Pitting corrosion testing of stainless steel AISI 304 in chloride solutions

Abstract

Stainless steels and their welded joints are often susceptible to pitting corrosion in solutions containing chloride ions. Testing of pitting corrosion of stainless steels is performed using chemical and electrochemical methods. In this work pitting corrosion of the stainless steel AISI 304 was tested in chloride solutions, without the presence and in the presence of sulphate or nitrate ions. The tests were performed in order to determine the efficiency of these ions to prevent pitting corrosion, as well as to present the capabilities of the methods applied. Electrochemical methods were used to determine the value of pitting potential (Epit) and the critical pitting temperature (Tpit). The values of these parameters represent a measure of the resistance of stainless steels and their welded joints to pitting corrosion.

Nerđajući čelici i njihovi zavareni spojevi često podležu piting koroziji u rastvorima koji sadrže hloridne jone. Ispitivanje piting korozije nerđajućih čelika se vrši primenom hemijskih i elektrohemijskih metoda. U ovom radu vršeno je ispitivanje piting korozije nerđajućeg čelika AISI 304 u rastvoru hlorida, bez prisustva i u prisustvu sulfatnih, odnosno nitratnih jona. Ispitivanja su izvedena u cilju određivanje efikasnosti navedenih jona u sprečavanju piting korozije, kao i prezentacije mogućnosti primenjenih metoda. Korišćene su elektrohemijske metode za određivanje piting potencijala (Epit) i određivanje kritične temperature pitinga (Tpit). Vrednosti navedenih parametara predstavljaju merilo otpornosti nerđajućih čelika i njihovih zavarenih spojeva prema piting koroziji.