Effects of Phosphorus and Nitrogen on Stress Corrosion Cracking of Austenitic Stainless Steels in Boiling Magnesium Chloride Solution

Abstract

Corrosion cracking occurs in the commercial grades of austenitic stainless steel (18 Cr–10 Ni) when exposed to tensile stress and certain environments. An extensive study was undertaken to develope a steel resistant to stress corrosion cracking. The influence of phosphorus and nitrogen in austenitic stainless steels on stress corrosion cracking has been investigated in boiling MgCl2 at 154°C by the U-bend and tensile methods. The results of the study showed the detrimental effects of phosphorus and nitrogen and the interaction of these elements on the sensitivity of the steels to stress corrosion cracking. A new stainless steel resistant to stress corrosion cracking can be developed by controlling the contents of phosphorus and nitrogen in 18 Cr–10 Ni stainles steel.The results have been elucidated by observing the dislocation structures of these steels by measuring the general corrosion rates and potential-time relations in boiling MgCl2 solution at 154°C.