Optimization of Mechanical/Corrosion Properties of TI-CODE 12 Plate and Sheet: Part 2, Thermomechanical Processing Effects

摘要

In an effort to determine and subsequently optimize mechanical and corrosion properties of the TI-CODE 12 alloy for DHLW container application, a two-stage study was conducted. Stage I was directed toward evaluation of the effect of compositional variations, within ASTM specification limits, on specific mechanical and corrosion properties of TI-CODE 12. Compositional variables investigated were weight percent molybdenum, nickel, oxygen, and iron. Compositional ranges of TI-CODE 12 were identified which correspond to select combinations of desirable properties. Stage II program objectives include evaluation of five distinct thermomechanical processes with respect to TI-CODE 12 0.25 inch (6.35mm) plate and 0.070 inch (1.78mm) sheet corrosion and mechanical propreties, with subsequent selection of a process route which achieves optimum properties. In addition to addressing effects of intermediate recrystallization and cross-rolling steps for reduction of property directionality, the influence of final product anneal is examined. In particular, the influence of a conventional mill anneal at 1450 sup 0 F (788 sup 0 C) is compared to that of the sub-eutectoid 1250 sup 0 F (677 sup 0 C) annual which is known to facilitate precipitation of nickel-rich intermetallic compound in TI-CODE 12. sup (18,19,20). Specific alloy properties considered include tensile strength and ductility, bend ductility, slow strain rate fracture toughness, creep strength, and general and crevice corrosion resistance. 24 refs., 25 figs., 24 tabs. (ERA citation 13:030099)