A hardening cladding flux-cored welding wire

Abstract

The present invention provides a surfacing flux-cored wire that can be work-hardened. The flux-cored wire includes a flux core and an outer skin. The flux core comprises components with the following mass fractions: high-carbon ferrochrome 40% - 60%, ferrosilicon 75# 0.5% - 1.5%, electrolytic manganese 3% - 7%, ferromolybdenum 6% - 15%, titanium additive 20% - 45%, arc stabilizing agent 0.5% - 2%, rare earth additive 0.5% - 1.5%, and the balance is iron powder, where the sum of the mass fractions of each component is 100%. The wire of the present invention can be prepared into 80%Ar + 20%CO2 gas shielded wires with diameters of 1.2 mm and 1.6 mm. The surfacing process is excellent. The hardness in the as-welded state is 40HRC - 50HRC, and the hardness increases by 5HRC - 15HRC after work hardening. It is suitable for the surfacing repair of workpieces that are in long-term service under conditions of strong impact and abrasive wear.

Description

Technical Field

[0001] The invention belongs to the field of welding wires, and in particular relates to a hardening cladding flux-cored welding wire. Background Art

[0002] The hammer of the crusher is a vulnerable and consumable part of the crusher. When the hammer rotates at high speed, it collides violently with the falling materials, thus crushing the materials. The hammer is in a state of high impact and high stress abrasive wear, and its wear and tear is very rapid. The hammer needs to be repaired by surfacing welding to restore its original size and improve the strength, hardness and impact resistance of the workpiece. At present, the wear-resistant materials used in the hammer of the hammer crusher are mainly high manganese steel, high chromium cast iron, etc.

[0003] Traditional high manganese steel materials have good toughness and work hardening ability, but the hardness value is low. When facing high impact, work hardening can occur, which greatly improves the hardness value of the material. Under small and medium impact conditions, due to the low degree of work hardening and very low hardness, the wear resistance of the material is very poor. Although high chromium cast iron materials have high hardness and good wear resistance, they have poor toughness and are prone to fracture under high impact conditions. Summary of the invention

[0004] In view of this, the present invention aims to overcome the defects in the prior art and proposes a hardening cladding flux-cored welding wire.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A hardened cladding flux-cored welding wire comprises a flux core and an outer sheath, wherein the flux core comprises the following components in mass fraction: 40%-60% high carbon ferrochrome, 0.5%-1.5% 75# ferrosilicon, 3%-7% electrolytic manganese, 6%-15% ferromolybdenum, 20%-45% titanium additive, 0.5%-2% arc stabilizer, 0.5%-1.5% rare earth additive, and the rest is iron powder, wherein the sum of the mass fractions of the components is 100%.

[0007] Furthermore, the flux-cored welding wire includes a flux core and an outer sheath, and the flux core includes the following components in mass fraction: 45%-55% high carbon ferrochromium, 0.6%-1.4% 75# ferrosilicon, 3%-7% electrolytic manganese, 6.5%-12% ferromolybdenum, 23%-40% titanium additive, 0.5%-2% arc stabilizer, 0.6%-1.4% rare earth additive, and the rest is iron powder, wherein the sum of the mass fractions of each component is 100%.

[0008] The particle size of each component of the flux-cored welding wire is 60 meshes to 200 meshes.

[0009] Furthermore, the titanium additive is at least one of titanium carbide and titanium-boron alloy.

[0010] Furthermore, the titanium additive is titanium carbide, the mass ratio of the titanium carbide to high carbon ferrochrome is 0.5-0.8:1, and the mass ratio of the titanium carbide to ferromolybdenum is 3.2-3.8:1.

[0011] Furthermore, the titanium additive is a titanium-boron alloy; the mass ratio of the titanium-boron alloy to high-carbon ferrochrome is 0.4-0.6:1.

[0012] Furthermore, the rare earth additive is at least one of rare earth ferrosilicon or yttrium-based heavy rare earth ferrosilicon.

[0013] Furthermore, the rare earth additive is rare earth ferrosilicon, and the mass ratio of the rare earth ferrosilicon to 75# ferrosilicon is 0.9-1.3:1.

