3. Coated carbon steels

A wide range of metallic coatings can be applied to steel to improve its resistance to corrosion or hot oxidation (see Surface treatments in the Metallic Materials treatise). Let's start by reviewing the main ones, which can be deposited in two very different ways: either by electrolytic deposition or by hot dip. The symbol used to designate coatings appears in brackets.

• Electrolytic pure zinc (+ZE). The deposit is very soft, which, contrary to popular belief, is not an advantage in terms of sheet metal sliding in tools. It is deposited at a very limited temperature (around 80°C) and therefore has very little effect on mechanical properties. The only slight modification that may result is a slight increase in yield strength, due to the fact that most processes require the strip to be subjected to a slight tensile stress, which may slightly strain-harden it if...