An Ni-Cr alloy material which attains excellent corrosion resistance even in high-temperature water environments. The alloy material has a uniform lattice strain (S) satisfying the relationships (1) and (2): S < 0.002 ... (1) S = D500 D < 200 ... (2) wherein the meaning of each symbol is as follows: S: uniform lattice strain (?) of the surface layer D500: spacing (?) of {111} lattice planes at a depth of 500nm from the surface of material D < 200: average (?) of spacings of {111} lattice planes at depths of 200nm or below from the surface of material
