Composite Metal Product

Abstract

A centrifugally cast composite metal product having an axis of rotational symmetry and a mass of at least 5 kg, comprises a host metal and insoluble solid refractory particles of & refractory material in a non-uniform distribution throughout the host metal. The particles have a density that is within 30% of the density of the host metal at its casting temperature.

1 . A centrifugally cast composite metal product having an axis of rotational symmetry and a mass of at least 20 kg and comprising a metal host and insoluble solid particles of a refractory material in a non-uniform distribution throughout the host metal, wherein the particles have a density that is within 20% of the density of the metal host at its casting temperature, and wherein the non-uniform distribution of refractory particles comprises a first concentration of particles in an exterior or interior surface layer of the product that is higher than a second concentration of particles in another layer in the product. 
     
     
         2 . (canceled) 
     
     
         3 . The composite metal product defined in  claim 1 , wherein the first concentration of refractory particles in the exterior surface layer of the product is in a range of 10-40 vol % of the total volume of the exterior surface layer. 
     
     
         4 . The composite metal product defined in  claim 1 , wherein the second concentration of refractory particles in the other layer of the product is in a range of 2-4.5 vol % of the total volume of the other layer. 
     
     
         5 . The composite metal product defined in  claim 1 , wherein the first concentration of refractory particles in the exterior surface layer of the product is 50-120 vol % higher than the nominal volume percentage of the refractory material in the product. 
     
     
         6 . The composite metal product defined in  claim 1 , wherein the exterior or interior surface layer of the product extends less than 50% of the radial thickness of the product from the exterior or interior surface of the product. 
     
     
         7 . The composite metal product defined in  claim 1 , wherein the exterior or interior surface layer of the product extends 1-50 mm from the exterior or interior surface of the product. 
     
     
         8 - 9 . (canceled) 
     
     
         10 . The composite metal product defined in  claim 1  having a mass of at least 50 kg. 
     
     
         11 . The composite metal product defined in  claim 1  having a mass of at least 75 kg. 
     
     
         12 . (canceled) 
     
     
         13 . The composite metal product defined in  claim 1 , wherein the refractory particles are carbides and/or borides and/or nitrides of one or more than one transition metal where the particles are a chemical mixture (as opposed to a physical mixture) of the carbides and/or borides and/or nitrides of the transition metals. 
     
     
         14 . (canceled) 
     
     
         15 . The composite metal product defined in  claim 1 , wherein the host metal is an alloy comprising any one of the following alloys:
 (a) Hadfield steel, for use for example in gyratory crusher mantles;   (b) 420C stainless steel, for use for example in shaft sleeves in slurry pumps; and   (c) high chromium white cast iron.   
     
     
         16 . The composite metal product defined in  claim 15 , wherein the host metal is Hadfield steel comprising:
 1.0-1.4 wt % C   0.0-1.0 wt % Si,   10-15 wt % Mn,   0.0-3.0 wt % Mo,   0.0-5.0 wt % Cr,   0.0-2.0 wt % Ni,   
       with the remainder being Fe and incidental impurities. 
     
     
         17 . The composite metal product defined in  claim 15 , wherein the host metal is a 420C stainless steel comprising:
 0.3-0.5 wt % C,   0.5-1.5 wt % Si,   0.5-3.0 wt % Mn,   0.0-0.5 wt % Mo,   10-14 wt % Cr,   0.0-1.0 wt % Ni,   
       with the remainder being Fe and incidental impurities. 
     
     
         18 . The composite metal product defined in  claim 15 , wherein the host metal is a high chromium white cast iron comprising:
 1.5-4.0 wt % C,   0.0-1.5 wt % Si,   0.5-7.0 wt % Mn,   0.0-1.0 wt % Mo,   15-35 wt % Cr,   0.0-1.0 wt % Ni,   
       with the remainder being Fe and incidental impurities. 
     
     
         19 . The composite metal product defined in  claim 1 , wherein the host metal a non-ferrous metal. 
     
     
         20 . The composite metal product defined in  claim 1  comprising a gyratory crusher mantle for a primary, secondary or tertiary crusher. 
     
     
         21 . The composite metal product defined in  claim 1  comprising a slurry pump shaft sleeve. 
     
     
         22 - 24 . (canceled) 
     
     
         25 . The method of centrifugally casting a composite metal product as defined in  claim 37 , wherein steps (a) and (b) are carried out under an inert environment. 
     
     
         26 - 27 . (canceled) 
     
     
         28 . The method of centrifugally casting a composite metal product as defined in  claim 37 , wherein step (b) comprises rotating the mould at a 10-120 G-Factor. 
     
     
         29 - 36 . (canceled) 
     
     
         37 . A method of centrifugally casting a composite metal product having an axis of rotational symmetry and a mass of at least 5 kg and comprising a host metal and a non-uniform dispersion of insoluble solid refractory particles of a refractory material, the method comprising:
 (a) forming a slurry comprising solid refractory particles dispersed in a liquid host metal, with the refractory particles comprising 5-50 vol % of the total volume of the slurry, with the refractory particles being insoluble at a casting temperature, and with the refractory particles having a density that is within 20% of the density of the metal host at the casting temperature; and   (b) pouring the slurry into a mould for the product and centrifugally casting the product in the mould by rotating the mould about the axis subsequent to and/or during pouring the slurry into the mould to cause a concentration of insoluble refractory particles at or near an exterior surface or at or near an interior surface of the product that is higher than the concentration of particles elsewhere in the product and obtaining a non-uniform distribution of insoluble solid particles throughout the host metal.   
     
     
         38 . A method of centrifugally casting a composite metal product having an axis of rotational symmetry and a mass of at least 5 kg and comprising a host metal and a non-uniform distribution of insoluble solid particles of a refractory material, the method comprising adding (a) niobium or (b) two or more than two of niobium and titanium and tungsten to a melt containing a host metal in a form that produces solid refractory particles of niobium carbide that are insoluble at a casting temperature and/or solid refractory particles of a chemical mixture of two or more than two of niobium carbide and titanium carbide and tungsten carbide that are insoluble at a casting temperature, with the solid refractory particles being in a range of 5-50 vol % of the total volume of the product, and centrifugally casting the product in a mould by rotating the mould about the axis subsequent to and/or during pouring the slurry into the mould to cause a concentration of insoluble refractory particles at or near an exterior surface or at or near an interior surface of the product that is higher than the concentration of particles elsewhere in the product and obtaining a non-uniform distribution of insoluble solid refractory particles throughout the host metal.