3. Mechanisms and general effects of metals and nitrogen on properties

It is customary to recall the influence of residual elements in a general form by considering them in homogeneous solid solution, for all products combined.

However, this approach leads to some confusion in the choice of limit contents, the values of which will depend on the actual role played by the element cited in the critical property(ies) of each product, while taking into account the manufacturing path. This is particularly true for non-alloyed low-carbon steels intended for high-end products.

From an overall point of view, the role of residuals in surface defect problems and their hardening influence on all products are particularly noteworthy.

It is then useful to recall some significant phenomena that have been the subject of detailed studies, such as the temper brittleness of heat-treated low-alloy steels,...