PURPOSE: To obtain the titled pipe body which maintains corrosion resistance and mechanical strength when immersed and used in high-pressure heated water by forming a coated layer on the inner and outer circumferential surfaces of a metallic pipe with a glass-mica plastic body obtained by using vitreous powder and synthesized mica powder having specified composition as the starting materials.

CONSTITUTION: A glass-mica plastic body obtained by using 1.0mol PbO, ≥0.2mol B2O3, 0.6W2.2mol total amt. of said B2O3 and SiO2, and 0.02W0.17mol ZrO2 as the starting materials is coated on the inner and outer circumferential surfaces of a metallic pipe to form a coated layer. The corrosion resistance and mechanical strength can be maintained when the pipe is immersed and used in high-pressure heated water at about 300°C. Accordingly, the life can be secured for at least one year, when the pipe is used as the casing of an oil layer part.