RESEARCH AND DEVELOPMENT OF TITANIUM ROCKET MOTOR CASE

Sustained-load notched strength of cold-rolled, aged sheet H content of 70 ppm at the 180,0 0 psi yield strength level is lower than that of 200 ppm H content sheet. The pronounced aging response at 900 F of press-forged material with 0.10 to 0.20 oxygen was reaffirmed. Multiplepass TIG welding on U- and V-type joints produced fine gains and superior ductility. Good tensile properties resulted from open-die press forging, and closed-die press forging of 14-in diameter domes. Closed-die hammer-forged pancakes exhibited nonuniform tensile properties after aging at 800 or 900 F. Subscale 14-in. diameter rings roll-forged at 1800 to 20 0 F were satisfactory in tensile ductility and flowturnability. Residual stresses of 165,000 psi average and 200,000 psi maximum were measured in the circumferential direction in as-flow-turned 9.4-in-diam. cylinders stress relief treatment at 900 to 950 f gave satisfactory relief.