Patent ID: 8444778
Filing Date: 2013-05-21
Classification: C22C,C22F,F28F

Abstract:
1. A boiler component made of a low-thermal-expansion Ni-base superalloy, the superalloy consisting essentially of, by mass, not more than 0.2% C, not more than 0.5% Si, not more than 0.5% Mn, 10 to 24% Cr, at least one of Mo and W in an amount in terms of an equation of “Mo+0.5W”=5 to 17%, 0.5 to 2.0% Al, 1.0 to 3.0% Ti, not more than 10% Fe, and at least one of B and Zr in amounts of from exclusive zero to 0.02% B and from exclusive zero to 0.2% Zr, and the balance of Ni and unavoidable impurities, wherein no precipitates of a γ′ phase having a size of not less than 20 nm exist in an alloy matrix of the Ni-base superalloy other than a weld portion and a heat affected zone by welding, and wherein the superalloy other than the weld portion and the heat affected zone by welding has a Vickers hardness of not more than 240.