US2010400A

US2010400A - Method of manufacturing tubes and pipes

Info

Publication number: US2010400A
Application number: US594127A
Authority: US
Inventors: Klein Ludwig
Original assignee: Vereinigte Stahlwerke AG
Current assignee: Vereinigte Stahlwerke AG
Priority date: 1931-05-11
Filing date: 1932-02-19
Publication date: 1935-08-06
Anticipated expiration: 1952-08-06
Also published as: GB389262A; BE385999A

Description

Aug. 6, 1935. L. KLEIN 2,010,400

METHOD OF MANUFACTURING TUBES ANDA PIPES Filed Feb. 19, 1932 Ihren/or.- z. /f am l Patented Aug. 6, 1935 UNITED STATES PATENT OFFICE METHOD F` MANUFACTURING TUBES AND PIPES Application February 19, 1932, Serial No. 594,127 In Germany May 11, 1931 e claims'. (C1. sli-62) My prior Patent No. 1,898,779 relates to a method of producing tubes and pipes with internally thickened ends by the pilgering process with the aid of a mandrel having an offset, the main feature being that while the thickened tube ,end is being rolled out over the oiset portion of the mandrel and during the time in which the rolls in rolling out the material over the part of the mandrel of normal thickness are still opera.- tive at the offset part of the mandrel, the material is expanded rearwards.

The object of the present invention is to apply this method to the manufacture of tubes and pipes of a desired length which have not only 1,. thickened ends, but have in general local inwardly extending thickenings at desired points.. Such pipes are used for instance as columns and generally in vall cases where a pipe having a smooth cylindrical external surface must at certain places 20 have a thickened cross-section for considerations of strength or for other reasons.

The invention relates moreover to tubes and pipes of a desired length which have local inwardly extending thickenings manufactured by the pilgering process with the aid of a mandrel having an offset portion, wherein said thickenings can be formed at desired and predetermined points along the inside of the tube or pipe, and independent of the length of the same such as to pro-l 30 duce tubes or pipes of a desired length with a desired number of said internal thickenings in desired spaces. Moreover the invention comprises the finished tube or pipe of a desired length which is provided at its one end and at predetermined points along its inside with local inwardly extending thickenings and at its other end with an outwardly extending thickening.

The method according to the invention is also suitable for the manufacture of tubular rods with inwardly thickened ends when the tubes are to be made not in single but in double or multiple lengths. Through the application of the new method for this purpose the output of the rolling ,mill is considerably increased, the waste of ma.-

4l terial reduced and the percentage turned out imy proved, so that the manufacturing costs become considerably lower.

The manufacture of tubes of a desired length with local inwardly extending thickenings at desired points is carried out according to the invention by the tubular blank being rolled down on the thicker part of a mandrel having an'oiiset end until a place which is to be thickened internally is reached, thereupon moving longitudinally and u securing the blank in place with respect to the mandrel in such a position that the material for producing the thickening encloses the offset end portion of the mandrel, and then rolling down the thickened part of the blank on said oilset portion. After this rolling down cf the thickening the work piece may be released on the mandrel for enabling the blank to be further rolled down.

For xing the blank with respect to the mandrel during the rolling down of the thickening a bridging piece is placed over the exposed portion of the part of the mandrel of normal thickness, which bears at both ends agailnst a stripping ring and an auxiliary ring respectively. After the thickening has beenl rolled the bridging piece is removed for enabling the next part of the tube of normal cross-section to be rolled down. Through the part of the mandrel of normal thickness becoming available again and through the blank resting with the thickening just formed against the oiset on the mandrel the exact rolling of the blank over the offset on the mandrel becomes possible, that is to say, the, material can yield rearwardly when rolling down the place where the thick-walled cross-section merges into the thin-walled cross-section.

In the accompanying drawing different phases of the method according to the invention are illustrated on a constructional example.

