A flux-cored wire having moisture resistance

Abstract

The utility model discloses a kind of flux-cored wires with moisture-proof performance, including the core layer consisting of alloy powder and mineral powder, the tubular skin layer formed by low carbon steel band spiral curl is arranged outside the core layer, and the skin layer is curled into shape along the length direction of welding wire and is formed into continuous sealing barrier by lap joint closure, and inside the skin layer is pre-coated with continuous hot-melt sealing adhesive strip along the length direction of steel band, moisture-proof layer is arranged between the core layer and the skin layer, and the moisture-proof layer is composed of microporous polymer coated desiccant particles, and breathable isolation film is arranged between the moisture-proof layer and the core layer, and the end sealing head sealed by hot-melt adhesive is arranged at both ends of the welding wire. The utility model realizes that welding wire inside actively absorbs moisture, even after opening package, still can keep the core dry, moisture-proof structure and desiccant decomposition product do not affect welding process performance when welding, simple structure, applicable to existing welding wire production line.

Description

Technical Field

[0001] This utility model relates to the field of welding materials technology, and in particular to a flux-cored welding wire with moisture-proof properties. Background Technology

[0002] Flux-cored welding wire is widely used in the welding field due to its excellent process performance, high production efficiency, and low overall cost. However, one of the biggest drawbacks of flux-cored welding wire is that its flux core is extremely susceptible to moisture absorption. Moisture-absorbing wire will cause a series of problems during welding, such as increased porosity, increased spatter, unstable arc, and decreased mechanical properties of the weld metal.

[0003] Existing flux-cored welding wires are prone to absorbing moisture in humid environments, leading to deliquescence of the flux components and defects such as porosity and cracks during welding, which seriously affects welding quality. Although methods such as vacuum packaging or desiccant encapsulation are used, they cannot provide continuous moisture protection after opening the package and lack active moisture-proof design in the structure. Utility Model Content

[0004] To address the aforementioned technical problems, a flux-cored welding wire with moisture-proof properties is provided, solving the problem that existing flux-cored welding wires cannot maintain moisture protection after being unpacked, thus achieving long-term moisture protection.

[0005] To achieve the above objectives, this utility model discloses a flux-cored welding wire with moisture-proof properties, comprising a flux-cored layer composed of alloy powder and mineral powder, a tubular outer skin layer formed by spirally coiling a low-carbon steel strip on the outside of the flux-cored layer, the outer skin layer being coiled and folded along the length of the welding wire to form a continuous sealing barrier, a continuous hot-melt sealing strip being pre-coated on the inner side of the outer skin layer along the length of the steel strip, a moisture-proof layer being provided between the flux-cored layer and the outer skin layer, the moisture-proof layer being composed of microporous polymer-coated desiccant particles, a breathable isolation membrane being provided between the moisture-proof layer and the flux-cored layer, and end sealing heads sealed with hot-melt adhesive at both ends of the welding wire.

[0006] Furthermore, the moisture-proof layer is continuously distributed along the axial direction of the welding wire, and the length of the moisture-proof layer is consistent with the length of the welding wire.

[0007] Furthermore, the end sealing head is nested on the surface of the outer skin layer and the contact position with the outer skin layer is coated with hot melt adhesive, and the end sealing head is provided with a positioning element embedded in the end face of the drug core layer.

[0008] Furthermore, the sealing strip is made of polyolefin hot melt adhesive or polyamide hot melt adhesive.

[0009] Furthermore, the desiccant is a molecular sieve or calcium oxide particles with a particle size of 0.1 mm to 0.5 mm.

[0010] Furthermore, the microporous polymer is polyethylene or polypropylene, with a thickness of 0.1 mm to 0.3 mm.

[0011] Furthermore, the breathable isolation membrane is a polytetrafluoroethylene membrane with a pore size ≤0.2μm.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model discloses a flux-cored welding wire with moisture-proof properties, which realizes active moisture absorption inside the welding wire and can keep the flux core dry even after the package is opened. The moisture-proof structure and the decomposition products of the desiccant during welding do not affect the welding process performance. The structure is simple and suitable for existing welding wire production lines. Attached Figure Description

[0013] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 This is a schematic diagram of the exploded structure of this utility model.

