High-manganese steel welding wire for repairing high-manganese steel frog and full-automatic efficient welding method

Abstract

The invention relates to the technical field of welding repair, in particular to a high-manganese steel welding wire for high-manganese steel frog repair and a full-automatic efficient welding method. The invention discloses a high-manganese steel welding wire for repairing a high-manganese steel frog. The high-manganese steel welding wire comprises the following chemical components in percentage by weight: 0.35 to 1.3 percent of C, 0.8 to 2.0 percent of Si, 22 to 35 percent of Mn, 0.5 to 5.0 percent of Mo, 0.05 to 2.0 percent of V, 0.2 to 0.6 percent of N, 0.05 to 0.15 percent of Nb, 0.05 to 0.1 percent of Ce, less than or equal to 0.002 percent of P, less than or equal to 0.002 percent of S and the balance of Fe. The element content of the proper components ensures that the deposited metal meets the strength, hardness and toughness required by frog service, and the relative balance of the three properties is achieved, so that the excellent impact wear resistance is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of welding repair, in particular to a high-manganese steel welding wire and a full-automatic and efficient welding method for repairing a high-manganese steel frog. Background Art

[0002] High-manganese steel frogs are core components of track-changing equipment on railway lines. The large distance between the frog's center rail and the wing rails puts significant pressure on the frog's center rail during track changes, leading to failures such as collapse, wear, and cracks, ultimately rendering the frog useless. Repairing damaged high-manganese steel frogs with welding can extend their service life and the replacement cycle of turnouts, effectively reducing the manpower, material, and financial resources associated with turnout replacement, thereby lowering line maintenance and operating costs. This is an effective cost-saving and energy-saving measure for line maintenance. Appropriate repair welding materials and welding processes are key to this technology.

[0003] In the prior art, laser cladding and wire welding are the main methods for repairing high-manganese steel frogs. However, the equipment and materials for laser cladding are relatively expensive, while the wire currently used for wire welding suffers from insufficient wear resistance after welding. For example, prior art CN115722846A discloses a method and system for repairing high-manganese steel frogs. The chemical composition and weight percentage of the manganese-chromium-nickel-molybdenum flux-cored self-shielded welding wire disclosed herein include the following characteristics: C: ≤0.6%; Si: ≤0.6%; Mn: 11%-18%; Cr: 2.0%-6.0%; Ni: ≤5.0%; Mo: ≤3.0%; S: ≤0.035%; and P: ≤0.035%. The mechanical properties and hardness of the deposited metal meet the following requirements: tensile strength ≥600 MPa, elongation after fracture ≥22%, impact energy absorption (room temperature) ≥47 J, hardness before hardening ≥180 HB, and hardness after hardening ≥40 HRC. The wear resistance of the deposited metal is related to its hardness, yield strength and toughness. After hardening, its hardness is too high, but its impact absorption energy is relatively small, resulting in a mismatch between the material's strength, hardness and toughness, causing its poor wear resistance and stability to be improved. In addition, this technology also has technical problems such as complex equipment and high cost. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned shortcomings of the prior art and propose a high-manganese steel welding wire and a fully automatic and efficient welding method for repairing high-manganese steel frogs, which can achieve good metallurgical bonding with the existing high-manganese steel frogs, achieve a relative balance between strength, hardness and impact toughness, and thus achieve good impact wear performance.

[0005] The first object of the present invention is to provide a high-manganese steel welding wire for repairing high-manganese steel frogs, wherein the chemical composition of the high-manganese steel welding wire is as follows: C is 0.35-1.3wt%, Si is 0.8-2.0%, Mn is 22-35wt%, Mo is 0.5-5.0wt%, V is 0.05-2.0wt%, N is 0.2-0.6wt%, Nb is 0.05-0.15wt%, Ce is 0.05-0.1wt%, P is less than or equal to 0.002wt%, S is less than or equal to 0.002wt%, and the remainder is Fe.

[0006] A second object of the present invention is to provide a fully automatic and efficient welding method for repairing a high manganese steel frog, characterized in that the above-mentioned high manganese steel welding wire is used, and the specific steps are as follows: S1: Derusting the steel wire rod that meets the above-mentioned high manganese steel welding wire composition, drawing it to a diameter of 1.2 mm, and then straightening, cutting it, and cleaning the surface oil to obtain the welding wire; S2: Grind and remove oil, rust and other dirt from the frog surface, ensure that the frog surface is smooth and flat, and clamp and fix the frog steel plate; S3: Set welding current, welding voltage, welding speed, and shielding gas according to material properties, determine the frog repair location and path, and perform fully automatic surfacing welding on the frog.

