MXPA97004676A - Method and apparatus for joining components with multip filler materials - Google Patents

Abstract

The present invention relates to a guide nozzle assembly of multiple filler material having a non-circular cross-sectional shape adapted to fit within a very narrow weld slot, comprising: a first nozzle for guiding a first filler material to a first desired location within the weld groove, the first nozzle having a first outlet for the first filler material at one end thereof, a second nozzle for guiding a second filler material to a second desired location of the weld groove , the second nozzle having a second outlet for the second filler material at a distal end thereof, and hardening means for maintaining a fixed positional relationship between the first and second exits of the first and second nozzles so that the first and second nozzles filling materials leave the first and second outputs respectively, where the end media Ureticators comprise a flat member having first and second edges, the first nozzle is connected with the first edge and the second nozzle is connected with the second nozzle.

Description

METHOD AND APPARATUS FOR JOINING COMPONENTS WITH MULTIPLE FILLER MATERIALS Field of the Invention This invention relates generally to methods and apparatus for joining components. In particular, the invention relates to automated welding in a small width slot for joining metal components.

BACKGROUND OF THE INVENTION The practice of conventional mechanized and automated welding (and to a lesser degree brazing) has focused on methods for improving the microstructural bonding condition and the level of residual stress, especially for materials susceptible to stress-induced cracking. such as stress corrosion cracking (SCC). In addition, emphasis has bplaced on improving bond productivity while maintaining or increasing bonding quality, especially for thick section materials. One of those modifications, in relation to conventional V-groove joints, has bto decrease the volume of the filler deposited by reducing the width of the weld joint. This technique is known in the art as "narrow slot" welding (or narrow space). Since the joints become narrower with stepped side wall angles, there are limitations of width and aspect ratio on the joint design that can be reliably completed, even when using only a single filler material. As technical and practical needs are increased to make even thinner joints, the difficulty of accurately locating and controlling the feeding of non-parallel, multiple filling materials within those narrow and relatively deep junctions using conventional equipment and procedures becomes even greater or is impractical for many applications. An additional problem for high aspect ratio, thin joints is the limitation in filler deposition velocity and the corresponding joint termination velocity, which are strongly controlled by the melting ratio that does not result in the risk of melt loss. or other defects. The practice of feeding only an individual filler into the melting vessel at any point of time during the deposition of a filler passage is inherently limited in its thermal efficiency to utilize the greater power of the heat source. The feeding of two fillers simultaneously, one of which is fed into the melt vessel although intentionally not located in the hotter or more effective cast portion of the heat source, is inherently limited in its thermal efficiency. These practices result in undesirable limitations in the melting rate of filler and productivity.

Commercial systems are available to feed multiple filler wires. The general approach used in the welding industry for the addition of multiple filler material is to feed using two nozzles, each feeding at different times. The nozzles are directed from different directions, typically from the front and rear sides of the torch (or other source of heat), with respect to the direction of torch displacement. One scheme is to feed from the two non-parallel nozzles, alternately opposed as the direction of torch displacement is periodically changed from a forward direction to a reverse direction, such as the continuous or orbital connection application while winding cables that have bwrapped around of a component as it moves in the forward direction during the deposition of multiple filling steps. This commercially available system configuration is commonly called "double wire feed" and allows productivity improvement for some bidirectional, multi-pass applications. Another known scheme is to feed from two opposite non-parallel nozzles simultaneously while being in the forward, backward or both direction, typically in an attempt to improve the filler deposition rate. A variation of this scheme is to try to align both filling nozzles and, therefore, the direction points of both wires, towards the desired point of the melting vessel (under the heat source).

Another variation used with lateral torch and oscillation of filler material is to synchronize the direction of one filler nozzle to the current position of the heat source and to synchronize the other nozzle to be addressed in the portion of the melt container from which the source Heat has been moved in an effort to use some of the excess / residual heat remaining in the container. In this latter configuration, the feed rate of the "cold" filling material is only a small fraction of the primary feed rate. The system is maintained to improve productivity through the use of cold wire feed from the back side out of additional phase. A number of welding systems are commercially available that allow to drive an individual filler material between two synchronized feed rates with arc pulsation between two energy levels. However, at higher pulse frequencies, the combination of the mechanical inertia in the drive mechanism (motor gear heads, etc.) and the free space between the internal dimension of the filling duct and the external dimension of the filling material causes the speeds of individual feed are re-rolled at an average value as the filler leaves the outlet end of the feed nozzle. Indeed, this averaging condition is aggravated by the mechanical inertia of the driving mechanisms and results in the inefficient use of significantly higher heating of the filler material and the melting capacity of the higher energy level. The heating and melting capacity of an electric welding arc, for example, is proportional to the square of the current, so that high current levels are significantly more effective in the melting filler material than lower current levels . Conventional filler nozzles are rigid and, due to their large width, can not be inserted into a very thin joint. The standard approach of increasing the filler retention beyond the tip of the nozzle to extend within a thin joint is limited by the lack of control of the position of the filler near the bottom of such joints if they are deep, as is the case in the thickest materials. This lack of position control not only leads to the melting inefficiencies of the filler as the direction towards the hottest part of the arc degrades, but also leads to contamination of the electrode, casting defects and process terminations when the filler material it makes inadvertent contact with the electrode (not consumable) and disturbs the arc geometry and the thermal properties. Multiple-filled material equipment designs using individual nozzles for multi-feed applications use vertical guide tubes that do not automatically compensate for the fact that the shape of the unsupported filler is not straight and that the end is not a straight path after to leave the mouthpiece. This design has a disadvantage of not providing directional control of the position of the wire after it leaves the outlet end of the nozzle, to compensate for the fact that the wire has a "cast" or helical configuration that remains from permanent flexure. what happens as it is wound on circular reels. The previously flexed wire jumps back into the curved configuration that reflects a portion of the bending deformation it had when it was in the container. This curvature is typically considered for the filler that is initially placed in relation to the heat source (such as the tip of the non-consumable electrode) and in some cases can be manually overlapped during the course of bonding with the use of nozzle positioners. multiple shaft motorized filler. This method depends on an operator for periodic direction adjustments and it would be very tedious when more than one filler is fed at the same time, especially with the high-speed joining practices.

