摘要：The non-metallic inclusions are metallurgical defect always present within the steel bulk. Although high cleanliness levels can be reached by the most up dated techniques, their presence is not avoidable, so the users of steel have to learn a correct management of such defects. This problem has become even more significant with the use of resulphurised steels, in which the sulphur is added to cause the precipitation of an abundant MnS population, which makes the steel more workable by the cutting tools. However, the presence of a not proper inclusional population can forbid the implementation of certain technological processes to be applied, i.e. welding, hot working etc.. Moreover, the sulphide inclusions improve the workability, but they remain within the product also after the technological transformations and they can weaken the whole material, so their use has to be decided only after a proper choice of the technological route. Thus, some indications about this topic have been obtained on the basis of some significant cases on which a failure analysis has been applied.