[0007] Furthermore, the welding current was set at 160-250 A, the welding voltage at 16-24 V, the welding speed at 40-60 cm / min, and the wire feed speed at 6-16 mm / s. CO2+Ar shielding gas was used. Heat input is a key factor influencing the quality of the deposited metal during high-manganese steel welding. While high-manganese steel possesses mechanical properties such as high toughness and a high work-hardening rate, its low thermal conductivity and high coefficient of thermal expansion significantly increase the risk of cracking due to weld deformation. Therefore, parameters influencing heat input, such as welding speed, current, voltage, and wire feed speed, must be strictly controlled.

[0008] Welding speed directly affects heat input and the quality of the deposited metal. If the welding speed is too slow, prolonged exposure to high temperatures can lead to the precipitation of large amounts of carbides in the heat-affected zone, exacerbating microstructure embrittlement. However, if the welding speed is too fast, it can cause poor fusion or defects in the deposited metal. Therefore, when welding high-manganese steel wire, the welding speed should be controlled within the range of 40-60 cm / min. The welding current is related to the wire diameter. The diameter of the high-manganese steel wire used in this invention is 1.2 mm. Excessively high current can cause localized overheating of the deposited metal, increasing susceptibility to thermal cracking. Excessively low current provides insufficient energy for stable melting of the wire, so the welding current is set between 160 and 250 A. Arc voltage is adjusted to match the welding current, typically between 16 and 24 V. The wire feed speed must be matched to the welding current, voltage, and speed to ensure a balance between the wire melting rate and the weld pool filling requirements. Feeding too slowly can result in insufficient weld pool filling, resulting in a depression in the deposited metal or incomplete fusion. Feeding too quickly can cause incomplete wire penetration or disrupted droplet transfer. The optimized wire feed speed range is 6-16 mm / s. Shielding gas is also a key factor influencing the formation of the deposited metal in high-manganese steel. Carbon dioxide has a certain oxidizing property. Mixing some carbon dioxide into argon can improve droplet transfer, increase arc energy density, and improve welding speed and penetration.

[0009] Furthermore, during the welding process, pulse current is used to change the traditional current characteristics.

[0010] Furthermore, the protective gas is 80%-98% Ar+2%-20% CO2.

[0011] Furthermore, in S3, fully automatic surfacing is performed, and the interlayer temperature is controlled below 100°C.

[0012] Furthermore, in S3, 4 layers are built up, with 3 passes in each layer.

[0013] Furthermore, the welding equipment includes: ABB robotic arm, Fronius welding machine, Fronius welding gun, and Fronius wire feeder.

[0014] The deposited metal produced by the welding wire and welding process of the present invention forms a good metallurgical bond with the frog steel base material. The metallographic structure of the deposited metal formed by the welding wire is entirely austenitic. The deposited metal of the welding wire has a hardness of ≥240 HV1, a yield strength of 448-495 MPa, a tensile strength of 664-745 MPa, an elongation after fracture of 38-50.5%, and a room temperature impact toughness of 140-180 J / cm 2 Compared with frog steel base metal under any impact load and impact number, the wear amount of the deposited metal of the present invention is lower than that of the frog steel base metal, and its impact wear resistance is significantly better than that of the frog steel base metal.

[0015] The present invention significantly reduces the use of precious alloying elements, simplifies the alloy composition system, and reduces the manufacturing cost of welding materials. The fully automatic welding process proposed by the present invention has simple equipment and can achieve higher welding efficiency and more stable and reliable deposited metal quality.