[0014] Furthermore, the carbon content of the high carbon ferrochrome is 6.0wt%-9.0wt%, the chromium content is 60.0wt%-70.0wt%, and the balance is iron; the silicon content of the 75# ferrosilicon is 74wt%-80wt%, and the balance is iron; the manganese content of the electrolytic manganese is greater than or equal to 99.70wt%; the molybdenum content of the ferromolybdenum is 57wt%-60wt%, and the balance is iron.

[0015] Preferably, the carbon content of the high carbon ferrochrome is 8.2wt%, the chromium content is 60.69wt%, and the balance is iron; the silicon content of the 75# ferrosilicon is 74.3wt%, and the balance is iron.

[0016] Furthermore, the particle size of the powder in the high carbon ferrochrome is 80-120 meshes.

[0017] Furthermore, the flux core accounts for 18%-25% of the total weight of the welding wire; and the outer skin is a carbon steel cold-rolled steel strip.

[0018] The hardenable cladding flux-cored wire is heated in 80% Ar + 20% CO 2 Application in gas shielded welding.

[0019] The 80%Ar+20%CO 2 The welding conditions for gas shielded welding are: current 180A-320A; voltage 22V-30V; gas flow rate 20L / min-25L / min; the thickness of each layer of deposited metal is greater than or equal to 2mm.

[0020] The application of the work-hardening surfacing flux-cored welding wire in the workpiece surfacing repair layer and the application of the work-hardening surfacing flux-cored welding wire in high manganese steel base material. The service environment is strong impact and high stress, the welded hardness is 40HRC-50HRC, and the hardness after work hardening is increased by 5HRC-15HRC.

[0021] The preparation method of the hardened cladding flux-cored welding wire comprises the following steps: rolling a carbon steel cold-rolled steel strip into a U-shaped groove, mixing and baking the powder and then adding it, and reducing the diameter by rolling and drawing to obtain the hardened cladding flux-cored welding wire. The welding wire is 80%Ar+20%CO with a diameter of 1.2mm or 1.6mm. 2 Gas shielded welding wire.

[0022] C: It forms carbides with alloy elements such as Cr and Mo. As the amount added in the powder increases, the hardness and wear resistance of the surfacing metal increase; but too high C content leads to increased brittleness of the alloy layer and decreased impact toughness. At the same time, since carbides are strong cathode phases of the matrix structure, they will accelerate the electrochemical corrosion of the surfacing metal and the base material.

[0023] Cr: Chromium can interact with carbon to generate carbides with higher hardness, thereby improving strength and hardness. These carbides can act as anti-wear phases, significantly improving the wear resistance of the cladding layer. At the same time, chromium has red hardness and high-temperature oxidation resistance, so that it can still maintain high hardness at high temperatures. Moreover, chromium can also be dissolved in the matrix, thereby improving the hardenability, hardness, wear resistance and corrosion resistance of the matrix structure.

[0024] Mo: It mainly exists in the weld metal in the form of eutectic carbides and solid solutions. Its role in the weld metal is to improve hardenability, produce solid solution strengthening, and inhibit temper brittleness; the formed carbides have an enhanced secondary hardening effect. It can not only improve the hardenability, strength and ductility of steel, but also greatly improve the impact toughness because molybdenum can eliminate or reduce the temper brittleness caused by other alloying elements. The distribution of molybdenum in the weld metal is mainly solid solution in the matrix to improve hardenability.

[0025] Si, Mn: Silicon and manganese are the most commonly used alloying elements in iron-based wear-resistant materials. They are dissolved in the matrix to improve the strength of the matrix. They have a greater affinity with O and are good deoxidizers, which are beneficial to reducing the oxygen content in the weld and preventing the formation of oxygen pores.

[0026] Ti: Titanium can preferentially precipitate TiC phase particles with a melting point of up to 3150°C and a microhardness of 3200 HV in situ in the liquid phase; fixing the free C atoms in the cladding metal reduces the probability of forming a brittle eutectic.

