Abrasion resistant steel, method of manufacturing an abrasion resistant steel and articles made therefrom

Abstract

An abrasion resistant steel consisting essentially of, in weight %: 0.20-0.30% carbon, 0.40-1.25% manganese, 0.05% maximum phosphorous, 0.01% maximum sulfur, 0.20-0.60% silicon, 0.50-1.70% chromium, 0.20-2.00% nickel, 0.07-0.60% molybdenum, 0.010-0.10% titanium, 0.001-0.10% boron, 0.015-0.10% aluminum, balance iron, and incidental impurities. The steel may be melted and cast into a steel ingot or slab, hot rolled to a desired plate thickness; austenitized at 1650-1700° F.; water quenched; and tempered at 350-450° F. The resulting steel plate may have a surface hardness of at least 440 HBW, a mid-thickness hardness of at least 90% of the surface hardness, and toughness in the transverse direction at −60° F. of at least 20 ft-lbs and at room temperature of at least 40 ft-lbs.

1 . An abrasion resistant steel consisting essentially of, in weight %: 0.20-0.30% carbon, 0.40-1.25% manganese, 0.05% maximum phosphorous, 0.01% maximum sulfur, 0.20-0.60% silicon, 0.50-1.70% chromium, 0.20-2.00% nickel, 0.07-0.60% molybdenum, 0.010-0.10% titanium, 0.001-0.10% boron, 0.015-0.10% aluminum, balance iron, and incidental impurities. 
     
     
         2 . The abrasion resistant steel according to  claim 1 , wherein the surface hardness is at least 440 HBW and the mid-thickness hardness is at least 90% of the surface hardness. 
     
     
         3 . The abrasion resistant steel according to  claim 1 , wherein the microstructure is tempered martensite. 
     
     
         4 . The abrasion resistant steel according to  claim 1 , wherein the toughness in the transverse direction at −60° F. is at least 20 ft-lbs and at room temperature is at least 40 ft-lbs. 
     
     
         5 . The abrasion resistant steel according to  claim 1 , wherein the surface hardness is at least 440 HBW. 
     
     
         6 . The abrasion resistant steel according to  claim 5 , wherein the surface hardness is between 440-514 HBW. 
     
     
         7 . The abrasion resistant steel according to  claim 1 , consisting essentially of, in weight %: 0.22-0.26% carbon, 0.70-0.90% manganese, 0.025% maximum phosphorous, 0.003% maximum sulfur, 0.20-0.40% silicon, 0.80-1.00% chromium, 0.40-0.60% nickel, 0.07-0.15% molybdenum, 0.010-0.04% titanium, 0.001-0.003% boron, 0.015-0.06% aluminum, balance iron, and incidental impurities. 
     
     
         8 . The abrasion resistant steel according to  claim 1 , consisting essentially of, in weight %: 0.24% carbon, 0.80% manganese, 0.010% maximum phosphorous, 0.003% maximum sulfur, 0.25% silicon, 0.90% chromium, 0.50% nickel, 0.10% molybdenum, 0.03% titanium, 0.0015% boron, 0.035% aluminum, balance iron, and incidental impurities. 
     
     
         9 . The abrasion resistant steel according to  claim 1 , wherein the steel has been austenitized at 1650-1700° F., water quenched, and tempered 350-450° F. 
     
     
         10 . The abrasion resistant steel according to  claim 1 , wherein Cr+Mn+Mo is 1.4% minimum. 
     
     
         11 . The abrasion resistant steel according to  claim 1 , wherein Ni+Si+Cr is 1.4% minimum. 
     
     
         12 . The abrasion resistant steel according to  claim 1 , wherein Cr+Si is 1% minimum. 
     
     
         13 . A method for producing an abrasion resistant steel plate comprising:
 a. melting and casting a steel ingot or slab consisting essentially of in weight %: 0.20-0.30% carbon, 0.40-1.25% manganese, 0.05% maximum phosphorous, 0.01% maximum sulfur, 0.20-0.60% silicon, 0.50-1.70% chromium, 0.20-2.00% nickel, 0.07-0.60% molybdenum, 0.010-0.10% titanium, 0.001-0.10% boron, 0.015-0.10% aluminum, balance iron, and incidental impurities;   b. hot rolling the ingot or slab to the desired thickness;   c. austenitizing the plate at 1650-1700° F.;   d. water quenching the plate; and   e. tempering the plate at 350-450° F.   
     
     
         14 . The method according to  claim 13 , wherein during the melting and casting step the steel is killed, desulfurized, vacuum degassed, treated for sulfide shape control, or a combination thereof. 
     
     
         15 . The method according to  claim 13 , wherein cross rolling is used during the hot rolling step. 
     
     
         16 . The method according to  claim 13 , wherein the microstructure is tempered martensite. 
     
     
         17 . The method according to  claim 13 , wherein the toughness in the transverse direction at −60° F. is at least 20 ft-lbs and at room temperature is at least 40 ft-lbs. 
     
     
         18 . The method according to  claim 13 , wherein the surface hardness is at least 440 HBW and the mid-thickness hardness is at least 90% of the surface hardness. 
     
     
         19 . The method according to  claim 13 , wherein the steel consisting essentially of, in weight %: 0.22-0.26% carbon, 0.70-0.90% manganese, 0.025% maximum phosphorous, 0.003% maximum sulfur, 0.20-0.40% silicon, 0.80-1.00% chromium, 0.40-0.60% nickel, 0.07-0.15% molybdenum, 0.010-0.04% titanium, 0.001-0.003% boron, 0.015-0.06% aluminum, balance iron, and incidental impurities. 
     
     
         20 . The method according to  claim 13 , wherein the steel consisting essentially of, in weight %: 0.24% carbon, 0.80% manganese, 0.010% maximum phosphorous, 0.003% maximum sulfur, 0.25% silicon, 0.90% chromium, 0.50% nickel, 0.10% molybdenum, 0.03% titanium, 0.0015% boron, 0.035% aluminum, balance iron, and incidental impurities. 
     
     
         21 . An abrasion resistant article made from the abrasion resistant steel of  claim 1 . 
     
     
         22 . The abrasion resistant article according to  claim 21 , wherein the microstructure is tempered martensite and the surface hardness is at least 440 HBW.