Brief Description of the Invention The present invention is a method and apparatus for feeding multiple filler materials into welds or brazing joints of high aspect ratio (depth to width ratio) of reduced width. The method and apparatus of the invention facilitate attachment with improved control and stability of the position of filler material as it enters the heat source and the adjacent melt container area. The method and the apparatus also provide higher thermal efficiency of filler melting and the corresponding deposition rates (unit fusion), which results in binding material properties and binding productivity benefits significantly over conventional more complex practices. These improvements are best executed when using a multiple filler material method with a multiple filler nozzle apparatus. The use of a nozzle capable of feeding generally parallel, multiple filling materials can significantly improve the bonding productivity while simultaneously maintaining the heat input at a minimum, which is a key feature of the new configuration. The distinction between the existing industrial practice of double wire feeding and the method described here is that the standard double wire feeding occurs alternately from different nozzles as the torch moves forward and backward or oscillates laterally through the joint, that in this new method multiple substantially parallel fillers, such as in the form of wires, are fed from the same nozzle simultaneously in the front or rear directions (or both directions). The main technical characteristics that provide more efficient heat transfer to and through the filler material from an external heat source, such as an arc or energy beam, are as follows: 1. The surface convection area for the transfer of heat at a given length of multiple wires, as compared to the area of an individual wire having the same length and volume (although of correspondingly greater thickness) is significantly increased. 2. The thickness of a non-circular shape (or shorter radius and diameter for a circular shape) of the wire that is smaller than the heat supplied externally must be conducted through it, before the wire is fully fused to its center and then through its full diameter, it is significantly reduced. 3. The time that this surface area of multiple filler material is exposed to the heat source is significantly increased and is proportionally greater than that of an individual smaller wire fed at a higher linear velocity. 4. The position of the multiple filling materials as they approach the welding or brazing vessel can be favorably selected with respect to the preferred position in temperature distribution through the heat source, allowing for the best heat transfer and therefore much higher thermal efficiency for the bonding process. The predetermined exit angle and the spacing between the nozzle orifices determines the convergence position of the filler.

. The multiple filler materials can be located in closer proximity to each other, allowing for better mixing and chemical homogeneity of the deposit when the wires of different compositions melt to produce a tight compound or alloy. 6. The redundancy of multiple filler materials allows for variations in the feed rate of one or more of the fillers - to be accommodated with less disturbance of the melting process, since each filler represents only a fraction of the total melting ratio. 7. The separation of the end of the filler material in relation to the non-consumable electrode, if present, is significantly improved due to the inherently superior stiffness of the described multiple filler nozzle design. A variation of the nozzle design is with the electrode made as a mechanically integral part of the nozzle assembly, which provides a precise and constant direction for the filler material relative to the heat source. 8. The directional consistency for each of the multiple fillers can be controlled even with substantial amounts of "casting" in the filler form (after being unrolled from a reel) due to the optional feature of self-aligning the holes of nozzle having a curved shape, forcing the filler in a curved manner to consistently follow the predetermined orientation of the curved shape of the nozzle. Each of the above effects (pp 1-8) allows the minimum energy required from the welding or brazing heat source to be reduced when using the finer wire and in turn improves the thermal efficiency of the weld joint or brazing Together, they provide an even greater improvement in the thermal efficiency of cast iron. The thermal efficiency is improved since with the lower energy input to fill a joint that has a fixed volume, less energy is wasted in the melting of the excess filler material. In addition, less thermal damage occurs in the bonded components (such as local contraction, general distortion and microstructural damage in the area affected by heat). 9. The feed rates of the multiple wires can be optionally synchronized by pulse with the periodic pulsation of the arc energy, if used. This feature allows the thermally more efficient casting of multiple fillers that have different casting points, with the high temperature casting fillers fed at a proportionally higher speed during the high energy portion of the cycle and, the low temperature casting fillers fed at a higher speed during the low energy pulse.

