1. Implementation criteria

For further details, please refer to the documentation section of this article entitled "Implementation criteria".

In order to withstand the very diverse stresses to which they are subjected in the course of their work, tools must have the following three functional properties:

• a high level of hardness at room temperature and, in some cases, even when hot;

• good resistance to wear at room temperature and also when hot;

• sufficient ductility to avoid sudden breakage.

Unlike mechanical parts, which usually work through their entire mass, tools are often stressed by their periphery, and it is therefore on the surface that these three properties must reach their maximum value. In most cases, it is surface damage that limits tool life....