Patent ID: 8105448

Claim:
A method for manufacturing of a sheet metal for use in a boiling water nuclear reactor, the method comprising: providing a material of a zirconium alloy, comprising zirconium, wherein the main alloying materials of the alloy comprises niobium, wherein no alloying material is present in a content exceeding 1.6 percent by weight and wherein the alloy comprises niobium containing secondary phase particles, subjecting the material to at least one hot-rolling, subjecting the material to at least a first β-quenching, subjecting the hot-rolled material to at least one cold-rolling, and, after said at least one cold-rolling and after said first β-quenching, transformation annealing the cold-rolled material, at a temperature below the phase boundary for secondary phase particles in the form of β-zirconium particles, for so long time that essentially all niobium containing secondary phase particles are transformed into β-niobium particles, which are particles in the zirconium alloy with a niobium content exceeding 90 percent by weight, wherein the main alloying materials are niobium, iron and tin, wherein the tin content is 0.7-1.1 percent by weight, the iron content is 0.09-0.15 percent by weight, and the niobium content is 0.8-1.2 percent by weight.