MULTI-LAYER SPIRAL TUBE FOR AUTOMOBILE AND ITS MANUFACTURE

摘要

PURPOSE: To prevent exhaust gas from leaking outside the tube, when the gas flowing inside the tube gains a high pressure, by connectedly welding plural corrugated sheets of a multi-layered spiral tube for which a corrugated sheet is spirally rolled up so as to be multi-layered. ;CONSTITUTION: First, in welding by brazing only the corrugated sheet of the first and the second layers counted from the outer side, a linear filler metal 3 is continuously fed on the rearmost groove m of the corrugated sheet 1 during its winding process. As a result, the tiller metal 3 is continuously arranged between the first and the second layer 5 of the higher part 2 in the semiprocessed product of a multi-layered spiral tube thus formed. After that, this semiprocessed product is heated until the filler metal 3 is melted, and then welded. As an alternative, TIG, plasma arc or laser welding may be applied on the multi-layered spiral tube by means of welding equipment provided with a welding torch while the torch is moved along the higher part on the external face of the tube. An arbitrary number of layers from the outer side may be welded by adjusting this joining and penetration quantity.;COPYRIGHT: (C)1996,JPO