Multifunctional passivation methods for hot dip galvanised steel
Hot dip galvanised sheet steels has many benefits in various applications of the metal fabricating industry. A wide variety of applications can be covered, for example, load-bearing structures, shelters/enclosures or mainly aesthetic functions. The only major limitation of galvanised sheet steel is the need for temporary protection during storage and transportation to prevent the formation of white rust. The overall goal of the proposed project was to find an effective and environmentally friendly passivation method for hot dip galvanised sheet steels (zinc coated, Galfan, Aluzink). The main objectives were: to find passivation methods with multi-purpose functions to substitute oiling, chromating and/or sealing processes for temporary corrosion protection of HDG steel; to develop novel passivation methods; to study the compatibility of passivation methods with typical manufacturing processes of sheet metal components and coil coated steel. Three different types of coatings were evaluated during the pre-screening phase of the project. This screening included testing of 24 different thin organic coatings (TOCs), 25 passivations, eight passivations with CCVD coatings and 13 UV-curable coatings. As a conclusion, it may be stated that none of the tested systems completely fulfil the objectives of a multi-purpose online post-treatment that should be compatible with all major manufacturing processes of sheet metal components and coil-coated steel and act as a replacement for oiling, chromating and sealing. However, several systems fulfil the requirement of being an effective and environmentally friendly passivation method for HDG steels. The final end-user application and application techniques of the coating (i.e. manufacturing line set-up) still set stringent requirements for choice of the coating technique and coating type.
Bibliographic Reference: EUR 22378 EN (2007), 125 pp. Euro: 25
Availability: Katalogue Number: KI-NA-22378-EN-S The paper version can be ordered online at: http://bookshop.europa.eu
ISBN: ISBN: 92-79-02657-7
Record Number: 200718831 / Last updated on: 2007-02-26
Original language: en
Available languages: en