Patent ID: 6019938
Filing Date: 2000-02-01
Classification: C21D,C22C

Abstract:
As a product, an alloy steel having high strength, excellent toughness, a low level of non-metallic inclusions, and minimal micro-chemical segregation, and having the following approximate chemical composition: C .33-.39 Mn .30-.50 P .025 max S .010 max Si .75-1.10 Ni .45 max Cr 4.75-5.25 Mo 2.70-3.00 V .24-.30 Fe balance alone or in the presence of elements which do not adversely affect performance N 70 ppm max O 30 ppm max H about 1 ppm max  said product being the product of a process having the steps offorming a heat of steel in an electric furnace by a two stage process,subjecting the heat to a vacuum treatment consisting of the simultaneous subjection to a vacuum sufficiently low to effectively remove deleterious gases and the upward passage of a purging agent,subjecting the heat at some time while under vacuum to the heating effect of an electric current arc,solidifying the steel,forming the solidified steel intoa vacuum arc remelt electrode,vacuum arc remelting the electrode utilizing DC current, andsolidifying the resultant product.