Abstract:
This is a very narrowly defined martensitic steel alloy fuel cladding material for liquid metal cooled reactors, and a process for making such a martensitic steel alloy material. The alloy contains about 10. 6 wt. % chromium, about 1. 5 wt. % molybdenum, about 0. 85 wt. % manganese, about 0. 2 wt. % niobium, about 0. 37 wt. % silicon, about 0. 2 wt. % carbon, about 0. 2 wt. % vanadium, 0. 05 maximum wt. % nickel, about 0. 015 wt. % nitrogen, about 0. 015 wt. % sulfur, about 0. 05 wt. % copper, about 0. 007 wt. % boron, about 0. 007 wt. % phosphorous, and with the remainder being essentially iron. The process utilizes preparing such an alloy and homogenizing said alloy at about 1000. degree. C. for 16 hours; annealing said homogenized alloy at 1150. degree. C. for 15 minutes; and tempering said annealed alloy at 700. degree. C.