Transformer steel - NLMK Group

52. ProcessGOES is melted in and tapped from basic oxygen furnaces (BOF) with subsequent castingat continuous casting machines (CCM).A comprehensive technology provides for liquid steel blowing with inert gases, vacuumdegassing and secondary metallurgy.Hot rolling is performed at continuous hot strip mill.Cold-rolled strip productionFirst strip surface is descaled at the pickling line. Then the strip undergoes first cold rollingat continuous 4-stand mill to obtain intermediate thickness.Cold-rolled strip is subjected to decarburization re-crystallization annealing at continuousannealing line.In the process of second cold rolling the strip is reduced to its final thickness.After heat-resistant coating is applied (MgO), the coils undergo high-temperature batchannealing in hydrogen atmosphere.Then the strip is cleaned from excessive MgO, coated with electric insulation coating andundergoes further processing at thermoflattening and electric insulation coating lines.Part of coils is laser-treated at laser facility (domain refining).Slitting and cut-to-length lines are used for edge trimming, slitting and commodity coilgeneration.Finished products are packed and shipped by railway or by trucks.