PURPOSE: To regulate the corrosion fatigue resistance to sea water to ≥30kg/cm2 and the Brinell hardness for obtaining the erosion resistance to ≥300 under the condition of no corrosion preventing, in the stainless steel-series propeller material having specified compsn., by specifying the contents of C, Cr, Ni and Mo.

CONSTITUTION: The propeller material is constituted of, by weight, ≤0.08%C, 0.1 to 1.5% Si, 0.1 to 3% Mn, 16.5 to 17.8% Cr, 5.5 to 6.5% Ni, 0.5 to 3% Mo and the balance iron. In the material, C is the most important element influencing the corrosion resistance and corrosion fatigue resistance; for the upper limit or more, the amt. of Cr carbide drastically increases to deteriorate the corrosion resistance and corrosion fatigue resistance. Cr is most important for deciding the corrosion resistance, mechanical properties and hardness; for the lower limit or less, the corrosion resistance can not be ensured and, for the upper limit or more, the hardness can not be ensured. As for Ni, lower limit or more is needed for ensuring the elongation and corrosion resistance, and on the other hand, for the upper limit or more, the mechanical properties and fatigue resistance are deteriorated. As for Mo, lower limit or more is needed for improving the corrosion resistance, but for the upper limit or more, the mechanical properties are adversely influenced.