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1. WO1995006758 - ALLIAGES DE RECHARGEMENT DUR CONTENANT DES CARBURES OU BORURES METALLIQUES PRECIPITES ET LEUR PROCEDE DE FABRICATION

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

- 14 - What is Claimed is:
1. An abrasion resistant hard surfacing alloy having a Rockwell C hardness greater than about 50 and improved abrasion resistance comprising:
from about 12% to about 20% tungsten from about 13% to about 30% chromium, from about 2.5% to about 5.5% boron, less than about .06% carbon and effective amounts of melting point depressants and fluxes with the balance being nickel, wherein a large population of metallic boride crystals are metallurgically bound in said alloy.

2. The hard surfacing alloy of Claim 1 wherein said melting point depressants and fluxes further comprise silicon and iron in amounts ranging from about 2% to about 5% each.

3. The hard surfacing alloy in accordance with Claim 1 wherein said metallic borides are chromium-tungsten borides encompassing a surface area of said alloy of from about 14% to about 22%.

4. The hard surfacing alloy of Claim 3 wherein said crystals are of a size of from about 15 to about 25 microns.

5. A process of manufacture of a high temperature, abrasion and corrosion resistant alloy having precipitated metallic borides comprising the steps of:
a) formulating a melt of from about 12% to about 20% tungsten from about 13% to about 30% chromium from about 2.5% to about 5.5% boron and less than .06% carbon and effective amounts of flux agents and melting point depressants and the balance being nickel; b) raising the mixture to a temperature of greater than 2500°F; and
c) atomizing the melt with rapid solidification wherein a powdered alloy containing precipitated metallic borides is produced.

- 15 - 6. The process of Claim 5 wherein the mixture is raised to a temperature of about

2800°F to about 3000°F prior to atomization.

7. The process of Claim 5 wherein an addition of from about 2% to about 5% silicon to the melt of step (b) immediately prior to atomization.

8. A hard surfacing alloy having high abrasion resistance and a Rockwell C hardness of from about 50 to about 70 consisting essentially of: from about 15% to about 18% tungsten; from about 14% to about 18% chromium; less than about .06% carbon; from about 3% to about 4% of silicon from about 3.5% to about 5% iron and from about 2.5% to about 4.5% boron; and
with the balance being nickel, said alloy including precipitated crystals of metallic borides.

9. The hard surfacing alloy of Claim 8 wherein the population of said metallic borides is from about 14% to about 22%.

10. The hard surfacing alloy of Claim 8 wherein said metallic boride crystals further comprise chromium-tungsten borides.

11. The hard surfacing alloy of Claim 8 wherein said metallic boride crystals have a size of from about 15 to about 25 microns.