Electrogalvanized sheet is manufactured by electroplating a pure zinc coating on one or two sides of carbon steel sheet. This continuous electrolytic coating process can be used to apply the coating onto the surface of the steel sheet with an exceptionally uniform thickness. In addition, the coated sheet has a smooth, matte appearance similar to cold rolled sheet. Thus, the surface quality is exceptionally good for applications that require a high finish after painting, such as automotive exposed panels. The excellent control of the coating thickness that is achieved with the electrolytic deposition process is beneficial to enhance forming and joining operations, especially by contributing to more reliable results from automatic and robotic welding systems. Both the zinc and zinc-iron electrogalvanized coatings are readily paintable, but to achieve good resistance to corrosion, the coated-steel surface should be pretreated and primed prior to application of the finish paint coating.
The mechanical properties of electrogalvanized sheet are approximately the same as those for the equivalent grade (steel designation) of cold rolled sheet because the steel coils are pre-annealed prior to processing on the electroplating line. For example, DDS cold rolled sheet and DDS electrogalvanized sheet have similar mechanical properties. This does not mean that electrogalvanized product will behave similarly during stamping/drawing.The coating influences the behavior during forming; thus, special practices are required when stamping electrogalvanized products. With the correct type of die material, clearances, etc., the stamping performance of the two products are similar.
- Uniform distribution of extremely thin zinc coating
- Spangle free
- Welds easily
- Good paintability