Community Research and Development Information Service - CORDIS

Abstract

Sheet steel used in the car industry must have several essential qualities. It must not corrode, even when painted, yet must remain stable during stamping or soldering procedures. It should also present a surface that will not become deformed. Galvannealled coatings have many advantages, including the price of manufacture, but suffer from deformation and powdering. This study set out to consider ways to counter mechanisms responsible for powdering and to ascertain heat cycles to guarantee an alloyed surface that is stable. The conclusion of the study confirmed the role that is played by the dielectric breakdown of hydrogen in the appearance of cratering on the surface. It also concluded that the craters are reduced by the addition of an iron-zinc electrolytic deposit. Control of powdering can be reduced by careful measuring of the chemical composition of the substrate (the quantities of Ti, Nb and P, and of aluminium in the zinc bath). The optimization of these factors means that heat regulation windows can be enlarged. In order to obtain steel that can be stamped the quantity of phosphorous should be controlled.

Additional information

Authors: QUANTIN D, SOLLAC;MATAIGNE J M, SOLLAC;VANCON D, SOLLAC;PRAT J M, SOLLAC;BLODEAU J P, SOLLAC
Bibliographic Reference: EUR 18644 FR (1998) 52pp
Availability: Available from OOPEC Sales agents
ISBN: ISBN 92-828-5143-5
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