INVESTIGATION OF WELDING OF COMMERCIAL COLUMBIUM ALLOYS.
Final rept., 16 Jan 61-15 Jan 62
THOMPSON RAMO WOOLDRIDGE INC LOS ANGELES CALIF
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An investigation was made of the welding characteristics of three commercial columbium base alloys, FS82, D31, and F48. Tungsten inert gas, electron beam, spot, and flash butt welding methods were included in this investigation. The effect of the welding variables travel speed, shielding gas composition and purity, filler metal additions, preheat and post heat were studied. Thermal cycles were measured in the fusion zone and heat affected zone of TIG welds to help explain mechanical properties and microstructure on the basis of physical metallurgy of each alloy. The effect of welding on all alloys investigated was to increase the ductile to brittle transition temperature. This temperature was increased 200 F for FS82, 800 F for D31, and 500 to 800 F for F48 over that of the as-received wrought sheet. Of several post heat treatments investigated those most beneficial in lowering the transition temperature of welds were 2000 F for 4 hours for FS82, 2100 F for 24 hours for D31, and 2500 F for 4 hours for F48. The electron beam welding process consistently produced more ductile welds than the TIG process. Author