Additional technical benefits not directly related to the thermal efficiency of the invention include the following: 1. Multiple nozzles can be used to compensate for the effects of welding dilution by the alloy to generate uniform, more uniform, gradient or gradient compositions in joints or steel cladding. These different composition configurations can be achieved fed at variable speeds two or more different alloys in the joint. It is preferred, for example, on free surfaces exposed to process fluids or on related metal interfaces when they are of a different composition than the filler material. 2. Multiple nozzles can also be used to supply additives to the welding vessel, such as powders for alloying effects including in-situ alloying with noble metal catalyst elements (eg palladium) or enrichment with SCC-resistant elements ( for example, chromium). As used herein, the term "noble metal" means a metal from the group comprising platinum, palladium, osmium, ruthenium, iridium, rhodium and mixture of elements of that group. The additives can be introduced that do not form an alloy with the welding material, but form a composite structure instead. The invention can also be used to deposit stainless steel coatings having custom alloy compositions using the in-situ alloy method and standard alloy filler materials. In addition, the multiple nozzles can be used for local supply of at least one of the filler materials containing solder flux surfactants and / or solder penetration agents to increase the performance of the other fillers, which can be made of alloys of standard composition or to increase the welding capacity of difficult "high purity" alloys, giving them an acceptable welding capacity. 4. Multiple nozzles can be used for functionally descending material (FGM) joints by welding or brazing, with the advantage that the inclination of the downward composition through the depth of the joint (typically the thickness of the material) can be adjusted better to adapt to an application. As an example, the gradient may be more uniform or have a reduced inclination as it is required to achieve the benefits in the properties of the downlink. A configuration of the nozzles that can produce this result is a vertical arrangement of the individual nozzles in the assembly. 5. The use of multiple nozzles can improve the melting ratio of the total filler using individually set feed rates, with each adjusted to a maximum value in accordance with its precise position in the arc temperature gradient (or other heat source). ). With one or more fillers placed in the hottest part of the arc and fed at a higher speed than the remaining fillers placed in the coldest portion of the arc and fed at a correspondingly lower speed (although maximized individually), the total feed speed maximum can then be set higher than if only a larger diameter filler was used, which is more difficult to melt. Other commercial advantages or practices of the described invention include the following: 1. Feed fine diameter wires (although metallurgically hard and rigid) at a slower linear feed rate, instead of feeding a single thinner wire at a more linear speed fast (corresponding to the same volumetric feed rate), it is advantageous in that the very fine wire is more prone to flaming and squashing in axial compression than the thicker wires as they are driven through the typically sinuous conduit system towards the guide nozzle. For a volumetric feed rate of filler material and a constant linear feed rate, a change from the amount of a larger cylindrical filler to an arbitrary amount of N cylindrical fillers of equal radius, smaller is controlled by the ratio: where Ri is the radius of the largest individual filler and RN is the radius of each of the smaller multiple fillers. Therefore, the increase in the surface area of N multiple fillers is N times greater than for a single filler fed at an equal feed rate. 2. Another practical benefit of multiple wires powered from a single, multiple port nozzle instead of several multiple nozzles is that the stability of their address point (s) can be maintained more accurately. This benefit exists for monolithic or fabricated nozzle designs. 3. A commercial advantage of using multiple fine wires instead of a finer single wire, which would be fed at a proportionally higher linear speed, is that very fine wires are more costly to manufacture per unit volume (or weight). In addition to the melting ratio of the filler, another significant limiting factor in welding productivity is typically the maximum size of the weld vessel that can be maintained in a stable manner while balancing the competing forces of gravity and surface tension. The use of smaller, thermally efficient multiple filler wires fed directly under the arc, as allowed by the multiple flat wire feed nozzle configuration, provides a higher filler deposition rate compared to cold wire feed methods on the previous side out of phase or single wire feed of the prior art). This effect is possible since the volume of the base material that is melted correspondingly with this practice was reduced and, in turn, keeps the total volume of the molten metal at any point in time within practical limits. The use of multiple wires fed at a lower linear speed, rather than a wire fed at a higher speed with a volumetrically equivalent feed rate, also allows the inertia tolerances for the wire spool pulse to moderate during starts and stops. . This consideration is important when feeding at very high speeds or, from massive wire spools, or both. Therefore, the invention allows the practical balancing between the higher thermal efficiency and the melting ratio of very fine filler material having inadequate handling characteristics and poor thermal efficiency and melting ratio of thicker filler material having characteristics. more lenient driving. The method and apparatus of the invention are suitable for improving many well-known automatic and machined arc and beam welding and welding practices and can be applied for wire deposition which is a combined consumable electrode and the filler metal or only a metal filling. The benefits of the invention are applied for joining non-metallic as well as metallic materials or a combination thereof, although the primary application may be for all-metal joints.

Other technical advantages include the option for multifunctional capabilities to improve the thermal efficiency and other characteristics of the welding or brazing process and the joining completed by using variations such as the simultaneous feeding of multiple wires of the same or different alloys and, electrically preheating one or more of the filling wires. A practical advantage of the invention is that it allows improved direct visual or remote camera viewing of the inner portion of the joint, without significant obstruction of sight by the wire feed guide nozzle. According to the invention, any obstruction of the view is limited only to one side of the welding or brazing vessel, as compared to the known technique of simultaneously feeding from several different sides. During joining with narrow width slots using the prior art, multiple materials are fed from the front and rear sides of the joint, resulting in significant obstruction of the potential field of vision for the current and previous joining steps. Also, the invention provides a better view of the welding passages due to the thin width of the nozzle, even for single-side filler feeding equipment. In summary, the advantages of welding and brazing productivity include the ability to increase the rate of deposition of the filler metal by increasing the feed rate of the filler material without increasing the specific heat input (or by alternately decreasing the heat input). for a fixed filler feed rate), reduce the number of filling steps required, and therefore reduce the time and cost of welding or total brazing. Additional productivity advantages include the incorporation of features that would otherwise lead to increased risk of welding or brazing defects, such as bonding at higher travel speeds or with alloys that have a lower wetting capacity, while maintaining a high speed Fixed filler deposition and specific heat input. In summary, the technical benefits for the combined use of the multiple filler material method and apparatus include the following: (1) higher melting thermal efficiency of the filler material; (2) higher melting (deposition) ratios of the filler material; (3) capacity for in-situ alloying and doping; (4) decreased heat input for predetermined filling speeds; and (5) improved filler synchronization and energy pulsation. Practical benefits include: (1) improved position control of the filler material; (2) reduced obstruction of the melting vessel view; (3) integration of complementary joining functions; (4) increased tolerance against several binding defects; (5) equipment and simplified filler material controls; and (6) higher overall bond production and (6) higher overall bond production (filling) rates.

Brief Description of the Drawings Fig. 1A is a schematic showing an isometric view of a multiple parallel wire feeder / mixer in accordance with a first preferred embodiment of the invention. Fig. 1B is a schematic showing an isometric view of a multiple parallel powder feeder / mixer in accordance with a second preferred embodiment of the invention. Fig. 2 is a schematic showing an isometric view of a nozzle assembly of multiple filler material with cylindrical stiffeners according to the first preferred embodiment. Fig. 3A is a schematic showing an isometric view of a nozzle assembly of multiple filler material having a segmented design with convergent separator and stiffener in accordance with a third preferred embodiment. Fig. 3B is a schematic view showing an isometric view of a nozzle assembly of multiple filler material having a monolithic design with converging filling guide nozzles in accordance with a fourth preferred embodiment. Fig. 4 is a schematic showing an isometric view of a nozzle assembly of multiple filler material carried by a non-consumable electrode according to a fifth preferred embodiment of the invention. Fig. 5A is a diagram showing a front view of the multiple filler material nozzle assembly of Fig. 4. Fig. 5B is a schematic showing a side view of the non-consumable electrode incorporated in the composite structure illustrated in Figs. Fig. 5A. Fig. 5C is a detailed plan view of a further variation of the composite structure illustrated in Fig. 5A in which the filler wire is preheated. Fig. 6 is a schematic showing an isometric view of a parallel three wire feeder / mixer in accordance with a sixth preferred embodiment. Fig. 7 is a schematic showing an isometric view of a three-nozzle assembly of filler material having a segmented design with convergent separator and stiffener in accordance with a seventh preferred embodiment. Figs. 8A-8C are diagrams illustrating three examples of alternating polygonal arrangements of multiple continuous filler materials in accordance with the invention. Fig. 9 is a schematic showing an isometric view of a nozzle assembly of curved multiple filler material having a filler casting control and the convergent direction design in accordance with an eighth preferred embodiment of the invention.

