| 摘要 |
Process and bending press for the bending of a straight pipe to form a pipe bend with an opening angle of less than 110 DEG , in a pipe section between legs which are straight after the bending operation, by means of bend-pressing. In the process, the straight pipe is introduced with the pipe section to be bent, heated to bending temperature, into the bending tools of a bending press having a pipe-bend female die assigned to the convex pipe-bend side and a pipe-bend male die assigned to the concave pipe-bend side. Between the pipe-bend female die and pipe-bend male die, the pipe is bent in a plurality of press-stroke steps to form the pipe bend. In the first press-stroke step, the straight pipe is bent to an opening angle of approximately 120 to 110 DEG . Thereafter, the pipe section held between the pipe-bend female die and pipe-bend male die is upset with the effect of thickening the pipe wall, specifically by means of upsetting forces which are exerted via the straight legs. Subsequently to this, the upsetting forces are cancelled and the upset pipe section is bent further by means of the pipe-bend female die and pipe-bend male die, and, if necessary, so on and so forth in renewed alternation between upsetting and bending until the finished pipe bend with an opening angle of less than 110 DEG is obtained. The bending press for carrying out this process possesses a clamping device for the legs, which is guided in the bending plane on arcuate guides and which, moreover, is designed as an upsetting device. <IMAGE>
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