INTERNALLY GROOVED HEAT EXCHANGER PIPE AND METAL BAR WORKING ROLL FOR INTERNALLY GROOVED HEAT EXCHANGER PIPES

摘要

The inner heat transfer pipe groove is formed according to the invention the shaft a plurality of regions continuing in the direction L of the pipe W1, and separated by W2, adjacent areas W1, W2, the lead in the axial direction L of the pipe angle θ, θ 'inner surface pin top angle α, α ', and the fin pitch p, p' fin (fin) different in at least one of 10 and 11, a number is formed, and adjacent areas W1, area W2 cross the boundary portion (a) of for the on-axis direction L of the tube it is formed by a meandering (蛇行).; Metal strip processing roll of the present invention groove on the outer peripheral surface (20, 21) a number of the plurality of roll pieces forming (2a, 2b) to and combined in a nested state in the axial direction, adjacent to the roll pieces (2a, 2b) cross the contact surface (c) is one with a slope.