[0016] The key technical points and beneficial effects of the present invention are: 1. The high manganese steel welding wire of the present invention is mainly composed of C, Mn and other alloying elements. The appropriate C element content ensures a good metallurgical bonding between the welding material and the high manganese steel frog steel base material. By increasing the content of the Mn element and the Si element, a synergistic effect is produced with the C element to improve the strength and hardness of the deposited metal, and by increasing the content of the Mn element, the toughness of the material is improved. By adding the V element, on the one hand, the vanadium element can synergistically act with the nitrogen element to produce a nano-precipitated phase V (C, N). The nano-precipitated phase is dispersed in the deposited metal, which can not only improve the initial hardness and strength of the material, but also cause the material to produce a continuous work hardening effect. On the other hand, On the one hand, vanadium (V) interacts with cerium (Ce), molybdenum (Mo), and niobium (Nb) to change the morphology of inclusions in the deposited metal, thereby improving the toughness of the deposited metal. The added niobium element can also refine the grains, improve the deposited metal structure, and form fine and dispersed NbC during the welding process. NbC particles act as non-uniform cores, promoting the generation of fine grains and improving the strength and toughness of the deposited metal. Increasing the content of the Mo element causes the deposited metal to form a higher density of deformation twins, exhibiting high strength and high elongation. In addition, the Mo element can also interact with the C element to form dispersed MoC particles, increasing the initial hardness and strength of the deposited metal. In summary, the element content of the appropriate components of the present invention ensures that the deposited metal meets the strength, hardness, and toughness required for frog service, and achieves a relative balance of the three properties to achieve excellent impact wear performance.

[0017] 2. This invention utilizes Fronius fully automatic welding equipment, which meets the requirements for controlling welding heat input, shielding gas, and current characteristics during the fully automatic welding process. This results in high welding efficiency and stable post-weld quality, avoiding the problem of large variations in the service life of the deposited metal.

[0018] 3. The present invention develops welding process parameters that match high manganese steel welding wire and welding equipment, and uses pulse current to change traditional current characteristics. Therefore, the present invention has the advantages of good formability of deposited metal, low sensitivity to thermal cracks, and high hardness of deposited metal.

[0019] The following is a brief explanation of the properties of each alloying element and the critical significance of the composition range.

[0020] C: Carbon not only expands the austenite phase, but also acts as an interstitial solid solution element. Carbon dissolved in the austenite lattice causes significant lattice distortion, hindering dislocation motion and increasing the strength of the steel. The carbon content should not be too low. High-manganese frog steel contains approximately 1.1wt% carbon. A significant difference in carbon content between the welding wire and the base metal can lead to uneven element distribution in the fusion zone during welding, compromising metallurgical bond strength. The carbon content should also be kept within a reasonable range, as a high carbon content increases the material's susceptibility to hot cracking. Therefore, to ensure a good metallurgical bond between the welding material and the base metal, carbon atoms should be added to enhance the strength of the deposited metal. Carbon, silicon, and manganese are all solid solution elements, so carbon can synergistically enhance the strength and hardness of the deposited metal with silicon and manganese. The carbon content in the welding wire should be controlled between 0.35wt% and 1.3wt%.

[0021] Si: Silicon can produce a solid solution strengthening effect, causing the lattice of steel to be distorted and hindering the movement of dislocations, thereby improving the ability of steel to resist deformation. At the same time, it can also improve the strength and hardness of steel materials and enhance the material's resistance to impact and wear. However, too high a silicon content may reduce the dissolution of carbon in austenite and form a large amount of carbides, which increases the brittleness of the material; in addition, a high silicon content will also increase the difficulty of smelting welding wire and reduce welding processability. Therefore, in order to enable silicon to play a role in improving the strength of the deposited metal while avoiding reducing the operational processability or increasing the difficulty of smelting the welding wire, the silicon content in the welding wire of the present invention is controlled at 0.8wt%-2.0wt%.

[0022] Mn: Manganese can expand the austenite phase area, stabilize the austenite structure, and keep the room temperature structure of high manganese steel as a single stable austenite structure. The maximum wear resistance of high manganese steel increases with the increase of manganese content, and moves towards high impact loads. However. If the manganese content is too high, it will not only reduce the toughness of the deposited metal, but also increase its thermal expansion coefficient. In addition, the manganese content of the frog steel base material is about 13wt%. The difference in manganese content between the weld and the base material is too large, causing cracks at the fusion line between the weld and the frog steel base material. Try to increase the manganese content in the deposited metal as much as possible without affecting the metallurgical bonding between the weld and the frog steel base material. In addition, manganese can also produce a synergistic effect with silicon to jointly deoxidize and reduce the oxygen content in the deposited metal to improve the comprehensive mechanical properties. Therefore, the manganese mass fraction of the welding wire of the present invention is 22wt%-35wt%.

