Systems and methods for using fluorine-containing gas for submerged arc welding.

(54) Title: SYSTEMS AND METHODS FOR THE USE OF GAS CONTAINING FLUORIDE FOR SUBMERGED ARC WELDING.

(54) Title: SYSTEMS AND METHODS FOR USING FLUORINE-CONTAINING GAS FOR SUBMERGED ARC WELDING.

(57) Summary

This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW). In one embodiment, a welding system includes a gas supply system configured to provide a fluorine-containing gas stream. The system also includes a wire supply system configured to provide solder wire, and a flux supply system configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly configured to receive the fluorine-containing gas flow and the welding wire and to provide the fluorine-containing gas flow and the welding wire near the welding arc during SAW.

(57) Abstract

This disclosure relates generally to welding, and more specifically, to submerged are welding (SAW). In an embodiment, a welding system (10) ineludes a gas supply system (16) configured to provide a fluorine-containing gas flow. The system also ineludes a wire supply system (14) configured to provide welding wire, and a flux supply system (17) configured to provide flux near a welding are during submerged are welding (SAW). The system further ineludes a welding torch assembly (18) configured to receive the fluorine- containing gas flow and the welding wire and to deliver the fluorinecontaining gas flow and the welding wire near the welding are during the SAW.

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PATENT TITLE No. 359254

Owner (s): ILLINOIS TOOL WORKS INC.

Address: 155 Harlem Avenue, Glenview, Illinois, 60025, USA

Name: SYSTEMS AND METHODS FOR THE USE OF FLUORINE CONTAINING GAS FOR SUBMERGED ARC WELDING.

Classification: CIP: B23K9 / 18; B23fc9 £ 9 * Qé3IW173

CPC: B23K9 / 18; B23K9 / 29; B23K9 / 164; B23K9 / 173; B23K9 / 186; B23K9 / 295

Inventor (s): KENNETH ALLEN FISHER; MARIO AMATA; STEVEN BARHORST; JOSEPH BUNDY

REQUEST

Number: Date of International Presentation:

MX / a / 2017/015861 March 25, 2013

Divisional of the Patented Number: 354878

PRIORITY

Stopped: Facha: Number:

US 27 January 2012 13 / 431,863

Validity: Twenty years

Due date! March 25, 2033 Issue Date: September 20, 2018

The reference patent is based on articles 1, 2, section V, $ 'frad 95ri Í8, and 59 of the Industrial Property Law.

Pursuant to article 23 of the Law of the lnduetri Property "l, lppfí &" the patent entity has a validity of twenty non-extendable articles, counted from the filing date, of the intemaetonál application and will be subject to the payment of the pear fee keep your rights in force.

Whoever signs this title does so based on the provisions of articles 6 * sections III and 7 · bis 2 of the Industrial Property Law (Official Gazette of the Federation (DOF) 06/27/1991 amended Q2 / B8M 994 10/26/198 «, 12/26/1997. 05/17/1999, 01/26/2004. 06/16/2005, 01/25/2006, 05/06/2009, 06/06/2010, 06/18/2010, 08/28/2010, 07/01/2012, 04/09/2012 08/08 / 2016 and 03/13/2018), articles 1 ', 3'fraction V subsection a), 4' and 12th sections I and lll of the Regulations of the Mexican Institute of Industrial Property (DOF 14/12/1999, reformed the 07/01/2002, 07/15/2004, 07/28/2004 and 09/07/2007); Articles 1, 3, 4 ·. 5 * fieecirtlt V subsection a), 16. sections I and lll and 30 of the Organic Statute of the Mexican Institute of Industrial Property (DOF, 12/27/1999, amended on 10/10/2002, 'W07 / 2004, O4 / 08Z2OOÍ4'y 13/89/2007); 1, 3 and 5 paragraph a) of the Agreement that delegates powers to the Deputy Directors General, Divisional Directors Coordinator, Regional Office Holders, Divisional Deputy Directors, Departmental Coordinators and other subordinates of the MejflfiSno Institute of Industrial Property (DOF, 12/15/1999, amended on 02/04/2000, 07/29/2004, 08/04/2004 and 09/13/2007).

This letter is signed with an advanced electronic signature (FIEL), based on articles 7 BIS 2 of the Industrial Property Law; 3rd of its Regulations, and 1 fraction III, 2 fraction V, 26 BIS and 26 TER of the Agreement establishing the guidelines for the use of the Electronic Payment and Services Portal (PASE) of the Mexican Institute of Industrial Property, in the procedures indicated.

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DIVISIONAL DIRECTOR OF PATENTS NAHANNY CANAL REYES

Original string:

NAHANNY MARISOL CANAL REYES | 00001000000403252793 | Administration Service

Tax | 1695 || MX / 2018/79488 | MX / a / 2017/015861 | Normal patent title with divisional PCT | 1220 | RRGO | Page (s) | 69J8HL4vqbPJKYWGzKdvYndhsvM =

Digital stamp:

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SYSTEMS AND METHODS FOR THE USE OF GAS CONTAINING FLUORINE POTATO _ SUBMERGED ARC WELDING

IMPI kjtttuto mlxican ©

SAY THE INDIAN ^ TRIAL FWOMBDAD

CROSS REFERENCE WITH RELATED REQUESTS

This application is a continuation in part of a US Patent Application No. 13 / 079,521, entitled "System and Method for Reducing Diffusible Hydrogen in Weld Metal," filed on April 4, 2011, which is incorporated herein as Reference in its entirety for all purposes.

BACKGROUND

This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW).

Welding is a process that is increasingly present in various industries and for a variety of applications. For example, welding is often used in applications such as shipbuilding, offshore platforms, construction, tube manufacturing, and so on. Certain welding techniques (for example, gas metal arc welding (GMAW), gas flux cored 20 arc welding (FCAW-G), and gas tungsten arc welding (GTAW)), therefore They generally employ a shielding gas (eg, argon, carbon dioxide, or oxygen) to provide a particular local environment in and around the weld arc and melt bath during the welding process. In contrast, other welding techniques (for example, submerged arc welding (SAW)) often use a granular flux that decomposes or releases gases under the conditions of

<img file="MX359254B_D0004.tif" />

INDUSTRIAL PROPERTY arch to provide local atmosphere near the arcq_N welding. In addition, SAW offers other advantages, such as increased deposition rates, compared to other welding techniques.

