Water Staining of Al 3104-H19 Can Body Stock: A Crevice Corrosion Study Utilizing the Double Crevice Assembly Test Method

Abstract

An electrochemical technique was developed to detect the initiation and monitor propagation of water staining on Al 3104-H19 (UNS A93104). Water staining is a crevice corrosion phenomenon occurring between adjacent layers of coiled aluminum can stock in the presence of a condensed water phase. One of the main forms of water stain prevention consists of electrostatic application of oil-based post-lubricants to the can stock surface prior to shipment. A double crevice assembly (DCA) method was developed to induce water staining in the laboratory as observed in the field. The relative inhibiting performance of various post-rolling protective lubricants and the susceptibility of various can stock alloying compositions used in the industry then were compared. Susceptibility of a can stock coupon and the ability of a given post-lubricant to inhibit crevice corrosion was related directly related to the water stain initiation time (t stain ) detected in the DCA technique by a negative shift in the electrochemical potential of creviced Al 3104-H19.