EFFECTS OF Ti, Mn AND S ON THE PITTING CORROSION PROPERTIES OF 18Cr-2Mo FERRITIC STAINLESS STEEL.

A study of pitting corrosion initiation in 18Cr-2Mo ferritic stainless steels has been made using both electrochemical and metallographic techniques. In particular, the effects of different Ti, Mn and S contents have been studied. It is concluded from the present work that both lowered S content and Ti stabilization serve to raise the pitting corrosion resistance of these steels. In addition, at low S contents, lowering the Mn content yields a considerable increase in the room temperature corrosion resistance in spite of the presence of titanium. At elevated electrolyte temperatures the existence of an optimum Mn content is strongly indicated. The pitting attack has been shown to be predominantly initiated at titanium sulfides in all stabilized steels.