Development of the modes of forging of bandships from high-carbon steel

The main materials for the manufacture of hot-rolled forged rolls are traditionally the chromium-nickel steels of the type C0,5CrNi and C0,6CrNi and steels with a higher carbon content of C7,5CrMo, C0,9Cr2, C0,9CrV and C0,9Cr2МoV, etc. One of the main elements determining the operational stability of the rolls is carbon whose content in forged rolls usually does not exceed 0.85–0.95%. High-carbon hypereutectoid steel is proposed for the production of hot-rolled forged rolls, which differs from the known steel C1,5CrNiMo (GOST 9487–80), used for the production of cast rolls, slightly smaller content of carbon, which makes it possible to produce not cast, but stronger forged rolls. C1,4Cr2NiMoWB contains 1.2–1.4% C, the carbide forming alloying elements (Cr, Mo, V and Nb) for increasing the wear resistance of the rolls, as well as Ni for increasing the hardenability. It was found that the proposed steel possesses ductility sufficient to conduct hot deformation (forging) with small single compressions. The temperature range of the ingot deformation is defined: the end temperature of the deformation should not be lower than 900°С, the heating tem-perature for forging – 1150°С. The probability of failure in different forging areas at different crimping intensities has been investigated and to determine the reduction regimes of the proposed hard-deformable steel to obtain a suitable forging have been determined. Mathematical modeling of the ring rolling process is performed by the finite element method using the QForm software package. As a result of the conducted researches, the regimes of rolling rings on a mandrel for new high-carbon steel are proposed. The recommended reduction in the thickness of the ring should be no more than 10–15% of the condition of absence of cracks in forging. According to the set of properties, steel is recom-mended for the production of all-rolled rolls and shrouds for compound hot rolling rolls from ingots weighing up to 10 tons.