The invention discloses a rare-earth
yttrium toughened high-
hardness alloy and a
casting and heat treatment method thereof. The
alloy comprises the following elements of, by
mass, 9.0-13.0% of Cr, 2.6-2.9% of B, 0.7-0.9% of C, 0.4-0.8% of Nb, 0.4-0.8% of V, less than 0.3 of Mn, 0.02-0.6% of Y, less than or equal to 0.01 of S, less than or equal to 0.01 of P and the balance Fe; and the sum of C andB is 3.3-3.6, the
mass ratio of C to Cr is 0.06-0.08, and the sum of Nb and V is 0.5-1.0. The method comprises steps that firstly, Fe-Y2O3
powder pressing blocks are prepared, the
alloy is subjectedto dosing,
smelting and modification treatment, then the alloy is subjected to
casting, and then
quenching-
tempering treatment is adopted. According to a cast
ingot of the rare-earth
yttrium toughenedhigh-
hardness alloy and the
casting and heat treatment method thereof, the overall
hardness is HRC 65.4-HRC 68.5, the
impact toughness reaches 13.3-17.1 J per cm<2>, and the bending strength reaches1340-1742 MPa.