Flux-cored wire for overhead welding and preparation method of flux-cored wire

Abstract

The invention relates to a flux-cored wire for overhead welding and a preparation method thereof, the flux-cored wire for overhead welding comprises an outer metal skin and an inner flux core filled in the outer metal skin, the outer metal skin is a low-carbon steel strip, and the inner flux core comprises the following components in percentage by mass: 7.5% of low-carbon ferromanganese, 13.8% of low-carbon silicon-manganese alloy, 0.6% of atomized aluminum powder, 13.4% of reduced iron powder, 45.4% of rutile and 19.3% of others. During preparation, the low-carbon steel strip is rewound, cleaned and dried firstly, then all components of the internal flux core are evenly mixed and then added into the low-carbon steel strip, the steel strip and the internal flux core are rolled and formed through a forming machine, and a flux-cored wire blank is prepared; and the flux-cored wire is pressed downwards through a plurality of rolling dies and a wire drawing round die until the flux-cored wire blank is drawn and compressed to the target size, and then the flux-cored wire is obtained. By adjusting the components and the content of the flux-cored wire, the prepared flux-cored wire has good deposited metal mechanical property and deposition efficiency and is suitable for overhead welding forming under the large current of 200 A or above.

Description

Technical Field

[0001] The invention relates to the technical field of welding materials, in particular to a flux-cored welding wire for overhead welding and a preparation method thereof. Background Art

[0002] As a new type of development material, flux-cored welding wire has a special production process and product characteristics. During the welding process, the powder wrapped inside the metal outer skin melts quickly, participates in the molten pool reaction with the base material, and quickly forms welding slag on the surface of the molten pool, which plays a role in protecting the molten pool and reducing air contact. Therefore, flux-cored welding wire generally has the advantages of small welding spatter, beautiful weld formation, and suitable for all-position welding. Compared with other welding materials, flux-cored welding wire has the advantages of long-term welding and good molten iron support, so it is particularly suitable for vertical welding and overhead welding of some large workpieces.

[0003] At present, with the continuous development of marine resources in the country, the prosperity of offshore platform projects and the shipbuilding industry, the use of welding materials for connection is also increasing. Such workpieces have more vertical welding and overhead welding positions, and flux-cored welding wire has excellent mechanical properties and long-term welding capabilities, so flux-cored welding wire is widely used in these two industries. However, most companies are now pursuing efficiency and cost. In order to shorten the manufacturing period and reduce production costs, it is inevitable that flux-cored welding wire has put forward the demand for overhead welding under high current conditions. Traditional flux-cored welding wire is prone to problems such as poor molten iron support, poor forming, and poor slag removal when performing overhead welding under high current. In addition, due to the burning problem, it also faces the problem of insufficient mechanical properties such as poor joint strength and impact toughness. Summary of the invention

[0004] The purpose of the present invention is to provide a flux-cored welding wire for overhead welding and a preparation method thereof, so as to improve the comprehensive welding performance of the flux-cored welding wire under overhead welding conditions.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The first aspect of the present invention provides a flux-cored welding wire for overhead welding, comprising an outer metal skin and an internal flux core filled in the metal outer skin, wherein the outer metal skin is a low-carbon steel strip, and the components of the internal flux core are as follows by mass percentage: 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, and 19.3% others; the filling rate of the internal flux core is 12~14%.

[0006] Furthermore, the chemical composition of the deposited metal of the internal flux core is calculated by mass percentage as follows: C: ≤0.12%; Mn: 1.10~1.75%; Si: 0.20~0.60%; S: ≤0.025%; P: ≤0.025%; Cr: ≤0.20%; Ni: ≤0.50%; Mo: ≤0.30%; V: ≤0.08%; Cu: ≤0.35%.

[0007] Furthermore, the chemical composition of the deposited metal of the internal flux core is C: 0.04%; Mn: 1.37%; Si: 0.42%; S: 0.011%; P: 0.005%; Cr: 0.035%; Ni: 0.010%; Mo: 0.003%; V: 0.015%; Cu: 0.011% by mass.

[0008] Furthermore, the chemical composition of the low carbon steel strip is as follows by mass percentage: C: 0.01-0.04%; Si: ≤0.03%; Mn: 0.15-0.35%; P: ≤0.015%; S: ≤0.015%.

[0009] Furthermore, the diameter of the flux-cored welding wire is 1.2 mm.

