Assimilation of Advanced Roll Materials in Rolling Production

The EVRAZ ZSMK 250-1 continuous small-section mill specializes in manufacture of rebars Nos. 10 and 12 and equal-flanged angles Nos. 2-4 from billets 100 xx 100 mm in cross section. Rebar manufacture is carried out by a slitting process from carbon and low-alloy steels for different standards governing rib transverse shape. The life of finishing stand reinforcing passes is mostly determined by channel shape at the bottom of grooves within which transverse ribs are formed. The lowest life of finishing stand passes is observed in rolling crescent shaped ribs. There is surface breakdown in these passes with formation of cracks and spalling. Cracks form during the first use of a set of rolls. Cracks penetrate to a depth up to 15 mm in rolls with high hardness. Tests are performed for different grades of cast iron for rolls of the finishing group with a minimum hardness of 60 HRC to a controlled depth of 15 mm from the roll body surface. The best operating properties are obtained in rolls of cast iron with a spheroidal graphite shape, alloyed with chromium, nickel, molybdenum, and vanadium.