After power current hardening the depth of the working surface is no less than: Work rolls for Coldrolling Mills of 9х1, 9х2, 9х2мф, 8х2сгф steel grades – 22 mm; 8х3сгф – 30 mm. Backup rolls for Coldrolling Mills of 90хф, 75хмф, 75х2мф steel grades – 50 mm; 75х3мфа – .