Fig. 9A is a detailed view of the distal ends of three filler wires that are guided by the curved multiple filler material nozzle assembly of Fig. 9 within the welding arc. Fig. 10A is a front view of a composite filler nozzle and a non-consumable electrode according to a ninth preferred embodiment of the invention. Fig. 10B is a sectional view taken along line 10B-10B shown in Fig. 10A. FIG. 10C is a front view of a ceramic ball insulator / guide loosely held in a corrugated seal sleeve. Fig. 11A is a schematic showing a front view of a nozzle assembly of multiple filler material having a double convex edge with edge roller decks, in accordance with another preferred embodiment of the invention. Fig. 11B and 11C are detailed plan views of further variations of the composite structure illustrated in Fig. 11A in which the filler wire is preheated.

Detailed Description of the Preferred Modes In accordance with a preferred embodiment of the invention shown in Fig. 1A, first and second wires 10a and 10b can be fed into the same multiple port nozzle guide assembly 12A by driving them with a stacked assembly of pairs of respective individual slot driver rolls 20a, 20b rotatably mounted on mutually parallel arrows 22. Alternatively, the multiple filler wires can be fed with a single pair of drive rolls (not shown) having multiple slots. Although only two wires are shown in FIG. 1A, the present invention comprises the concept of feeding two or more wires through a single multiple port nozzle guide assembly. To vary the relative velocity of only some of the multiple wires, they can be fed with additional roller sets driven independently or driven and controlled in synchronous manner as required. The multiple port nozzle assembly can be manufactured from small pieces of circular or non-circular pipe 16a and 16b, at least the tips of which are attached to a pair of steel stiffeners in high strength rod or rod. (see Figure 1A) placed on opposite sides thereof. In the alternative, only a stiffener can be used. The filling wires 10a and 10b are fed respectively through pipe 16a and 16b, with the nozzle assembly 12A being positioned so that the ends of the filling wires 10a and 10b are located at the weld bead site that is going to to form. Pipe 16a and 16b (hereinafter "filler guide nozzle") can be made of tungsten (as produced by the chemical vapor deposition technique) or other wear resistant, high strength material, such as metal carbide. The stiffeners 18, as well as the filling guide nozzles 16, can be made of carbide, tungsten, etc., in order to produce the most rigid heat resistant and wear resistant nozzle assembly, or of high strength hardened steel to produce the firmer assembly (resistant to fracture). Alternatively, hoppers 24a and 24b can be used to feed respective particle fillers 25a and 25b into the pipe 16a and 16b of the multiple port nozzle assembly shown in FIG. 1B. Other mechanical mechanisms may be used as desired to feed the multiple port nozzle assembly with continuous solid materials, particle fillers, gas fluidized powders or separate gases. The multiple filler metal tubes can be joined essentially parallel to each other along their length, or alternatively at a small angle to each other, so that the filler material leaving the nozzles is moving in directions converging near or in the focus (higher energy density / temperature portion) of the heat source for a thermally more efficient and faster melting capacity. An example is schematically shown in Fig. 2 for a high aspect ratio arc welding junction of very narrow width using a flat electrode configuration. In particular, the filler nozzle assembly of the present invention of the present invention can be used as part of a gas tungsten arc welding (GTAW) system adapted to weld a narrow gauge slot 2 to form a welded joint. 4 between parts 6a and 6b. The GTAW system has mechanized torch movement and a tungsten electrode 8 with a geometry designed to fit in the reduced width slot 2. The side walls of the slot 2 preferably have an acute angle less than 5 °. The electrode blade 8 has a non-circular cross section. In particular, the cross section of the blade has an elongated dimension that is oriented parallel to the length of the weld joint and a reduced dimension that is oriented perpendicular to the length of the joint, for example, a cylinder having a cross section generally rectangular. The weld beads 4 are deposited within the slot 2 using the elongate tungsten alloy electrode 8 to melt the filling wires 10a and 10b fed into of the groove by a nozzle assembly of filler material 12A. The electrode 8 fits within the slot 2 with free space between the electrode and the side walls. The electrode blade 8 is optionally covered with a ceramic coating to prevent bowing to the side walls of the groove 2. The welding electrode 8 is energized by a conventional arc power supply (not shown) to produce a primary arc. The flat electrode 8 and the nozzle assembly of flat filler material 12A, in conjunction with the small bevel angle and the selected welding parameters, produce a very thin weld joint. During welding, the arc is preferably observed using at least one remote viewing chamber 14. In accordance with the preferred embodiments of the invention, the filler material nozzle apparatus (e.g., 12A in Fig. 2) has a non-circular cross section. In particular, the cross-sectional shape of the filler material guide nozzle assembly is designed to be thin in a direction perpendicular to the depth and length of the weld seam and width in a direction parallel to the seam. Also, the height and / or width can be tapered along the length of the nozzle assembly in order to provide as much stiffness as possible towards the inlet end (mounted) and to be as narrow and thin as possible towards the entrance end. Alternatively, the filler wire or strip of noncircular cross section can be used to increase the surface area and thus improve the heat transfer area and the melting efficiency. The reasons for using a non-circular nozzle apparatus (e.g., blade-shaped) include the following: A) provide lateral stiffness towards the nozzles sufficient to maintain the proper material-filling position guide, while providing only the width minimum practical (in a direction perpendicular to the walls) when used in joints of reduced width that would otherwise be too narrow to be filled; B) provide increased nozzle bending strength both parallel and perpendicular to the depth of the joint so that the desired metal guide is maintained, despite inadvertent physical handling or abusive nozzle machining; C) providing a minimum nozzle width (in a direction perpendicular to the weld seam) so that the view is not obstructed by the portion of the nozzle passing through the view; D) provide sufficient nozzle height (in a direction parallel to the attachment depth) to allow multiple functions related to the joint to be simultaneously performed, or to implement specific simple functions more efficiently and productively with the same nozzle assembly as it was used for the joining process; and E) allowing the nozzle to extend near the bottom of a junction of very narrow width for powder feed additions directly into the filler metal melting vessel. The fluidized powder, if fed from a larger nozzle outside the joint, would diverge excessively within the joint and result in a significant loss of deposition efficiency of the filler material within the container. The multiple tubes can also be attached to a thin tapered stiffener along its length and at a small angle to each other, with the stiffener part preferably made of high-strength transfer-point material (such as tungsten alloy or cut stainless steel). in a thin, elongated form) so that the filler material converges to a point near a predetermined location. One efficient form of said