Method for manufacturing stainless steel for polymer fuel cell separator having excellent contact resistance

A method of manufacturing a stainless steel for a polymer fuel cell separator, the method comprising:

• electrolyzing to remove a first passivation film formed on a cold-rolled sheet of a stainless steel comprising, in percent (%) by weight of the entire composition, C:
• greater than 0 to 0.1%, N:
• greater than 0 to 0.02%, Si:
• greater than 0 to 0.25%, Mn:
• greater than 0 to 0.2%, P:
• greater than 0 to 0.04%, S:
• greater than 0 to 0.02%, Cr:
• 29.7 to 30.1%, Ti:
• greater than 0 to 0.5%, Nb:
• greater than 0 to 0.5%, the remainder of iron (Fe) and inevitable impurities;
• and
• immersing in an acid solution to form a second passivation film on the stainless cold-rolled sheet,
• wherein the electrolyzing is performed in 5 to 30% by weight of sulfuric acid solution at 40 to 80° C. and a cathode applied current density (Ic) is 4 to 15 A/dm2,
• the immersing in the acid solution is performed in 10 to 15% by weight of nitric acid at 40 to 60° C.,
• the acid solution does not comprise hydrofluoric acid,
• a contact resistance of the second passivation film is 18.2 mΩcm2 or less, and
• no surface rust is found on a surface of the polymer fuel cell separator after performing a static potential endurance test at 0.6V for 300 hours.