China E470 20mnv6 E410 Hot Rolled and Deep Hole Bored or Cold Drawn Seamless Honed Steel Tube for Hydraulic Cylinder, Hollow Piston Rod or Telescopic Cylinder, Find details about China E470 Honed Steel Tube, E470 Seamless Honed Tube from E470 20mnv6 E410 Hot Rolled and Deep Hole Bored or Cold Drawn Seamless Honed Steel Tube for Hydraulic Cylinder, Hollow Piston Rod or Telescopic Cylinder