[0027] Rare earth elements: A small amount of RE has the effects of dehydrogenation, deoxidation, grain refinement, purification of impurities S and P, improvement of high-temperature oxidation resistance of cladding metal and enhancement of corrosion resistance; but when too much rare earth is added, it is easy to cause loose structure of cladding layer and reduce hardness.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] The hardenable surfacing flux-cored welding wire of the present invention controls the composition of the surfacing metal by means of the powder composition and content, specifically: C, Cr, and Ti elements are transitioned into the surfacing metal by means of titanium carbide and high carbon ferrochrome, and Mo elements are transitioned by means of ferromolybdenum; TiC is preferentially precipitated during the cooling process of the surfacing metal, and as the temperature decreases, the preferentially nucleated TiC will serve as the core of heterogeneous nucleation, making Mo 2 C and Cr 7 C 3 Depends on TiC nucleation; Appropriate content of titanium carbide, high carbon ferrochrome and ferromolybdenum will make TiC precipitate as the main carbide during the cooling process, and Mo and Cr will be more dissolved in the matrix, forming only a small amount of carbides, thereby improving the hardness of the matrix and increasing the stability of the matrix; Excessive addition of titanium carbide, high carbon ferrochrome and ferromolybdenum will cause the surfacing metal to form more residual austenite during the cooling process after welding, thereby reducing the hardness of the surfacing metal; and the carbides of Mo and Cr will be more dependent on TiC nucleation, resulting in coarse carbides, reducing the mechanical properties of the surfacing metal, and at the same time weakening the pinning effect of TiC and reducing the work hardening ability; Lower additions of titanium carbide, high carbon ferrochrome and ferromolybdenum will reduce the in-situ precipitation of TiC in the surfacing metal and the solid solution strengthening produced by Mo and Cr, thereby reducing the hardness of the surfacing metal and the effect of inducing martensitic phase transformation caused by TiC after impact.

[0030] The work-hardening cladding flux-cored welding wire of the present invention has the characteristic of "self-strengthening" during use and can be prepared into 80%Ar+20%CO2 with a thickness of 1.2 mm and 1.6 mm. 2 Gas shielded welding wire has excellent cladding technology, stable arc, small spatter, beautiful weld bead shape, and is convenient for on-site welding.

[0031] The titanium carbide in the work-hardenable cladding flux-cored welding wire of the present invention has a face-centered cubic lattice and can form a good coherent or semi-coherent relationship with the austenite matrix. It is well bonded to the matrix during the plastic deformation of the matrix under impact, and has a stronger crack resistance. The cladding deposited metal contains fine dispersed titanium carbide (2μm-3μm), which plays a role of pinning dislocations and hindering the movement of dislocations during the impact wear hardening process. At the same time, plastic deformation causes a large number of deformation twins to be generated in the alloy. These deformation twins and dislocations are entangled around the titanium carbide, which increases the energy density and promotes the transformation of the austenite structure into twinned martensite and distribution around the titanium carbide. The rapidly increased martensite structure increases the hardness of the cladding metal by 5HRC-15HRC, and improves the wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A metallographic diagram of the welded microstructure of the work-hardenable cladding flux-cored welding wire according to an embodiment of the present invention;

[0033] Figure 2 This is a metallographic diagram of the work-hardened cladding flux-cored welding wire according to an embodiment of the present invention after work-hardening. DETAILED DESCRIPTION

[0034] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0035] The present invention will be described in detail below with reference to the embodiments.

[0036] The components of the flux cores of each welding wire in Examples 1-4 and Comparative Examples 1-4 are shown in Table 1. The welding wire is obtained by rolling a carbon steel cold-rolled steel strip into a U-shaped groove, mixing and baking the flux powder, and then adding it, and then rolling and drawing to reduce the diameter. The diameter of the welding wire is 1.6 mm. The metallographic structure of the obtained welding wire as welded and the metallographic structure after work hardening are as follows: Figure 1-2 shown.

[0037] Table 1 Core components

[0038]

[0039] The surfacing flux-cored welding wires obtained in Examples 1-4 and Comparative Examples 1-4 were surfacing-welded on high manganese steel base materials for 10 layers according to relevant standards to ensure that the surfacing metal component was pure deposited metal. The welding shielding gas was 80% Ar + 20% CO 2 . Then perform the following tests:

[0040] 1. Chemical composition test

[0041] The chemical composition of the cladding layer was determined by direct reading spectrometer, and the specific values ​​are shown in Table 2.

[0042] Table 2 Chemical composition of cladding metal

[0043]

[0044] The workable and hardenable cladding flux-cored welding wire of the present invention controls the cladding metal composition by means of the powder component and content. Different amounts of powder added result in different chemical compositions of the deposited metal.

