High-toughness high-manganese steel flux-cored wire for laser cladding and preparation method thereof

Abstract

The application discloses a high-toughness high-manganese steel flux-cored wire for laser cladding and a preparation method thereof. The flux-cored wire comprises a welding sheath and a core. The welding sheath is a low-carbon steel strip. The components of the core include Mn, C, Si, Mo, and the balance of Fe and inevitable impurities. The application removes the components for generating protective gas in the core, avoids leaving pores when the generated protective gas overflows from the molten pool, and avoids the oxidation of the coating by the protective gas device of the laser. The welding sheath is made of low-carbon steel, and the core is added with appropriate amounts of manganese and carbon elements, so that the composition ratio of the high-manganese steel can be maintained after the coating is subjected to melting, mixing and solidification, the wear resistance is maintained, and the interference of work hardening of the high-manganese steel sheath in production, transportation, processing and use on the laser cladding of the filler wire is avoided.

Description

TECHNICAL FIELD

[0001] The application relates to a flux-cored wire, in particular to a high-toughness high-manganese steel flux-cored wire for laser cladding and a preparation method thereof, and belongs to the technical field of laser cladding material preparation. BACKGROUND

[0002] With the development of science and technology and harsh working conditions, higher requirements are put forward for the wear resistance of metal equipment parts. Various laser cladding technologies for the purpose of manufacturing wear-resistant coatings have developed rapidly, among which, the wire filling laser cladding has an irreplaceable cost-effective advantage.

[0003] Laser cladding is an advanced metal product repair and surface modification technology. Specifically, a laser beam is used to irradiate a base material and a functional material, so that the molten functional material and the base material form a molten pool together, and finally a cladding coating with good metallurgical bonding and better performance is obtained. Wire filling laser cladding uses a wire-shaped functional material for cladding, which has high material utilization, good composition stability, little impact on equipment, and broad prospects. Among various wear-resistant materials, high-manganese steel is favored by wear-resistant coating manufacturers due to its low price and excellent heavy-load wear resistance.

[0004] In the prior art, a kind of ultra-low temperature high manganese steel welding wire, welding rod and its preparation method are disclosed in the patent with publication number CN113458654A. The welding wire greatly reduces the use of Ni, and through C, Mn, Cr, Mo alloying, the cladding metal formed by the welding material forms austenitic structure, producing excellent performance, saving Ni resources and reducing cost. The welding rod adds a special low-component coating to the welding wire to form a cladding metal that can fully meet the use requirements of liquefied natural gas storage tanks. However, existing high-manganese steel welding wires are often directly wrapped with a high-manganese steel sheath to produce a protective gas. On the one hand, existing high-manganese steel welding wires are often used in the electric welding industry, where the working environment is usually difficult to provide protection, so a self-generating protective gas core is needed. However, laser cladding requires rapid melting and rapid solidification, and the demand for oxidation prevention is high, so laser cladding equipment often has its own gas protection device. In this case, the effect of the protective gas generated by the welding wire itself will be very limited, and even when the protective gas generated by the core overflows from the molten pool, it will leave pores in the coating, greatly weakening the performance of the coating. On the other hand, the excellent work hardening capacity of high-manganese steel makes it difficult for existing welding wires that directly use high-manganese steel as a sheath to be stably filled into laser cladding. SUMMARY

[0005] The purpose of this invention is to solve at least one of the above-mentioned technical problems by providing a high-toughness high-manganese steel flux-cored welding wire for laser cladding and its preparation method.

[0006] The present invention achieves the above objectives through the following technical solution: a high-toughness high-manganese steel flux-cored welding wire for laser cladding, comprising a welding skin and a flux core, wherein the flux core is wrapped inside the welding skin;

[0007] The flux core of the low-carbon steel strip weld bead consists of Mn, C, Si, Mo, with the balance being Fe and unavoidable impurities. The flux core components are configured in the following two ways:

[0008] When the low-carbon steel strip of the welding coating is Q195 carbon structural steel, the flux core is composed of the following components by mass percentage: Mn: 36-44 wt%; C: 2-3.5 wt%; Si: 1-2 wt%; Mo: 0.5-1.5 wt%, with the balance being Fe and unavoidable impurities, and the sum of the above components is 100%.

