Material:10# 20# 45#345b 25mn 15crmo 42crmo 40cr Standard:gb/t3639 din2391 OD:8-270mm Wt:2-25mm Tolerance OD&ID+-0.05-0.10mm Wt+_0.1-0.20mm Processing form cold rolled cold drawn finish rolling. OD:8-270mm Wt:2-25mm Tolerance OD&ID+-0.05-0.10mm wt+/-(0.1-0.20mm)