Fine-grained high carbide cast iron alloys

Abstract

Embodiments of alloys having high, fine-grained carbide content, and methods of manufacturing such alloys. The alloys can be determined through the use of thermodynamic, microstructural, and compositional criterial in order to create a high strength and high toughness alloy. In some embodiments, the alloys can be used as a wear resistant component.

What is claimed is: 
     
         1 . An article of manufacture comprising:
 an alloy comprising Fe, Cr, and C;   wherein a total carbide and boride content in a microstructure of the alloy exceeds 40 volume %; and   wherein a grain size of all carbides and borides is less than or equal to 50 micrometers in their longest dimension.   
     
     
         2 . The article of manufacture of  claim 1 , wherein the alloy is an iron based alloy and comprises:
 C: 2.2-4.02 wt. %; and   Cr: 10-34 wt. %.   
     
     
         3 . The article of manufacture of  claim 1 , wherein the alloy comprises:
 C: 2.5-3.8 wt. %;   Cr: 10-28 wt. %;   Nb: 0-5 wt. %; and   W: 0-9 wt. %.   
     
     
         4 . The article of manufacture of  claim 3 , wherein the alloy further comprises:
 Mn: 0-1 wt. %;   Mo: 0-1 wt. %;   Si: 0-1 wt. %;   Ti: 0-0.5 wt. %; and   V: 0-3 wt. %.   
     
     
         5 . The article of manufacture of  claim 1 , wherein the alloy comprises:
 C: 2.2-4.02 wt. %;   Cr: 12.7-34 wt. %;   Nb: 3.8-5 wt. %; and   W: 4.37-9 wt. %.   
     
     
         6 . The article of manufacture of  claim 1 , wherein the total carbide and boride content exceeds 45 volume %. 
     
     
         7 . The article of manufacture of  claim 6 , wherein the total carbide and boride content exceeds 50 volume %. 
     
     
         8 . The article of manufacture of  claim 1 , wherein the grain size of all carbides and borides does not exceed 25 micrometers in their longest dimension. 
     
     
         9 . The article of manufacture of  claim 8 , wherein the grain size of all carbides and borides does not exceed 5 micrometers in their longest dimension. 
     
     
         10 . The article of manufacture of  claim 1 , wherein the article of manufacture comprises a sleeve or layer for use in pipelines designed to carry abrasive slurries. 
     
     
         11 . A wear resistant component comprising the article of manufacture of  claim 1 . 
     
     
         12 . An article of manufacture comprising:
 an alloy comprising Fe, Cr, and C;   wherein a total carbide and boride content in a microstructure of the alloy exceeds 0.4 mole fraction; and   wherein a total volume of segregated carbides is less than 0.05 mole fraction, segregated carbides being defined as Fe or Cr-rich boride or carbide meeting the equation: Fe+Cr>50 wt. %, wherein the segregated carbides are thermodynamically stable at a temperature above a temperature at which austenite of the alloy is thermodynamically stable.   
     
     
         13 . The article of manufacture of  claim 12 , wherein the alloy is an iron based alloy and comprises:
 C: 2.2-4.02 wt. %; and   Cr: 10-34 wt. %.   
     
     
         14 . The article of manufacture of  claim 12 , wherein the alloy comprises:
 C: 2.5-3.8 wt. %;   Cr: 10-28 wt. %;   Nb: 0-5 wt. %; and   W: 0-9 wt. %.   
     
     
         15 . The article of manufacture of  claim 13 , wherein the alloy further comprises:
 Mn: 0-1 wt. %;   Mo: 0-1 wt. %;   Si: 0-1 wt. %;   Ti: 0-0.5 wt. %; and   V: 0-3 wt. %.   
     
     
         16 . The article of manufacture of  claim 12 , wherein the alloy comprises:
 C: 2.2-4.02 wt. %;   Cr: 12.7-34 wt. %;   Nb: 3.8-5 wt. %; and   W: 4.37-9 wt. %.   
     
     
         17 . The article of manufacture of  claim 12 , wherein the total carbide and/or boride content exceeds 0.45 mole fraction. 
     
     
         18 . The article of manufacture of  claim 17 , wherein the total carbide and/or boride content exceeds 0.50 mole fraction. 
     
     
         19 . The article of manufacture of  claim 12 , wherein the article of manufacture comprises a sleeve or layer used in pipelines designed to carry abrasive slurries. 
     
     
         20 . A wear resistant component comprising the article of manufacture of  claim 12 . 
     
     
         21 . A method of forming a component comprising:
 providing an alloy comprising Fe, Cr, and C;   wherein a total carbide and boride content in a microstructure of the alloy exceeds 40 volume %; and   wherein a grain size of all carbides and borides is less than or equal to 50 micrometers in their longest dimension; and   forming a component from the alloy.   
     
     
         22 . The method of  claim 21 , wherein the alloy is an iron-based alloy and comprises:
 C: 2.2-4.02 wt. %; and   Cr: 10-34 wt. %.   
     
     
         23 . The method of  claim 21 , wherein the alloy comprises:
 C: 2.5-3.8 wt. %;   Cr: 10-28 wt. %;   Nb: 0-5 wt. %;   W: 0-9 wt. %;   Mn: 0-1 wt. %;   Mo: 0-1 wt. %;   Si: 0-1 wt. %;   Ti: 0-0.5 wt. %; and   V: 0-3 wt. %.   
     
     
         24 . The method of  claim 21 , wherein the alloy comprises:
 C: 2.2-4.02 wt. %;   Cr: 12.7-34 wt. %;   Nb: 3.8-5 wt. %; and   W: 4.37-9 wt. %.   
     
     
         25 . The method of  claim 21 , wherein the total carbide and/or boride content exceeds 0.45 mole fraction. 
     
     
         26 . The method of  claim 25 , wherein the total carbide and/or boride content exceeds 0.50 mole fraction. 
     
     
         27 . The method of  claim 21 , wherein forming the component comprises forming the component via a casting process. 
     
     
         28 . The method of  claim 21 , wherein forming the component comprises forming the component into a sleeve or layer.