[0023] Mo: Molybdenum can refine the grain size of high manganese steel. During the deformation process, Mo is more likely to activate twins, forming higher density deformation twins, showing high strength and high elongation. High manganese steel itself has a strong work hardening ability. Adding alloy Mo elements to high manganese steel can make high manganese steel form a hardened surface with high hardness and a deeper strain layer, showing better wear resistance. However, too high a molybdenum content will cause a large amount of large-sized carbides to precipitate, which will greatly increase the strength of the material and greatly reduce the toughness, resulting in a mismatch between material strength and toughness, and will also increase the manufacturing cost of the welding rod. Therefore, the molybdenum content of the welding wire of the present invention is controlled at 0.5wt%-5.0wt%.

[0024] V: Vanadium is a strong carbide-forming element. Its affinity for carbon is stronger than that of iron, making it more susceptible to the formation of carbides such as vanadium carbide. Vanadium carbide particles dispersed in austenite significantly increase the hardness of high-manganese steel. However, excessive vanadium can still reduce the toughness of the deposited metal, resulting in a mismatch between strength and toughness, and reducing the reliability of the deposited metal's mechanical properties. Furthermore, vanadium can synergize with nitrogen to form nano-precipitates of V(C,N). Dispersed in the deposited metal, these nano-precipitates hinder dislocation motion, causing dislocation pile-up and increasing the initial hardness and strength of the deposited metal during service. Furthermore, they inhibit the formation of deformation twins, increasing the critical stress for deformation twinning and encouraging the formation of deformation twins under greater stresses, thereby achieving continuous work hardening. However, excessive vanadium content can form network carbides, increasing the brittleness of the deposited metal and deteriorating its impact wear resistance. Therefore, the vanadium content of the welding wire of the present invention is controlled at 0.05wt%-2.0wt%, and the nitrogen content is controlled at 0.2wt%-0.6wt%.

[0025] Nb: Niobium can refine the grains, improve the deposited metal structure, and form fine and dispersed NbC during the welding process. The NbC particles act as non-uniform cores to promote the formation of fine grains and improve the strength and toughness of the deposited metal. Niobium dissolved in the matrix can increase the resistance to dislocation movement, causing the surface of the deposited metal to undergo work hardening during wear, further improving wear resistance. Niobium alloyed metals are more suitable for impact wear and alternating load conditions. If the niobium content is too high, coarse NbC particles or network carbides may be formed, reducing the toughness of the deposited metal and causing the wear resistance of the material to decrease due to brittle peeling. Excessive niobium may also interact with other alloying elements to cause element segregation and weaken the strengthening effect. Therefore, the niobium element in the welding wire of the present invention is controlled at 0.05wt%-0.15wt%.

[0026] Ce: The rare earth element cerium has a strong affinity with sulfur and oxygen, reducing the content of harmful elements in the deposited metal and minimizing the tendency to thermal cracking and porosity. Cerium also interacts with other alloying elements (molybdenum, vanadium, and niobium) to improve inclusion morphology and toughness in the deposited metal. Evenly distributed rare earth compounds increase the hardness of the deposited metal and reduce the surface friction coefficient, thereby improving the material's impact and wear resistance. However, excessive cerium content can form large rare earth phases or inclusions, reducing toughness and potentially causing material spalling during impact wear. Furthermore, cerium is a rare earth element with extremely high chemical activity. Therefore, the cerium content in the welding wire of this invention is controlled to 0.05wt%-0.10wt%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a macroscopic image of single-pass thin-wall molding; Figure 2 Schematic diagram of sampling for mechanical properties of a single thin-wall; Figure 3 A picture of the metallographic structure of the deposited metal formed by the welding wire; Figure 4 This is a macroscopic diagram of the surfacing wall; Figure 5 Graph showing the variation of wear of deposited metal and frog steel base metal with impact times under different loads in Example 1; Figure 6 This is a graph showing how the wear of the deposited metal and frog steel base material in Comparative Example 1 changes with the number of impacts under different loads. DETAILED DESCRIPTION

[0028] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0029] The element contents in the welded frog in the embodiment are: C: 1.06-1.13 wt%, Mn: 12.64-12.67 wt%, Si: 0.58-0.62 wt%, P: 0.031-0.032 wt%, and S: 0.010-0.012 wt%.

[0030] Example 1 A fully automatic and efficient welding method for repairing high manganese steel frogs comprises the following steps: The composition of high manganese steel welding wire is: C 0.35wt%, Si 0.8%, Mn 35wt%, Mo 0.5wt%, V 0.05wt%, N 0.2wt%, Nb 0.05wt%, Ce 0.05wt%, P≤0.002wt%, S≤0.002wt%, and the rest is Fe.

