The hot rolled billets specified in various technical standards has nearly 400 steel grades and thousands of specifications.
According to the production method, the hot rolled billets can be divided into the following types:
(1) The blooming billet is produced by the billet rolling mill and the square-slab rolling mill; it has been phased out except for some special steel grades;
(2) Medium and small billet, produced by billet mill and three-roll blooming mill;
(3) Forging slab, produced by the hydraulic press and forging press;
(4) Continuous casting billet, produced by continuous casting machine.
According to the shape of the section, the billet can be divided into:
(1) Square billet and rectangular billet with a side length of 40~450mm;
(2) Thick slabs, thickness 100~300mm, width 450~1600mm;
(3) various steel strips;
(4) Round tube blank, diameter 50~160mm;
(5) Various shaped blanks.
Billets can also be classified according to steel grade and use, for example: rough rolled billet and medium and small billet, thin slab, high quality carbon steel round billet, carbon steel hot rolled billet, axle slab for railway rolling billet, alloy structural steel round and seamless tube blanks for tube blanks and high pressure boilers, etc.