[en] Double containment in Hastelloy C-276 capsules is used. Remote filling, welding, and handling operations unavoidably contaminate the capsule surface with strontium fluoride in a form that is extremely difficult to remove. Electropolishing was investigated as an alternative surface decontamination technique for the inner storage capsule. Initial feasibility studies using contaminated dummy capsules and capsule sections demonstrated the ability of electropolishing to rapidly and effectively remove the external strontium fluoride contamination. A 20-l electropolishing system incorporating a cylindrical cathode to preserve capsule dimensions and special design features to facilitate remote manipulator operation was developed for installation in the B-plant encapsulation facility. The following supporting studies also were conducted to establish optimum operating conditions and to test the capsule facility design concepts: operating parameter, solution life, spectral emittance, and capsule profile. (12 fig)

[en] Abrasive waterjet milling (AWJ Milling) is a machining method as it can be used to quickly process a wide range of industrial materials without adversely affecting their properties. The viability of using AWJ milling to machine Hastelloy C-276 Ni-Mo-Cr super alloy was investigated here in detail for the first time. Experiments were performed by varying AWJ milling process parameters, including the water jet pressure, standoff distance, traverse speed, and abrasive flow rate using the Taguchi orthogonal array. A desirability function analysis was applied to identify the optimum AWJ milling conditions for maximizing material removal rate and minimizing surface roughness. The surface morphology of the super alloy samples was studied to determine the material removal mechanism under the optimal milling conditions. In addition, a semi-empirical model was developed to predict the surface roughness of Hastelloy C-276 processed using AWJ milling. These findings are expected to promote the wider use of AWJ milling for machining of Hastelloy C-276 super alloy, which could improve the processing efficiency and quality of parts for chemical and nuclear industries, among others. (paper)

[en] The sensitivity of Hastelloy B-2 and Hastelloy C-4 to intercrystalline corrosion in the heat-affected zone of welded joints was investigated. The temperature-cycles in welded joints typically used in the construction of chemical equipment were experimentally determined. The effect of thermal stress on both the structural stability and corrosion sensitivity was then determined by metallographic examination. The results showed Hastelloy C-4 to have a distinctly improved structural stability over the previously available Hastelloy C-276. Under the test conditions we employed no negative effect on corrosion sensitivity in the area of the heat-affected zone of the welded joints is to be expected. Hastelloy B-2 shows - dependent on heat input - more or less significant structural changes of the grain boundary, the existence of droplet-like heterogenicity suggests the possibility of intergranular corrosion. (orig.) 891 HP/orig. 892 MB

No abstract available

[en] Co-60 sources represent one of the key factors in industrial radiation processing and applications such as sterilization of disposable products and food preservation. Design of the sources being currently used in wet gamma irradiators can be improved with the purpose of increasing the source corrosion stability and mechanical integrity during use. This paper describes the proposed new design of Co-60 source for wet gamma irradiators. As a result of changes in capsule material and some dimensions, product quality and reliability can be improved with no additional cost for end user

[en] The corrosion behavior of Hastelloy C-276 was investigated to identify its applicability for carbon-anode-based oxide reduction (OR), in which Cl₂ and O₂ are simultaneously evolved at the anode. Under a 30 mL·min^-1 Cl² + 170 mL·min^-1 Ar flow, the corrosion rate was less than 1 g·m^-2·h^-1 up to 500℃, whereas the rate increased exponentially from 500 to 700℃. The effects of the Cl₂-O₂ composition on the corrosion rate at flow rates of 30 mL·min^-1 Cl₂, 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂, and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ with a constant 170 mL·min^-1 Ar flow rate at 600℃ was analyzed. Based on the data from an 8 h reaction, the fastest corrosion rate was observed for the 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ case, followed by 30 mL·min^-1 Cl₂ and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂. The effects of the chlorine flow rate on the corrosion rate were negligible within the 5–30 mL·min^-1 range. A surface morphology analysis revealed the formation of vertical scratches in specimens that reacted under the Cl₂-O₂ mixed gas condition

[en] Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

[en] Residual stress in YBCO films on Ag and Hastelloy C substrates was determined by using 3-D optical interferometry and laser scanning to measure the change in curvature radius before and after film deposition. The residual stress was obtained by appropriate analysis of curvature measurements. Consistent with residual thermal stress calculations based on the thermal expansion coefficient mismatch between the substrates and YBCO film, the measured residual stress in the YBCO film on Hastelloy C substrate was tensile, while it was compressive on the Ag substrate. The stress values measured by the two techniques were generally in good agreement, suggesting that optical interferometry and laser scanning have promise for measuring residual stresses in thin films

[en] Highlights: • Low and moderate strain treatments were used for optimizing the GBCD in C-276 alloy. • Convoluted Σ3 (incoherent Σ3) boundaries were observed in different annealing time. • Evolution of coherent & incoherent Σ3 boundaries was studied in annealing treatment. • Through activating SIBM without the SRX, the GBCD of C-276 alloy could be optimized. • Control of deformation and annealing may produce more incoherent Σ3 boundaries. Hastelloy C-276 samples were cold-rolled with their thickness reduction of 7.5% and 15%, and then annealed at 1100 °C for 5–60 min in solid solution. The grain boundary character distributions (GBCDs) were characterized by a technique of electron back scatter diffraction (EBSD). Results indicated that, more convoluted Σ3 boundaries (i.e. incoherent Ʃ3 boundaries) are generated by reasonable annealing time in low strain (7.5%) sample during strain-induced boundary migration (SIBM) processing. They can induce higher Ʃ3ⁿ fraction and activate more interactions between special boundaries for GBE. Instead, more coherent Ʃ3 boundaries were produced by moderate strain (15%) and annealing treatment with the occurrence of static recrystallization (SRX). The recrystallized fine grains possess fewer incoherent Ʃ3 boundaries cannot promote to get more multiple twinning for optimization of GBCD. Therefore, reasonable deformation and annealing treatment parameters lead to more incoherent Ʃ3 boundaries would play an important role in the optimization of GBE.

[en] Results on the compatibility of Hastelloy C-276 and Bi₂Te₃ are presented. At temperatures of 600⁰C and above, compatibility is found to be poor. (W.D.L.)