[0031] Step 1: Derust the steel wire rod that meets the above-mentioned high manganese steel welding wire composition, draw it to a diameter of 1.2 mm, and then straighten, cut it, and remove the surface oil stains to obtain the welding wire.

[0032] Step 2: Grind to remove oil, rust and other dirt from the frog surface, ensure that the frog surface is smooth and flat, and clamp and fix the frog steel plate.

[0033] Step 3: Set the welding current, welding voltage, welding speed, and shielding gas according to the material properties, and conduct trial welding on the frog steel plate to determine the welding process parameters. The welding current is set to 236-250A, the welding voltage is 16.4-17.6V, the welding speed is 40-60cm / min, the wire feeding speed is 9.9-10.7mm / s, and the welding adopts 98%Ar+2%CO2 as the shielding gas with a gas flow rate of 15L / min. During the welding process, pulse current is used to change the traditional current characteristics. Among them, the macro diagram of thin-wall forming during the trial welding process is shown as follows Figure 1 shown.

[0034] Step 4: Determine the repair position and path of the frog, and perform full-automatic surfacing welding on the frog (4 layers, 3 passes per layer), below 100℃, and the wall after welding should be as Figure 4 shown.

[0035] According to the standards GB / T 228.1-2021 and GB / T 229-2020, the deposited metal was subjected to micro-tensile and Charpy pendulum impact tests respectively. Figure 2 Schematic diagram of sampling.

[0036] According to the standard T / CFA010604.05-2017 (including sampling and parameter setting), the impact wear test was carried out on the cladding specimens.

[0037] The deposited metal using the welding wire and welding process of the embodiment can form a good metallurgical bond with the frog steel base material. The metallographic structure of the deposited metal formed by the welding wire is all austenitic. Figure 3 The weld metal hardness of the welding wire is ≥240HV1, the yield strength is 448 MPa, the tensile strength is 664 MPa, the elongation after fracture is 50.5%, and the room temperature impact toughness is 180 J / cm 2 .

[0038] Compared with frog steel base metal under the same impact wear test conditions, the wear amount of deposited metal is lower than that of frog steel base metal under any impact load and impact number, and its impact wear resistance is significantly better than that of frog steel base metal.

[0039] Example 2 A fully automatic and efficient welding method for repairing a high-manganese steel frog. The high-manganese steel welding wire comprises the following components: C: 0.65 wt%, Si: 0.8%, Mn: 22.4 wt%, Mo: 2.0 wt%, V: 1.0 wt%, N: 0.3 wt%, Nb: 0.07 wt%, Ce: 0.07 wt%, P: ≤ 0.002 wt%, S: ≤ 0.002 wt%, and the remainder: Fe.

[0040] The rest is the same as Example 1.

[0041] The deposited metal produced by the welding wire and welding process of the present invention forms a good metallurgical bond with the frog steel base material. The metallographic structure of the deposited metal formed by the welding wire is entirely austenitic. The deposited metal of the welding wire has a hardness of ≥240 HV1, a yield strength of 485 MPa, a tensile strength of 705 MPa, an elongation after fracture of 45.5%, and a room temperature impact toughness of 165 J / cm 2 Under the same impact wear test conditions, the wear of the deposited metal is lower than that of the frog steel base metal under any impact load and impact number. Its impact wear resistance is significantly better than that of the frog steel base metal. The results are as follows: Figure 5 As shown in (a)-(c).

[0042] Example 3 A high-manganese steel welding wire for repairing a high-manganese steel frog comprises the following chemical components: 1.15 wt% C, 0.8% Si, 29 wt% Mn, 5.0 wt% Mo, 2.0 wt% V, 0.6 wt% N, 0.15 wt% Nb, 0.1 wt% Ce, P≤0.002 wt%, S≤0.002 wt%, and the remainder being Fe.

[0043] The rest is the same as Example 1.