[0009] When the low-carbon steel strip of the welding coating is Q235 carbon structural steel, the flux core is composed of the following components by mass percentage: Mn: 35~43wt%; C: 3~4wt%; Si: 0~1.5wt%; Mo: 0.5~1.5wt%; the balance is Fe and unavoidable impurities, and the sum of the above components is 100%.

[0010] As a further aspect of the present invention, the flux-cored wire has a flux-cored filling rate of 28-32 wt%.

[0011] As a further aspect of the present invention, the diameter of the flux-cored welding wire is φ1.0mm-φ3.0mm.

[0012] As a further embodiment of the present invention: the purity of Mn in the core is ≥99%, and the particle size is ≤0.3mm; the purity of C is ≥98%, and the particle size is ≤0.3mm; the purity of Si is ≥98%, and the particle size is ≤0.3mm; the purity of Mo is ≥99%, and the particle size is ≤0.3mm; the purity of Fe is ≥99%, and the particle size is ≤0.3mm.

[0013] As a further aspect of the present invention: after the flux-cored welding wire is subjected to filler wire laser cladding, the wear-resistant high-manganese steel coating produced has the following composition: Mn: 10-14wt%, C: 0.9-1.5wt%; Si: <1wt%; P: <0.05wt%; S: <0.05wt%; Mo: 0.15-0.45wt%; the balance being iron and unavoidable impurities.

[0014] A method for preparing a high-toughness, high-manganese steel flux-cored welding wire for laser cladding, comprising the flux-cored welding wire, the method including the following steps:

[0015] S1. When the low-carbon steel strip of the weld bead is preferably made of Q195 carbon steel, the following raw material powders shall be weighed according to the following mass percentages: Mn: 42-44%; C: 2-3.5%; Si: 1-2%; Mo: 0.5-1.5%, with the balance being Fe and unavoidable impurities. The sum of the above components shall be 100%.

[0016] S2. When the low-carbon steel strip of the weld bead is preferably made of Q235 carbon steel, the following raw material powders shall be weighed according to the following mass percentages: Mn: 40-43%; C: 3-4%; Si: 1-2%; Mo: 0.5-1.5%, with the balance being Fe and unavoidable impurities. The sum of the above components shall be 100%.

[0017] S3. Place the raw material powder weighed in S1 into a vacuum heating furnace and heat it to remove the water of crystallization from the raw material; after drying, use a powder mixer to mix the raw material powder thoroughly to obtain the core.

[0018] S4. Use alcohol to remove the grease from the surface of the carbon steel strip in S1, and use a flux-cored wire drawing device to wrap the flux core prepared in S2 inside the steel strip to form a process flux-cored wire.

[0019] S5. Perform the first drawing of the flux-cored welding wire in the process;

[0020] S6. After the first drawing process is completed, repeat the drawing process multiple times to gradually reduce the diameter of the flux-cored wire until a flux-cored wire with a diameter of 1.0-3.0 mm is obtained.

[0021] S7, and then the workpieces that meet the size requirements in S6 are wound in layers to obtain the formed high manganese steel welding wire.

[0022] As a further aspect of the present invention: in S7, the high-manganese steel welding wire prepared is used in laser cladding applications and requires external application of protective gas.

[0023] As a further aspect of the present invention, the protective gas is high-purity argon.

[0024] As a further aspect of the present invention, high manganese steel welding wire is suitable for the repair, surface modification, and additive manufacturing of easily worn parts of various crushers, high manganese steel rails, turnouts, and bulldozers subjected to impact.