convergent and stiffener separator is a triangular truncated plate 18A having a smaller base dimension than that of its adjacent sides, as shown in the nozzle assembly 12B of FIG. 3A. Similar shapes with curved sides are described below. Additional nozzles may be added to tube 16a or tube 16b or both to form a nozzle stack in the plane of the stiffener plate. A stiffener configuration is a thin triangular piece of steel in tungsten alloy sheet (or other high yield strength material such as carbide) that is brazed, mechanically fastened, or otherwise attached to the filler nozzle tube with the narrow apex of the tube. This configuration provides the greatest resistance against bending when the nozzle assembly is mounted on a mounting bracket (not shown) as a cantilever at the wide end of the triangle. The mounting bracket is connected to a drive apparatus (not shown) for raising and lowering the filler material nozzle assembly. Fig. 3B shows a monolithic filling nozzle 12C having an oval shape with two (26a, 26b) or more (26c) port holes for filling materials (10a, 10b, 10c), and with the option of additional ports 26d and 26e for feeding the gases required by the process, lighting, heating, or detection / control laser light beams, electrical conductors, etc. The guide nozzle, which is supported by a mounting bracket 24, guides the filler material from the out points from the weld groove to a desired position within the weld groove, i.e., in proximity to the weld sediment The filler material is guided into the nozzle by means of a respective conduit 20, alternatively, the cross-section of the monolithic assembly it can be a rectangle instead of an oval. Ports 26a-26c can also be used to supply solid additives to the welding vessel, such as powders for alloying effects, which include m-situ alloy with noble metal catalyst elements (eg palladium), enrichment with SCC-resistant elements (eg, chromium), or fluxes and surfactants to improve weld penetration and / or wetting Additives can also be introduced so that they do not form an alloy with the welded material, but form a composite structure Optional ports 26d and 26e of monolithic nozzle 12C can also be used to supply the main source or an auxiliary casting heat source for the joining process, such as laser light passing through fibers optics in the nozzles This variation can be especially useful for work in unions of very small width with laser systems that have higher beam quality, which allow heat sufficiently focused to be supplied optically by fiber to the casting vessel without the need for lenses of objective that occupy space at the end of the fiber. A significantly different variation of the filler nozzle according to the invention is to mount the filler nozzles on the straight or curved edges of a wider base triangle of thin, electrically conductive, heat-resistant, mechanically strong material, for example, the flat electrode 28, to form the nozzle guide assembly of filler material 12D which is seen in Figures 4, 5A and 5B. The flat electrode 28 provides the functions of a monolithic stiffener for the filler material nozzles 16a and 16b and non-consumable electrodes. Alternatively, the triangular plate of the nozzle assembly serves as a combination stiffener for the nozzles and support for a consumable electrode tip (not shown in the drawings). The preferred combination design has a tip that is electrically and mechanically connected to the stiffener, even that it is removable. The filler feed tubes at the edges should be electrically insulated from the electrode tip and the body. The wider base triangular variation has the advantage of providing relative position stability between the electrode tip and the casting end of the continuous filling materials or, filler streams if they are fed as a gas fluidized product. Other port holes may be used as desired for required process or support purposes, such as providing protection or plasma forming gases, or laser light beams for lighting, heating, tracking, etc. Vertical edges are shown in Fig. 4, however, the advantages of curved edges similar to those shown in Fig. 10A apply to this wider base triangular shape. The Fígs. 5A-5C show details of the embodiment illustrated in Fig. 4. A non-circular nozzle assembly can be made with a triangular (or bar-shaped) stiffener 28 made from tungsten or other suitable high-temperature alloy, which functions as a non-consumable welding electrode and as a nozzle stiffener. A triangular shaped electrode / stiffener made from sheet steel with tungsten alloy can provide sufficient cross-sectional area at its base (width) so that it can successfully resist unacceptable bending, as well as carry arc current exceptionally high despite its minimum thickness. The base of the triangle is clamped or otherwise supported by an electrode holder 30. The electrode holder 30 is preferably made of an oxidation-resistant material, conductive such as copper alloy (e.g., beryllium-copper alloy), optionally electrodeposited with silver or nickel. The electrode holder takes the form of a T-shaped metal body, comprising a rod 30a and a crosspiece 30b. The rod 30a is connected to a conventional welding torch (not shown). The crosspiece 30b has a longitudinal groove formed to receive the triangular blade base with sufficient clearance to allow easy insertion and removal. The blade base is securely held in the cross-piece slot by holding a pair of the parts. clamping screws 32 in a corresponding pair of threaded holes formed in the crosspiece The blade can be easily removed from the support after the screws have been loosened This allows easy replacement of a damaged electrode / stiffener blade Alternately, instead of using screws, the blade may be secured to the support by brazing to create a monolithic blade assembly, i.e., the blade may not be easily replaceable. The blade body 28 is preferably covered with an insulating coating, example, Al203 or Y203, to avoid arcing towards the side walls of weld groove Likewise, all the thick edges on the stamped or cut blade are removed the burrs to avoid bowing In accordance with this preferred embodiment, the triangular blade flat incorporates one or more insulative compartments 34 Each section 34 consists of a piece of insulating material, for example, Al203 or Y203, having a cylindrical peripheral wall and a pair of slightly convex opposite surfaces or radiated edges at each end of the cylinder. better seen in Fig 5B, each insulating section 34 protrudes on both sides of the elect 28 beyond the plane of the blade surface These sections serve to maintain a minimum space between the side walls of the weld groove and the flat sides of the electrode / stiffener blade, thus avoiding scratching or excessive wear of the blade. Ceramic coating during the displacement of the electrode in the welding groove. A scratch sufficiently deep on the coated surface of the blade will remove the ceramic coating, leaving the blade susceptible to bowing along the uncoated site. If one of the filling guide nozzles 16a or 16b is electrically common with the stiffener 28, then the filler wire returns to the consumable electrode, as in the welding of inert metal gas (MIG). In this case, the replaceable tip 25 can be removed (see Figure 5A). Alternatively, if the nozzles 16a and 16b are electrically isolated from the stiffener 28, then the stiffener is also a non-consumable electrode, as in the welding of inert tungsten gas (TIG). The optional auxiliary nozzles 36, for example, for transporting the inert shielding gas, are shown by dotted lines in Fig. 5A. Protective gas nozzles reduce the tendency to contamination, as would occur if the shielding gas were blown in a wide-deep slot from the outside of the slot, providing protection gas in pure form locally when necessary, ie , which covers the solder sediment.

