Low cobalt hard facing alloy

Abstract

A stainless steel alloy comprising essentially 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 4.5 to 5.75 percent by weight silicon, 0.8 to 2.2 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 1.2 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 0.0 to 9.0 percent by weight niobium, 0.005 to 0.6 percent by weight titanium, 0.3 to 6.0 percent by weight molybdenum, and the balance iron plus impurities.

1 . An alloy comprising essentially of 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 4.5 to 5.75 percent by weight silicon, 1.7 to 2.2 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 1.2 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 0.0 to 9.0 percent by weight niobium, 0.005 to 0.6 percent by weight titanium, 0.3 to 6.0 percent by weight molybdenum, and the balance iron plus impurities. 
     
     
         2 . An alloy according to  claim 1  wherein the impurities consist of 0 to 0.03 percent by weight phosphor, 0 to 0.03 percent by weight sulphur. 
     
     
         3 . An alloy according to  claim 1  wherein the alloy comprises 4.0 to 6.0 percent by weight molybdenum. 
     
     
         4 . An alloy according to  claim 1  comprising essentially of 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 4.5 to 5.25 percent by weight silicon, 1.8 to 2.2 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 0.4 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 6.5 to 8.0 percent by weight niobium, 0.005 to 0.05 percent by weight titanium, 0.3 to 0.5 percent by weight molybdenum, and the balance iron plus impurities. 
     
     
         5 . An alloy according to  claim 1  comprising essentially of 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 5.25 to 5.75 percent by weight silicon, 1.7 to 2.0 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 0.4 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 8.0 to 9.0 percent by weight niobium, 0.3 to 0.5 percent by weight titanium, 0.3 to 0.5 percent by weight molybdenum, and the balance iron plus impurities. 
     
     
         6 . A method of forming an alloy comprising the step of providing an alloy in powder form, the alloy comprising essentially of 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 4.5 to 5.75 percent by weight silicon, 1.7 to 2.2 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 1.2 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 0.0 to 9.0 percent by weight niobium, 0.005 to 0.6 percent by weight titanium, 0.3 to 6.0 percent by weight molybdenum, and the balance iron plus impurities; and heating and isostatically pressing the powder. 
     
     
         7 . An article having a coating comprising an alloy comprising essentially of 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 4.5 to 5.75 percent by weight silicon, 1.7 to 2.2 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 1.2 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 0.0 to 9.0 percent by weight niobium, 0.005 to 0.6 percent by weight titanium, 0.3 to 6.0 percent by weight molybdenum, and the balance iron plus impurities. 
     
     
         8 . An article having a coating according to  claim 7 , comprising essentially of 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 4.5 to 5.25 percent by weight silicon, 1.8 to 2.2 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 0.4 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 6.5 to 8.0 percent by weight niobium, 0.005 to 0.05 percent by weight titanium, 0.3 to 0.5 percent by weight molybdenum, and the balance iron plus impurities. 
     
     
         9 . An article having a coating according to  claim 7 , comprising essentially of 19 to 22 percent by weight chromium, 8.5 to 10.5 percent by weight nickel, 5.25 to 5.75 percent by weight silicon, 1.7 to 2.0 percent by weight carbon, 0.0 to 0.2 percent by weight nitrogen, 0.2 to 0.4 percent by weight cobalt, 3.0 to 7.0 percent by weight manganese, 8.0 to 9.0 percent by weight niobium, 0.3 to 0.5 percent by weight titanium, 0.3 to 0.5 percent by weight molybdenum, and the balance iron plus impurities.