In general, for steel related welding applications, a concern is the amount of diffusible hydrogen present in the weld during welding and after the welding process is complete. Hydrogen can be introduced into the weld from a number of sources, including moisture from the atmosphere, the metal surface, the welding electrode, or flux. Hydrogen can also be introduced from oils, lubricants, or other coatings onto the surface of the metal or welding wire during the welding operation. Hydrogen is easily soluble in steel exposed to high temperatures during the welding process; however, as the weld cools, the hydrogen can become increasingly insoluble in the steel and be rejected from the solution. This can cause hydrogen to build up in discontinuities and grainy contours within the weld metal. These regions of high pressure and stress can cause the weld to become brittle and crack, which can eventually lead to weld failure.

One method of limiting diffusible hydrogen in the weld is by preheating the metal, for example, to limit the amount of moisture present on the metal surface during the welding operation and / or to provide better control of the metal microstructure by regulating the rate at which the metal cools. Such a preheat method can be common for situations involving the welding of thicker steel plates or high-strength steels. However, in certain situations, such as underwater welding applications, it may be difficult or impossible to control the amount of moisture present during the welding process.

In addition, manufacturers may incur large costs | Jl ^ eJHiJio ^^^ fe ^ equipment, time, etc.) associated with the preheating of steel para ^ iretfi / eir ra ^ 3g - hydrogen cracking disease. In other cases, the prcoalontamionto puodoa ^ be applied incorrectly and only a superficial preheating is achieved instead of a soaking preheating.

SHORT DESCRIPTION

In one embodiment, a welding system includes a gas supply system configured to provide a fluorine-containing gas stream. The system also includes a wire supply system configured to provide solder wire, and a flux supply system configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly configured to receive the fluorine-containing gas flow and the welding wire and to provide the fluorine-containing gas flow and the welding wire near the welding arc during SAW.

In another embodiment, one method includes delivery of a fluorine-containing gas stream through a plurality of passages surrounding an arc from a submerged arc weld (SAW), such that a flux bed over a bath of welding is practically unchanged.

In another embodiment, a system includes a welding torch having a welding torch body with a gas line configured to flow a fluorine-containing gas through the body of the welding torch. The welding torch also includes a contact tip that has one or more gas lines

<img file="MX359254B_D0005.tif" />

ladura.

configured to flow fluorine-containing gas into the

Furthermore, the contact tip is configured to couple ^ SÜferp ^ S ^ weld weld so that the body gas duct Lsx ^^ eiaxlfi ^ ldaclurSLS is in fluid communication with the one or more gas ducts of the tip of the Contact.

DRAWINGS

These and other features, aspects, and advantages of the present invention will be better understood when the following detailed description is read with reference to the accompanying drawings, in which the like characters represent similar parts in all the drawings, wherein:

Figure 1 is a block diagram of a hybrid submerged arc welding (HSAW) system, in accordance with the modalities of the present disclosure;

Figure 2 is a block diagram demonstrating the internal circuitry of an HSAW welding system, in accordance with the modalities of the present disclosure;

Figure 3 is a perspective view of a welding torch of an HSAW welding system, in accordance with embodiments of the present disclosure;

Figure 4 is a cross-sectional view of the welding torch illustrated in Figure 3 taken within line 4-4, in accordance with embodiments of the present disclosure;

Figure 5 is an enlarged cross-sectional view of the contact tip illustrated in Figure 4, in accordance with embodiments of the present disclosure;

Figure 6 is a perspective view of the distal end of the contact tip, in accordance with embodiments of the present disclosure; and

Figure 7 is a flow chart that ilijt ^^

MEXICAN INSTITUTE _r, are involved in the elimination of hydrogen; diffusion * "3 ^ wetá

<img file="MX359254B_D0006.tif" />

trust that

Freezing using a fluorine-containing gas during SAW, ^ 'arrlo with modalidodej-dc the present disclosure.

DETAILED DESCRIPTION

As described in detail below, modalities of welding systems and methods are provided herein that use a gas flow to control an atmosphere close to (for example, surrounding or close to) the arc and / or weld pool during submerged arc welding (SAW) or hybrid submerged arc welding (HSAW). In addition, this document provides modalities of welding systems and methods that specifically use a fluorine-containing gas to reduce the amount of diffusible hydrogen in the weld metal during submerged arc welding (SAW) or hybrid submerged arc welding ( HSAW).

As such, the term "hybrid submerged arc welding" or "HSAW" can generally be used to refer to disclosed systems incorporating one or more gases (eg, shielding gases, fluorine-containing gases, or any mixture of the themselves), similar to GMAW (active gas metal arc welding), but generally the solder is immersed in a flux bed. It should be appreciated that the disclosed modalities are generally directed toward the provision of one or more gases (eg shielding gas, fluorine-containing gas, or any mixture thereof) for arc welding processes (eg SAW ) which do not normally involve providing a gas flow. Furthermore, it should be appreciated that although the present description may focus specifically on SAW, the inclusion of a fluorine-containing gas as described in this documJit ^ JeP ^ n ^^ fe ^ touier

Mexican INSTITUTE arc welding process that seeks to minimize the hldrógeñcuiíffiwSífe er ^^ firatíras.