[0015] Figure 2 This is a schematic diagram of the internal structure of this utility model.

[0016] Figure 3 This is a schematic diagram of the end sealing head of this utility model.

[0017] Figure 4 This is a schematic diagram of the inner side of the outer skin layer of this utility model.

[0018] In the diagram: 1 is the outer skin layer; 11 is the sealing strip; 2 is the drug core layer; 3 is the moisture-proof layer; 31 is the microporous polymer; 32 is the desiccant; 4 is the breathable isolation membrane; 5 is the end sealing head; 51 is the positioning component. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] One embodiment of this utility model is as follows: Figure 1 , Figure 2 and Figure 4As shown, a tubular outer skin layer 1, formed by spirally coiling a low-carbon steel strip, is provided on the outer side of the flux core layer 2. The outer skin layer 1 is coiled along the length of the welding wire and closed by overlapping to form a continuous sealing barrier, effectively preventing ambient moisture from penetrating into the interior of the flux core layer through the overlap gaps, significantly reducing the moisture absorption rate, and greatly extending the shelf life and usage time of the welding wire after opening. A continuous hot-melt sealing strip 11 is pre-coated on the inner side of the outer skin layer 1 along the length of the steel strip. A moisture-proof layer 3 is provided between the flux core layer 2 and the outer skin layer 1. The moisture-proof layer 3 is composed of microporous polymers. The welding wire is composed of a desiccant 32 granules coated with a compound 31. A breathable isolation membrane 4 is provided between the moisture-proof layer 3 and the core layer 2, allowing water vapor to pass through in one direction. Both ends of the welding wire are provided with end sealing heads 5 sealed with hot melt adhesive, realizing active moisture absorption inside the welding wire. Even after opening the package, the core can still be kept dry. The moisture-proof structure and the decomposition products of the desiccant during welding do not affect the welding process performance. The structure is simple and suitable for existing welding wire production lines. Only the glue coating and heating and pressurizing processes need to be added to the existing flux-cored welding wire production line, without the need for complex equipment modification.

[0021] The moisture-proof layer 3 is continuously distributed along the axial direction of the welding wire, and the length of the moisture-proof layer 3 is consistent with the length of the welding wire.

[0022] like Figure 3 As shown, the end sealing head 5 is nested on the surface of the outer skin layer 1 and the contact position with the outer skin layer 1 is coated with hot melt adhesive to form a hot melt sealing ring, which cuts off the internal environment of the welding wire from the outside, ensuring the bonding strength between the wire and the outer skin layer to prevent detachment. The end sealing head 5 is provided with a positioning element 51 embedded in the end face of the core layer 2. The positioning element is specifically a needle-shaped structure with a pointed end. It is embedded in the core layer to allow the sealing head to rotate circumferentially, improving the sealing performance and maintaining the sealing integrity under temperature cycling from -20℃ to 80℃.

