EP 0372360 A3 19910320 - METHOD OF MAKING TUBULAR CONSTRUCTION PARTS

Title (en)

METHOD OF MAKING TUBULAR CONSTRUCTION PARTS

Publication

EP 0372360 A3 19910320 (DE)

Application

EP 89121939 A 19891128

Priority

DE 3840938 A 19881205
DE 3906957 A 19890304

Abstract (en)

[origin: EP0372360A2] The invention relates to a method of making tubular construction parts, a tube being formed starting from a sheet and the two ends being welded to one another and the tube thus obtained being subjected to an expanding process. The object of the invention is to provide a method of making tubular construction parts with which high-quality tubular construction parts, for example for baking tubes, can be made in a cost-effective and operationally reliable manner. The invention essentially consists in the tube being mechanically pre-expanded before the expanding process and in the pre-expanded tube, with its two ends sealed, being subjected in a closed manner to a hydroforming expanding process. The advantages achieved consist in particular in the fact that, when the method is used, there is a considerable saving of material with regard to the body to be made and virtually no scrap arises in the course of the manufacturing process. Furthermore, low tool costs result for the changeover if various types of tubular construction parts are made. There is also no problem in using sheets of the most varied quality, e.g. normal deep-drawing steel as well as austenitic and ferritic stainless steel. Different sheet thicknesses can also be readily processed. <IMAGE>

IPC 1-7

B21D 53/74

IPC 8 full level

B21D 26/02 (2011.01); B21D 26/033 (2011.01); B21D 53/00 (2006.01); B21D 53/04 (2006.01); B21D 53/74 (2006.01)

CPC (source: EP)

B21D 26/033 (2013.01); B21D 51/18 (2013.01); B21D 53/00 (2013.01)

Citation (search report)

[Y] DE 2131811 A1 19721228 - SIEMENS ELEKTROGERAETE GMBH
[Y] FR 2156092 A1 19730525 - ROPER CORP
[A] EP 0234243 A1 19870902 - ZANUSSI ZELTRON INST [IT]
[A] US 3908854 A 19750930 - LONG OLAN L
[A] US 3310972 A 19670328 - ERLANDSON PAUL M, et al
[A] CH 462080 A 19680915 - CONTRAVES AG [CH]

Designated contracting state (EPC)

AT BE CH DE ES FR GB IT LI LU NL SE

DOCDB simple family (publication)

EP 0372360 A2 19900613; EP 0372360 A3 19910320; DE 3906957 A1 19900906

DOCDB simple family (application)

EP 89121939 A 19891128; DE 3906957 A 19890304