A fluorine-containing gas, as I know here, that is unique. a mixture of gases, which possess substantially at least one fluorine atom per gas molecule. For example, the fluorine-containing gas can be a carbon-based gas, such as carbon tetrafluoride (CF₄), perfluoroethane (C₂F₆), or chlorotrlfluoromethane (CF₃CI), or it can be an inorganic gas, such as nitrogen trifluoride (NF₃), boron trifluoride (BF₃), silicon tetrafluoride (SiF₄), fluorine (F₂), tungsten hexafluoride (WF₆), or any of its mixtures. A shielding gas, as used herein, can refer to any gas or gas mixture that can be provided to the arc and / or weld pool in order to provide a particular local atmosphere (for example, to protect the arc , improve the stability of the arc, limit the formation of metal oxides, improve the wetting of metal surfaces, alter the chemistry of the weld deposit, and so on). In certain embodiments, the shielding gas stream may be a single shielding gas or a shielding gas mixture (for example, argon (Ar), helium (He), carbon dioxide (CO₂), oxygen (O₂), nitrogen (N₂), suitable similar shielding gases, or any of their mixtures). For example, a shielding gas stream may include Ar, Ar / CO mixtures₂, Ar / CO mixtures₂/OR₂, Ar / He mixes, and so on. Furthermore, unless otherwise indicated, all references to percentages of gas mixtures are indicative of volume percent.

In general, the disclosed HSAW modalities incorporate a gas stream (eg, a shielding gas stream and / or a fluorine-containing gas stream) that can, alone or in combination with the flux, provide an environment private room near the arc and / or weld pool. Therefore, the disclosed HSAW modalities allow greater freedom in the selection of flux components as this gas flow can provide

<img file="MX359254B_D0007.tif" />

local during the welding process. On the other hand, they incorporate a flow of gas containing fluorine and, as such, could allow on-mélüdü to effectively reduce the amount of diffusible hydrogen in a weld, in a more cost-effective way than other solutions, such like the preheat method described above. However, it should be appreciated that the disclosed modalities using a fluorine-containing gas stream can be used in combination with a preheat method to provide a combined effect on the diffusible hydrogen content in the weld, and can also reduce the amount (or degree) of preheat typically used for a given welding operation. It should also be noted that the modalities currently described may employ a fluorine-containing gas instead of a fluorine-containing solid. Fluorine-containing gases offer advantages for the welding operator, such as greater flexibility in welding wire selection and reduced spatter during the welding operation.

Returning to the figures, Figure 1 illustrates an embodiment of a hybrid submerged arc welding (HSAW) system 10 that uses a gas flow to provide at least a portion of the local atmosphere during the welding process, in accordance with embodiments of this disclosure. System 10 includes a welding power unit 12, a welding wire feeder 14, a gas supply system 16, a flux supply system 17, and a welding torch 18. The welding power unit 12 generally supplies power to the welding system 10 and can be coupled to the welding wire feeder 14 through the cable bundle 20, as well as coupled to a workpiece 22 by a connecting cable 24 that has a clamp 26. In the illustrated mode, the welding wire feeder 14 is coupled to the welding torch of 28 Mexican cables sold in order to supply welding wire, “('(Siá ^^ Sfiipfe ^ BHwFe of solid core or flux core welding) and power to the gnpiptn Hp gnidnriurn ia during the operation of the welding system 10. In another embodiment, the welding power unit 12 can be coupled to and directly supply power to the welding torch 18.

In the embodiment depicted, the welding system 10 includes a gas supply system 16 that supplies a flow of gas (eg shielding gas, fluorine-containing gas, or any mixture thereof) to the welding torch 18 , in which the gas flow provides at least a portion of the local atmosphere at or near (for example, about 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, or less than about 30mm ) the welding arc and / or welding bath. In the embodiment shown, the gas supply system 16 is directly coupled to the welding torch 18 through a gas conduit 30. In another embodiment, the gas supply system 16 may be coupled, instead, to wire feeder 14, and wire feeder 14 can regulate gas flow from gas supply system 16 to welding torch 18. The flux supply system 17 of the HSAW 10 illustrated system provides flux to the welding torch 18 through a flux duct 31. Accordingly, the welding torch 18, illustrated, generally receives welding wire and power from the welding wire feeder 14, a gas flow from the gas supply system 16, and a flux from flux to starting from the flux supply system 17 in order to perform the HSAW (hybrid submerged arc welding) of the workpiece 22. During operation, the welding torch 18 can be brought close to the workpiece 22 so that an arc 32 can be formed between the welding torch 18 and the workpiece 22. It should be appreciated.^!BlR $ 5^8ent

INSTITUTO MEXICANO disclosure is the control of the energy supply, the alamBreí ^ roitíao ^^^^ as, and the flux, with the torch 18, the arc 32, and / or the solder bath on the workpiece dp 22 , to control the welding process.

The gas supply system 16 of the illustrated welding system 10 includes a gas source 34 in which the gas or gases (eg shielding gas, fluorine-containing gas, or any mixture thereof) can, for example, being stored together in a gas cylinder. For example, one or more shielding gases (for example, Ar, He, CO₂, OR₂, N₂, or any mixture thereof) can be stored in the gas source 34 to provide a shielding gas flow.

Furthermore, one or more fluorine-containing gases may, additionally or alternatively, be stored in the gas source 34 to provide a flow of fluorine-containing gas. Non-limiting examples of fluorine-containing gases can include any of: C_mF_nX_p, NF₃, BF_3i YesF₄, F_2i or WF_6i or any mixture thereof. For C_mF_nX_p, X can be a hydrogen or chlorine atom, m can be any value between 1 and 5, n can be any value between 1 and 18, and p can be any value between 0 and 18. For example, the fluorine-containing gas can be any of CF₄, CF₃CI, CF₂H₂CFCI₃, C₂F₆, C₂F_4i C₂F₅CI, C₂F₄H₂, C₃F₇H, C₄F_1st, etc., or any mixture thereof. For example, in certain embodiments, the gas supply system 16 may include a single gas cylinder containing approximately 95% CF₄ and about 5% F₂. As such, in certain embodiments, the fluorine-containing gas concentration provided by gas source 34 may be zero (i.e., substantially 0%) or between approximately 0.1% and 10% (eg, 0.2%, 0.5%, 0.75%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 7%, 8%, 9%, 10%, etc. ) fluorine-containing gas, the remainder being a shielding gas or a shielding gas mixture. In one modality, the percentage of gas

<img file="MX359254B_D0008.tif" />

Containing fluorine in the total flow of gas supplied ii is between approximately 0.5% and 5%. In one embodiment, the percentage of fluorine-containing gas in the total gas flow is less than about 0.1%, 1%, 2%, 3%, 4%, or

5%.

