Method for bending tubular articles with a relative ratio of the bending radius and the outer diameter of the finished pipe which is less than 3

#The present invention relates to a method and a die for bending tubular elements.

#It is known in the technical sector relating to the manufacture of large-size tubular piping which is normally made by means of forging that there exists the need to obtain curved sections by means of bending of the pipe.

#Although the bending methods performed for example using bending machines are per se conventional, these methods however are not suitable in the particular case where it is required to bend pipes which have relative ratios of the bending radius R and the outer diameter D of the pipe with values less than 3.

#Further details may be obtained from the following description of a non-limiting example of embodiment of the subject of the present invention provided with reference to the accompanying drawings in which:

#FIG. 1 shows a side view of a pipe with radial branches, inserted inside a die according to the present invention;

#FIG. 2 shows a front view of the assembly according to FIG. 1;

#As shown in FIG. 1 and assuming for the sole sake of convenience of description and without limiting the description, a set of three reference axes in a longitudinal direction X-X, transverse direction Y-Y and vertical direction Z-Z, respectively, the pipe 1a to be bent extends in the longitudinal direction X-X and has an outer diameter D.

#The straight article 1a used as the basic part for the method according to the present invention is obtained by forging a bloom of the material required and will have a form (produced at the steelworks), diameters, thicknesses and lengths which are suitable for obtaining the finished part with the required dimensions after forming/forging according to the present invention.

#The forged straight article (such as a forged pipe) 1a also has bosses 2a of material which project radially in specific zones and from which, using the methods described below, the integral branches 2 projecting radially from the surface of the finished pipe 1 will be obtained.