MXPA99001161A - Assembly and method for sun - Google Patents

Abstract

A welding assembly includes a structure member and a plurality of repositionable torches supported by the structure member adjacent a linear path of travel of a metal strip. The method includes the steps of welding the metal strip, asserting the character of the weld, and replacing the supports to alter the character of the weld

Description

ASSEMBLY AND METHOD FOR WELDING BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a torch assembly and to a method for welding, and more particularly, to an assembly for welding with inert gas of tungsten.

Description of the Prior Art Inert gas welding of tungsten generally involves the use of a torch with a tungsten electrode, and an element for ejecting an inert gas, such as argon or helium, near the distal end of the electrode. The electrode generates an electric arc between its distal end and a metal, while the inert gas forms a protective atmosphere for the arc, which melts the metal and forms a weld. The prior art includes a wide variety of torch assemblies, including those that operate in the production lines to manufacture products such as seamless tubes. In these applications, the character of the weld depends in part on the speed of advancement of the product. Additionally, environmental conditions can affect the structural and visual integrity of the weld joint. The assembly of the present invention allows the welding product to be rapidly advanced, while maximizing the structural and visual integrity of the welded joint. It uses a torch of multiple electrodes, with linearly aligned electrodes, elements to adjust the inter-electrode spacing, and elements to effectively discharge the inert gas at the distal ends of the electrodes. The assembly of this invention is a simple and compact system that allows a product to be welded in a continuous and effective manner.

SUMMARY OF THE INVENTION In accordance with one embodiment of this invention, a welding assembly includes a structure adjacent to an elongated path of travel of the strip element that welds the torch assembly, and a plurality of torch elements supported by the member of the torch. structure in a side-by-side relationship, separated along the path of travel. Each of the torch elements has a relatively elongated body, with a supply end and a working end. This torch element includes electrode elements with a tip extending beyond the working end of the body to the arc with the strip element. Each torch element body defines a hole with an outlet proximate the end of the tip of its electrode element. Inert gas flows through the hole, and is discharged out the outlet around the tip of the electrode element. The inert gas protects the electric arc formed between the tip and the strip element, to facilitate welding of the strip element. In the embodiment described below, the electrode element extends through the hole and exits through the outlet. The welding assembly also includes an element operably associated with the torch element, to vary the longitudinal spacing of the tips of two adjacent electrode elements. This feature allows to have a better control and variation of the time between the application of a first electric arc and the following electric arcs that the torch assembly produces in the welding operation. The welding operation includes providing a plurality of electrode stations along the linear path of travel of the strip element, and moving the strip element along the path, and welding the strip element. It also includes the steps of asserting the character of the weld, and varying the separation of the stations along the trajectory, to alter the character of the weld.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of this invention, reference should now be made to the embodiment illustrated in greater detail in the accompanying drawings, and described below in the manner of an example of the invention. In the drawings: Figure 1 is a schematic view of a production line including the welding assembly of the present invention. Figure 2 is a perspective view of the welding assembly of the present invention. Figure 3 is a sectional view taken along line 3-3 of Figure 2. Figure 4 is a side elevational view of a torch member used in the welding assembly of the present invention. Figure 5 is another side elevational view of the torch member shown in Figure 4 (the side of this figure being perpendicular to the side shown in Figure 4). Figure 6 is a side elevational view of the electrode used in the torch member of Figures 4 and s. Figure 7 is a sectional view taken along line 7-7 of Figure 5. Figure 8 is an enlarged view of the cross-sectional view shown in Figure 7. Figure 9 is a perspective view of the lower end of the body of the torch member shown in Figures 4, 5, and 7. Figure 10 is a separate view in parts of the body of the torch member and the electrode extending through the body. Figure 11 is a partial perspective view of a portion of the torch assembly, showing an opening through which gas flows from a central hole in the electrode to a passage between the electrode and the body of the torch member. Figure 12 is a sectional view taken along line 12-12 of Figure 3. Figure 13 is a perspective view of a shoe segment of a structure member that supports the torch members. Figure 14 is a sectional view taken along line 14-14 of Figure 13. Although the following disclosure describes the invention in relation to an embodiment and modifications of that embodiment, it should be understood that the invention is not limited to this modality and its modifications. In addition, it should be understood that the drawings are not to scale, and that the graphic symbols, the diagrammatic representations, and the fragmentary views, illustrate in part the modality. In certain cases, the disclosure may not include details that are not necessary for an understanding of the present invention, such as conventional fabrication and assembly details.

