SEMI-FINISHED STEEL PRODUCTS (SEMIS)

Intermediate solid steel products obtained by Hot rolling/Forging of ingots (in conventional process) or by Continuous casting of liquid steel are known as Semis. These are called so since they are intended for further rolling/forging to produce Finished steel products.

Various types of semis are as under:

BLOOMS : A Semi-finished product, usually in square (at times in rectangular) section of cross sectional size exceeding 5”x5” (125mm X 125mm). In some of the modern mills, the term bloom is used to cover such products of cross sectional size exceeding 8”x8”. These are inputs for producing Heavy sections and Sheet piling section normally by hot rolling. At times, like in VSP, blooms are used to produce billets by hot rolling in the Billet Mill.

BILLETS: A semi-finished product which are similar to blooms but of smaller cross sectional size (usually less than or 5’’x5’’/7’’x7’’. These are used as input material for production of Finished Steel long products viz bars & rods, light sections etc.

SLABS: A semi-finished Rectangular, wide , semi-finished steel product intended for production of finished Hot Rolled Flat products viz Plates, sheets, Strips etc. They are normally of width 150-250mm wherein width is at-least 3 or 4 times of thickness.

THIN SLABS : In modern thin slab casting machine, liquid steel is continuously cast into much thinner slabs of 35-50mm directly which are used for production of Finished Hot Rolled Flat products upon heating on-line.