Patent ID: 8246767

Claim:
A method of producing a heat treated 9 Cr-1 Mo material, comprising the following steps in the order named: austenizing a 9 Cr-1 Mo alloy comprising 0.05-0.15 wt. % carbon, 8.0-13.0 wt. % chromium, 0.5-1.5 wt. % molybdenum, 0.1-1.0 wt. % silicon, 0.2-1.0 wt. % manganese, 0.1-0.4 wt. % vanadium, 0.02-0.2 wt. % niobium, 0.05-0.2 wt. % titanium, balance Fe and unavoidable impurities, wherein the 9 Cr-1 Mo alloy contains primary TiC 0.5-3.0 μm in diameter, at a temperature wherein the solubility of the primary TiC is sufficient to dissolve about 40-60% of the primary TiC, placing titanium and carbon in solution; cooling the 9 Cr-1 Mo alloy using an initial cooling step to generate a martensitic microstructure wherein titanium and carbon remain in solution; tempering the 9 Cr-1 Mo alloy such that titanium and carbon in solution diffuse to precipitate secondary TiC, such that a mass ratio of secondary to primary TiC is from about 1:1.5 to about 1.5:1 in the tempered 9 Cr-1 Mo alloy, where the mass ratio of secondary to primary TiC is the mass of the primary TiC divided by the mass of the secondary TiC; and, cooling the 9 Cr-1 Mo alloy in a final cooling treatment.