[0044] The deposited metal produced using the welding wire and welding process of the embodiment can form a good metallurgical bond with the frog steel base material. The metallographic structure of the deposited metal formed by the welding wire is entirely austenitic. The deposited metal of the welding wire has a hardness of ≥240 HV1, a yield strength of 495 MPa, a tensile strength of 745 MPa, an elongation after fracture of 38%, and a room temperature impact toughness of 140 J / cm 2 Under the same impact wear test conditions, the wear of the deposited metal was compared with that of the frog steel base metal. Under any impact load and impact number, the wear of the deposited metal was lower than that of the frog steel base metal, and its impact wear resistance was significantly better than that of the frog steel base metal.

[0045] Comparative Example 1 A high-manganese steel welding wire for repairing high-manganese steel frogs, comprising the following chemical components: 0.65 wt% C, 0.8% Si, 22.4 wt% Mn, 0 wt% Mo, 1.0 wt% V, 0.3 wt% N, 0.07 wt% Nb, 0.07 wt% Ce, P ≤ 0.002 wt%, S ≤ 0.002 wt%, and the remainder being Fe. Other chemical components are the same as those in Example 2.

[0046] The deposited metal produced using the comparative example welding wire and welding process exhibits a good metallurgical bond with the frog steel base metal. The metallographic structure of the deposited metal formed by the welding wire is entirely austenitic. The deposited metal hardness of the welding wire is ≥200 HV1. The composition of the comparative example 1 differs from that of the example 2 in that the comparative example 1 does not contain Mo. The deposited metal of the welding wire exhibits a yield strength of 395 MPa, a tensile strength of 606 MPa, an elongation of 43.4%, and a room temperature impact toughness of 168 J / cm. 2 This is because without the effect of molybdenum (Mo), only a small amount of dispersed carbides exist in the deposited metal. During the impact wear deformation process, the number of twins generated is insufficient, resulting in low strength and hardness of the deposited metal. Compared with the frog steel base material under the same impact wear test conditions, the wear amount of the deposited metal is significantly higher than that of the frog steel base material. The impact wear results are as follows: Figure 6 shown.

[0047] Comparative Example 2 A high-manganese steel welding wire for repairing high-manganese steel frogs, comprising the following chemical components: 0.65 wt% C, 0.8% Si, 22.4 wt% Mn, 6.0 wt% Mo, 1.0 wt% V, 0.3 wt% N, 0.07 wt% Nb, 0.07 wt% Ce, P ≤ 0.002 wt%, S ≤ 0.002 wt%, and the remainder being Fe. Other chemical components are the same as those in Example 1.

[0048] The deposited metal produced using the comparative example welding wire and welding process exhibits a good metallurgical bond with the frog steel base metal. The metallographic structure of the deposited metal formed by the welding wire is entirely austenitic. The compositional difference between Comparative Example 1 and Example 2 lies in the excessive molybdenum (Mo) content. The deposited metal of the welding wire exhibits a hardness ≥ 240 HV1, a yield strength of 485 MPa, a tensile strength of 705 MPa, an elongation of 28%, and a room temperature impact toughness of 95 J / cm. 2 This is because excessive molybdenum (Mo) content will form too many large MoC particles in the deposited metal, resulting in a certain increase in strength, but a decrease in room temperature impact toughness. Compared with the frog steel base material under the same impact wear test conditions, the wear of the deposited metal is higher than that of the frog steel base material under any impact load and impact number.

[0049] Comparative Example 3 A fully automatic and efficient welding method for repairing high manganese steel frogs comprises the following steps: The high manganese steel welding wire composition is as follows: C 0.65 wt%, Si 0.8%, Mn 22.4 wt%, Mo 2.0 wt%, V 1.0 wt%, N 0.3 wt%, Nb 0 wt%, Ce 0.07 wt%, P ≤ 0.002 wt%, S ≤ 0.002 wt%, and the remainder is Fe. Other components are the same as those in Example 1.

[0050] The deposited metal produced using the comparative welding wire and welding process achieved a good metallurgical bond with the frog steel base metal, and the metallographic structure of the deposited metal formed by the welding wire was entirely austenitic. Compared to Example 2, the niobium (Nb) content was 0wt%, and the deposited metal of the welding wire had a hardness of ≥215 HV1, a yield strength of 420 MPa, a tensile strength of 615 MPa, an elongation of 34%, and a room temperature impact toughness of 120 J / cm. 2 This is because the absence of niobium (Nb) prevents the formation of NbC particles as heterogeneous cores, resulting in coarser grains in the deposited metal and worsening its strength and toughness. Compared to frog steel parent metal under the same impact wear test conditions, the wear loss of the deposited metal is higher than that of the frog steel parent metal at all impact loads and impact times.