[0025] The beneficial effects of this invention are:

[0026] 1) This invention ensures the toughness of the welding wire through the rational allocation of elements, reduces the interference of the welding wire's own hardening on the laser cladding of the filler wire, and ensures that the generated metal coating is a high-manganese steel wear-resistant coating. Furthermore, it removes the components in the flux core used to generate gas, reducing porosity;

[0027] 2) This invention removes the components that generate protective gas in the flux core, thus preventing the protective gas from overflowing from the molten pool and leaving pores. The protective gas device built into the laser can prevent coating oxidation. Furthermore, the use of low-carbon steel to make the weld skin and the addition of appropriate amounts of manganese and carbon elements to the flux core ensure that the coating can maintain the composition ratio of high-manganese steel after melting, mixing, and solidification, thereby maintaining its wear resistance. At the same time, it avoids the interference of work hardening generated during the production, transportation, processing, and use of high-manganese steel weld skin on the filler wire laser cladding. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the cross-sectional structure of the flux-cored welding wire of the present invention;

[0029] In the diagram: 1. Steel strip; 2. Flux core. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1, as Figure 1 As shown, this embodiment provides a high-toughness high-manganese steel flux-cored welding wire for laser cladding, including a welding skin 1 and a flux core 2, wherein the flux core 2 is wrapped inside the welding skin 1;

[0032] The weld skin 1 is a low-carbon steel strip, and the composition of the flux core 2 includes Mn, C, Si, Mo, with the balance being Fe and unavoidable impurities;

[0033] The low-carbon steel strip of the welding skin 1 is Q235 carbon structural steel. The flux core 2 is composed of the following components by mass percentage: Mn: 35-43wt%; C: 3-4wt%; Si: 0-1.5wt%; Mo: 0.5-1.5wt%; with the balance being Fe and unavoidable impurities. The sum of the above components is 100%.

[0034] Example 2: This example provides a high-toughness high-manganese steel flux-cored welding wire for laser cladding, including a welding skin 1 and a flux core 2, wherein the flux core 2 is wrapped inside the welding skin 1;

[0035] The weld skin 1 is a low-carbon steel strip, and the composition of the flux core 2 includes Mn, C, Si, Mo, with the balance being Fe and unavoidable impurities;

[0036] When the low-carbon steel strip of the welding skin 1 is Q235 carbon structural steel, the flux core 2 is composed of the following components by mass percentage: Mn: 35~43wt%; C: 3~4wt%; Si: 0~1.5wt%; Mo: 0.5~1.5wt%; the balance is Fe and unavoidable impurities, and the sum of the above components is 100%.

[0037] In addition to all the technical features included in Embodiment 1, this embodiment also includes:

[0038] The flux-cored wire has a flux-cored filling rate of 28-32 wt%.

[0039] The diameter of the flux-cored welding wire is φ1.0mm-φ3.0mm.

[0040] The purity of Mn in core 2 is ≥99%, and the particle size is ≤0.3mm; the purity of C is ≥98%, and the particle size is ≤0.3mm; the purity of Si is ≥98%, and the particle size is ≤0.3mm; the purity of Mo is ≥99%, and the particle size is ≤0.3mm; the purity of Fe is ≥99%, and the particle size is ≤0.3mm.

[0041] After the flux-cored welding wire is filled with filler wire and laser cladding, the wear-resistant high-manganese steel coating produced has the following composition: Mn: 10-14wt%, C: 0.9-1.5wt%; Si: <1wt%; P: <0.05wt%; S: <0.05wt%; Mo: 0.15-0.45wt%; the balance is iron and unavoidable impurities.

[0042] It should be noted that,

[0043] Mn: To ensure the performance of high-manganese steel, a sufficient manganese content is necessary. If the manganese content is too low, a single austenitic structure cannot be formed. The final Mn content of the high-manganese steel welding wire of this invention is 10-14 wt%, which meets the requirements for producing a single austenitic high-manganese steel coating.

[0044] Carbon (C) is the element that most significantly improves the strength and hardness of steel. When the carbon content in steel is too low, it is insufficient to produce an effective work hardening effect; while when the carbon content is too high, a large amount of carbides, especially coarse carbides, will appear in the as-cast state. Therefore, to avoid carbide precipitation, the carbon content must be controlled to prevent it from becoming too high. The high-manganese steel coating produced by the high-manganese steel welding wire of this invention has a final C content of 0.9-1.5 wt%. Within this range, the C content in the flux core can be appropriately adjusted to meet specific requirements.

[0045] Si: Si and Mn have a combined deoxidizing effect, which can reduce the oxygen content in metal coatings and prevent the formation of pores. Si reduces the solubility of carbon in austenite, promotes the precipitation of carbides, and reduces the wear resistance and impact toughness of steel. Therefore, the silicon content should be controlled at the lower limit of the specification.

