A pipe for a steam turbine is formed of a centrifugal casting material to
achieve resistance against higher temperatures and improve reliability of
the pipe by employing, as a pipe material, a centrifugal casting material
normalized to contain uniform and finer crystal grains. The centrifugal
casting material is made of steel having a columnar structure in the
radial direction with the crystal grain size number of 5 or more in a
plane perpendicular to the radial direction. The steel includes 0.05-0.5%
by mass C, not more than 1.0% Si, 0.05-1.5% Mn, 0.01-2.5% Ni, 8.0-13.0%
Cr, 0.05-2.5% Mo, not more than 3.0% W, 0.05-0.35% V, 0.01-0.5% Nb, not
more than 5% Co, 0.01-0.1% N, not more than 0.03% B, and not more than
0.05% Al.