Rolling of Steel in small and medium sized Rolling Mills Jun09

Rolling of Steel in small and medium sized Rolling Mills...

Rolling of Steel in small and medium sized Rolling Mills Rolling of steel consists of passing the material, usually termed as rolling stock, between two rolls driven at the same peripheral speed in opposite directions (i.e. one clockwise and the second anti-clockwise) and so spaced that the distance between them is somewhat less than the thickness of the steel section entering them. In these conditions, the rolls grip the material and deliver it reduced in thickness, increased in length and probably somewhat increased in width. This is one of the most widely used processes among all the metal forming processes, because of its higher productivity, close control of the rolled product, and lower operating cost. Rolling is able to produce a product which is having constant cross section throughout its length. Many shapes and sections are possible to roll by the steel rolling process. Rolling of steel is a metal forming process used for plastic deformation of the steel. Plastic deformation is caused by the compressive forces applied through the rotating rolls. High compressive stresses are as a result of the friction between the rolls and the surface of the steel material. The steel material gets squeezed between the pair of rolls mounted in a roll stand, as a result of which the thickness of the steel being rolled gets reduced and the length is increased. Steel sections are generally rolled in several passes, whose number is determined by the ratio of initial input material and final cross section of finished product. The cross section area is reduced in each pass and form and the size of the rolling stock gradually approach to the desired profile. Mostly, rolling is done at high temperature, which is called hot rolling, because of requirement of large deformations....