C75 corrosion

Hi everybody,
I need a suggestion, how is the resistance of C75 quenched steel (C
0,70=F70,80
% Mn 0,60=F70,80
% Si 0,15=F70,40
% P 0,035
% max S 0,035 )
to corrosion. How many hours it can stay in salt spary fog
(DIN50021-SS) chamber without any corrosion point?
Thank you for help!