Abstract: A spray forming pattern of a first metal having a melting point at a first temperature is formed. The spray forming pattern has a surface defining a cavity that has the shape of a master pattern. Steel particles having a carbon content in the range of 0.01-0.9% by weight are sprayed onto the spray forming pattern to form a deposit on the spray forming pattern. The deposit has a thickness of at least 0.5 inches and the temperature of the steel particles increases as the thickness of the steel deposit increases. The spraying conditions are controlled so that the steel particles coming into contact with the spray forming pattern results in a surface temperature of the spray forming pattern of less than about 80.degree. C. The deposit and the spray forming pattern are heated to a second temperature, which is higher than the first temperature, to melt the spray forming pattern from the deposit. The resulting deposit has the general shape of the master pattern.

Abstract: Method of sprayforming bulk metal deposits that replicate a master pattern: (i) casting and solidifying ceramic about a master pattern to form a spraying pattern; (ii) after removing the spraying pattern from the master pattern, heating the ceramic spraying pattern to a sustained temperature to effect an isothermal diffusion dependent microstructural transformation; (iii) while in such heated condition, thermally spraying allotropic metal particles onto the heated spraying pattern to form a deposit having a bulk thickness, the particles impacting the spraying pattern, or previously deposited particles, at a temperature above the sustained temperature of the spraying pattern; (iv) holding the deposit on the heated spraying pattern sufficiently long enough to allow the particles of the deposit to undergo a diffusion reaction that relieves internal stresses due to deposition and solidification; and (v) thereafter gradually cooling the deposit to room temperature to produce a unitary article with essentially no d