[0010] A second aspect of the present invention provides a method for preparing a flux-cored welding wire for overhead welding, comprising the following steps: S1 steel strip rewinding: winding the steel strip raw material onto the I-shaped wheel; S2 Steel Strip Cleaning and Drying: The rewound steel strip is cleaned and dried with high-temperature cleaning water to remove surface grease and impurities; S3 Preparation of the internal medicine core: Prepare the components of the internal medicine core according to the proportion, bake, pass through a 60-mesh sieve, and stir and mix; S4: initial forming of flux-cored welding wire: the steel strip cleaned and dried in step S2 is formed into a U shape by a plurality of forming machines, and then the internal flux core prepared in S3 is added to the U-shaped steel strip at a uniform speed through a feeding belt, and the opening of the steel strip is closed by the forming machine to obtain a flux-cored welding wire blank; S5: drawing and forming the flux-cored welding wire: the size of the flux-cored welding wire blank is compressed downward through a plurality of rolling dies and a wire drawing round die, until the flux-cored welding wire blank is drawn and compressed to a predetermined target size, thus obtaining the flux-cored welding wire; S6 Cleaning the surface of the flux-cored welding wire: Clean the surface of the drawn and sized flux-cored welding wire by a wire wiping device; S7 wire reel: reel the cleaned flux-cored welding wire onto the I-shaped wheel; S8 layer winding: the flux-cored welding wire on the I-shaped wheel is neatly arranged on the plastic disc through the layer winding machine; S9 packaging: packaging the flux-cored welding wire obtained in step S8.

[0011] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The present invention provides a flux-cored welding wire for overhead welding and a preparation method thereof, wherein the flux-cored welding wire comprises an outer metal skin and an inner flux core, wherein the components of the inner flux core are as follows by mass percentage: 7.5% low manganese, 13.8% low carbon silicon manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, and 19.3% others. By adjusting the components and contents of the flux-cored welding wire, the tensile strength of the prepared flux-cored welding wire reaches 500-600MPa, the yield strength reaches 450-540MPa, the elongation satisfies ≥22%, the impact absorption energy satisfies ≥47J (-20°C), the deposition efficiency satisfies ≥85%, and under a high current of 200-220A, it still has good molten iron dependence and formability. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings: Figure 1 It is a flow chart of a method for preparing a flux-cored welding wire for overhead welding according to the present invention; Figure 2 It is a welding forming diagram of titanium slag flux-cored welding wire in the prior art; Figure 3 This is a welding forming diagram of the flux-cored welding wire provided in the present invention. DETAILED DESCRIPTION

[0013] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0014] The invention provides a flux-cored welding wire for overhead welding, comprising an outer metal skin and an inner flux core filled in the outer metal skin. The outer metal skin is made of a low-carbon steel strip, and the chemical composition of the low-carbon steel strip is calculated by mass percentage as follows: C: 0.01-0.04%; Si: ≤0.03%; Mn: 0.15-0.35%; P: ≤0.015%; S: ≤0.015%. Of course, it is not limited to using the chemical composition within the above content range as the selection standard for the low-carbon steel strip, as long as it meets the actual use requirements or production standards.

[0015] For the above-mentioned internal flux core, in the embodiment of the present invention, the components of the internal flux core provided are 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, and 19.3% others by mass percentage. Compared with the component content of titanium slag flux-cored welding wire in the prior art, the original components are 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 1.2% atomized aluminum powder, 20.2% reduced iron powder, 38.0% rutile, and 19.3% others by mass percentage.

[0016] Generally speaking, the amount of iron alloy in titanium slag cored wire accounts for about 30-40% of the total core, including iron powder and other alloy materials. If too much iron powder is added, it is easy to reduce the viscosity of the welding slag, reduce the surface tension of the molten pool, and easily cause the molten iron to fall during overhead welding, affecting welding. However, if there is too little iron powder, it is easy to reduce the conductivity and cause poor welding process.

[0017] Rutile is the main component of titanium slag flux-cored welding wire, generally accounting for 35~60%. Appropriate rutile can improve the arc starting and arc stabilization performance of the welding wire, and deoxidize and remove impurities to enhance the mechanical properties of the weld. However, too much rutile can also cause slag removal difficulties.

[0018] Therefore, in the embodiment of the present invention, in order to improve the viscosity of the welding slag, the amount of iron powder in the components is reduced, and in order to correspondingly compensate for the reduction in conductivity and process performance caused by the reduction in iron powder, the amount of rutile is increased to ensure the welding process performance of the flux-cored welding wire.

[0019] The above process is further described below by way of examples.

