Reasons Analysis on Emanation Quantity Over-proof of Chromium Ions in Ferritic Stainless Steel Utensils

The over-proof of chromium ions released from 430 ferritic stainless steel utensils was found during heavy metal migration test. The corrosion susceptibility of the 430 ferritic stainless steel samples was evaluated by electrochemical potentiodynamic reactivation method. And the corrosion morphology, microstructure, distribution of carbon and chromium elements of the samples were analyzed by optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. The results show that the improper heat-treatment of the 430 ferritic stainless steel utensils during the production process led to the generation of impurity carbide segregation and residual martensite. Then the galvanic corrosion happened in the corrosive medium, and eventually resulted in the emanation quantity over-proof of chromium ions.