The flux supply system 17 can provide a flow of a granular flux through conduit 31 at or near (eg, within 1mm, 2mm, 3mm, 5mm, or less than about 30mm from) arc 32. As flux flux is supplied near arc 32, it can accumulate as a flux layer or near bed (eg, over, coating, and / or near) the weld pool. At least a part of the flux can partially decompose and / or degas (eg release one or more gases after heating) in or near arc 32 and / or the solder bath and work in conjunction with the gas 16 to provide a suitable local environment in or near (eg within 1 mm, 2 mm, 3 mm, or approximately less than 30 mm from) the weld pool. The flux may, additionally or alternatively, promote wetting of the workpiece 22, limit the formation of metal oxides, remove chemical impurities from the weld, and / or play similar roles in promoting the welding process. The flux in general can include fluxes, such as typical agglomerated, bonded, or fused fluxes. These fluxes can be neutral, semi-neutral, or active fluxes and can have a range of different levels of acidity or basicity. A non-limiting list of examples of fluxes include: rutile aluminate (AR), basic aluminate (AB), basic fluoride aluminate (AF), basic fluoride (FB), or calcium silicate (CS) fluxes. In addition, in certain modalities, the flux can be selected from a flux according to the EN (European standard) 760 specification.

Furthermore, it is an aspect of the present disclosure that, in certain

<img file="MX359254B_D0009.tif" />

ΜΡΙ ΜΡΙ modalities, the flux can be mixed substantiallrrteqte'GCSícJáJo. *. For example, a flux of shielding gas and / or fluorine-containing gas) at or near (eg, within 1 mm, 2 mm, 3 mm, or approximately less than 30 mm from) arc 32 during processing welding. That is, as described in detail with reference to Figures 3-6 below, certain embodiments of the HSAW 10 system may include a welding torch 18 that is configured to ensure that the flow of gas (eg, a flow of shielding gas and / or fluorine-containing gas) generally displaces the normal air dispersed within the granular flux before or as the flux reaches arc 32. In other embodiments, the flux supply system

17 may, additionally or alternatively, store the flux under an atmosphere of the shielding gas and / or the fluorine-containing gas such that the flux supplied to the welding torch 18 can be premixed with the gas flow (eg, a gas of protection and / or gas flow containing fluorine).

It should be appreciated that in general, in certain types of

HSAW 10, the use of gas flow (for example, including shielding gases, fluorine-containing gases, or any mixture thereof) can generally allow the use of different types of fluxes (for example, fluxes). which may not be compatible with typical SAW processes). That is, gas flow (eg, including shielding gases and / or fluorine-containing gases) can help control the local atmosphere nearby (eg, about 1mm, 2mm, 3mm, or about less mm of the arc 32, the weld pool, and / or the flux bed at the surface of the workpiece 22. As such, the quality of the weld may be less dependent on the local atmosphere provided by the flux. As such, lower cost flux can be used with the present HSAW 10 system. In addition, using the fluorine-containing gas stream, other components typically used in the flux or electrode

<img file="MX359254B_D0010.tif" />

such as (for example, flux-cored wire, with no fluoride salts or other solid fluorine sources, can be reduced or eliminated entirely. This can generally allow more freedom to select a flux and / or wire electrode, based on other considerations (for example, related to cost of flux and / or wire, desired solder properties, solder chemistry desired, slag removal, bead shape, penetration, deposition rates, and so on). For example, in modalities that use a fluorine-containing gas stream, acidic fluxes that are generally selected to reduce the resulting hydrogen content in the weld may be supplanted by more basic fluxes, while welds that contain similar hydrogen.

As mentioned, the illustrated HSAW 10 system controls the welding process by controlling the power supply, the welding wire, the gas, and the flux to the torch 18, arc 32, and / or melt bath in the surface of the workpiece 22. In addition, in certain embodiments, by controlling the chemistry of the shielding gas and / or fluorine-containing gas, the chemistry of the arc 32 and / or the resulting weld can be adjusted. For example, when welding metals that are especially sensitive to the presence of diffusible hydrogen, the gas supply system 16 may supply a higher flow rate of a fluorine-containing gas or use a gas containing a higher relative concentration of fluorine ( for example, between 5% and

10% gas containing fluorine in shielding gas) to maximize diffusible hydrogen uptake. For example, when a fluorine-containing carbon-based gas is used, the use of gases with a higher number of carbons (i.e. the larger m values) may contribute a greater amount of carbon in the resulting weld, which may be desirable for certain steel applications, reducing

<img file="MX359254B_D0011.tif" />

same time the amount of diffusible hydrogen. How; use fluorine-containing carbon-based gases, using gases that have some hydrogen (i.e. X is a hydrogen atom and p is greater than 0) can provide benefits for the arc, such as increased arc temperature and arc penetration into the workpiece, while still limiting the amount of hydrogen delivered to the weld metal during the welding operation. However, not all fluorine-containing gases are compatible with applications involving certain metals. For example, while sulfur hexafluoride (SF₆) can be used as a shielding gas additive to reduce the amount of diffusible hydrogen present in a weld, some materials (eg steel) are not SF compatible₆ since the amount of sulfur (eg iron sulfide) remaining in the weld after the welding process can cause cracking due to sulfur segregation during soldering of the weld. As such, the fluorine-containing gases used by certain embodiments, currently disclosed, are substantially sulfur-free.

For some implementations, it may be desirable for the gas supply system 16 to supply a fluorine-containing gas stream (eg, including CF₄, F₂, CF₂CI₂, similar gases containing fluorine or gas mixture) and a shielding gas flow (eg Ar, He, CO₂, OR₂, N₂, or any mixture thereof) from separate gas sources. Returning to Figure 2, a block diagram of another embodiment of an HSAW 40 system is presented. More specifically, Figure 2 illustrates some of the Internal components of a welding system 40 that can employ a fluorine-containing gas flow. to reduce the diffusible hydrogen in the welds, according to a certain embodiment of the present disclosure. Furthermore, similar to the HSAW 10 system of Figure 1, the HSAW system 40 illustrated in Figure 2

<img file="MX359254B_D0012.tif" />

It generally includes a solder welding power unit 14, a soldering torch 18, a flux supply system 17. ——.........

