A method for producing a hardfacing flux-cored welding wire

Abstract

This invention discloses a wear-resistant hardfacing flux-cored welding wire and its preparation method, relating to the field of flux-cored welding wire technology. The flux-cored welding wire prepared by this invention forms hard borides in the cladding metal crystalline matrix, thereby imparting high hardness to the cladding metal. Furthermore, boron carbide is distributed in the weld overlay layer, improving wear resistance. The cladding metal formed by the flux-cored welding wire prepared by this invention has good fluidity and does not require shielding gas during welding, thus saving costs. This invention encapsulates the powdered flux core in a steel shell, improving the corrosion resistance of the welding wire. Through two drawing processes and titanium diffusion treatment, the components are bonded together, the grain size is refined, the hardface quality is improved, and the corrosion resistance and wear resistance of the welding wire are enhanced.

Description

Technical Field

[0001] This invention relates to the field of flux-cored welding wire technology, specifically to a method for preparing a wear-resistant hardfacing flux-cored welding wire. Background Technology

[0002] Hot forging is an advanced processing method that offers high production efficiency, good workpiece quality, and material savings. It is widely used in various industrial sectors, including machinery, locomotives, automobiles, tractors, aviation, light industry, petrochemicals, and power. The demand for hot forging dies in industrial production is substantial. However, due to the harsh working conditions and short service life of hot forging dies, premature failures such as burr opening, wear, collapse, and thermal fatigue are common. Therefore, repairing hot forging dies through welding to extend their service life has significant economic implications.

[0003] Flux-cored welding wire, also known as powder-cored welding wire or tubular welding wire, can be divided into two main categories: gas-shielded and non-gas-shielded. The outer surface of flux-cored welding wire is the same as that of solid welding wire, made of materials with good plasticity such as low-carbon steel or low-alloy steel, while the inner surface contains flux to give the wire different welding functions. The manufacturing process of flux-cored welding wire typically involves first rolling a steel strip into a U-shaped cross-section, then filling the U-shaped steel strip with a pre-mixed flux, pressing it tightly with a rolling mill, and finally drawing it into flux-cored welding wires of different specifications. Summary of the Invention

[0004] The purpose of this invention is to provide a wear-resistant hardface welding flux-cored wire and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a wear-resistant hardfacing flux-cored welding wire, comprising the following preparation steps:

[0006] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide, and grind them to obtain core powder;

[0007] (2) Roll the steel strip into a U-shaped groove;

[0008] (3) The core powder will be filled into the U-shaped groove, then the U-shaped groove will be rolled and closed, drawn, and annealed at 630~650℃ for 45~53min to obtain the welding wire blank;

[0009] (4) Place the welding wire blank in the equipment and treat it at 930~950℃ for 10~20 minutes in a gas atmosphere to obtain pretreated welding wire;

[0010] (5) Pull out the pretreated welding wire and anneal it at 630~650℃ for 45~53min to obtain wear-resistant hardface welding flux-cored wire.

[0011] Furthermore, the mass ratio of ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in step (1) is 5~8:2.0~2.8:3~5.5:9.5~11.1:12.6~13.9:50:1~3:3~6:1~2.

[0012] Furthermore, in step (1), the grinding is carried out to a mesh size of 150-200.

[0013] Furthermore, the thickness of the steel strip in step (2) is 0.25~0.40mm and the width is 7.5~12.5mm.

[0014] Furthermore, the diameter of the U-shaped groove in step (2) is 3.0~3.4mm.

[0015] Furthermore, step (3) involves drawing the material to a diameter of 2.0~2.8 mm.

[0016] Furthermore, the gas atmosphere in step (4) is titanium tetrachloride gas.

[0017] Furthermore, the titanium tetrachloride gas is prepared by heating liquid titanium tetrachloride and vaporizing it in a vaporization chamber, where the pressure is 10~30 kPa.

[0018] Furthermore, step (5) involves drawing the material to a diameter of 1.4~2.0 mm.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0020] The flux-cored welding wire prepared by this invention forms hard borides in the crystalline matrix of the cladding metal, thereby imparting high hardness to the cladding metal. Furthermore, boron carbide is distributed in the weld overlay, improving wear resistance. The cladding metal formed by the flux-cored welding wire prepared by this invention has good fluidity and does not require shielding gas during welding, thus saving costs. This invention encapsulates the powdered flux core in a steel shell, improving the corrosion resistance of the welding wire. The first drawing process allows the powder particles to bond together and form studded grain boundaries on the surface of the steel shell, refining the grains and improving the hard surface quality. Then, titanium diffusion treatment embeds titanium elements into the surface steel shell, improving the corrosion resistance of the skin and enhancing the rust prevention ability of the welding wire. A second drawing process further fuses the steel skin and titanium, further embedding them into the steel shell, improving the corrosion resistance and wear resistance of the welding wire. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0022] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride and molybdenum trioxide in a mass ratio of 5:2.0:3:9.5:12.6:50:1:3:1 and grind to 200 mesh to obtain core powder;

