specification: diameter 60---800; length≤6000; weight≤8T material: 9Cr2MoR,MC3,MC5 barrel hardness: HSD75----90 (higher hardness) barrel hardness evenness: ≤3HSD hardness depth (one side) 12---35mm standard: GB/T13314-2008; GB/T15547-1995 used for: cold rolling mill manufacturing process: ingot-forging-UT-rough machining-UT-QT-2th rough machining-UT -magnetic particle test-quenching-magnetic particle test-finished machining-UT -magnetic particle test-oiling-packing-shiping