METHOD AND APPARATUS FOR COOLING INNER SURFACE OF METAL PIPE

摘要

of the disclosure A cooling method and apparatus wherein in the process of continuously hardening a metal pipe by heating the metal pipe as it passes through a heating unit and then cooling the inner surface of the metal pipe, an annular cooling nozzle having a large number of nozzle openings is placed in the metal pipe, and the spray direction of jets of cooling medium from the nozzle openings is selected so as to maintain a dip angle of between 30.degree. and 70.degree. and a transversal angle of between 30.degree. and 90.degree. and either cooling water or a mixture of cooling water and compressed air is sprayed with a jet velocity of greater than 5 meters per second onto a large number of points on the circumference of the inner wall of the metal pipe.