The main reason for controlled rolling is usually to refine grain structure and, thereby, to improve the two strength and toughness of steel inside the as-hot-rol1ed condition. If your survey is constructed of the growth of controlled rolling, it could be seen that controlled rolling is made up of three stages: (a) deformation from the recrystallization region at high temperatures; (b) deformation from the non-recrystallization region in just a low temperature range above Ar3; and (c) deformation within the austenite-ferrite region.
It is stressed that the significance of deformation inside the nonrecrystallization region is within dividing an austenite grain into several blocks by the creation of deformation bands inside it. Deformation inside the austenite-ferrite region offers a mixed structure composed of equiaxed grains and subgrains after transformation and, thereby, it improves further the strength and toughness.
The basic distinction between conventionally hot-rolled and controlled -rolled steels lies in the point that the nucleation of ferrite occurs exclusively at austenite grain 34dexppky inside the former, although it occurs in the grain interior and also at grain boundaries within the latter, ultimately causing a much more refined grain structure. In Stainless Steel Clad Plate a crystallographic texture develops, which causes planar anisotropies in mechanical properties and embrittlement within the through -thickness direction.
The second is demonstrated to end up being the main reason for the delamination which appeared inside the fractured Charpy specimens. Fundamental areas of controlled rolling, like the recrystallization behaviour of austenite, the retardation mechanism of austenite recrystallization on account of niobium, microstructural changes accompanying deformation, factors governing strength and toughness, etc., are reviewed. The practice of controlled rolling in plate and strip mills is outlined.