[0023] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0024] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed, drawn to a diameter of 2.6 mm, and annealed at 640℃ for 48 min to obtain the welding wire blank;

[0025] (4) Place the welding wire blank in the equipment and treat it at 930°C for 10 minutes in a titanium tetrachloride gas atmosphere to obtain pretreated welding wire;

[0026] (5) The pretreated welding wire is drawn to a diameter of 1.8 mm and annealed at 640°C for 48 min to obtain wear-resistant hardface welding flux-cored wire. Example 2

[0027] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 5.7:2.2:3.6:9.9:13.0:50:1.5:3.7:1.2 and grind to 200 mesh to obtain core powder;

[0028] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0029] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed, drawn to a diameter of 2.6 mm, and annealed at 640℃ for 48 min to obtain the welding wire blank;

[0030] (4) Place the welding wire blank in the equipment and treat it at 930°C for 20 minutes in a titanium tetrachloride gas atmosphere to obtain pretreated welding wire;

[0031] (5) The pretreated welding wire is drawn to a diameter of 1.8 mm and annealed at 640°C for 48 min to obtain wear-resistant hardface welding flux-cored wire. Example 3

[0032] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 6.5:2.4:4.3:10.3:13.2:50:2:4.5:1.5 and grind to 200 mesh to obtain core powder;

[0033] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0034] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed, drawn to a diameter of 2.6 mm, and annealed at 640℃ for 48 min to obtain the welding wire blank;

[0035] (4) Place the welding wire blank in the equipment and treat it at 940°C for 15 minutes in a titanium tetrachloride gas atmosphere to obtain pretreated welding wire;

[0036] (5) The pretreated welding wire is drawn to a diameter of 1.8 mm and annealed at 640°C for 48 min to obtain wear-resistant hardface welding flux-cored wire. Example 4

[0037] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 7.3:2.6:4.9:10.7:13.6:50:2.5:5.2:1.8 and grind to 200 mesh to obtain core powder;

[0038] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0039] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed, drawn to a diameter of 2.6 mm, and annealed at 640℃ for 48 min to obtain the welding wire blank;

[0040] (4) Place the welding wire blank in the equipment and treat it at 940°C for 15 minutes in a titanium tetrachloride gas atmosphere to obtain pretreated welding wire;

[0041] (5) The pretreated welding wire is drawn to a diameter of 1.8 mm and annealed at 640°C for 48 min to obtain wear-resistant hardface welding flux-cored wire. Example 5

[0042] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 8:2.8:5.5:11.1:13.9:50:3:6:2 and grind to 200 mesh to obtain core powder;

[0043] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0044] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed, drawn to a diameter of 2.6 mm, and annealed at 640℃ for 48 min to obtain the welding wire blank;

[0045] (4) Place the welding wire blank in the equipment and treat it at 950°C for 20 minutes in a titanium tetrachloride gas atmosphere to obtain pretreated welding wire;

[0046] (5) The pretreated welding wire is drawn to a diameter of 1.8 mm and annealed at 640°C for 48 min to obtain wear-resistant hardface welding flux-cored wire.

[0047] Comparative Example 1

[0048] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 8:2.8:5.5:11.1:13.9:50:3:6:2 and grind to 200 mesh to obtain core powder;

[0049] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0050] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed to obtain the welding wire blank;

[0051] (4) Place the welding wire blank in the equipment and treat it at 950°C for 20 minutes in a titanium tetrachloride gas atmosphere to obtain pretreated welding wire;

[0052] (5) The pretreated welding wire is drawn to a diameter of 1.8 mm and annealed at 640°C for 48 min to obtain wear-resistant hardface welding flux-cored wire.

[0053] Comparative Example 2

[0054] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 8:2.8:5.5:11.1:13.9:50:3:6:2 and grind to 200 mesh to obtain core powder;

[0055] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0056] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed, drawn to a diameter of 2.6 mm, and annealed at 640℃ for 48 min to obtain the welding wire blank;

[0057] (4) The pretreated welding wire is drawn to a diameter of 1.8 mm and annealed at 640°C for 48 min to obtain wear-resistant hardface welding flux-cored wire.