In the embodiment illustrated in Figure 2, the welding power unit 12 includes current conversion circuits 42 that receive input current from an alternating current power source 44 (for example, the AC mains, a motor / generator set, or a combination thereof), condition the input current, and provide the output current through cable 46 to supply the weld wire feeder 14 which, in turn, feeds the welding torch 18, according to the demands of system 40. Accordingly, in some embodiments, current conversion circuits 42 may include circuit elements (eg, transformers, rectifiers, switches, and so on) capable of converting AC input power to positive electrode direct current. (DCEP) output, a negative electrode direct current (DCEN) output, or a variable balance output AC (for example, balanced or unbalanced), as dictated by the requirements of system 40. Connection cable 24 terminating at clamp 26 couples current conversion circuits 42 to workpiece 22 and closes the circuit between welding power unit 12, the part 22 and welding torch 18.

The welding power unit 12 also includes control circuits that are configured to receive and process a plurality of inputs with respect to the performance and demands of the welding system 40. The control circuits 48 Include processing circuits 50 and memory 52. Memory 52 can include volatile and nonvolatile memory, such as ROM, RAM, magnetic storage memory, optical storage memory, or a combination thereof.

In addition, a variety of control parameters can be ls¿ffótfRSídft52

DE IA PWOHEDAP INDUSTRIAL along with the code configured to provide a specific output (for example, start wire feed, enable gas flow, enable flux flow, etc.) during operation. Processing circuits 50 may also receive one or more inputs from a user interface 54 through which a user can choose a process, and the desired input parameters (eg, voltages, currents, in particular pulsed rates). or not pressed welding, and so on). For example, in certain embodiments, user interface 54 may allow the user to adjust parameters with respect to magnitude and amplitude of positive electrode (EP) or negative electrode (EN) current (eg, for application welding involving variable equilibrium alternating current (AC).

On the basis of such inputs received from the operator, the control circuits 48 operate to control the generation of the welding power output that is applied to the welding wire to carry out the desired welding operation, for example, through control signals transmitted to current conversion circuits 42. On the basis of such control commands, the current conversion circuits 42 are adapted to create the output current that is finally applied to the welding wire in the welding torch 18. For this purpose, as noted above, they can be employ various current conversion circuits, including switches, boost circuits, buck circuits, converters, inverters, and so on. Still further, in the embodiment of Figure 2, control circuits 48 also include interface circuits 56 configured to interact with the electronics of the weld wire feeder 14 during operation. Interface circuits 56 are coupled to processing circuits 50, as well as components of the solder wire feeder 14. In addition, processing circuits 50

<img file="MX359254B_D0013.tif" />

they provide control signals, associated with the operation of the solder wire 14 via a cable 58 coupled to the interface circuits 56.

As before, the welding power unit 12 and the welding wire feeder 14 can be coupled to each other through the cable bundle 20, and the welding torch 18 can be coupled to the welding wire feeder 14 through the wiring harness 28.

In the illustrated embodiment, the gas supply system 16 includes one or more fluorine-containing gas sources 57 and one or more shielding gas sources 59. That is, the illustrated gas supply system 16 is configured to supply a fluorine-containing gas stream (for example, including CF₄, F₂, CF₂CI₂, similar fluorine-containing gases, or any mixture thereof) and a shielding gas stream (eg Including Ar, He, CO₂, OR₂, N₂, or any mixture thereof) to a flow control system 60 located in the weld wire feeder 14. In other embodiments, the shielding gas source (s) 59 may not be used. (s) and the flux supplied by the flux supply system 17 can provide substantially a protective atmosphere over the melt bath, while the fluorine-containing gas captures residual hydrogen from the solder bath. In the depicted embodiment, the gas supply system 16 individually supplies the gases to the flow control system 60 through one or more shielding gas lines 62 (eg, line assembly) and one or more gas lines containing fluorine 64 (eg conduit set). In another embodiment, the gas supply system 16 may be coupled to a single premixed gas source (eg 2% CF₄98% Ar / CO₂1: 1) that can be coupled to flow control system 60 through a single gas line, similar to the embodiment of Figure 1.

In the HSAW system 40 of Figure 2, the flow control system 60

IMPIféa can be coupled to multiple sources of gas that »aawifefigu &lt;afor tSgTWffimo to industrial multiple sources of shielding gas 59. For example, flow control system 60 can receive individual flows from two sources of shielding gas 59 (eg. , Ar and CO₂) through different ducts in shielding gas duct assembly 62, and receiving three sources of fluorine-containing gas (eg CF₄, CF₃CI, and F₂) through different lines in the fluorine-containing gas line assembly 64, and provide a mixed gas flow from five separate gas sources. It should be appreciated that certain modalities can employ any number of gas lines and gas sources. In another embodiment, the flow control system 60 can receive and regulate a gas flow from one or more shielding gas sources and from one or more fluorine-containing gas sources 57 and, instead of mixing the gases , emit the gases individually (that is, through different conduits) to the welding torch 18. Furthermore, the flow control system 60 includes a plurality of valves 66, and may contain a plurality of regulators, gas flow sensors, and so on, that regulate the flow of incoming gas flows, as well as the flow of exhaust gas, which passes through the gas line 68 to reach the welding torch 18.

Shielding Gas Source (s) 59 may contain any of Ar, He, CO₂, OR₂, N₂, or any mixture thereof. For example, shielding gas source 59 may contain 100% CO₂, a mixture of approximately 85% of

Ar / 15% CO₂, a mixture of approximately 75% Ar / 24% CO₂/ 1% 02, a mixture of approximately 95% CO2 / 5% N2, 100% CO2, etc. Fluorine-containing gas source (s) 57 may contain any of C_mF_nXp, NF₃, BF₃, SiF₄, F_2j or WF₆, or any mixture thereof. For C_mF_nX_p, X can be a hydrogen or chlorine atom, m can be any value between 1 and 5, n can be any value

<img file="MX359254B_D0014.tif" />

C4F7H3, etc., or any mixture thereof. Or, for example, he yatt What contains fluorine can contain a mixture of approximately 98% CF4 / 2% CF₂CI₂, a mixture of approximately 90% CF₃H / 10% BF₃, a mixture of approximately 85% C2F4 / 13% CF4 / 2% WF₆, etc. In one embodiment, the percentage of fluorine-containing gas in the total flow of gas supplied to welding torch 18 by flow control system 60 is between about 0.01% and 10%. In one embodiment, the percentage of fluorine-containing gas in the total gas flow is less than about 0.1%, 1%, 2%, 3%, 4%, or 5%.