[0023] In one specific embodiment of this application, a low-carbon steel strip with a thickness of 0.3 mm is selected as the outer skin layer. Using a precision coating device, two EVA-based hot-melt sealant strips, each 0.5 mm wide and 0.05 mm thick, are pre-coated along the length of the inner surface of the steel strip, approximately 0.2 mm from the overlap edge. These strips are completely vaporized and decomposed under the high temperature of the welding arc, without introducing harmful impurities or adversely affecting arc stability or weld performance. The coated steel strip is then fed into a forming unit, where it is gradually coiled and shaped by forming wheels. Powder is then added, and the coiling continues. The opening is closed by a compression roller to form an overlap, with a core filling rate of 25%. Before or simultaneously with the overlap closure, the overlap area is locally heated to 90°C (higher than the melting point of the selected EVA adhesive, 80°C) using a heating device (hot air or infrared heating). Under the pressure of the compression roller, the two sealing strips in the overlap area melt, press against each other, and fully bond, simultaneously filling the overlap gap. After cooling, a continuous sealing layer is formed. The moisture-proof layer uses a polyethylene microporous membrane coated with molecular sieve desiccant, with a thickness of 0.2 mm. The desiccant content is 5wt%–10%. The filler content (wt%) is uniformly dispersed in the microporous polymer. The theoretical total moisture absorption is ≥ 3 times the maximum water content of the core. The equilibrium moisture absorption of the molecular sieve at 25℃ and 60%RH is ≈ 20%. Calcium oxide expands in volume after being converted to calcium hydroxide by water, further reducing porosity and creating a self-sealing effect that prevents reverse diffusion of water vapor. The microporous polymer only allows slow diffusion of H2O molecules, while large N2O2 molecules can hardly pass through. Therefore, the moisture absorption rate is "limited" to 0.2 mg / (m·d)~0.5 mg / (m·d). At the mg / (m·d) level, this design prevents rapid moisture absorption that could lead to localized overheating while ensuring long-term effectiveness. The breathable membrane uses a 0.1μm PTFE membrane with unidirectional channels, allowing moisture to diffuse only from the core layer towards the moisture barrier, preventing desiccant migration into the core layer. The membrane surface is hydrophobically treated, with a contact angle >110°. The sealing strip 11 uses polyolefin hot melt adhesive, polyamide hot melt adhesive, or a specially formulated synthetic rubber-based hot melt adhesive. Both ends of the welding wire are sealed with hot melt adhesive. After being placed at 35℃ and 85%RH for 30 days, the core moisture content of this welding wire is ≤0.1%, and the weld is free of defects such as pores and cracks.

[0024] Several points need to be clarified: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly, and can refer to mechanical or electrical connections, or internal connections between two components, or direct connections. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships, and the relative positional relationships may change when the absolute position of the described objects changes. Second, in this document, relational terms such as "first" and "second" are only used to distinguish one entity from another entity, and do not necessarily require or imply any such actual relationship or order between these entities.

[0025] The examples above are merely illustrative of this utility model and do not constitute a limitation on the scope of protection of this utility model. All designs that are the same as or similar to this utility model are within the scope of protection of this utility model.

Claims

1. A flux-cored welding wire with moisture-proof properties, comprising a flux-cored layer (2) composed of alloy powder and mineral powder, characterized in that, The outer side of the core layer (2) is provided with a tubular outer skin layer (1) formed by spirally coiling a low carbon steel strip. The outer skin layer (1) is coiled along the length of the welding wire and closed by overlapping to form a continuous sealing barrier. The inner side of the outer skin layer (1) is pre-coated with a continuous hot melt sealing strip (11) along the length of the steel strip. A moisture-proof layer (3) is provided between the core layer (2) and the outer skin layer (1). The moisture-proof layer (3) is composed of microporous polymer (31) coated with desiccant (32) particles. A breathable isolation membrane (4) is provided between the moisture-proof layer (3) and the core layer (2). The two ends of the welding wire are provided with end sealing heads (5) sealed with hot melt adhesive.

2. A flux-cored welding wire with moisture-proof properties according to claim 1, characterized in that, The moisture-proof layer (3) is continuously distributed along the axial direction of the welding wire, and the length of the moisture-proof layer (3) is consistent with the length of the welding wire.

3. A flux-cored welding wire with moisture-proof properties according to claim 1, characterized in that, The end sealing head (5) is nested on the surface of the outer skin layer (1) and the contact position with the outer skin layer (1) is coated with hot melt adhesive. The end sealing head (5) is provided with a positioning element (51) embedded in the end face of the core layer (2).

4. A flux-cored welding wire with moisture-proof properties according to claim 1, characterized in that, The sealing strip (11) is made of polyolefin hot melt adhesive or polyamide hot melt adhesive.

5. A flux-cored welding wire with moisture-proof properties according to claim 1, characterized in that, The desiccant (32) is a molecular sieve or calcium oxide particles with a particle size of 0.1 mm to 0.5 mm.

6. A flux-cored welding wire with moisture-proof properties according to claim 1, characterized in that, The microporous polymer (31) is polyethylene or polypropylene with a thickness of 0.1 mm to 0.3 mm.

7. A flux-cored welding wire with moisture-proof properties according to claim 1, characterized in that, The breathable isolation membrane (4) is a polytetrafluoroethylene membrane with a pore size ≤0.2μm.

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