[0058] Comparative Example 3

[0059] (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 8:2.8:5.5:11.1:13.9:50:3:6:2 and grind to 200 mesh to obtain core powder;

[0060] (2) The steel strip is rolled into a U-shaped groove with a diameter of 3.2 mm; the thickness of the strip is 0.32 mm and the width is 10 mm;

[0061] (3) The core powder will be filled into the U-shaped groove, and then the U-shaped groove will be rolled and closed, drawn to a diameter of 1.8 mm, and annealed at 640℃ for 48 min to obtain the welding wire blank;

[0062] (4) Place the welding wire blank in the equipment and treat it at 950°C for 20 minutes in a titanium tetrachloride gas atmosphere to obtain wear-resistant hardface welding flux-cored wire.

[0063] Example of effect

[0064] Arc welding tests were conducted on the flux-cored welding wires prepared according to the preparation method of the present invention in Examples 1 to 5 above, as well as the flux-cored welding wires prepared in Comparative Examples 1 to 3. Various mechanical properties of the welded metal were measured. The hardness (HRC) was measured according to the national standard GB / T230.1-2004 "Metallic materials - Rockwell hardness test - Part 1: Test method", and the wear resistance was measured according to the national standard GB / 12444.1-1990 "Metallic materials - Wear test - M-type wear test". The results are shown in Table 1 below.

[0065] The welding process conditions are as follows:

[0066] Welded steel plate: Q235B type steel plate (350mm×150mm×20mm)

[0067] Welding method: Flat welding

[0068] Arc voltage: 25~28V

[0069] Welding current: 180~200A

[0070] Welding speed: 25cm / min

[0071] Wire feeding speed: 150cm / min

[0072] Table 1

[0073]

[0074] The flux-cored welding wire prepared by this invention forms hard borides in the crystalline matrix of the cladding metal, thereby imparting high hardness to the cladding metal. Furthermore, boron carbide is distributed in the weld overlay, improving wear resistance. The cladding metal formed by the flux-cored welding wire prepared by this invention has good fluidity and does not require shielding gas during welding, thus saving costs. This invention encapsulates the powdered flux core in a steel shell, improving the corrosion resistance of the welding wire. The first drawing process allows the powder particles to bond together and form studded grain boundaries on the surface of the steel shell, refining the grains and improving the hard surface quality. Then, titanium diffusion treatment embeds titanium elements into the surface steel shell, improving the corrosion resistance of the skin and enhancing the rust prevention ability of the welding wire. A second drawing process further fuses the steel skin and titanium, further embedding them into the steel shell, improving the corrosion resistance and wear resistance of the welding wire.

[0075] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a wear-resistant hardfacing flux-cored welding wire, characterized in that, The preparation steps include the following: (1) Mix ferrosilicon powder, chromium carbide, ferromanganese powder, nickel metal powder, borax, calcium carbonate, reduced iron powder, lanthanum fluoride, cerium fluoride, and molybdenum trioxide in a mass ratio of 5~8:2.0~2.8:3~5.5:9.5~11.1:12.6~13.9:50:1~3:3~6:1~2 and grind them to obtain core powder; (2) Roll the steel strip into a U-shaped groove; (3) The core powder will be filled into the U-shaped groove, then the U-shaped groove will be rolled and closed, drawn, and annealed at 630~650℃ for 45~53min to obtain the welding wire blank; (4) Place the welding wire blank in the equipment and treat it at 930~950℃ for 10~20 minutes in a gas atmosphere to obtain pretreated welding wire; (5) Pull out the pretreated welding wire and anneal it at 630~650℃ for 45~53min to obtain wear-resistant hardface welding flux-cored wire.

2. The method for preparing a wear-resistant hardfacing flux-cored welding wire according to claim 1, characterized in that, The grinding process described in step (1) involves grinding the material to a mesh size of 150-200.

3. The method for preparing a wear-resistant hardfacing flux-cored welding wire according to claim 1, characterized in that, The thickness of the steel strip in step (2) is 0.25~0.40mm and the width is 7.5~12.5mm.

4. The method for preparing a wear-resistant hardfacing flux-cored welding wire according to claim 1, characterized in that, The diameter of the U-shaped groove in step (2) is 3.0~3.4mm.

5. The method for preparing a wear-resistant hardfacing flux-cored welding wire according to claim 1, characterized in that, Step (3) involves drawing the material to a diameter of 2.0~2.8 mm.

6. The method for preparing a wear-resistant hardfacing flux-cored welding wire according to claim 1, characterized in that, The gas atmosphere in step (4) is titanium tetrachloride gas.

7. The method for preparing a wear-resistant hardfacing flux-cored welding wire according to claim 6, characterized in that, The titanium tetrachloride gas is prepared by heating liquid titanium tetrachloride and vaporizing it in a vaporization chamber at a pressure of 10~30 kPa.

8. The method for preparing a wear-resistant hardfacing flux-cored welding wire according to claim 1, characterized in that, Step (5) involves drawing the material to a diameter of 1.4~2.0 mm.

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