[0046] Mo: Mo can inhibit the precipitation of carbides in steel. The addition of Mo to high manganese steel welding wire can improve the crack resistance and wear resistance of the coating.

[0047] P and S: P reduces the impact toughness of steel and makes castings prone to cracking, while S increases the corrosivity of steel and reduces its ductility and toughness. Therefore, the P and S content in steel should be minimized. This invention ensures that the P and S content in the resulting metal coating is within the lower limit of the specification by reducing the P and S content in both parts of the welding wire—the weld skin and the flux core, i.e., S < 0.05 wt%, P < 0.05 wt%.

[0048] Example 3: A method for preparing a high-toughness, high-manganese steel flux-cored welding wire for laser cladding, comprising the flux-cored welding wire, the preparation method including the following steps:

[0049] S1. When the low-carbon steel strip of weld skin 1 is preferably made of Q195 carbon steel, the following raw material powders shall be weighed according to the following mass percentages: Mn: 42-44%; C: 2-3.5%; Si: 1-2%; Mo: 0.5-1.5%, with the balance being Fe and unavoidable impurities, and the sum of the above components shall be 100%.

[0050] S2. When the low-carbon steel strip of weld skin 1 is preferably made of Q235 carbon steel, the following raw material powders shall be weighed according to the following mass percentages: Mn: 40-43%; C: 3-4%; Si: 1-2%; Mo: 0.5-1.5%, with the balance being Fe and unavoidable impurities, and the sum of the above components shall be 100%.

[0051] S3. Place the raw material powder weighed in S1 into a vacuum heating furnace and heat it to remove the water of crystallization in the raw material; after drying, use a powder mixer to mix the raw material powder thoroughly to obtain the core 2.

[0052] S4. Use alcohol to remove the grease from the surface of the carbon steel strip in S1, and use a flux-cored wire drawing device to wrap the flux core 2 prepared in S2 inside the steel strip to form a flux-cored wire.

[0053] S5. Perform the first drawing of the flux-cored welding wire in the process;

[0054] S6. After the first drawing process is completed, repeat the drawing process multiple times to gradually reduce the diameter of the flux-cored wire until a flux-cored wire with a diameter of 1.0-3.0 mm is obtained.

[0055] S7, and then the workpieces that meet the size requirements in S6 are wound in layers to obtain the formed high manganese steel welding wire.

[0056] The high-manganese steel welding wire prepared for laser cladding applications requires the application of an external protective gas, which is high-purity argon. This removes the components of the protective gas that are generated in the flux core 2, and instead uses an external protective gas, thus preventing the gas generated in the flux core 2 from overflowing from the molten pool and leaving pores.

[0057] High manganese steel welding wire is suitable for the repair, surface modification, and additive manufacturing of easily worn parts of various crushers, high manganese steel rails, turnouts, and bulldozers subjected to impact. It has a wide range of applications and can meet different usage needs.

[0058] The welding wire comprises two parts: a welding skin 1 and a flux core 2. Low-carbon steel is selected as the welding skin material, avoiding the direct use of high-manganese steel. By controlling the composition of the flux core 2, a high-toughness high-manganese steel flux-cored welding wire for laser cladding, suitable for manufacturing high-manganese steel wear-resistant coatings, has been achieved. The self-generated shielding gas component in the flux core 2 has been removed, and an external shielding gas is used instead, preventing the gas generated by the flux core 2 from escaping from the molten pool and leaving porosity. Low-carbon steel has good toughness and weak work hardening ability, avoiding the impact of high-manganese steel welding skin work hardening on the stability and accuracy of filler wire laser cladding.

[0059] 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 reference numerals in the claims should be construed as limiting the scope of the claims.

