Powder-Metallurgically Produced Steel Material Containing Hard Material Particles, Method for Producing a Component from Such a Steel Material, and Component Produced from the Steel Material

Abstract

A steel material which has a minimised density, a good wear resistance and a concomitantly high service life with maximised resistance to extreme temperature changes and likewise optimised corrosion resistance. The steel material is produced by powder metallurgy and constituted as follows (in wt. %): C: 1.5-5.0%, Si: 0.3-2.0%, Mn: 0.3-2.0%, P: 0-<0.035%, S: 0-<0.35%, N: 0-<0.1%, Cr: 3.0-15.0%, Mo: 0.5-2.0%, V: 6.0-18.0%, optionally one or more elements from the group Nb, Ni, Co, and W, wherein the content of Ni, Co and W is respectively at most 1.0% and the content of Nb is at most 2.0%, residual iron and unavoidable impurities, wherein separately added hard material particles in contents of 2.5 to 30 wt. % are embedded in the steel matrix. From steel alloy powder alloyed in this way, a solid semifinished product is formed by a sintering process or an additive process, which undergoes a heat treatment and is then finished to form the respective component.

1 . A steel material produced by powder metallurgy and having a steel matrix comprising (in wt. %): 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   C: 
                   1.5-5.0%  
                 
                     
                   Si: 
                   0.3-2.0%, 
                 
                     
                   Mn: 
                   0.3-2.0%, 
                 
                     
                   P: 
                   0-<0.035%  
                 
                     
                   S: 
                   0-<0.35%,  
                 
                     
                   N: 
                    0-<0.1%, 
                 
                     
                   Cr: 
                   3.0-15.0%,  
                 
                     
                   Mo: 
                   0.5-2.0%, 
                 
                     
                   V: 
                   6.0-18.0%,  
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
               
            
           
         
         optionally one or more elements selected from the group consisting of Nb, Ni, Co, and W, wherein the content of Ni, Co, and W is respectively at most 1.0% and the content of Nb is at most 2.0%, and 
         residual iron and unavoidable impurities, 
         wherein 2.5-30 wt. % of separately added hard material particles are embedded in the steel matrix. 
       
     
     
         2 . The steel material according to  claim 1 , wherein, when the Cr content of the steel matrix is up to 8.0 wt. %, the C content of the steel matrix with a maximum deviation of at most 0.2 wt. % corresponds to a target quantity % CTarget, where % CTarget=0.2×% V+0.4 wt. % and % V denotes the respective V content of the steel matrix. 
     
     
         3 . The steel material according to  claim 1 , wherein, when the Cr content of the steel matrix is at least 11.0 wt. %, the C content of the steel matrix with a maximum deviation of at most 0.2 wt. % corresponds to a target quantity % CTarget, where % CTarget=(0.2×% V+0.4 wt. %)×1.3 and % V denotes the respective V content of the steel matrix. 
     
     
         4 . The steel material according to  claim 1 , wherein, when the Cr content of the steel matrix is more than 8 wt. % and less than 11 wt. %, the C content of the steel matrix is between % CTarget1 and % CTarget2 where % CTarget1=0.2×% V+0.4 wt., % CTarget2 (0.2×% V+0.4 wt. %)×1.3, and % V denotes the respective V content of the steel matrix. 
     
     
         5 . The steel material according to  claim 1 , wherein the Si content of the steel matrix is at least 0.7 wt. % and at most 1.5 wt. %. 
     
     
         6 . The steel material according to  claim 1 , wherein the Mn content of the steel matrix is at least 0.7 wt. % and at most 1.5 wt. %. 
     
     
         7 . The steel material according to  claim 1 , wherein the S content of the steel matrix is at least 0.035 wt. %. 
     
     
         8 . The steel material according to  claim 1 , wherein the Mo content of the steel matrix is at least 0.9 wt. % and at most 1.5 wt. %. 
     
     
         9 . The steel material according to  claim 1 , wherein the steel matrix further comprises one or more elements selected from the group consisting of (in wt. %): 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   Ni: 
                   0.2-0.4%, 
                 
                     
                   Co: 
                         0.3-0.5%, and 
                 
                     
                   W: 
                   0.3-0.5%. 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
               
            
           
         
       
     
     
         10 . The steel material according to  claim 1 , wherein the hard material particles are TiC particles. 
     
     
         11 . The steel material according to  claim 1 , wherein the hard material particles are present in a D50 particle size of at most 50 μm. 
     
     
         12 . A method for producing a component which comprises a steel material according to  claim 1 , comprising:
 a) preparing a steel alloy powder comprising (in wt. %) 1.5-5.0% C, 0.3-2.0% Si, 0.3-2.0% Mn, <0.035% P, <0.35% S, <0.1% N, 3.0-15.0% Cr, 0.5-2.0% Mo, 6.0-18.0% V, optionally one or more elements from the group consisting of Nb, Ni, Co, and W, wherein the content of Ni, Co, and W is respectively at most 1.0% and the content of Nb is at most 2.0%, and the remainder iron and unavoidable impurities,   b) mixing the steel alloy powder with hard material particles, wherein the content of hard material particles in the steel alloy powder and hard material particle mixture is 2.5 to 30 wt. %,   c) optionally, drying the steel alloy powder or the steel alloy powder and hard material mixture,   d) forming a solid semifinished product from the steel alloy powder or the steel alloy powder and hard material particle mixture by a sintering process,   c) processing the resulting semifinished product into the component.   
     
     
         13 . The method according to  claim 12 , wherein the alloy constituents of the steel alloy powder are respectively provided in powder form and mixed into the steel alloy powder. 
     
     
         14 . The method according to  claim 12 , wherein the processing of the resulting semifinished product comprises a material-removing machining of the semifinished product. 
     
     
         15 . A component which performs movements involving high acceleration or velocity comprising a steel material according to  claim 1 . 
     
     
         16 . The method according to  claim 12 , wherein the sintering process is one of hot isostatic pressing and an additive process.