... .Material:Alloy steel 3.Diameter:25,32,38 or requested Heat Exchanger Finned Tube 1.Bare tube size: OD25mm-OD160mm 2.Fins ... .Precision machiningCNC machining, milling machine, drilling machine, numerical lathe, all types of lathe.7.Surface finish processpolishing, sand blasting, heat treatment, painting, powder coating ...