DETAILED DESCRIPTION OF THE DRAWINGS Turning now to the drawings, and referring specifically to Figures 1 and 2, a production display that manufactures, for example, seamless stainless steel tube, includes a source of strip elements (a flat strip) elongated stainless steel) 11; a first configuration unit 12, a second configuration unit 13, and a third configuration unit 14, which bend the flat stainless steel strip into a round tube P, as shown in Figure 2; the welding assembly of the present invention 15, which closes a longitudinal seam S in the rounded tube P; and a reconfiguration unit 16 and a cutting unit 17, which additionally configure the tube P and cut it into predetermined lengths. A support ensures of the units in predetermined locations, where they define a linear path of travel for the metal strip and tube formed. The welding assembly of the present invention shown at 15, generally includes a member of structure 18 and three torch members 19, 20, and 21 supported by the structure member close to the linear path of travel of the metal tube P. one of the torch members 19-21 generates an electric arc with the metallic tube P. The first torch member 19 preheats the tube; the second torch member 20 solders it, in such a way that the temperature along the seam S rises to a level at which the metal melts and bridges the seam S; and the third torch member 21"washes" the pipe P (ie, the weld ends to form a smooth continuous surface for the pipe P). The structure member 18 includes an articulated arm 18a that secures the structure member to the support that holds the welding assembly 15 and other components 11-14 and 16-17 of the production line. The frame member 18 also includes a lower shoe segment 18b (see Figures 12 and 14), and an upper body segment 18c (see Figure 12). These segments 18b and 18c define a traversed passage 22 that receives the torch members 19-21. The torch members 1-21 remain in this passage traversed 22; and its lower ends extend outwardly from passage 22 (as shown in Figure 3), to positions close to tube P. The torch members 19-21 generate a large amount of heat, some of which is transferred to the structure 18. Accordingly, the body segment 18c defines passages (not shown) receiving refrigerant from a supply tube 23, and discharging it through a discharge tube 24. In a similar manner, the shoe segment 18b of the structure member 18 defines passages (not shown) receiving refrigerant from a supply line 25, and discharging it into a discharge tube 26. In addition, different insulating plates protect the structure member 11 from the torch members 19-21 . The traversed passage 22 contains the insulating plates 27-30 which are generally vertically between the torch members 19-21 and the side walls of the passage 22, as shown in Figures 3 and 12. In addition, it contains lower insulating plates 31. and 32, which are generally horizontally between the torch members 19-21 and a flange 18d of the shoe segment 18b. (See Figures 13 and 14). The crossed passage 22 also contains the insulating plate 33 disposed between the torch members 19 and 20, and an insulating plate 34 disposed between the torch members 20 and 21. To secure the torch members 19-21 and the insulating plates in place in the traversed passage 22, the assembly of welding 15 includes a movable support plate 35 and an insurance arm 36 pivotally mounted to the body segment 18c. The support plate 35 moves horizontally from left to right in Figure 3; it is coupled with the insulating plate 27; and transmits the force provided by the safety arm 36, to force the insulating plates 27 29, 33, and 34 and the torch members 19-21 against each other and against the opposite wall of the traversed passageway 22. The lock arm 36 pivots from a release position shown in Figure 3, in the clockwise direction, to a insurance position not shown. A cam segment 36a disposed at one end of the lock arm 36 engages with the support plate 35 and urges it when the arm 36 pivots in the clockwise direction. A ball segment 36b allows an operator to firmly grip the arm 36, and move it as described above. The welding assembly 15 provides an inert gas atmosphere below the shoe segment 18b of the structure member 18. This atmosphere surrounds and protects the electric arcs provided by the torch members 19-21. A gas supply conduit 37 directs the gas to the passage 18e; gas flows through passage 18e; and is discharged through the outlets 18f and 18g, as shown in Figures 13 and 14. Each of the torch members 19-21 further provides a curtain of inert gas around the area immediately adjacent to the arc it generates, as described later. Two magnetic coil members 38 and 39 help to direct and focus each electric arc generated by each of the torch members 19-21 towards the tube P. The coil members 38 and 39 are fixedly secured to the body segment 18c of the member of structure 18, on the opposite sides of the torch members 19-21 (see Figure 2). The coil member 38 includes an electrical supply conduit 38a, a refrigerant supply pipe 38b, and a refrigerant discharge pipe 38c. In a similar manner, the coil member 39 includes an electrical supply conduit 39a, a refrigerant supply pipe 39b, and a refrigerant discharge pipe 39c. Figures 4 to 10 show the construction of the torch member 19; but the other two torch members 20 and 21 have the same construction. (In addition, although the weld assembly mode shown includes three torch members, it may alternatively include less than or more than three torch members). The torch member 19 generally includes an elongated body 40 and an elongate electrode 41 that extends through a central hole 40a of the body 40. The body 40 allows for easy mounting on the structure member 18; and the electrode effectively applies an electric arc to the tube P. The body of the torch member 40 has a flat, generally rectangular configuration. It includes a main segment 40b having rectangular shoulders 40c-f, and a portion of inlet tube 40g; and includes a tip or mandrel segment 40h threaded into the main segment 40b. The main segment 40b defines a coolant passage, which includes a hole 40i, a hole 40j, and a connection hole 40. The hole 40i receives refrigerant through a conduit 42 (which includes a connection 42a); and it contains a helical sling 43 which facilitates the flow of the refrigerant.