[0060] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high-toughness high-manganese steel flux-cored welding wire for laser cladding, comprising a welding sheath (1) and a flux core (2), wherein the flux core (2) is encased within the welding sheath (1); characterized in that: The weld skin (1) is a low-carbon steel strip, and the composition of the flux core (2) includes Mn, C, Si, Mo, with the balance being Fe and unavoidable impurities; The filling rate of the core (2) is 28-32 wt%; The components of the core (2) include the following two types: When the low-carbon steel strip of the weld skin (1) is Q195 carbon structural steel, the flux core (2) is composed of the following components by mass percentage: Mn: 36-44 wt%; C: 2-3.5 wt%; Si: 1-2 wt%; Mo: 0.5-1.5 wt%, with the balance being Fe and unavoidable impurities, and the sum of the above components is 100%. When the low-carbon steel strip of the weld skin (1) is Q235 carbon structural steel, the flux core (2) is composed of the following components by mass percentage: Mn: 35-43wt%; C: 3-4wt%; Si: 0-1.5wt%; Mo: 0.5-1.5wt%; the balance is Fe and unavoidable impurities, and the sum of the above components is 100%.

2. The high-toughness high-manganese steel flux-cored welding wire for laser cladding according to claim 1, characterized in that: The diameter of the flux-cored welding wire is φ1.0mm-φ3.0mm.

3. The high-toughness high-manganese steel flux-cored welding wire for laser cladding according to claim 1, characterized in that: The core (2) has the following properties: Mn purity ≥ 99%, particle size ≤ 0.3 mm; C purity ≥ 98%, particle size ≤ 0.3 mm; Si purity ≥ 98%, particle size ≤ 0.3 mm; Mo purity ≥ 99%, particle size ≤ 0.3 mm; Fe purity ≥ 99%, particle size ≤ 0.3 mm.

4. The high-toughness high-manganese steel flux-cored welding wire for laser cladding according to claim 1, characterized in that: The wear-resistant high-manganese steel coating produced by laser cladding of the flux-cored welding wire has the following composition: Mn: 10-14wt%, C: 0.9-1.5wt%, Si: <1wt%. P: <0.05wt% S: <0.05wt%; Mo: 0.15-0.45wt%; balance is iron and unavoidable impurities.

5. A method for preparing a high-toughness, high-manganese steel flux-cored welding wire for laser cladding, comprising methods for preparing the flux-cored welding wire according to any one of claims 1-4, characterized in that: The preparation method includes the following steps: S1. When the low-carbon steel strip of the weld skin (1) is made of Q195 carbon steel, the following raw material powders are weighed according to the mass percentage: Mn: 42-44%; C: 2-3.5%; Si: 1-2%; Mo: 0.5-1.5%, with the balance being Fe and unavoidable impurities. The sum of the above components is 100%. When the low-carbon steel strip of the weld bead (1) is made of Q235 carbon steel, the following raw material powders are weighed according to the mass percentage: Mn: 40-43%; C: 3-4%; Si: 0-1.5%; Mo: 0.5-1.5%, with the balance being Fe and unavoidable impurities. The sum of the above components is 100%. S2. Place the raw material powder weighed in S1 into a vacuum heating furnace and heat it to remove the water of crystallization in the raw material; after drying, use a powder mixer to mix the raw material powder thoroughly to obtain the core (2). S3. Use alcohol to remove the grease from the surface of the carbon steel strip in S1, and wrap the flux core (2) prepared in S2 inside the steel strip using a flux core wire drawing device to form a flux core wire. S4. Perform the first drawing of the flux-cored welding wire in the process; S5. After the first drawing process is completed, repeat the drawing process multiple times to gradually reduce the diameter of the flux-cored wire until a flux-cored wire with a diameter of 1.0-3.0 mm is obtained. S6, and then the workpieces that meet the size requirements in S5 are wound in layers to obtain the formed high manganese steel flux-cored welding wire.

6. The application of the high-manganese steel flux-cored welding wire manufactured according to the preparation method of claim 5, characterized in that: The high-manganese steel flux-cored welding wire prepared for laser cladding applications requires the application of a protective gas from the outside.

7. The application of the high-manganese steel flux-cored welding wire manufactured according to the preparation method of claim 6, characterized in that: The protective gas is high-purity argon.

8. The application of the high-manganese steel flux-cored welding wire manufactured according to the preparation method of claim 7, characterized in that: The high-manganese steel flux-cored welding wire is suitable for the repair, surface modification, and additive manufacturing of easily worn parts of various crushers, high-manganese steel rails, turnouts, and bulldozers subjected to impact.

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