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M-25, Butt Welds in Process Piping

Description: Metal-arc and inert-gas shielded tungsten-arc processes were compared for circumferential butt welding of austenitic stainless steel process pipe. Inert-gas tungsten-arc welding was superior to other techniques. (C.J.G.)
Date: July 10, 1958
Creator: Litman, A. P.
Partner: UNT Libraries Government Documents Department

CORROSION ASSOCIATED WITH FLUORINATION IN THE OAK RIDGE NATIONAL LABORATORY FLUORIDE VOLATILITY PROCESS

Description: : : 9 7 7 8 6 9 : = 7 9 9used during the fluorination of fused-salt fuels and subsequent associated operations in the Oak Ridge National Laboratory (ORNL) Fluoride Volatility Process was evaluated. Corrosive attack is reported as mils per month based on molten salt residence time or mils per hour based on fluorine exposure time. Two fluorinators were used in the VPP to carry out the fluorination reactions. These vessels, Mark I and Mark II, were fabricated into right cylinders, approx 4 1/2 ft in height, from the same heat of L (low carbon nickel. The first vessel contained equimolar NaF- ZrF/sub 4/ or NaF-ZrF/sub 4/-UF/sub 4/ (48-48-4 mole%) for approx 1250 hr at 600 to 725 deg C. Over a period of 61 hr, 57,500 standard liters of F/sub 2/ were sparged into the slats. This constituted a F/sub 2/:U mole ratio of 3:1 beyond theoretical requirements. The Mark II fluorinator contained fluoride salts of approxi-mately the same compositions plus small additions of PuF/sub 4/ during three runs. The salts were kept molten at 540 to 730 deg C for approx 1950 hr and about sixty 500 standard liters of F/sub 2/ were sparged into the Mark II melts in 92 hr. Both fluorinators sustained large corrosion losses consisting of extensive wall thinning, severe interior inter- granular attack, and a moderate exterior oxidation attack. Maximum deterioration on the Mark I vessel occurred in the middle vapor region at a calculated rate of 1.2 mils/hr, based on fluorine sparge time, or 46 mils/month, based on time of exposure to molten salts. The second vessel showed maximum attack in the salt-containing region at similarly calculated rates of 1.1 mils/hr and 60 mils/month. Some evidence was found to indicate that the intergranular attack may have resulted from sulfur in ...
Date: June 19, 1961
Creator: Litman, A.P. & Goldman, A.E.
Partner: UNT Libraries Government Documents Department

CORROSION OF NICKEL-BASE SPECIMENS EXPOSED IN THE VOLATILITY PILOT PLANT MARK III FLUORINATOR

Description: The combination of operating temperatures around 550 deg C with LiF present in the salt baths produces about the same bulk metal losses on Ni and Ni- base alloys as was found by operating at 650 deg C without Li in the salt baths. The presence of U accelerates corrosion of Ni and Ni-base alloys during the Volatility Process fluorination cycle. Prior F conditioning of L Ni decreases corrosion of the material during subsequent fluorination. Prior F conditioning of INCO-61 weld metal increases the attack on INCO 61 during subsequent fluorination. Bulk metal losses on L Ni and the Ni-binary alloys containing Al, Co, Fe, or Mn are about the same during fluorination at 550 deg C with Li present in the fluoride salt baths. The presence of the alloying elements, Al, Fe, or Mn, in Ni drastically reduces or lelements intergranular attack usually found in unalloyed Ni exposed to a fluorination environment. In fluorination environments, the effect of adding Co to Ni on subsequent corrosion by intergranular attack of the binary is unclear. These reported tests showed that serious intergranular attack of a 95% Ni --5% Co specimen occurred. On the other hand, this test series and previous series showed good resistance to this form of corrosion by Ni containing 10 and 20 wt% Co. resistance to bulk metal losses, intergranular attack, and grain-boundary modifications when exposed to fluorination environments than L Ni and all Ni alloys tested. (auth)
Date: November 13, 1962
Creator: Kegley, T. M., Jr. & Litman, A. P.
Partner: UNT Libraries Government Documents Department

CORROSION ASSOCIATED WITH HYDROFLUORINATION IN THE OAK RIDGE NATIONAL LABORATORY FLUORIDE VOLATILITY PROCESS

Description: Studies carried out on corrosion associated with the hydrofluorination- dissolution phase in the fused-salt Fluoride Volatility Process are summarized. Corrosion for hydrofluorination-dissolver vessels used in bench-scale and semiworks-scale process development at ORNL is discussed. The results of a study on construction materials for the dissolution phase are presented. Corrosion studies at ANL are described for comparison purposes. A full-size hydrofluorinator dissolver is described. (M.C.G.)
Date: November 15, 1961
Creator: Goldman, A.E. & Litman, A.P.
Partner: UNT Libraries Government Documents Department