PRODUCTION OF HOLLOW MEMBER HAVING CORROSION RESISTANCE AND ABRASION RESISTANCE

摘要

PROBLEM TO BE SOLVED: To more inexpensively produce a hollow member having sufficient corrosion resistance and abrasion resistance against molten plastic. SOLUTION: The single-screw barrel of an extrusion molding machine is equipped with a cylindrical main body part 12, the decarburization layer 13 formed on the inner peripheral surface thereof and the surface coating layer 14 bonded to the decarburization layer. The main body part 12 is made of spheroidal graphite cast iron (e.g. FCD 600) and a cooling pipe 15 is spirally cast along the inner peripheral surface of the main body part. The decarburization layer 13 is formed by immersing the main body part in a salt bath of NaOH (or subjecting the same to decarburization treatment in a decarburizing atmosphere furnace). The surface coating layer 14 is formed by the plasma spraying of an Ni-base self-fluxing alloy (or a Co-base self-fluxing alloy).