[0020] Example 1 This embodiment provides a method for preparing a flux-cored welding wire for overhead welding, comprising the following steps: S1 steel strip rewinding: winding the steel strip raw material onto the I-shaped wheel; S2 Steel Strip Cleaning and Drying: The rewound steel strip is cleaned and dried with high-temperature cleaning water to remove surface grease and impurities; S3 Preparation of internal core: Prepare the components of the internal core in proportion, bake, pass through a 60-mesh sieve, and stir to mix; the proportion of the internal core here is 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, 1.2% titanium boron, 0.8% titanium iron, 2.0% sodium fluoride, 2.3% magnesium powder, 2.0% aluminum-magnesium alloy, 4.2% potassium sodium titanate, 4.1% quartz, 2.5% bauxite, and 0.2% bismuth oxide; S4: Initial forming of flux-cored welding wire: The steel strip cleaned and dried in step S2 is formed into a U shape by a plurality of forming machines, and then the internal flux core prepared in S3 is added to the U-shaped steel strip at a uniform speed through a feeding belt, and the opening of the steel strip is closed by the forming machine to obtain a flux-cored welding wire blank. At this time, the powder filling rate inside the flux-cored welding wire is 12.0%; S5: drawing and forming the flux-cored welding wire: the size of the flux-cored welding wire blank is compressed downward through a plurality of rolling dies and a wire drawing round die, until the flux-cored welding wire blank is drawn and compressed to a predetermined target size, thus obtaining the flux-cored welding wire; S6 Cleaning the surface of the flux-cored welding wire: Clean the surface of the drawn and sized flux-cored welding wire by a wire wiping device; S7 wire reel: reel the cleaned flux-cored welding wire onto the I-shaped wheel; S8 layer winding: the flux-cored welding wire on the I-shaped wheel is neatly arranged on the plastic disc through the layer winding machine; S9 packaging: packaging the flux-cored welding wire obtained in step S8.

[0021] Example 2 This embodiment provides a method for preparing a flux-cored welding wire for overhead welding, comprising the following steps: S1 steel strip rewinding: winding the steel strip raw material onto the I-shaped wheel; S2 Steel Strip Cleaning and Drying: The rewound steel strip is cleaned and dried with high-temperature cleaning water to remove surface grease and impurities; S3 Preparation of internal core: Prepare the components of the internal core in proportion, bake, pass through a 60-mesh sieve, and stir to mix; the proportion of the internal core here is 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, 1.2% titanium boron, 0.8% titanium iron, 2.0% sodium fluoride, 2.3% magnesium powder, 2.0% aluminum-magnesium alloy, 4.2% potassium sodium titanate, 4.1% quartz, 2.5% bauxite, and 0.2% bismuth oxide; S4: Initial forming of flux-cored welding wire: The steel strip cleaned and dried in step S2 is formed into a U shape by a plurality of forming machines, and then the internal flux core prepared in S3 is added to the U-shaped steel strip at a uniform speed through a feeding belt, and the opening of the steel strip is closed by the forming machine to obtain a flux-cored welding wire blank. At this time, the powder filling rate inside the flux-cored welding wire is 13.0%; S5: drawing and forming the flux-cored welding wire: the size of the flux-cored welding wire blank is compressed downward through a plurality of rolling dies and a wire drawing round die, until the flux-cored welding wire blank is drawn and compressed to a predetermined target size, thus obtaining the flux-cored welding wire; S6 Cleaning the surface of the flux-cored welding wire: Clean the surface of the drawn and sized flux-cored welding wire by a wire wiping device; S7 wire reel: reel the cleaned flux-cored welding wire onto the I-shaped wheel; S8 layer winding: the flux-cored welding wire on the I-shaped wheel is neatly arranged on the plastic disk through the layer winding machine; Example 3 This embodiment provides a method for preparing a flux-cored welding wire for overhead welding, comprising the following steps: S1 steel strip rewinding: winding the steel strip raw material onto the I-shaped wheel; S2 Steel Strip Cleaning and Drying: The rewound steel strip is cleaned and dried with high-temperature cleaning water to remove surface grease and impurities; S3 Preparation of internal core: Prepare the components of the internal core in proportion, bake, pass through a 60-mesh sieve, and stir to mix; the proportion of the internal core here is 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, 1.2% titanium boron, 0.8% titanium iron, 2.0% sodium fluoride, 2.3% magnesium powder, 2.0% aluminum-magnesium alloy, 4.2% potassium sodium titanate, 4.1% quartz, 2.5% bauxite, and 0.2% bismuth oxide; S4: Initial forming of flux-cored welding wire: The steel strip cleaned and dried in step S2 is formed into a U shape by a plurality of forming machines, and then the internal flux core prepared in S3 is added to the U-shaped steel strip at a uniform speed through a feeding belt, and the opening of the steel strip is closed by the forming machine to obtain a flux-cored welding wire blank. At this time, the powder filling rate inside the flux-cored welding wire is 14.0%; S5: drawing and forming the flux-cored welding wire: the size of the flux-cored welding wire blank is compressed downward through a plurality of rolling dies and a wire drawing round die, until the flux-cored welding wire blank is drawn and compressed to a predetermined target size, thus obtaining the flux-cored welding wire; S6 Cleaning the surface of the flux-cored welding wire: Clean the surface of the drawn and sized flux-cored welding wire by a wire wiping device; S7 wire reel: reel the cleaned flux-cored welding wire onto the I-shaped wheel; S8 layer winding: the flux-cored welding wire on the I-shaped wheel is neatly arranged on the plastic disk through the layer winding machine; Comparative Example 1 This embodiment provides a commercially available flux-cored welding wire of model LT·E501 (ie, American standard E71T-1C).

