SE442484B

SE442484B - Method and apparatus for the cold drawing of thick metal tubes

Info

Publication number: SE442484B
Application number: SE8101609A
Authority: SE
Inventors: G Enkvist
Original assignee: Sandvik Ab
Priority date: 1981-03-13
Filing date: 1981-03-13
Publication date: 1986-01-13
Also published as: SE8101609L; SE446512B; SE8105474L

Abstract

The invention concerns a method and an apparatus for tube manufacture. The invention enables the cold-drawn production of curved tubes by means of a hollow tube (10) first undergoing a sub-process for the reduction of the external diameter and thickness of the tube wall. The invention is characterised by a straight tube being drawn through a drawing tool held by a drawing plate (13) and by a mandrel (12), which is short and straight relative to the tube and is positioned centrally within it. After exiting the drawing plate the tube takes up the requisite curved shape because the tube drawing device (15,16) holding the end of the tube draws it into a predetermined curved path, in surface contact with a guide (17) with the above mentioned requisite curved surface, mounted on the drawing plate.<IMAGE>

Description

810i6Û9~9 2 Uppfinningen kommer att beskrivas närmare i samband med det på ritningen visade utföringsexemplct, som schema- tiskt visar framställningen av ett krökt rör enligt upp- finningen. 810i6Û9 ~ 9 2 The invention will be described in more detail in connection with the exemplary embodiment shown in the drawing, which technically, the production of a curved pipe according to the finding.

Sättet för kalldragning av rör enligt uppfinningen inne- fattar, att ett på känt sätt framställt rörämne 10 i rakt utförande, bringas att genomgå en dimensionsmínskníng ge- nom att kalldragas genom en ringspalt, som är utbildad mellan en i änden på en stång ll fästad rak dorn 12, som är inskjuten i röret och en dragskiva 13, varvid dornens 12 längd är kort i förhållande till rörämnet. Dragskivans lj ínloppsdel är på konventionellt sätt konvergerande i rörets genomloppsriktning.The method of cold drawing pipes according to the invention comprises understands that a tube blank 10 produced in a known manner in a straight line execution, is subjected to a dimensional reduction given by being cold drawn through a ring gap, which is trained between a straight mandrel 12 attached to the end of a rod 11, which is inserted into the tube and a pull plate 13, the mandrel of which 12 length is short in relation to the pipe blank. Drawstring lj inlet part is converging in a conventional manner in the direction of passage of the tube.

Mellan rörämnets 10 ínneryta och dornen ie är utbildat ett spel 14 av sådan storlek, att man säkerställer en obe- hindrad inskjutning av dornen i rörämnet 10. Vid dragningen tillföres glidmedel, dels mellan röret och dragskivan 13, dels mellan dornen 12 och röret lO. Utmärkande är att dor- nens 12 dimension överensstämmer med önskad invändig di- mension på det färdiga röret. Vid dragningen av röret 10 över dornen 12 hålles den sistnämnda l huvudsak stilla- stående relativt röret. Alternativt kan dock det omvända utförandet I vissa fall ifrågakomma, dvs stillastålende rör och rörligt dragverktyg.Between the inner surface of the tube blank 10 and the mandrel ie is formed a game 14 of such size as to ensure an unobtrusive prevented insertion of the mandrel into the pipe blank 10. When pulling lubricant is supplied, partly between the pipe and the traction sheave 13, partly between the mandrel 12 and the tube 10. Characteristic is that dor- The dimension of the 12 corresponds to the desired internal dimension. mension on the finished pipe. When pulling the pipe 10 over the mandrel 12, the latter 1 is kept substantially stationary. standing relative to the tube. Alternatively, however, it can be the other way around the execution In some cases come into question, ie stagnant pipes and movable traction tools.

