INNER COVERING MATERIAL FOR TUBULAR PRODUCT

摘要

PURPOSE:To line the inner surface of a steel tube with an expanded covering layer by a simplified method in which a covering material formed by housing a curved resilient metal thin plate in the inside of a heat-expansible tubular material is inserted into the steel tube and expanded by heating. CONSTITUTION:A curled resilient metal thin plate 2 is housed on the inside of a heat-expansible tubular part 1 made of polyethylene mixed with a blowing agent to form a covering material. The covering material is inserted into the aperture 6 in a steel tube to be lined for its inside and heated to cause the tubular part 1 to expand, and the tubular part is pressed on the inner surface of the steel tube by the metal thin plate 2 to closely bond the tubular part to the inner surface of the steel tube for convering. The metal thin plate 2 is then pulled out of the steel tube 3. The lining of the inside of the steel tube can thus be simply attained.