In Fig. l, of which Fig. la represents a section along y-y, the tubular blank a is provided at its forward end in accordance with the method described lin my said prior patent with an inwardly extending thickening and has been rolled down next to this thickening over a certain length to the normal tubular'cross-section. In order to produce at a desired place an inwardlyextending local thickening, the blank is held with respect to the mandrel in such a position that the material required for producing the thickening is over tion, the bridging piece d has been removed. For

this reason and because the blank bears with the thickening just produced against the shoulder g of the mandrel, in rolling down the transitional part the material can yield rearwardly,

until the rings e and f bear against one another 5 as shown in Fig. 3, whereupon the rolling down oi the tube proceeds in the normal manner, that is to say, the material is stretched out forwardly. The outwardly extending thickening or pilger head a remaining at the rear end of the tube, as shown in Fig. 3, may thereupon be rolleddown in the manner described in my said prior patent so as to produce an inwardly thickened tube end.

Instead of making one local inwardly extending thickening in addition to the inwardly thickened tube ends, `it is of course possible to make any number ofthickenings by the new method.

What I claim is:

l. A method of manufacturing a tube or pipe having local inwardly extending thickenings at desired points, consisting in rolling down a tubular blank on the thicker part of a mandrel having an offset end smaller than its other portions until a place which is to be thickened internally is reached, thereupon moving longitudinally and securing the blank in place with respect to the mandrel in such a position that the material for producing the thickening encloses the oiset end portion of the mandrel, and then rolling down. the thickened partici the blank on said offset end portion, as set forth.

2. A method of manufacturing tubes and pipes of a desired length with' local inwardly extending thickenings atA desired points, consisting in rolling down a tubular blank on the thicker part of a mandrel having a smaller offset portion until a place is reached which is to be thickened internally, thereupon moving the blank or mandrel longitudinally with respect the one to the other andl securing the blank with respect to the mandrel in such a position that the material for producing the thickening encloses the smaller offset portion of the mandrel, then rolling down the thickened part of the blank onto said offset and releasing the blank with respect to the mandrel for enabling the blank to be further moved longitudinally and rolled down, as and for the purpose set forth. I

3. /A method of manufacturing tubes and pipes of a desired'length with local inwardly extending thickenings at desired points, consisting in rolling down on a mandrel having different diameters a tubular blank on the thicker part of the mandrel having a smaller offset end portion until a place is reached which is to be thickened internally, thereupon placing a bridging piece covering only a part of the circumference of the mandrel on the exposed part of the mandrel, whereby the thickenings at desired points, consisting in rollv ing dow-n a tubular blank on the thicker part of a mandrel having a smaller offset end portion until a place is reached which is to b e thickened lnternally, thereupon placing a bridging piece covering only a part of the circumference of the mandrel on the exposed part of the mandrel, thereby securing the blank from longitudinal motion with respect to the mandrel in such a position that the material for producing the thickening encloses the oiset portion of the mandrel, then rolling down the thickened part of the blank and thereupon removing the bridging piece from the mandrel thereby releasing the blank with respect to the mandrel for enabling the blank to be further rolled down, as and for the purpose set forth.

5. A. method of manufacturing a tube or pipe having local inwardly extending thickenings at de'sired points consisting in rolling down a tubular blank which has been constricted near its front end on the smaller offset end portion of a mandrel so as to produce an inner end thickening of the blank, thereupon rolling out the blank on the thicker part of the mandrel until a place is reached which. is to be thickened internally, thereupon moving the blank longitudinally with respect to the mandrel and securing the blank with respect to the mandrelA in such a position that the material for producing the thickening encloses the smaller oiset portion of the mandrel, then rolling down the thickened part of the blank onto said offset, releasing'the blank with respect to the mandrel for enabling the blank to be further moved longitudinally and rolled down in its normal thickness and rolling an inner thickening at the rear end of the blank.

6. A tube or pipe of a desired length being provided at its one end and at predetermined LUDWG KLEIN.