[0022] The present invention conducted performance tests on the products of Examples 1 to 3 and Comparative Example 1, and the specific test results are as follows: The flux-cored welding wire involved in the present invention comprises an outer metal skin and an inner flux core, and the components of the inner flux core are 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, and 19.3% others by mass percentage. By adjusting the components and contents of the flux-cored welding wire, the tensile strength of the prepared flux-cored welding wire reaches 500-600 MPa, the yield strength reaches 450-540 MPa, the elongation is ≥22%, the impact absorption energy is ≥47J, and the deposition efficiency is ≥85%. By adaptively adjusting the components of the flux-cored welding wire, the rapid slag-forming performance and reliance of the molten iron are correspondingly enhanced, so that it is suitable for overhead welding conditions, and under overhead welding conditions, it reflects good welding mechanical properties and deposition efficiency.

[0023] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A flux-cored welding wire for overhead welding, comprising an outer metal skin and an inner flux core filled in the outer metal skin, characterized in that: The outer metal skin is a low-carbon steel strip, and the components of the inner core are as follows by mass percentage: 7.5% low-carbon ferromanganese, 13.8% low-carbon silicon-manganese alloy, 0.6% atomized aluminum powder, 13.4% reduced iron powder, 45.4% rutile, and 19.3% others; the filling rate of the inner core is 12~14%.

2. A flux-cored welding wire for overhead welding according to claim 1, characterized in that: The chemical composition of the deposited metal of the internal flux core is C: ≤0.12% by mass; Mn: 1.10-1.75%; Si: 0.20-0.60%; S: ≤0.025%; P: ≤0.025%; Cr: ≤0.20%; Ni: ≤0.50%; Mo: ≤0.30%; V: ≤0.08%; Cu: ≤0.35%.

3. A flux-cored welding wire for overhead welding according to claim 2, characterized in that: The chemical composition of the deposited metal of the internal flux core is C: 0.04%; Mn: 1.37%; Si: 0.42% by mass percentage; S：0.011%； P: 0.005%; Cr: 0.035%; Ni: 0.010%; Mo: 0.003%; V: 0.015%; Cu: 0.011%.

4. The flux-cored welding wire for overhead welding according to claim 1, characterized in that: The chemical composition of the low carbon steel strip is as follows by mass percentage: C: 0.01-0.04%; Si: ≤0.03%; Mn: 0.15-0.35%; P：≤0.015%； S：≤0.015%。 5. The flux-cored welding wire for overhead welding according to claim 1, characterized in that: The diameter of the flux-cored welding wire is 1.2 mm.

6. The method for preparing a flux-cored welding wire for overhead welding according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1 steel strip rewinding: winding the steel strip raw material onto the I-shaped wheel; S2 Steel Strip Cleaning and Drying: The rewound steel strip is cleaned and dried with high-temperature cleaning water to remove surface grease and impurities; S3 Preparation of the internal medicine core: Prepare the components of the internal medicine core according to the proportion, bake, pass through a 60-mesh sieve, and stir and mix; S4: initial forming of flux-cored welding wire: the steel strip cleaned and dried in step S2 is formed into a U shape by a plurality of forming machines, and then the internal flux core prepared in S3 is added to the U-shaped steel strip at a uniform speed through a feeding belt, and the opening of the steel strip is closed by the forming machine to obtain a flux-cored welding wire blank; S5: drawing and forming the flux-cored welding wire: the size of the flux-cored welding wire blank is compressed downward through a plurality of rolling dies and a wire drawing round die, until the flux-cored welding wire blank is drawn and compressed to a predetermined target size, thus obtaining the flux-cored welding wire; S6 Cleaning the surface of the flux-cored welding wire: Clean the surface of the drawn and sized flux-cored welding wire by a wire wiping device; S7 wire reel: reel the cleaned flux-cored welding wire onto the I-shaped wheel; S8 layer winding: the flux-cored welding wire on the I-shaped wheel is neatly arranged on the plastic disk through the layer winding machine; S9 packaging: packaging the flux-cored welding wire obtained in step S8.

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