In accordance with another variation shown in Fig. 5C, a filling guide nozzle 16c is welded to the stiffener 28 and a nozzle 38 for receiving the temperature sensing means (not shown) is welded to the filling guide nozzle 16c. For the case where the filler wire is a consumable electrode and a filler material, such as in MIG welding and a flow-centered arc weld, the nozzle is designed to electrically conduct towards the filler wire to establish and maintain an arc from the filler wire. casting end of the wire towards work. In this variation the nozzle is electrically isolated from the rest of the welding torch. The filling guide nozzle 16c in this case comprises an electrical conductor 40 surrounded by an electrical insulator 42, which in turn is surrounded by the structural pipe 44. The stiffener (s) can be joined to be electrically common (es) with the filling nozzle guide apparatus by high temperature brazing, precision welding (eg, laser, electronic beam, electrical resistance) or other means without risk of overheating and melting the joint (s) (is) the assembly during use. A variation of the external nozzle orifice pattern that allows for increased utilization of the non-linear temperature distribution through the heat source is a pattern having two or more different filler materials and / or sizes. This thermally deflected pattern can be configured with a higher temperature / larger size filler centered approximately on the hottest portion of the heat source and, with a lower / smaller cast iron temperature filler or on each side 34 of the Very thin nozzle required for the preferred reduced width joint design. For the selected filler wire sizes, the casting ratios can be subsequently optimized for the current heat source and the heat reduction conditions of the joining process by making relatively small changes to their respective feed rates without significant degradation of thermal efficiency unique for the filler melt obtained with the combination of the number of multiple fillers, the "filler position and the size of the filler." An optional method to use the triangular pattern of Fig. 7 provides individual adjustment of the loa feed rates. smaller filler materials in relation to each other, as well as in relation to the larger filler This option uses the benefits of the larger surface area and the thinner thickness of the finer fillers, with the preferred filler geometrical pattern for utilization of improved heat for cast iron In addition, the combined benefits include the ability to adjust the alloy content of the primary filler (typically larger) with the secondary and / or tertiary fillers (typically smaller, as well as the control characteristics of the casting vessel, such as Surface wetting and bond penetration of the primary filler with active elements contained in the additional fillers. The locations of the primary and secondary fillers can be transported depending on the relative melting points and sizes of the fillers. Additional triangular / polygonal patterns can be used, as shown in Figs. 8A-8C as an advantage to improve the efficiency of the ratio. of melting at predetermined heat input levels and therefore to increase bonding productivity. FIGS. 8A and 8B show triangular filler configurations consisting of a large filler wire 10c and two small filler wires 10a and 10b, with a third wire optional small filler 10d indicated by dotted circles In Fig 8c, the filler configuration consists of two large wire fillers 10c and 10d and two small filler wires 10a and 10b placed at the corners of a parallelogram and third and fourth filler wires 10e and 10f and the third large filler wire 10g indicated by dotted circles s Those patterns, which have more than three fillers, can use parallel type filler drives, each feeding more than one filler piece. Alternatively, they can be operated with individual feeder drivers to adjust the feed rate of one or more filler materials in a more sophisticated design According to the present invention, the edge configuration of the convergent separator / stiffener plate can be curved or straight For the nozzle assembly 12F shown in Figs. 9 and 9A, the preferred edge shape of spacer / stiffener 18B is curved in the plane of the nozzle. This curvature easily allows the fixed flexible pipe 16a-16c to be curved. The curved holes for the filler guide path over straight holes are preferred over the vertical holes for the following functional reasons: a) a benefit of the curved holes is that they maintain the flat alignment and convergence of the filler materials typically curved as they exit of the nozzles (see Fig. 9A). The remaining curvature ("cast") after they have been unrolled from a spool can lead to significant deviation from their respective directional positions if the direction of the curvature is allowed to find its own azimuth position with respect to the axis of the curvature. mouthpiece. b) a second benefit of the curved nozzle is the significantly shorter length of the nozzle than that required to reach from the outside of a junction to the area of origin. This feature becomes more important as either the thickness of the materials being joined increases or, as the filler inlet angle (with respect to the surface of the origin) decreases). A nozzle assembly 18A having a converging point design is shown in dotted lines in FIG. 9 for comparison with the nozzle assembly 18B having a pouring filler and converging junction design. 37 c) a third benefit is that as the bend of the nozzle approaches the approximate curvature of the filler (instead of forcing the filler to a straight configuration within the nozzle), the sliding friction between the filler and the filler nozzle This reduction in friction decreases the reliable feeding of finer filler materials without the inherently increased risk of lateral bending in unsupported portions of the axial compression length, such as occurs downstream of the feeder mechanism. d) a fourth benefit is that the preferred shorter nozzle, as described above in bp), will be lighter for a predetermined cross section shape, while reducing the load requirements for stable placement of other torch assembly handlers , for the oscillation and voltage control actuators. e) a fifth benefit for shorter curved nozzles is that they are stiffer and therefore can maintain an improved filler direction during uneven handling or use, for a predetermined cross-sectional shape of the nozzle. f) A sixth benefit, applicable to multiple type filler nozzles, is that when the filler holes are located on opposite edges of a flat stiffener having different radius of curvature on each edge, the fillers have different degrees of curvature ( "cast") can be selectively fed through the hole that has the closest coupling in curvature, obtaining in turn the benefit noted in pc). Another preferred embodiment of the invention is illustrated in Figs. 10A and 10B. In contrast to the triangular electrode / stiffener 28 seen in FIG. 5A, the electrode / stiffener 50 has convex edges 52 and 52 'along its lower portion. The electrode / stiffener 50 comprises a blade 54 and a rod 56, each of which is removably replaceable. The blade has a plurality of through holes 58 that receive respective folded retainer sleeves 60. Each sleeve is folded (see Fig. 10C) to retain the sleeve in a respective hole and to retain a respective ceramic bullet 62 in the sleeve. In the embodiment shown in Fig. 10B, the ceramic ball 62 has a diameter greater than the thickness of the electrode / stiffener 50. Alternatively, the retainer sleeves may be asymmetrically shaped to hold smaller balls so that some balls protrude on only one side of the electrode / stiffener and the other balls protrude over only the other side of the electrode / stiffener. In each case, the balls act as insulators for rolling. The balls must be positioned and dimensioned so that the balls on each side of the electrode / stiffener make contact with the opposite slot side wall while the electrode / stiffener is separated from the slot side wall by a sufficient gap to avoid lateral arch.

