MANUFACTURING METHODS AND PILOT PRODUCTION OF TITANIUM ALLOY CASTINGS AND REPORTS. Interim Engineering Report No. 1. Phase II: Experimental, September 4 to December 4, 1956

ABSTRACTS A total of nine 6 lb heats of pure Ti were poured from a 9-in. diameter tllt pour skull arc furnace into machined graphite molds in an attempt to obtain gas free castings. Pumping in the pressure range below 10 mu while molten and during freezing and subsequent remelting, as well as heating the mold, did not eliminate gas porosity. The vacuum operation of permanent W electrodes was shown to be possible although somewhat difficult. It is suggested that mold reaction or mold gas desorption is a major source of gas porosity. It is recommended that further studies continue to pursue the elimination of gas porositywith major emphasis put on mold material. (auth)