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US-12623307-B2 - Welding electrode with functional coatings

US12623307B2US 12623307 B2US12623307 B2US 12623307B2US-12623307-B2

Abstract

The disclosed technology generally relates welding electrodes, and more particularly to consumable welding electrodes having functional coatings. In one aspect, a welding electrode comprises a core wire having a base metal composition and two or more coatings covering at least a portion of the core wire. The two or more coatings comprise an electrically conductive coating including one or more electrically conducting elements or compounds in addition to or other than copper (Cu). The two or more coatings additionally comprises an additional functional coating including one or more additional elements or compounds adapted to modify a surface tension of a molten droplet formed from the welding electrode. In another aspect, a method of manufacturing a welding electrode comprises providing the core wire having the base metal composition and forming the two or more coating layers.

Inventors

  • Badri Narayanan
  • Vivek Sengupta
  • David B. Russell
  • Stephen Farah
  • Yijian Zhou

Assignees

  • LINCOLN GLOBAL, INC.

Dates

Publication Date
20260512
Application Date
20220909

Claims (19)

  1. 1 . A welding electrode, comprising: a solid core wire having an iron (Fe)-based base metal composition; an electrically conductive coating formed on the solid core wire and including one or more electrically conducting elements or compounds in addition to or other than copper (Cu), and an additional functional coating formed on the electrically conductive coating and including one or both of elemental antimony (Sb) and one or more Sb oxides, wherein the additional functional coating comprises sub-micron particles comprising the elemental Sb and the one or more Sb oxides, and wherein the additional functional coating is a porous layer comprising a plurality of pores formed between adjacent particles of the sub-micron particles.
  2. 2 . The welding electrode of claim 1 , wherein a total amount of Sb in the welding electrode is effective to reduce a surface tension of a molten droplet formed from the welding electrode by 10% or more, relative to a reference molten droplet formed under the same welding conditions from a reference welding electrode that is the same as the welding electrode except for the presence of Sb.
  3. 3 . The welding electrode of claim 2 , wherein the welding electrode is configured for forming a weld metal at a travel speed that is higher by 30% or more relative to a travel speed for forming a reference weld metal under the same welding conditions using the reference welding electrode that is the same as the welding electrode except for the presence of Sb or one or more Sb oxides.
  4. 4 . The welding electrode of claim 2 , wherein the total amount of Sb is 0.0005-2 weight %.
  5. 5 . The welding electrode of claim 4 , wherein the welding electrode is configured such that a weld metal formed using the welding electrode incorporates therein 25-60% of the total amount of Sb.
  6. 6 . The welding electrode of claim 1 , wherein the sub-micron particles comprise elemental Sb particles and Sb 2 O 3 particles.
  7. 7 . The welding electrode of claim 1 , wherein the pores expose the underlying electrically conductive coating.
  8. 8 . The welding electrode of claim 1 , wherein the one or more electrically conducting elements or compounds are selected from the group consisting of magnesium (Mg), aluminum (AI), zinc (Zn), tin (Sn), chromium (Cr), platinum (Pt), silver (Ag), graphite, graphene, graphene oxide and titanium (Ti).
  9. 9 . The welding electrode of claim 8 , wherein the one or more electrically conducting elements or compounds are present in the electrically conductive coating without Cu.
  10. 10 . The welding electrode of claim 8 , wherein the one or more electrically conducting elements or compounds are present in addition to Cu in an amount exceeding 90 atomic % of a combined sum of the one or more electrically conducting elements or compounds and Cu.
  11. 11 . A welding electrode, comprising: a solid core wire having an iron (Fe)-based base metal composition; and two or more coatings covering at least a portion of the solid core wire, wherein the two or more coatings comprise: an electrically conductive coating formed on the solid core wire including one or more electrically conducting elements or compounds in addition to or other than copper (Cu), and an additional functional coating including antimony (Sb) and having a porous structure and formed on the electrically conductive coating.
  12. 12 . The welding electrode of claim 11 , wherein a total amount of Sb present in the welding electrode is an amount effective to increase a contact angle of oxide islands formed on a weld metal formed from the welding electrode by 10% of more, relative to a contact angle of reference oxide islands formed on a reference weld metal formed under the same welding conditions and from a reference welding electrode that is the same as the welding electrode except for the presence of Sb.
  13. 13 . The welding electrode of claim 12 , wherein the total amount of Sb is 0.0005-2 weight %.
  14. 14 . The welding electrode of claim 11 , wherein the Sb is in the form of elemental Sb and one or more Sb oxides.
  15. 15 . The welding electrode of claim 14 , wherein the additional functional coating comprises sub-micron particles comprising the elemental Sb and the one or more Sb oxides.
  16. 16 . The welding electrode of claim 15 , wherein the sub-micron particles comprises elemental Sb particles and Sb 2 O 3 particles.