Efter utträdet ur dragskivan lá har röret in bibringats önskad slutlig dimension och erhåller sin slutliga form därigenom att ett organ, innefattande en dragstång 15 med i änden anordnad ringskiva lt, bringas i ingripande sam~ verkan med den främre röränden och en kraft bringas att dra röret 10 i en förutbestämd krökt bana. Vid det i fi~ guren illustrerade utförandet sker dctta därigenom att rö- ret 10 bringas att löpa mot en ledare 17 med förutbestämd krökt yta lö, mot vilken rörets 10 ytteryta glider. Häri- 8101609-9 3 genom erhåller röret sin slutliga form. Som exempel på lämpligt utförande enligt uppfinningen kan nämnas, att vid dragning av rör med en krökningsradle ca ö m en vin- kel av ea 90 bär anordnas mellan oragskivans Jj centrum- axel och rörets 10 centrumaxel vid utträde ur dragskivan.After exiting the traction sheave, the pipe has been brought in desired final dimension and obtains its final shape in that a means, comprising a drawbar 15 with ring plate lt arranged at the end, is brought into engaging co ~ effect with the front pipe end and a force is brought to pull the tube 10 in a predetermined curved path. At that in fi ~ illustrated embodiment, this is done by the 10 is caused to run towards a conductor 17 with predetermined curved surface lo, against which the outer surface of the tube 10 slides. Here in- 8101609-9 3 through which the tube acquires its final shape. As an example of suitable embodiment according to the invention may be mentioned, that when pulling pipes with a radius of curvature approx. of 90 berries are arranged between the center of the shaft and the center shaft of the tube 10 on exit from the traction sheave.

Enligt ett alternativt utförande av uppfinningen kan dor- nen 12 vara utformad med i dragningsriktning utefter sin längd delvis koniskt avtagande tvärsektion. Härigenom ges möjlighet att genom viss förskjutning av dornen 1 genomloppsriktningen under dragningens gång ändra det färdiga rörets innermätt.According to an alternative embodiment of the invention, nen 12 be designed with in the pulling direction along its length of partially conically decreasing cross-section. Hereby is given the opportunity to by some displacement of the mandrel 1 the direction of passage during the pull change it finished the inner tube of the tube.

Den beskrivna tekniken för rördragnlng kan tillämpas på rör med olika form, såsom rund, fyrkant eller dylikt.The described technique for piping can be applied to tubes of different shapes, such as round, square or the like.

Tekniken är även tillämplig för kalldragning av olika ty- per av plastiskt formbart metalliskt material, såsom stål, koppar och liknande.The technology is also applicable for cold drawing of various types of plastically moldable metallic material, such as steel, copper and the like.

Claims

8 '! Û¶6Û9 ~ 9 1D- Patent Claim

l. Methods for cold drawing of coarse metal pipes such as molds for continuous casting and the like, wherein a pipe in straight design is made to undergo a dimensional reduction by cold drawing through a ring gap, which is formed between a straight mandrel arranged inside the pipe and a drawing plate, wherein the length of the mandrel is short in relation to the pipe blank, and the diameter of the mandrel is dimensioned so that a clearance is formed between the pipe and the mandrel before entering the traction sheave, and the mandrel is designed so that its dimension corresponds to the desired internal dimension of the finished tube, whereby the tube is given a final curved shape and dimension by applying a force in the end of the tube (10) exiting the draw plate (13) and applying drawing of the tube in a predetermined curved path, known as the force being applied so that the center axis of the drawn tube forms a certain angle with the center axis of the draw plate immediately upon exit from the draw plate.

2. A method according to claim 1, characterized in that the mandrel during the drawing of the pipe is kept substantially stationary relative to the pipe.

3. A method according to claim 1, characterized in that a mandrel formed with a partially conically decreasing transverse section in the drawing direction is applied inside the pipe blank before drawing, whereby the mandrel is given a certain axial displacement forward in the passage direction during drawing.

Device for carrying out the method according to any one of claims 1-3, comprising a pull plate with an inlet part converging in the passage direction, a mandrel arranged inside the pipe with a short length relative to the pipe, the mandrel being designed with a dimension corresponding with the desired dimension of the finished pipe, and pipe-pulling means coupled to the drawing disc, and where the pipe-drawing means (l5, l6) are arranged to pull the pipe in a predetermined curved path, and in a single drawing operation the final curved shape and dimension of the tube, characterized in that the center axis of the drawn tube forms a certain angle with the center axis of the draw plate immediately upon exit from the draw plate.

Device according to Claim 4, characterized in that the mandrel (12) is designed with a partially conically decreasing cross section in the direction of passage.

Device according to claim 4, characterized in that guide means (17) of predetermined curved design are arranged at the outlet end of the traction sheave (13), against which means (17) the tube is arranged to be forcibly guided in the application of traction force in the traction means (15). , l6).