The refrigerant is discharged through the hole 40j (which also contains a sling 44), and a conduit 45 (which includes a connection 45a). The hole 40a extending through the body 40, lies on the longitudinal centerline of the side shown in Figure 4; but it is out of phase by a predetermined distance away (to the right) from the center line of the side shown in Figure 5. In other words, the dimension A is greater than the dimension B in Figure 5. Since the members of the torch they remain in a side-by-side relationship with the face shown in Figure 4 disposed adjacent a similar face of the adjacent torch member, a 180 ° rotation of a torch member changes the spacing between the upper segments 40h of the torch members , and in accordance with the foregoing, the separation of the electrode joints making arc with the tube P. The electrode 41 generates the electric arc provided by the torch member, and cooperates with the body 40 to define a passage for inert gas, which forms a curtain type barrier around the arch (see Figures 6, 7, and 10). It comprises an outer upper tube 46, which includes the posts 46a and 46b, which cooperate with the slots 401 and 40n of the inlet tube portion 40g, in order to releasably secure the electrode 41 to the body 40. An internal upper tube 47 it extends through the outer tube 46 in a sliding coupling with the tube 46. A connection 48 connects the upper end of the tube 47 with a conduit 48a that supplies inert gas, and has an internal cable that provides current to the tube 47. A tube coupling 49 connects the lower end of the inner upper tube with a lower tube 50. The coupling tube 43 supports an O-ring 51 which prevents the inert gas from flowing upwards, as described below. A compression spring 52 urges the tubes 47, 49, and 50 downwardly with respect to the body 40, such that the lower end 50a of the lower tube 50 engages the truncoconical seat at the upper end of the tip segment 40h of the body 40. This end 50a has four grooves 50b cut into it, which facilitate the biting and cutting of a tungsten rod 53. This rod 53 forms the lower tip of the electrode 41, and extends through a central hole in the tip segment 4Oh. The distal end 53a of the rod 53 extends below the lower end of the tip segment Oh by a previously determined distance above the tube P, as shown in Figure 7. As shown in Figure 8, the inert gas flows to through the center of the inner upper tube 47, towards the upper part of the lower tube 50, then out of the tube 50 through the openings 50c, and towards a passage defined by the walls of the hole 40a in the body 40 and the outer surface of the tube 50. Then the gas flows into the grooves 54 formed in the outer surface of the tip segment 4Oh of the body 40, and towards the openings 55 connecting the grooves 54 with the hole extending through the center of the tip segment 4Oh The gas continues to flow down between the rod 53 and the walls of the central hole in the tip segment 4 Oh, until it is discharged around the distal end of the rod 53, providing a curtain-type barrier for the electric arc that generates the rod. By way of a specific example, a torch member was fabricated with an electrode end rod 53 of 3.96 millimeters in diameter, a hole (through which the lower part of the lower tube 50 extends) of 9.39 millimeters in diameter, an outer diameter for the lower tube 50 of 6.35 millimeters, an upper part of the central hole in the tip segment 40h of 4.03 millimeters in diameter, and a bottom of 5.94 millimeters in diameter, grooves 54 of 1.57 millimeters x 1.34 millimeters, and openings 55 of 1.85 millimeters in diameter. Although the foregoing description and the drawings disclose and illustrate one embodiment and different modifications, it should be understood, of course, that the invention is not limited to this embodiment and its modifications. Those skilled in the art to which the invention pertains may make other modifications and other modalities employing the principles of this invention, particularly when considering the foregoing teachings. Accordingly, by the appended claims, the applicant seeks to cover any modifications and other embodiments that incorporate those features that constitute the essential features of this invention.

Claims (24)

1. A welding assembly, comprising: a structure member, a plurality of torch members supported by the structure member in a side-by-side relationship close to a path of travel of a strip to be welded, including each member of torch an electrode with a tip, and elements operably associated with the torch members to vary the spacing of the tips of the torch members.

The assembly of claim 1, wherein the structure member has a traversed passageway extending in a direction transverse to the path of travel, the torch members being re-positioned in the passageway to vary the spacing of the legs. electrode tips longitudinally of the path of travel.

