wear-resistant coating, wherein 
 the edge portion of the blade is coated with surface-reinforcing coating applied by laser technique, so that the metallurgical binding is present between said wear-resistant coating and the steel strip, and the edge portion has a hardness of more than 1000 HV.    
   
   
       2 . Doctor or coater blade according to  claim 1 , wherein the wear-resistant coating has a level of surface hardness of at least 850 HV.  
   
   
       3 . Doctor or coater blade according to  claim 1 , wherein the edge portion of the blade has a surface layer applied by laser coating, the thickness of which layer constitutes 5-15% of the thickness of the blade.  
   
   
       4 . Doctor or coater blade according to  claim 1 , wherein the edge portion of the blade has a surface-reinforcing portion applied by laser coating or laser impregnation, the thickness of which portion constitutes 5-15% of the thickness of the blade.  
   
   
       5 . Doctor or coater blade according to  claim 1  wherein the steel is a carbon steel with a chemical composition in % by weight being 0.8-1.2% of C, preferably about 1% of C, 0.20-0.35% of Si, 0.35-0.50% of Mn, maximum 0.02% of P, maximum 0.01% of S, with Fe as balance and the content of some additional element in the periodic system in contents below 0.5%.  
   
   
       6 . Method for the manufacture of a doctor or coater blade according to  claim 1  wherein a material manufactured from steel is first rolled out and edge-treated to have an edge portion formed along one of the edges, said edge portion then is provided with a surface-reinforcing layer applied by laser technique, in such a way that a metallugical binding arises between said layer and the subjacent steel substrate, and the edge treatment is provided in the way that the steel substrate is subjected to a laser treatment during supply of powder at such a supply of heat that the powder is fused with the steel substrate while forming an atomic/metallurgical binding.  
   
   
       7 . Method for the manufacture of a doctor or coater blade according to  claim 1  wherein a material manufactured from steel is first rolled out and edge-treated to have an edge portion formed along one of the edges, said edge portion then is provided with a surface-reinforcing layer applied by laser technique, in such a way that a metallugical binding arises between said layer and the subjacent steel substrate, and the edge treatment is provided in the way that the steel substrate is subjected to a laser impreganation and recovery, material particles of a ceramic material penetrating into the surface melt by laser, so that an atomic/metallurgical binding arises.  
   
   
       8 . Method according to  claim 6 , wherein the supplied powder essentially contains aluminum oxide.  
   
   
       9 . Method according to  claim 6 , wherein the supplied material essentially contains stellite.  
   
   
       10 . Method according to  claim 7 , wherein the impregnation is carried out in the way that carbides and nitrides, such as TiC, NbC and/or TiN, are supplied to the steel substrate.  
   
   
       11 . Method according to  claim 6 , wherein the chemical composition of the steel in % by weight is 0.8-1.2% of C, preferably about 1% of C, 0.20-0.35% of Si, 0.35-0.50% of Mn, maximum 0.02% of P, maximum 0.01% of S, with Fe as balance and the content of some additional element in the periodic system in contents below 0.5%.  
   
   
       12 . Method according to  claim 6 , wherein the wear-resistant coating has a level of surface hardness of more than 850 HV.  
   
   
       13 . Doctor or coater blade according to  claim 2 , wherein the steel is a carbon steel with a chemical composition in % by weight being 0.8-1.2% of C, preferably about 1% of C, 0.20-0.35% of Si, 0.35-0.50% of Mn, maximum 0.02% of P, maximum 0.01% of S, with Fe as balance and the content of some additional element in the periodic system in contents below 0.5%.  
   
   
       14 . Doctor or coater blade according to  claim 3 , wherein the steel is a carbon steel with a chemical composition in % by weight being 0.8-1.2% of C, preferably about 1% of C, 0.20-0.35% of Si, 0.35-0.50% of Mn, maximum 0.02% of P, maximum 0.01% of S, with Fe as balance and the content of some additional element in the periodic system in contents below 0.5%.  
   
   
       15 . Doctor or coater blade according to  claim 4 , wherein the steel is a carbon steel with a chemical composition in % by weight being 0.8-1.2% of C, preferably about 1% of C, 0.20-0.35% of Si, 0.35-0.50% of Mn, maximum 0.02% of P, maximum 0.01% of S, with Fe as balance and the content of some additional element in the periodic system in contents below 0.5%.  
   
   
       16 . Method according to  claim 7 , wherein the supplied powder essentially contains aluminum oxide.  
   
   
       17 . Method according to  claim 7 , wherein the supplied material essentially contains stellite.  
   
   
       18 . Method according to  claim 7 , wherein the chemical composition of the steel in % by weight is 0.8-1.2% of C, preferably about 1% of C, 0.20-0.35% of Si, 0.35-0.50% of Mn, maximum 0.02% of P, maximum 0.01% of S, with Fe as balance and the content of some additional element in the periodic system in contents below 0.5%.  
   
   
       19 . Method according to  claim 7 , wherein the wear-resistant coating has a level of surface hardness of more than 850 HV.  
   
   
       20 . Method according to  claim 16 , wherein the impregnation is carried out in the way that carbides and nitrides, such as TiC, NbC and/or TiN, are supplied to the steel substrate.