What is a galvanneeled product and how is it produced ?


A galvannealed sheet is carbon steel sheet coated with zinc on both sides by the continuous hot dip process. Immediately as the strip exits the coating bath, the zinc coating is subjected to an in-line heat treatment that converts the entire coating to a zinc-iron alloy. Conversion to the alloy results in a non-spangled matte finish which makes the sheet suitable for painting as shipped, if not chemically treated or oiled. The zinc-iron alloy coated surface enhances welding. The coating is harder than regular galvanized coating and is more resistant to scratching and manufacturing damage. After painting with properly selected primers and paints, the combined paint / galvannealed coating offers excellent resistance to peeling and/or blistering of the paint, compared with conventional galvanized sheet.