Iron-Based Powder Combination

Abstract

The invention relates to a powder metallurgical combination comprising an iron-based powder A essentially consisting of core particles of iron pre-alloyed with molybdenum and having 6-15%, preferably 8-12% by weight of copper diffusion alloyed to the core particles, an iron-based powder B essentially consisting of particles of iron pre-alloyed with molybdenum and having 4.5-8%, preferably 5-7% by weight of nickel diffusion alloyed to the core particles, and an iron-based powder C essentially consisting of particles of iron pre-alloyed with molybdenum. The invention also relates to the powders A and B per se. Further the invention relates to a method for preparing an iron-based sintered component comprising 0.3-2% by weight of molybdenum, 0.2-2%. Preferably 0.4-0.08% by weight of copper and 0.1-4% by weight of nickel and to a method to obtain a sintered component having a predetermined strength and a predetermined dimensional change during sintering.

1 . A powder metallurgical combination comprising: 
 an iron-based powder A, essentially consisting of core particles of iron-prelloyed with molybdenum, whereby 6-15% by weight of powder A is copper being diffusion alloyed to the core particles,    an iron-based powder B, essentially consisting of core particles of iron pre-alloyed with molybdenum, whereby 4.5-8% by weight of powder B is nickel being diffusion alloyed to the core particles, and    an iron-based powder C, essentially consisting of particles or iron pre-alloyed with molybdenum.    
     
     
         2 . The powder metallurgical combination according to  claim 1 , wherein the amount of copper in powder A is 8-12% by weight.  
     
     
         3 . The powder metallurgical combination according to  claim 1 , wherein the amount of nickel in powder B is 5-7% by weight.  
     
     
         4 . The powder metallurgical combination according to  claim 1 , wherein the amount of molybdenum in each of powder A, B or C is 0.3-2% by weight.  
     
     
         5 . The powder metallurgical combination according to  claim 1 , wherein the amount of molybdenum is essentially the same in each of powder A, B or C.  
     
     
         6 . The powder metallurgical combination according to  claim 1 , wherein the amount of copper in the combination is within the range 0.2-2% by weight.  
     
     
         7 . The powder metallurgical combination according to  claim 6 , wherein the amount of nickel in the combination is within the range 0.1-4% by weight.  
     
     
         8 . The powder metallurgical combination according to  claim 1 , further comprising up to 1% graphite by weight.  
     
     
         9 . The powder metallurgical combination according to  claim 1 , comprising other additives selected from the group consisting of lubricants, binders, other alloying elements, hard phase materials, machinability enhancing agents.  
     
     
         10 . The powder metallurgical combination according to  claim 1 , wherein powder C is essentially free from Cu and Ni.  
     
     
         11 . A diffusion alloyed iron-based powder essentially consisting of core particles of iron pre-alloyed with 03.-2% by weight of molybdenum, whereby 6-15% by weight of said powder is copper diffusion alloyed to the core particles.  
     
     
         12 . A diffusion alloyed iron-based powder essentially consisting of core particles of iron pre-alloyed with 03.-2%, by weight of molybdenum, whereby 4.5-8% by weight of said powder is nickel diffusion alloyed to the core particles.  
     
     
         13 . A method of preparing an iron-based sintered component comprising 0.3-2% by weight of molybdenum, 0.2-2% by weight of copper and 0.1-4% by weight of nickel comprised mixing powders A, B, C as defined in  claim 1  and graphite, 
 compacting the mixture to form a compacted body, and sintering the body.    
     
     
         14 . A method to obtain a sintered component, having a predetermined strength and a predetermined dimensional change during sintering, comprising the steps of: 
 determining the required amounts of copper, nickel, molybdenum and carbon in the sintered component needed for obtaining the predetermined strength and dimensional change,    determining the respective amounts of powder A, B and C as defined in  claim 1 ,    mixing the determined amounts of powders A, B and C with graphite and optional other additives,    compacting the mixture to form a powder compact; and    sintering the powder compact.    
     
     
         15 . The powder metallurgical combination according to  claim 2 , wherein the amount of nickel in powder B is 5-7% by weight.  
     
     
         16 . The powder metallurgical combination according to  claim 1 , wherein the amount of molybdenum in each of powder A, B or C is 0.5-1.5%, by weight.  
     
     
         17 . The powder metallurgical combination according to  claim 1 , wherein the amount of copper in the combination is within the range 0.4-0.8% by weight.  
     
     
         18 . The powder metallurgical combination according to  claim 1 , further comprising 0.3-0.7% graphite by weight.  
     
     
         19 . A diffusion alloyed iron-based powder essentially consisting of core particles of iron pre-alloyed with 0.5-1.5% by weight of molybdenum, whereby 8-12% by weight of said powder is copper diffusion alloyed to the core particles.  
     
     
         20 . A diffusion alloyed iron-based powder essentially consisting of core particles of iron pre-alloyed with 0.7-1.0% by weight of molybdenum, whereby 8-12% by weight of said powder is copper diffusion alloyed to the core particles.