In accordance with the embodiment shown in Fig. 10A, a pair of nozzles 64 and 64 ', which can be used, for example, to supply local cover gas, will be welded to respective convex edges 52 and 52' of the electrode / stiffener 50. A pair of hot wire guide nozzles 66 and 66 'are in turn connected to gas nozzles 64 and 64'. As shown in Fig. 10B, the hot wire guide nozzle 66 has an electrical conductor 68 surrounding the filler wire 10a and is in turn surrounded by an electrical insulator 70. The electrical insulator 70 is encased in the structural pipe 72 , which is welded to the gas nozzle 64. The conductor 68 is used to preheat the filler wire 10a before it is fused by the arc from the electrode / stiffener 50. The nozzle 66 'is similar in construction to preheat the filler wire 10b. The preheating of the filler wire reduces the amount of heat input into the weld joint and the areas affected by the heat of the weld by the electrode arc, which in turn reduces the level of residual stress in the weld. Fig. 11A shows a variation of the embodiment of Fig. 10A, in which the ceramic ball decks are replaced by ceramic roller decks 74 rotatably mounted on flexed wires 76 attached to the edges, for example, by welding . The apartments illustrated by dotted lines are optional. The edges of the rollers are radiated to prevent the rollers from being clogged on rough surfaces. In the embodiments shown in Figs. 11 B and 11C, each roller 74 has a diameter greater than the thickness of the electrode / stiffener 50 and is symmetrically positioned relative to the median plane of the electrode / stiffener 50. Alternatively, a plurality of flexed wires 76 may be inclined from the plane of the electrode / stiffener on both sides of it and on both edges. Each flexed wire carries a roll apart that may have a smaller diameter than the thickness of the electrode / stiffener. One set of rollers extends on one side of the electrode / scaler and the other rollers extend from the other side of the electrode / stiffener. In each case, the rollers act as insulating devices. The rollers must be positioned and dimensioned so that the rollers on each side of the electrode / stiffener make contact with the opposite slot side wall while the electrode / stiffener itself is separated from the slot side wall by a sufficient gap to avoid the bow of the side wall. Fig. 11 B shows a roller apart attached to a hot wire nozzle of the type previously shown in Fig. 10B. Fig. 11C shows a roller apart attached to a respective hot wire nozzle comprising a conductive tube 68 'welded to the gas nozzle 64. The conductive tube 68' is electrically isolated from the electrode / stiffener 50 by means of a 41 electrical insulator 80 placed between the gas nozzle 64 and the electrode / stiffener 50. Many of the benefits of the invention for a bonding application can also be perceived for a steel coating application where the thickness of the filler material nozzle is not of great importance. These include all the technical and productivity benefits for joining, except for those that relate specifically to a very thin form of the nozzle apparatus. Full-size functional prototypes of the multiple filler nozzle assemblies have been manufactured as shown in Figs. 2, 3A, 7 and 9. Various combinations of material suitable for the production of bonding applications were used to manufacture those prototype units. These combinations include metal carbide tubing with carbide stiffeners (two-hole type nozzle), hardened stainless steel pipe with steel tool stiffeners (triangular, two and three-hole pattern type nozzles), hardened stainless steel pipe without stiffeners (in-line pattern type nozzle, with three holes, with central tube taking the place of the stiffener) and stainless steel pipe with carbide stiffener (three-hole triangular pattern type nozzle). The multiple orifice nozzles have been evaluated with stainless steel wire Type ER 347 that has diameters of 0.0381, 0.0406 and 0.043 cm, stainless steel wire Type ER 42 308L that has diameters of 0.0508, 0.0584 and 0.0635 cm, wire Inconel Type ER 82 that have diameters of 0.0508, 0.0635 and 0.0762 cm and carbon steel type ER 70S6 that has a diameter of 0.0508 cm. For GTAW use, the three-hole nozzles were assembled with the largest diameter hole closest to the planned location of the non-consumable electrode (which is the highest and hottest energy density portion of the heat source when the arc is present), with the smallest diameter hole farthest from the electrode. Those patterns were manufactured in the straight designs and the curved preferred. The two-hole nozzles were assembled with two fillers of equal diameter or, with larger and smaller fillers with the larger one selected to be closer to the heat source. This orifice size position placement can be reversed for fillers with significantly different casting properties, so that the harder to melt filler is in close proximity to the heat source regardless of its relative size. The assembly methods used for the prototypes included brazing or resistance point welding of stainless steel sheet strips (all types of carbide), direct resistance point welding or resistance spot welding of stainless steel sheet strips (stainless steel tube, steel tools and types of carbide stiffener) and, high temperature welding (all kinds of stainless steel tube). The filling wire feed 43 through each of those nozzle assemblies demonstrated that they provide the necessary rigidity in the preferred thin profile for improved position control and remote viewing capability and, the correct annular convergence of the steering positions of the wire. In order to adapt the basic designs and most of the options and variations of the invention of multiple filler material, very little modification of equipment is necessary since the commercially available energy supplies and the welding heads have the capacity to feed double wire of parallel alignment and alternating period (instead of the opposite alignment feed, of simultaneous period). These systems can be easily re-wound to run in an electrically parallel motor circuit, operated by the existing individual controller. In this configuration, the currently available motors would simultaneously feed the multiple ports of an individual nozzle, instead of the existing design of two individual alternating feed port nozzles. The relative speeds of each feeder in a parallel system can be adjusted simply with a serial wiring adjustment potentiometer, which reduces the motor voltage (and therefore the speed) of a "secondary" unit with respect to the unit "main" programmed. Since each feeder in the existing parallel system is identical, either unit can be selected as the "secondary" with the other as the "main" unit, or they can be operated at equal speeds with a selectable ratio between their driving wheels. respective. In addition to providing the ability to adjust the composition of the filler deposited in joints between materials that have filled slots, the investment can also be used to deposit steel coatings having customary alloy compositions using the in-situ alloy method with standard alloy filler steel. The above preferred embodiments of the invention have been described for the purposes of illustration. Variations and modifications of the described method will be readily apparent to practitioners with experience in the joining technique. All those variations and modifications that do not depart from the concept of the present invention are intended to be encompassed by the claims set forth hereinafter. For example, the multiple nozzles may be mounted so that the respective filler materials exit the nozzle outlets in parallel or at an acute angle in relation to one another. As used in the claims, the term "acute angle" means an angle <; 90 °, including 0 ° (that is, in parallel). In addition, the inventive compartments can be mounted directly to the edges of a flat electrode that does not perform the double function of supporting gas nozzles and filler wire.