As illustrated in Figure 2, in addition to the flow control system 60, the weld wire feeder 14 also includes a user interface 70 that allows system parameters (eg, wire feed rates, processes, selected currents, voltage or power levels, relative concentrations of fluoride-containing / shielding gas and flow rates, flux flows, and so on) are set in the weld wire feeder 14. As such, user interface 70 is coupled to a controller 72, which allows wire feed speeds to be controlled according to operator's selections, and it allows these settings to be fed to the power supply unit 12 through interface circuits 56. The controller also controls the flow control system 60 according to the user defined configuration and adjusts the relative ratios and flow rates of each of the individual gases to produce the desired flow of mixed gas to be delivered to the welding torch 18 through gas line 68. As mentioned above, in one embodiment, the flow control system 60 can separately supply the fluorine-containing gas and shielding gas to the welding torch M ^ J ^ jg ^ fe v ^^ w® gas 68. Furthermore, in certain embodiments, controller 72 can be coupled to flux supply system 17 such that the operation of flow supply system 17 (eg, a flux hopper 73) can be controlled through the configuration of user entered from the user interface

70.

The welding wire feeder 14 also includes components for feeding the wire to the welding torch 18 and thereby the welding application, under the control of controller 72. For example, one or more wire supplies 74 (eg, spools ) of the welding wire 76 are housed in the welding wire feeder 14. A wire feeder drive unit 78 can unwind the weld wire 76 from the reels 74 and progressively feed the weld wire 76 to the welding torch 18. To this end, the wire feeder drive unit 78 may include such components. such as circuits, motors, rollers, and so on, configured in a suitable manner to establish an appropriate wire feed. For example, in one embodiment, the wire feeder drive unit 78 may include a feed motor that mates with the feed rollers to push wire from the weld wire feeder 14 toward the welding torch 18. The energy of the welding power unit 12 is applied to the powered wire, typically via cable 46.

The illustrated HSAW system 40 includes the flux supply system 17 having a flux hopper 73. The flux supply system 17 can generally provide a flow of granular flux to the welding torch 18 through a conduit 75. As discussed in detail later, in certain

Ϊ ^ ϊ modalities, the welding torch 18 may include one configured to replace any air in the granular flux with the shielding gas flow, the fluorine-containing gas flow, or any mixture thereof, provided by the flow control 60. In other embodiments, the flux supply system 17 may be coupled to the gas supply system 16 such that the flux stored in the flux supply system (eg, in the flow hopper 73) can be kept under a atmosphere including a fluorine-containing gas, a shielding gas, or a fluorine-containing / shielding gas mixture, prior to being supplied to the welding torch 18 through line 75.

In addition, as mentioned, in certain embodiments, the flux supply system 17 may be controlled by controller 72 such that the user can control the rate at which flux is supplied to welding torch 18 and / or workpiece 22.

In the illustrated embodiment, the welding torch 18 may include a control switch 80, wire transfer components 82, gas transfer components 84, and a flux delivery component 85. Other aspects of certain torch embodiments Welds 18 are discussed in detail below, with respect to Figures 3-6. In general, during operation of the welding system, the welding wire can be advanced through the wire harness 28 toward the welding torch 18. In the welding torch 18, additional wire transfer components 82, such as an additional traction motor and associated drive roller can be provided. The traction motor can be regulated to provide the desired wire feed speed. In addition, gas transfer components 84 (eg, nozzles, control valves, gas diffusers, etc.) can be included in the torch.

<img file="MX359254B_D0015.tif" />

solder is 18 to control and direct the flow of the shielding mixture (the gas that contains fluorine, or any of its mixtures) that is received through ___im___ ... ------ i - · of the gas conduit 68 . Welding torch 18 may also include a control switch 80, coupled to controller 72 in weld wire feeder 14 through control line 86, which can provide a signal to controller 72 to allow the welding process be leveled and stopped by the operator. These in / stop signals can be propagated from controller 72 to flow control system 60 and weld power unit 12. Accordingly, activating Control Switch 80 can cause the gas flow to flow, flux is provided, feed wire forward, and power is applied to the forward weld wire.

In another embodiment, the welding torch 18 may also include one or more sensors coupled to the welding wire feeder controller 72 14. During operation, the sensors may be configured to measure one or more parameters of the welding torch 18 that are Indicative of the welding environment.

To do this, the one or more sensors (eg thermal sensors, gas flow sensors, chemical sensors, optical sensors, etc.) can continuously measure the desired parameters or at desired intervals through the welding operation. As the sensors acquire this data, they can be communicated to the controller 72 in the weld wire feeder 14 such that the parameters of the weld system 40 (eg, concentrations and flow rates of fluorine-containing gases, velocities of wire feed, flux flows, which arc voltage and current, etc.) can be adjusted by controller 72 during system operation.

