Annex 1

EFFECT OF CHEMICAL COMPOSITION OF STEEL ON ZINC COAT

We would like to draw your attention to several pieces of advice relating to the purchasing of material to be submitted for hot zinc dipping.

The appropriate materials for hot zinc dipping are non killed grade 11 steels or Aluminium killed steels where the Si content ranges between 0.12% and 0.25%. Class 12 steels or Silicon killed steels - for the adversary effects of the Si and P contents, see below - are characterised by high iron-zinc reactivity.

We do not recommend zinc coating steels with the Si content ranging between 0.03 and 0.12% (by weight - so-called Sandeline's effect) and with the SI content in excess of 0.25%. A higher P content in addition to the silicon content contributes to strengthening of the reaction between the iron and zinc, ultimately leading to a thicker zinc coat.

Excessive thickness of the coat is associated with a higher need for zinc, leading to increased costs and affecting the price of the hot zinc dipping treatment.

Inappropriate Chemical Composition of Steel for Hot Zinc Dipping:

1. Si content + 2,5 x P content ranging between 0,03 and 0,12% and exceeding 0,25%

2. Si content + Al content ranging between 0,03 and 0,12% and exceeding 0,25%

3. P content in excess of 0,020%

Fig. The high reactivity for Si concentrations ranging between 0.03 and 0.12% is referred to as Sandeline's effect