GB2517731A - Process for swaging metal tubes and machine for performing said process - Google Patents

Abstract

A process and swaging machine for tubular objects comprising a hydraulic ram which has at least two swaging dies (1 & 2 fig 1) axially assembled on its working face and a clamping block 10 holding a product blank. In operation the ram moves the dies toward the clamping block and through axial pressure forms the blank into a desired product preferably in at least two swaging actions carried out in one linear movement of the hydraulic ram. The dies may be disposed so that the first swaging die is crimping die and the second is a bulging die. Where the bulging die may be in two halves of which one is mounted on the ram and the matching half is mounted on the working face of the clamping block. Alternatively the second half of the bulging die is formed directly into the working face of the clamping block. The process may be such that the first of the swaging actions is crimping and the second is a bulging action. The dies may be polished tungsten carbide and a wheat based lubricant may be applied to the work to conduct heat away from the work.

Description

Process for swaging metal tubes and machine for performing said process.

Swaging is a well established process for cold forming metal items by applying pressure to reshape the said metal items. Tt is a well-established process of shaping mild steel, particularly tubes or rods.

There arc many Iffiown swaging machines which can do several processes consecutively or simultaneously. But the known machines all appear either to need one or more tool change or a different action in between the stages of the process.

Another known process uses explosion welding to expand a metal tube into a new shape.

This involves clamping the tube into a die of the shape to be obtained and setting of a controlled explosion inside the tube to expand it and weld it as required. Such a machine is known from GB 1285511 (Yorkshire Imperial Metals) wherein a metal tube is expanded and welded to a face plate of the same material. This process has several disadvantages. Because of the explosion used for applying the required pressure it is extremely difficult to obtain exact shapes in the finished product and it can only be used for expanding the diameter or interior space of hollow objects.

In conventional multiple swaging, the hcat build-up is such that only very few parts can be produced to accurate shapes before the swaging die overheats and fails.

The present invention enables several shape changes to be initiated simultaneously and enables the production of several thousand pieces before it is necessary to re-polish the swaging dies.

The inventive swaging machine essentially consists of a high pressure hydraulic ram which drives a swaging die against a clamping block. The swaging dies are made from highly polished Tungsten Carbide and a wheat based lubricant is applied to the work prior to the operation.

This combination of metal and lubricant produces the effect of heightened heat conductivity away from the work and stops the overheating of the dies and the work piece.

As an example, the figures show the clamping block holding the object to bc swaged -the work piece -in position for the hydraulic ram carrying the swaging die to drive said die onto the product blank andthus deforming itto marrythe shapes of the interior of the shaping die. The example taken is a double shape modification of a mild steel tube.

Figure 1 shows an example of an exploded view of a swaging die mounted on a hydraulic ram, which is not shown.

Figure 2 shows that same swaging die assembled ready for use.

Figure 3 shows an end view of the assembled die Figure 4 shows the clamping block holding the work (shaded tubing) and the swaging die driven against said clamping block and thus forming thc dcsircd product.

The invention will now be described in detail by means of the example shown in the drawings.

Figure 1 shows an example of a swaging die ready to be assembled. References (1) and (2) indicatc thc two swagmg tools to bc unitcd into a singic unit by bolts (6) to (8) bcing threaded into the spacer (3) from opposite ends of the die unit.

In figurc 2 the cxamplc dic unit is shown assembled with the crimping tool on the right and part of the "bulging" chamber on the left and figure 3 is an end view of the crimping tool.

Thc othcr half of thc "bulging" chambcr (9) is formcd on thc Icading facc of thc clamping block as shown in figure 4 or may bc a scparatc half dic boltcd onto thc face of the clamping block.

Thcsc arc only examplcs of the possiblc dic units which may bc mountcd onto thc hydraulic ram. The essence of the invention lies in the way in which several swaging dies or die units can be assembled and used to achieve accurate complex products in a single opcration.

The inherent flexibility of the above arrangement allows for virtually any shape to be crcatcd in a singlc opcration thus rcducing production tirnc and costs.

Claims (11)

1. Claims.1. Swaging machine for tubular objects comprising a hydraulic ram which has at least two swaging dies axially assembled on its working face and comprises fbrther a clamping block holding a product blank, which ram moves said dies toward said clamping block and through axial pressure forms said blank into a desired product.
2. 2. Swaging machine for tubular objects according to claim 1 wherein said at least two swaging dies are mounted axially onc behind the other on said working face of said hydraulic ram.
3. 3. Swaging machine for tubular objects according to claims 1 or 2 wherein the first swaging die is a crimping die and the second is a bulging die.
4. 4. Swaging machine for tubular objects according to claims 1 to 3 wherein the bulging die is in two halves of which one half is mounted on said ram and the matching half is mounted on the working face of said clamping block.
5. 5. Swaging machine for tubular objects according to claim 4 wherein the second half of said bulging die is formed directly into the working face of said clamping block.
6. 6. Swaging machine for tubular objects according to claims 1 to 5 wherein the swaging dies are made from highly polishedtungsten carbide.
7. 7. Process for forming a tubular product by means of the machine of claim 1 whereby at least two swaging actions are carried out in one linear movement of that machine's hydraulic swaging ram.
8. 8. Process for forming a tubular product according to claim 7 whereby several swaging dies are assembled axially on the working surface of said high pressure hydraulic ram and where said die assembly is pushed toward said clamping block presenting a product blank for shaping into the desired product.
9. 9. Process for forming a tubular product according to claim 7 whereby the two swaging actions are first a crimping and second a bulging action.
10. 10. Process for forming a tubular product according to claim 7 whereby the product blank is coated with a wheat based lubricant prior to the operation.Amendments to the claims have been filed as follows Claims.1. Swaging machine for tubular objects comprises a clamping block for holding a product blank, further comprising a hydraulic ram which has at least two separate swaging dies mounted on its working face, wherein upon operation of said machine a first die creates a diameter reduction and a second die creates a diameter increase on said product blank, and which ram moves said dies simultaneously toward said clamping block and through axial pressure forms said blank into a desired product in one single operation.2. Swaging machine for tubular objects according to claim 1, wherein said two swaging dies are mounted one behind the other on said working face of said hydraulic ram.3. Swaging machine for tubular objects according to claims I and 2, wherein said diameter reduction die is a crimping die and said diameter increasing die is a bulging die.4. Swaging machine for tubular objects according to claims 1, 2 or 3, wherein said bulging die consists of two halves of which one half is mounted on said ram and the matching half is mounted on the working face of said clamping block.5. Swaging machine for tubular objects according to claim 3, wherein said second half C\I of said bulging die is formed directly into the working face of said clamping block.6. Swaging machine for tubular objects according to claims ito 4, wherein the swaging dies are made from highly polished tungsten carbide.7. Process for forming a tubular product by means of the machine of claims I to 6whereby at least two differing swaging actions are carried out simultaneously in one linear movement of said machine's hydraulic ram.8, Process for forming a tubular product according to claim 6, whereby several swaging dies are assembled axially on the working surface of said hydraulic ram and where said die assembly is pushed toward said clamping block presenting a product blank for shaping into the desired product.9. Process for forming a tubular product according to claim 7, whereby said swaging actions are a crimping and a simultaneous bulging action.10. Process for forming a tubular product according to claim 8, whereby said swaging actions are performed on different parts of the product blank.
11. 11. Process for forming a tubular product according to claim 7 whereby the product blank is coated with a wheat based lubricant prior to the operation to increase the useful life span of said dies, * * ******** * * * * * * * * * * * ****