It should be appreciated that, in general, it may be desirable for the flow of fluorine-containing gas to be regulated (eg, the flow of shielding gas, of gas that

<img file="MX359254B_D0016.tif" />

ΙΜΡΙ contains fluorine, or any of its mixtures) from the soldering point 18, in such a way that the flux bed supplied by the flux supply system 17 is not disturbed on the surface of the workpiece 22 (eg, moved or removed from the surface of the workpiece 22) during the welding process. However, it should also be appreciated that, in certain embodiments, it may be desirable for the gas flow supplied to the welding torch 18 to be completely mixed with the granular flux supplied by the flux supply system 17. Accordingly, it is described below a modified welding torch 18 (with respect to Figures 3-6) that can generally provide these desired characteristics. That is, the modified torch mode described below provides a modified contact tip that allows gas (eg shielding gas, fluorine-containing gases, or any mixtures thereof) to be supplied through a series of conduits that They surround the welding wire 76 as it is supplied to the welding arc 32. By supplying the gas flow 15 through ducts, as currently disclosed, relatively low pressures and flow rates can be used. This generally prevents the flux bed from being disturbed, while the gas flow (for example, shielding gas flow, fluorine-containing gas flow, or any of its mixtures) may still be sufficient to provide the effect or effects. desired effects (for example, scavenging of residual hydrogen, control of weld chemistry, stabilizing arc, control of workpiece surface chemistry, etc.). In addition, the welding torch embodiment described below allows complete mixing of the granular flux and gas flow at the contact point of the welding torch before they reach the arc and / or weld pool. It should be appreciated that although the welding torch described with respect to Figures 3-6 is a specific embodiment of the torch

IMPROPER welding for HSAW welding, also from welding torches that supply the gas stream at or near the welding arc and / or weld pool (for example, welding torches that have only one internally arranged gas duct or externally with respect to the body of the welding torch).

With the above in mind, Figure 3 is a perspective view of one embodiment of a hybrid submerged arc welding torch (HSAW) 18 that is configured to provide a flow of gas, solder wire, and flux to the surface. of workpiece 22. The illustrated HSAW 18 torch includes a body 90 that encapsulates a number of passages (discussed in detail below) through which the welding wire and gas (eg shielding gas, fluorine-containing gas, or any of their mixtures) can pass through before exiting near a distal end 92 of the welding torch 18. That is, the welding wire 76 and the gas flow 68 being provided, separately, by the welding wire feeder 14 to the welding torch 18, generally can enter the torch from an end portion 93 (by example, proxlmal) and can, in general, come out near a contact tip at the distal end 92 of the torch 18. Furthermore, for the torch embodiment illustrated in Figure 3, a flux supply component 85 has been attached to the torch body 90 18 through a clamping mechanism 94 such that the flux supply component 85 surrounds the contact tip near the far end) 92 of the welding torch 18. In other embodiments, the flux supply component 85 may be a conduit that is attached to the body 90 of the soldering torch 18 that deposits flux near the solder arc without surrounding the contact tip. In addition, the illustrated flux supply component 85 includes a conduit 96 which can be coupled to conduit 75 in order to receive the flux from the flux supply system 17. In general, the touch supply component,

<img file="MX359254B_D0017.tif" />

in such a way that the gas emanating from the contact tip of the welding torch 18 can be completely mixed with the flux, and in such a way that a substantial amount of the air contained in the granular flux can be displaced by the gas (for example, shielding gas, gas containing fluorine, or any of its mixtures). Furthermore, it should be appreciated that since the illustrated flux supply component 85 surrounds the contact tip, generally lower gas pressures and / or flow rates can be used to displace this air, which can be generally desirable, in order to limit disturbance of the flux bed by gas flow.

In certain embodiments, by adding a fluorine-containing gas stream in or near a weld pool during submerged arc welding, lower hydrogen levels, as well as improved mechanical properties, can be achieved. That is, adding the fluorine-containing gas stream to the SAW process offers better control over soldering chemistry than can be achieved using only a shielding gas or a granular flux. In addition, in certain embodiments, it may be desirable, in general, to supply a sufficiently high level of fluorine-containing gas flow as close as possible to arc 32 to ensure that the gas is capable of reaching the arc plasma stream without substantially disturbing the flux bed. As such, the illustrated HSAW 18 welding torch generally provides an improved system that enables the delivery of gas (eg shielding gas, fluorine-containing gas, or any mixture thereof), wire, and flux. Immediately at arc 32 to achieve results that provide the desired amount of mixture of all constituents at or near arc 32.

Figure 4 is a cross-sectional view of the welding torch 18

<img file="MX359254B_D0018.tif" />

, 4 illustrates that a contact tip 100 that is charged in one portion (JSHÍfitéVpo dsrsó ^ ete 90 and encompassed by the fundtsulu 85 supply component 85) is illustrated in Figure 3 taken within the line.^,wrS5pR? te 90 includes a passage 102 (eg, a longitudinal passage) that can be coupled to conduit 68 (eg, from flow control system 60 of weld wire feeder 14) and can provide a path for flow of gas 103 (for example, shielding gas flow, fluorine-containing gas flow, or any mixtures thereof) through torch body 90. In addition, the torch body 90 includes another passage 104 that can provide a conduit for supplying the weld wire 76 (eg, provided from the weld wire feeder 14) to the contact tip 100 at the distal end 92 of the welding torch 18. The illustrated embodiment of the welding torch body 90 further includes a generally conical cavity 106 (eg, a coupling cavity) within which the contact tip 100 is adapted to fit securely. The flux supply component 85 can generally provide a flux flow 107 in a cavity 109 between the flux supply component 85 and the soldering torch body 90 and / or the contact tip 100 such that the flux of Gas 103 exiting contact tip 100 can be completely mixed with the supplied flux flux 107 (eg, to displace any air) before reaching the weld pool.

The illustrated contact tip 100, when inserted into the body of the welding torch 90, can provide a sealed connection such that the flow of gases (for example, the flow of shielding gas, the flow of gas that contains fluorine, or any of its mixtures) was conveniently supplied from the body of the welding torch 90 into and through the contact tip 100. The contact tip

1M p;

100 It is retained within the body of the conventional welding torch'SWRSIffifijtlSdi ^^^^^ s (for example, a threaded ring or nut 108, a lock, a retaining ring, or the like), which can snap on and hold the contact tip 100 in an operating position. Generally speaking, precise engagement of the cavity with contact tip 100 helps ensure positive gas flow in the direction of arc 32 (i.e., the distal end 92 of torch 18) and not back into the body of the torch. welding torch 90. When the contact tip 100 is placed in the conical cavity 106 of the body of the welding torch 90, a chamber 110 is formed between the machined slot 112 of the welding torch body 90 and the machined slot 114 of the contact tip 100 when these grooves are aligned, as shown. In addition, the illustrated chamber 110 is coupled to the passage 102 that carries the gas through the body of the welding torch 90 (ie, all three are in fluid communication). This chamber 110 generally receives gas from passage 102 before introducing the gas flow to contact tip 100. Due to the mating surfaces of contact tip 100 and conical cavity 106 that are closely engaged, chamber 110 and passage 102 are insulated to prevent gas (eg shielding gas, fluorine-containing gas, or any mixture thereof) from escaping through passage 102.