[0051] Comparative Example 4 A fully automatic and efficient welding method for repairing high manganese steel frogs comprises the following steps: The high manganese steel welding wire composition is as follows: C 0.35 wt%, Si 0.8%, Mn 22.4 wt%, Mo 2.0 wt%, V 1.0 wt%, N 0.3 wt%, Nb 0.3 wt%, Ce 0.07 wt%, P ≤ 0.002 wt%, S ≤ 0.002 wt%, and the remainder is Fe. Other components are the same as those in Example 1.

[0052] The rest is the same as Example 1.

[0053] The deposited metal produced using the comparative welding wire and welding process exhibited excellent metallurgical bonding with the frog steel base metal. The metallographic structure of the deposited metal formed by the comparative welding wire was entirely austenitic. Compared to Example 2, the deposited metal of the comparative welding wire exhibited a hardness of ≥225 HV1, a yield strength of 438 MPa, a tensile strength of 626 MPa, an elongation of 29%, and a room temperature impact toughness of 95 J / cm. 2This is because excessive niobium (Nb) content not only forms coarse NbC particles or network carbides, reducing the toughness of the deposited metal, but also interacts with other alloying elements, causing element segregation and weakening the strengthening effect. Compared with frog steel parent metal under the same impact wear test conditions, the wear loss of the deposited metal is higher than that of the frog steel parent metal under all impact loads and impact times.

[0054] Comparative Example 5 A fully automatic and efficient welding method for repairing high manganese steel frogs comprises the following steps: The high manganese steel welding wire composition is as follows: C 0.35 wt%, Si 0.8%, Mn 22.4 wt%, Mo 2.0 wt%, V 0 wt%, N 0.3 wt%, Nb 0.07 wt%, Ce 0.07 wt%, P ≤ 0.002 wt%, S ≤ 0.002 wt%, and the remainder is Fe. Other components are the same as those in Example 1.

[0055] The rest is the same as Example 1.

[0056] The deposited metal produced using the comparative welding wire and welding process exhibited excellent metallurgical bonding with the frog steel base metal, and the metallographic structure of the deposited metal formed by the welding wire was entirely austenitic. Compared to Example 2, the deposited metal of the welding wire, containing 0 wt% vanadium (V), had a hardness of ≥200 HV1, a yield strength of 406 MPa, a tensile strength of 585 MPa, an elongation of 42.5%, and a room temperature impact toughness of 158 J / cm. 2 This is because the absence of vanadium (V) reduces the dislocation density in the deposited metal, weakening its strength and hardness, and reducing the number of deformation twins in the deposited metal during impact deformation. Compared with frog steel base metal under the same impact wear test conditions, the wear loss of the deposited metal is higher than that of the frog steel base metal under all impact loads and impact times.

[0057] Comparative Example 6 A fully automatic and efficient welding method for repairing high manganese steel frogs comprises the following steps: The composition of high manganese steel welding wire is: C 0.35~0.55wt%, Si 0.8~1.2%, Mn 22.4wt%, Mo 2.0wt%, V 3.0wt%, N 0.3wt%, Nb 0.07wt%, Ce 0.07wt%, P≤0.002wt%, S≤0.002wt%, and the rest is Fe.

[0058] The rest is the same as Example 1.

[0059] The deposited metal produced using the comparative example welding wire and welding process exhibited excellent metallurgical bonding with the frog steel base metal, and the metallographic structure of the deposited metal formed by the welding wire was entirely austenitic. Compared to Example 2, the vanadium (V) content was 3.0 wt %. The deposited metal had a hardness of ≥230 HV1, a yield strength of 468 MPa, a tensile strength of 721 MPa, an elongation of 27.5%, and a room temperature impact toughness of 106 J / cm. 2 This is because excessive vanadium (V) forms coarse carbides in the deposited metal, deteriorating the material's toughness. Compared to frog steel parent metal under the same impact wear test conditions, the deposited metal exhibited greater wear than the frog steel parent metal at all impact loads and impact times.

[0060] Any matters not mentioned above shall be subject to the existing technology.

[0061] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments or replace them in similar ways, but they will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high manganese steel welding wire for repairing high manganese steel frogs, characterized in that: Its chemical composition is: C is 0.35~1.3wt%, Si is 0.8~2.0%, Mn is 22~35wt%, