Objectives:


The final finishing operations are performed to produce a product for a given application, which ranges from structural to space applications. In this connection it is important to note the role of steelmaking to produce steels of desired chemistry and cleanliness. Impurities like sulphur and phosphrous are detrimental to most of the steel grades for all finishing operations. In aluminum killed steels, alumina inclusions must be suitably modified prior to deformation processing. Other types of inclusions must be suitably distributed within the matrix. The objectives of these operations are to generate the mechanical properties in the steel product required for a given application. The important properties are:


Strength : Measure of the resistance of material to permanent deformation

Ductility : Measure of the degree of plastic deformation

Hardness : Resistance to localized deformation

Creep : Resistance to time dependent deformation under load

Fatigue: Resistance of a material against fluctuating stresses.

Fracture toughness : Resistance to brittle failure

The above properties depend strongly on the number , size and size distribution of phases and the impurities.