[0045] 2. Hardness test

[0046] The hardness of the cladding layer was measured using a HBRV-187.5 Brinell hardness tester. Ten hardness points were taken for each cladding layer of each embodiment, and finally the average Rockwell hardness value of the cladding layer of the embodiment was obtained. The specific values ​​are shown in Table 3.

[0047] Table 3 Metal hardness of cladding deposited metal

[0048]

[0049] Appropriate content of titanium carbide, high carbon ferrochromium and ferromolybdenum will produce a better solid solution strengthening effect and form fine in-situ titanium carbide to improve the hardness of the surfacing metal. After adding titanium-boron alloy, B and C form boron carbide, which improves the initial hardness of the surfacing metal. The addition of rare earth elements will refine the grain size and improve the weld hardness.

[0050] 3. Hammer test

[0051] After each example was subjected to hardness test, impact stress was provided to the cladding metal by hammering, so that the surface of the cladding layer was work-hardened. The hardness of the cladding layer after hammering was measured by a HBRV-187.5 Brinell hardness tester, and 10 hardness points were taken for each example. Finally, the average Rockwell hardness value of the cladding layer of the example was obtained, and the specific values ​​are shown in Table 4.

[0052] Table 4 Hardness of weld deposited metal after hammering

[0053]

[0054] The increase in hardness is mainly due to the "self-strengthening" effect of in-situ titanium carbide. The formation of in-situ titanium carbide is mainly controlled by the titanium additives in the welding wire and the addition of high-carbon ferrochrome. The appropriate addition will form more fine in-situ titanium carbides, making them evenly dispersed in the matrix. After being subjected to impact stress, a large amount of twin martensite is formed around the titanium carbide. The rapidly increasing martensitic structure increases the hardness of the surfacing metal by 5HRC-15HRC.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A hardenable cladding flux-cored welding wire, characterized in that: The flux-cored welding wire comprises a flux core and an outer sheath, wherein the flux core comprises the following components by mass fraction: 40%-60% high carbon ferrochrome, 0.5%-1.5% 75# ferrosilicon, 3%-7% electrolytic manganese, 6%-15% ferromolybdenum, 20%-45% titanium additive, 0.5%-2% arc stabilizer, 0.5%-1.5% rare earth additive, and the rest is iron powder, wherein the sum of the mass fractions of the components is 100%; The titanium additive is titanium carbide, the mass ratio of the titanium carbide to high carbon ferrochrome is 0.5-0.8:1, and the mass ratio of the titanium carbide to ferromolybdenum is 3.2-3.8:1; The rare earth additive is rare earth ferrosilicon, and the mass ratio of the rare earth ferrosilicon to 75# ferrosilicon is 0.9-1.3:

1.

2. The hardenable cladding flux-cored welding wire according to claim 1, characterized in that: The flux-cored welding wire comprises a flux core and an outer sheath, wherein the flux core comprises the following components in mass fraction: 45%-55% high carbon ferrochromium, 0.6%-1.4% 75# ferrosilicon, 3%-7% electrolytic manganese, 6.5%-12% ferromolybdenum, 23%-40% titanium additive, 0.5%-2% arc stabilizer, 0.6%-1.4% rare earth additive, and the rest is iron powder, wherein the sum of the mass fractions of the components is 100%.

3. The hardenable cladding flux-cored welding wire according to claim 2, characterized in that: The carbon content of the high carbon ferrochrome is 6.0wt%-9.0wt%, the chromium content is 60.0 wt%-70.0wt%, and the balance is iron; the silicon content of the 75# ferrosilicon is 74wt%-80wt%, and the balance is iron; the manganese content of the electrolytic manganese is greater than or equal to 99.70wt%; the molybdenum content of the ferromolybdenum is 57wt%-60wt%, and the balance is iron.

4. The hardenable cladding flux-cored welding wire according to claim 2, characterized in that: The particle size of the powder in the high carbon ferrochrome is 80-120 meshes.

5. The hardenable cladding flux-cored welding wire according to claim 2, characterized in that: The flux core accounts for 18%-25% of the total weight of the welding wire; the outer skin is a carbon steel cold-rolled steel strip.

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