Characterising the surface waviness of hot dip galvanised steel sheets for optical high-quality paintability (Carsteel)
Waviness in the surface of steel sheets may cause waviness in the topcoat ('orange peel effect') of painted sheets. This is undesirable because it impairs the optical impression and customers interpret this as bad paint quality. Therefore, the production of high-quality sheets needs the control of waviness in the sheet surface. At present, this is difficult since car producers demand different parameters to quantify waviness with regard to paintability. The aim of this project is to characterise and optimise the paintability of hot dip galvanised sheets on the basis of uniform parameters accepted by both the steel and automotive industry. To achieve this aim the 'Carsteel' project was carried out by a consortium of 16 partners (five steel, eight automotive, two paint industries and one research institute). It was discovered that the hot dip galvanising process generates total new surface topographies; the waviness is influenced only by the skin pass process. The surface waviness of the work rolls and the skin pass process are thus the main influencing parameters for the strip surface waviness. Therefore a target of further investigations should be to minimise the work roll surface waviness for the different used work roll texturing methods without altering the work roll surface roughness. On the basis of laboratory and paint shop paintings, the interrelationship between steel sheet surface waviness and top coat appearance was investigated with regard to all European used waviness characterising parameters. Thereafter, a practical measuring procedure and waviness characterising parameter was developed to assess the paintability of automotive sheets in practice. Furthermore, a new waviness gauge was designed and produced, that allows the calibrating of the required measuring systems and verifying the parameter calculation.
Bibliographic Reference: EUR 23854 EN (2009), 133 pp. Euro: 20
Availability: Katalogue Number: KI-NA-23854-EN-S The paper version can be ordered online and the PDF version downloaded at: http://bookshop.europa.eu
ISBN: ISBN: 978-92-79-11303-1
Record Number: 200910244 / Last updated on: 2009-04-10
Original language: en
Available languages: en