Contact tip 100 has a central passage 114 for the weld wire to pass through, as well as to provide electrical contact to form arc 32 with workpiece 22. Contact tip 100 further includes a number of passages 116 (eg, arranged around central passage 114) carrying the gas (eg shielding gas, fluorine-containing gas, or any of its mixtures) to the distal end 92 of contact tip 100. In certain modalities, these passages116 can be oriented coaxially or radially around the "IMPIS ^

INSTITUTO MEXICANO JS central passage 114. In addition, there can be any number&gt; ^ eo ^ dO * 3 ^! ^ Jes 116 to provide a path for gas from chamber 110 to end 92 of welding torch 18. For example, certain torch modes may include 1, 2, 3, 4, 5, 6, 8, 10, or 12 passages 116 arranged around the central passage 114 in order to effectively disperse the gas (for example, shielding gas , the gas containing fluorine, or any of its mixtures) in the solder and flux arc.

Figure 5 illustrates a cross section of the contact tip 100 that is removed from the body of the welding torch 90. Accordingly, the mating portion of the contact tip 100 includes a generally tapered portion 118 with the machined groove. 112 which generally matches in shape to provide a secure fit when fitted into the body 90 of the welding torch 18. Contact tip 100 includes center passage 114 to provide the wire and power to arc 32, while surrounding passages 16 provide a flow of gas (eg shielding gas, fluorine-containing gas, or whatever of its mixtures) from chamber 110 to arc 32, as well as to flux flow 107 provided by flux supply component 85 which is disposed near (eg, close to, around, or surrounding) contact tip 100 . In addition, Figure 6 illustrates a perspective view of the distal end 92 of one embodiment of the contact tip 100. The illustrated contact tip mode includes center passage 114 to provide the wire and power for arc 32 while surrounding passages 116 provide a flow of gas (eg shielding gas, containing gas fluorine, or any of its mixtures) to arc 32 and / or to flux provided by flux supply component 85. In addition, the illustrated contact tip 100 includes six gas supply passages 116 surrounding the central passage 114; however, it should be appreciated that any number of passages 116

IMPI / g&gt; 3 can be used to supply the gas stream.

while the illustrated passages 116 form circular holes that are symmetrically distributed around a central passage 114, any number of passage shapes or arrangements that provide gas flow near arc 32 and / or flux (eg, elliptical passages , one or more coaxial passages with central passage 114, non-symmetrical arrangements, and the like) are also, currently contemplated.

For certain embodiments, once the flux, the wire, and the fluorine-containing gas have been delivered to the contact tip 100 of the welding torch 18, a series of events, represented in the block flow diagram of Figure 7, it is believed that they will be carried out to remove the diffusible hydrogen from the solder. The first stage of process 130 is the introduction (block 132) of a flux flux and a fluorine-containing gas flow (block 134) at or near arc 32 and / or solder bath at contact tip 100 of the torch welding 18. It should be appreciated that the flow rates for both the fluorine-containing gas flow and the flux flow can be controlled such that the fluorine-containing gas can generally displace any residual air that may be present in the granular flux and continue producing a substantially unchanged flux bed (for example, the granular flux bed generally follows covering the solder bath despite the flow of gas containing fluorine and not significantly removed). It should also be appreciated that, for HSAW modalities that use only a shielding gas flow (i.e., fluorine-free gas), the overall welding process may incorporate similar steps to provide a flux flow near the arc of weld, and thoroughly mix the shielding gas with the granular flux to displace any residual air without substantially disturbing the flux bed disposed on the weld pool.

Below, the conditions in and around

<img file="MX359254B_D0019.tif" />

<img file="MX359254B_D0020.tif" />

• t MtOntOAD INDUSTRIAL voltage and high-temperature environment can then begin to break chemical bonds in the fluorine-containing gas and release (block 136) a reactive species of the fluorine-containing gas molecules. As used herein, reactive species can be any residual radical (i.e., F ·, CF₃·, Cl ·) or ion (i.e. CF₃⁺, F, Cl, etc.) produced from the decomposition of fluorine-containing gas, or any combination thereof. The released reactive species can then permeate (block 138) the molten metal from the weld pool. In one embodiment, a portion of the fluorine-containing gas can enter the weld pool before the reactive species is released. Regardless of when it is released, the reactive species released in the weld pool (block 140) binds with the diffusible hydrogen that is dissolved in the weld pool, reacting with it to form a product gas (eg HF, HCI , CF₃H, etc.). Since the product gas may be less soluble in the molten metal than hydrogen, it may be released (block 142) from the molten solder bath before or as the solder cools, resulting in a solder having reduced hydrogen content diffusible. It should be noted that the released reactive species can also react with the hydrogen present in the arc before reaching the weld pool, and therefore can also reduce the amount of hydrogen in the weld pool in a preventive way.

It should be appreciated that the role of fluorine atoms in fluorine based gas in the embodiment presented in Figure 7 can be of two types. First, the decomposition of the fluorine-based gas produces reactive species, such as F 'and F ·, which can be very suitable for reacting with diffusible hydrogen in the deposition or removal of the weld metal. However, the second, a more subtle role for fluorine atoms in the fluorine-based gas molecular structure, is the

<img file="MX359254B_D0021.tif" />

ιβη electronic stabilization of other reactive species, talísA4pí ^&gt; jL

KJTTTMTO MtXICANO or the rgoritOAc „may be able to react with diffusible hydrogen in SW09tfbra.

While only a few features of 1'ii'wui iiiúi i ser hai r HcrsTrad ^ and described herein, many modifications and changes will occur to those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all modifications and changes that fall within the true spirit of the invention.

1.