Four. Five CLAIMS 1. A system for welding in a very small weld slot, comprising a welding torch; a welding electrode (8, 28, 50 or 54) extending from the welding torch and adapted to fit in the welding groove; and a multiple filler material guide nozzle assembly having a non-circular cross-sectional shape adapted to fit within the weld groove, comprising: a first nozzle (16a) for guiding a first filler material to a first desired location within of the welding groove, the first nozzle having a first outlet for the first filler material at a distal end thereof; a second nozzle (16b) for guiding a second filler material to a second desired location within the weld slot, the second nozzle having a second outlet for the second filler material at a distal end thereof; and means (18A, 18B or 12C) for maintaining a positional relationship between the first and second outputs of the first and second nozzles so that the first and second filling materials

Claims (14)

1. 46 exit the first and second exits respectively at a predetermined angle in relation to one another.
2. The welding system assembly as defined in claim 1, wherein the means for maintaining a fixed positional relationship between the first and second outputs of the first and second nozzles comprise means for joining the first nozzle to the second nozzle .
3. 3. The welding system assembly as defined in claim 1, the means for maintaining a fixed positional relationship between the first and second outputs of the first and second nozzles comprise a separator (18A or 18B) made of rigid material, the first and second nozzles being attached to the separator.
4. The welding system assembly as defined in claim 1, wherein the means for maintaining a fixed positional relationship between the first and second outputs of the first and second nozzles comprise means for joining the first and second nozzles to the electrode .
5. 5. The welding system assembly as defined in claim 1, wherein each of the first and second nozzles are curved.
6. The welding system assembly as defined in claim 1, wherein the first nozzle has a channel with a first diameter and the second nozzle has a channel with a second diameter, the first diameter being different than the second diameter.
7. 7. The welding system assembly as defined in claim 1, wherein the first nozzle is electrically connected to an energy supply.
8. 8. A system for welding in a very small weld slot, comprising: a welding torch; a welding electrode (8, 28, 50 or 54) extending from the welding torch and adapted to fit in the welding groove, the welding electrode comprising a tip; a curved filler material guide nozzle (16a or 66) adapted to fit in the weld groove, the guide nozzle having an outlet for filler material at a distal end thereof; and means for maintaining a predetermined positional relationship between a portion of the guide nozzle and the welding electrode.
9. 9. A welding electrode assembly comprising a flat electrode (50), a straight member (76) supported by the electrode, and a roller housing (74) rotatably mounted on the vertical member, the roller having a circular cylindrical surface and it is made of electrically insulating material.
10. 10. A hot wire welding electrode assembly comprising a flat electrode (28 or 50) having a thickness, a hot filler wire nozzle (16C, 68 or 68 ') supported by the electrode and located in a plane of the electrode and an electrical insulator (42, 70 or 80), the hot filler wire nozzle 48 comprising an electrical conductor (40, 68 or 68) and the electrical insulator being positioned to electrically isolate the electrical conductor from the electrode.
11. 11. A method for welding in a very small weld groove having a bottom, comprises the steps of: inserting a welding electrode (8) into the weld groove (2), the welding electrode having a separate tip from the bottom of the welding slot by means of a space; generate an electric arc through space; feeding a first filler material (10a) towards a first site in the weld groove, the first filler material at the first site being melted by heat from the arc; feeding a second filler material (10b) to a second site in the weld slot, the second filler material in the second site being fused by heat from the arc, the first and second sites being positioned so that the first and second fused materials they form a weld sediment; and letting the solder sediment of the first and second molten filler materials melt.
12. The method as defined in claim 11, wherein the first and second filler materials are different in composition.
13. 13. The method as defined in claim 11, wherein at least the first and second filler materials contain at least some noble metal. The method as defined in claim 11, wherein the first and second filler materials are fed at different feed rates. 50 SUMMARY A multiple filler material guide nozzle assembly (12A-12F) to feed multiple fusible metal filler wire (10) or other metal shapes into metal joints of aspect ratio-height ratio (depth to width ratio), reduced width ( 2) with control and stability of the filler metal position as it enters the area of the casting vessel. The multiple filler materials are fed concurrently thereto or at different feed rates. To control the directional consistency of each of the multiple fillers including substantial amounts of "casting" in the filling form (after being unwound from a reel), the nozzle orifices can be bent to couple the curvature of the casting wire "casting" " This forces the curved filler wire to consistently follow the predetermined orientation of the curved shape of the nozzle. The multiple nozzles can be used to compensate for the effects of welding dilution by the alloy to generate more uniform, gradient or staggered compositions in joints or steel cladding. These different composition configurations can be achieved by variable feed rates of two or more different alloys in the joint. The multiple nozzles can also be used to supply additives to the welding vessel, such as powders for alloying effects including in-situ alloy 51 with noble metal catalyst elements (e.g., palladium) or enrichment with elements resistant to corrosion cracking. SCC voltage (for example, chromium).