| 摘要 |
PURPOSE:To manufacture a boiling heat transfer pipe having high performance, by forming a reticular continuous cavity opened by many opening parts provided regularly in the circumferential direction and the axial direction of a pipe. CONSTITUTION:A rolling tool 6 is pressed and rolled on the outside face of a blank pipe 3 on which many linear projecting lines and longitudinal grooves 2 extending in the pipe axial direction are formed alternately, and each independently projecting fin F is formed by cutting the projection line and the longitudinal groove 2 in the axial direction. In the final stage of the rolling, a many independent projection like fins F are formed in the circumferential direction, on the surface of the pipe on which many tunnellike cavities 9 extending in the axial direction are provided on the lower layer of the surface of the pipe over the circumferential direction, and an opening part 10 for communicating with the cavities 9 is formed between respective fins. Subsequently, the fins F are crushed in the axial direction and the circumferential direction by a roll, and an axial direction cavity 15 and a circumferential direction cavity 16 opened by opening parts 14 arranged regularly in a reticular shape over the axial direction and the circumferential direction are formed continuously. |