  17. 17 . The welding electrode of claim 15 wherein the sub-micron particles partly cover the electrically conductive coating such that portions of the electrically conductive coating are exposed between adjacent ones of the sub-micron particles.
  18. 18 . The welding electrode of claim 11 , wherein the Sb is present in the welding electrode in an amount and form such that a volume of silica islands formed on a weld metal formed from the welding electrode is lower by at least 50% relative to a volume of reference silica islands formed on a reference weld metal formed under the same welding conditions using a reference welding electrode that is the same as the welding electrode except for the presence of Sb.
  19. 19 . The welding electrode of claim 11 , further comprising calcium (Ca) at an interface region between the solid core wire and the two or more coatings in an amount of 0.0005-1 wt. % of a weight of the welding electrode.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Application No. 63/261,462, entitled “WELDING ELECTRODE WITH FUNCTIONAL COATINGS,” filed Sep. 21, 2021, the content of which is hereby incorporated by reference in its entirety. BACKGROUND Field The disclosed technology generally relates welding electrodes, and more particularly to consumable welding electrodes having functional coatings on core wires. Description of the Related Art Various welding technologies utilize consumable welding electrodes that serves as a source of the weld metal. For example, in metal arc welding, an electric arc is created when a voltage is applied between a consumable weld electrode, which serves as one electrode that advances towards a workpiece, and the workpiece, which serves as another electrode. The arc melts a tip of the metal wire, thereby producing droplets of the molten metal electrode that deposit onto the workpiece to form a weld metal or weld bead. Technological and economic demands on welding technologies continue to grow in complexity, with the need for higher manufacturing flexibility and the need for higher mechanical performance coexisting. In addition, optimization of one performance parameter of the weld metal can compromise another. Some welding technologies aim to address these competing demands by improving the consumables, e.g. by improving the physical designs and/or compositions of the consumable electrodes. The disclosed technology addresses a need for improved consumable welding electrodes having functional coatings. SUMMARY In a first aspect, a welding electrode comprises a solid core wire having an iron (Fe)-based base metal composition and an electrically conductive coating formed on the solid core wire. The electrically conductive coating includes one or more electrically conducting elements or compounds in addition to or other than copper (Cu). The welding electrode additionally comprises an additional functional coating formed on the electrically conductive coating and including one or both of elemental antimony (Sb) and one or more Sb oxides. In a second aspect, a welding electrode comprises a solid core wire having an iron (Fe)-based base metal composition and two or more coatings covering at least a portion of the core wire. The two or more coatings comprise an electrically conductive coating formed on the solid core wire including one or more electrically conducting elements or compounds in addition to or other than copper (Cu). The two or more coatings additionally comprise an additional functional coating having a porous structure formed on the electrically conductive coating and including antimony (Sb). BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an arc welding system that can be used in conjunction with consumable electrodes according to embodiments disclosed herein. FIG. 2 illustrates a process of welding using a consumable electrode according to embodiments disclosed herein. FIG. 3 illustrates a covered welding consumable electrode according to embodiments. FIG. 4A illustrates a covered welding consumable electrode comprising two or more coatings, according to embodiments. FIG. 4B illustrates a covered welding consumable electrode comprising three or more coatings, according to embodiments. FIG. 5 illustrates a method of fabricating a covered welding consumable electrode, according to embodiments. FIG. 6A illustrates a weld metal formed using a conventional consumable electrode. FIG. 6B illustrates a weld metal formed using a consumable electrode having functional coatings according to embodiments. DETAILED DESCRIPTION Some welding electrodes have two main components: a core wire or a rod and a covering or coating. The core includes base alloying elements of the weld metal. The coating can include various materials that serve various functionalities. For example, the coating can serve to provide, among other things: shielding of the weld metal, stabilization of the arc, alloying elements for the weld metal for various physical properties, slag for fluxing, reduction of gas pockets in the weld metal, increased electrical conductivity or insulation, protection from the environment, lubrication for feeding and attractive appearance, to name a few. Some traditional solid welding wires are coated with a coating comprising copper on the surface of the wires to enhance the electrical conductivity and corrosion resistance of the wire and the welding nozzle, and to reduce the friction with the feeding hose or the welding nozzle. However, during the welding process, some of the copper can undesirably melt into the weld. The copper contamination of the weld can cause “copper cracking” or reduce the mechanical properties of the weld joints, especially the impact toughness and elongation at low temperature. The copper also oxidizes into copper particles and escapes into the air, which is harmful to human health when inhaled. The production of cop