Effect of metallurgical factors on the susceptibility to pitting initiation in steels

The pitting propagations of six low-carbon steels and one low-alloy steel with representative metallurgical characteristics were compared by means of occluded corrosion cell (OCC) stimulation test. Combined their metallurgical characteristic with corrosion appearance, the effect of metallurgical factors on the pitting propagation was researched. The results show that dissolved oxygen, inclusions, calcium treatment, phosphorus content and phosphoric segregation, and Ni and Cr elements in steels have important influence on the pitting propagation. A higher amount of dissolved oxygen, phosphorus, Ni and Cr elements, and calcium treatment are beneficial to restraining pitting propagation.