公开(公告)号：US3584367A

公开(公告)日：1971-06-15

申请号：US3584367D

申请日：1969-08-13

Applicant: DANFOSS AS

Inventor： KIERSGAARD JORGEN

IPC: B21C37/20 ,  B21D22/20 ,  B23P17/00 ,  B23P19/04

CPC classification number: B21D22/203 ,  B21C37/205 ,  Y10T29/49805 ,  Y10T29/49877 ,  Y10T29/49927 ,  Y10T29/4994

Abstract: THE INVENTION RELATES TO A METHOD FOR PRODUCING CORRUGATED TUBES HAVING MULTIPLE WALLS WHICH MAY BE USED AS BELLOWS AND HAVE OTHER USES. STARTING WITH TWO THIN PLATES, A TEMPERATURE RESISTANT PROTECTIVE COATING OF A MATERIAL SUCH AS TITANIUM IS APPLIED TO AT LEAST ONE PLATE AND THE PLATES ARE SUPERIMPOSED WITH THE COATING BEING BETWEEN THE PLATES. THE PLATES ARE SUBJECTED TO A DEEP DRAWING OPERATION TO FORM A DOUBLE WALLED CUP SHAPED MEMBER WHICH IS SUBSEQUENTLY SUBJECTED TO A CORRUGATING OPERATION. THE TEMPERATURE-RESISTANT COATING PREVENTS THE WELDING TOGETHER OF THE TWO PLATES DURING THE DRAWING OPERATION SO THAT ENGAGING PORTIONS OF THE PLATES ARE RELATIVELY DISPLACEABLE DURING THE CORRUGATING OPERATION. THIS MOBILITY OR RELATIVE DISPLACEABILITY OF THE PLATES PREVENTS STRESSES FROM FORMING WHICH WOULD OTHERWISE CAUSE UNDESIRED DISTORTIONS OF THE METAL DURING THE CORRUGATING OPERATION.