SCREW COATED WITH GLASSY LAYER OR ENAMEL AND INJECTION OR EXTRUSION DEVICE HAVING THE SCREW

摘要

PROBLEM TO BE SOLVED: To provide a screw excellent in corrosion resistance and abrasion resistance by simple structure in a screw type pressure ejection apparatus which injects or extrudes a material by a screw, an injection device, and an extrusion device. SOLUTION: A glassy layer or an enamel coat 24 is formed on the screw 7 of the screw type pressure ejection apparatus, or the glassy layers or the enamel coats 24 are formed on both the screw 7 and a check ring 13.