On at least one surface of a base metal plate (1) of an α-γ transforming Fe or Fe alloy, a metal layer (2) containing ferrite former is formed. Next, the base metal plate (1) and the metal layer (2) are heated to an A3 point of the Fe or the Fe alloy, whereby the ferrite former are diffused into the base metal plate (1) to form an alloy region (1b) in a ferrite phase in which an accumulation degree of {200} planes is 25% or more and an accumulation degree of {222} planes is 40% or less. Next, the base metal plate (1) is heated to a temperature higher than the A3 point of the Fe or the Fe alloy, whereby the accumulation degree of the {200} planes is increased and the accumulation degree of the {222} planes is decreased while the alloy region (11b) is maintained in the ferrite phase.