COLD STRETCHHDRAWING METHOD FOR DEFORMED FINNED STEEL PIPE

摘要

PURPOSE:To prevent generation of the inner surface shrinkage of the pipe and the outer surface shrinkage of the fin, and to smooth the surface skin, by projecting out the middle part of the outward form line of the fin into cherson-type, at stretch- drawing the deformed finned steel pipe possessing asymmetric sectional shape. CONSTITUTION:The stretch-drawing pipe blank P3 for manufacturing the finned steel pipe has the sectional shape which is asymmetry with respect to the X-axis and is symmetry with respect to the Y-axis; the center axis X3 of the fin of this pipe blank P3 is a little shifted to the side of X-axis similarly to the pipe blank P2. Furthermore, the outward form line of the fin is not made straight, but is made approximate chevron-type formed by suitable projecting the middle part out of both ends. Besides, the sectional area of the fin of this pipe blank P2 is made equal to the sectional area of the fin of the pipe blank P3.