Hardfacing structure

Claim 1

AN IMPROVED, METAL, EARTH -PENETRATING TOOL HAVING SURFACES SUBJECT TO SEVERE OR CONSTANT ABRASION, FREQUENTLY ACCOMPAINED BY HEAVY IMPACTS, AND HAVING AN INNER LAYER OF HARDFACING BONDED TO PORTIONS OF SUCH SURFACES, SUCH HARDFACING COMPRISING A METALLIC BINDER AND WEAR RESISTANT PARTICLES DISPERSED THROUGHOUT SUCH BINDER, THE IMPROVEMENT COMPRISING AT LEAST ONE OUTER LAYER OF HARD FACING SIMILARLY COMPRISING WEAR RESISTANT PARTICLES DISPERSED IN A METALLIC BINDER OF SAID OUTER LAYER BEING A METAL FACING LAYER, THE BINDER OF SAID OUTER LAYER BEING A METAL SELECTED FROM THE CLASS CONSISTING OF ALLOY CAST IRON, HIGH CARBON ALLOY STEEL, ALLOY OF NICKEL AND ALLOYS OF COBALT, CHARACTERIZED BY REASONABLE WEAR RESISTANCE, TOUGHNESS, AND A MELTING POINT LOWER THAN THAT OF THE NEXT INNER LAYER BY AT LEAST 100*F. AND PREFERABLY BY 200* TO 500* F. OR MORE, SAID INNER LAYER HAVING A BINDER METAL SELECTED FROM THE CLASS CONSISTING OF ALLOYS OF IRON, ALLOYS OF NICKEL AND ALLOYS OF COBALT, WHEREBY THE HARDFACING ON SUCH TOOL IS OF INCREASED WEAR RESISTANCE AND TOUGHNESS.