Community Research and Development Information Service - CORDIS


New developments in galvannealing are being used to improve the finish and ease of manufacture of steel sheets used in car manufacture. Galvannealing is a technique involving coating iron with a thick layer of zinc under high temperature ('hot dip strip coating') so that the metals mix to form a heterogeneous alloy. This method makes it easier to paint and spot-weld, and harder to chip. However, galvanneal tends to flake particles of metal when placed under strain, and when coated it can have tiny thinly coated spots caused by contamination with foreign matter. To minimize these disadvantages, researchers at the R&D project have investigated different coatings of galvanneal, using flash and phosphate coating. Flash coating involves an electrolyte, and was found under optimum conditions to produce a product with a better finish after painting, without losing the advantages of normal galvanneal. Phosphate coating was also successfully used to produce a smooth finish, although the spot-welding properties were adversely affected. However, after the project established the most effective method, this technique has been successfully used in batch production of cars by an American company. Other application fields could include domestic appliances, commercial refrigeration and air conditioners.

Additional information

Authors: WORMUTH R, Thyssen Krupp Stahl, Dortmund, (DE)
Bibliographic Reference: EUR 19365 DE (2000) 74 pp.
Availability: Available from the European Commission
ISBN: ISBN 92-828-9462-2
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