The assembly of claim 2, wherein the structure member is equipped with fastening elements for fixing the positions of the torch members.

The assembly of claim 3, wherein each of the torch members includes a body with an electrode receiving hole extending between the ends of the body, each body having a rectangular shoulder between the ends of the body to be received in said passage crossed.

The assembly of claim 4, wherein the hole is offset from the longitudinal axis defined by the intersection of the diagonals of the rectangular shoulder on at least one of the torch members, whereby, a 180 ° rotation of the first member of torch around its longitudinal axis, the spacing between its tip and the tip of an adjacent torch member will vary.

The assembly of claim 5, wherein the body shoulder is equipped with coolant flow passages flanking the body bore, and conduit elements connected to the flow passages, for introducing and removing the coolant.

The assembly of claim 6, wherein each of the flow passages is equipped with sling elements.

The assembly of claim 7, wherein the sling element is an elongated helix.

The assembly of claim 6, wherein the conduit member is internally equipped with a cable element for applying energy to the electrode.

The assembly of claim 1, wherein the structure member is equipped with a pair of magnetic coil elements to provide a magnetic field on each side of each electrode tip.

11. The assembly of claim 1 in combination with a support element for providing the path of travel, a strip source element on the support element at one end of the path to provide the strip element followed by the configuration element of strip to configure the strip element and the welding assembly.

12. A welding assembly, comprising: a structure member having an element to be mounted adjacent an elongated path of the strip element to be welded longitudinally, the structure member having a spanned passageway extending in a direction transverse to the trajectory for mounting at least three torch elements in a side-by-side relationship spaced along the path; the at least three torch elements being relatively elongate in the transverse direction, mounted in the passage through, and each having a body with a supply end and a working end, each torch element being equipped with an electrode element , each electrode element being also relatively elongate in the transverse direction, and having a tip extending beyond the working end of the body, up to the arc with the strip element; and an element operably associated with the torch element for varying the longitudinal spacing of the tips of two of the electrode elements.

13. The assembly of claim 12, wherein the at least two torch elements can be repositioned in the passage to vary the longitudinal spacing of the electrode elements.

14. An apparatus for inert gas welding of tungsten of continuous metal strip elements, which comprises a support defining a linear path, a source of metal strip elements at one end of the path, elements in the path for advancing the metal strip elements in the path towards a torch assembly while the metal strip elements are configured in a predetermined shape, a torch assembly downstream of the path including a structure member on the support, which has a passage through, three elongated electrode carrying torches mounted in the passage through, elements on the structure member to releasably hold the torches, their lengths extending perpendicular to the linear path, each torch electrode having a tip placed adjacent to the metal strip element in the path to create an arc that develops plasma with the elem Each strip is equipped with elements that carry the electrodes, whereby the repositioning of a torch develops a different inter-tip spacing.

15. The assembly of claim 14, wherein the carrier element includes a hole in each torch offset from a longitudinal axis of the torch.

16. A method for welding with inert gas of tungsten, which comprises the steps of providing a linear path of travel for a metal product to be welded, providing a plurality of electrode stations along the path, moving the metallic product along the linear path of travel, assert the character of the welding that is developing through the stations, and vary the separation of the electrode stations along the trajectory, to alter the character of the weld that it is developing.

The method of claim 16, wherein the electrode stations include a pre-heating station, a welding station, and a washing station; and the steps include altering the separation between the welding and washing stations.

The method of claim 16, wherein the steps include providing a torch equipped with an electrode for each of the stations, each torch having a longitudinal center line, providing a hole in each torch offset from its center line, and returning to Place a first torch to change the electrode gap between the first torch and the second torch.

19. A torch member for a welding assembly, which comprises: a body segment defining a hole for carrying inert gas; and an electrode element disposed in the hole, and including a tip extending outwardly from the bore and the body segment; the electrode element and the hole defining a passage with a discharge outlet for the inert gas, the discharge outlet being constricted relative to the remaining passage, and extending around the tip of the electrode to discharge inert gas around the tip with a higher speed than gas velocity when entering the hole.

The torch member of claim 19, wherein the hole is offset from a longitudinal axis of the body segment, wherein the 180 ° rotation of the torch member changes the position of the tip of the electrode.

The torch member of claim 20, wherein the body has a rectangular shoulder equipped with coolant flow passages flanking the bore, and a conduit element connected with the flow passages for introducing and removing the coolant .

22. The torch member of claim 21, wherein each of the flow passages is equipped with sling elements.

23. The torch member of claim 22, wherein the sling member is an elongated helix.

24. The torch member of claim 21, wherein the conduit member is internally equipped with a cable element for applying energy to the electrode element.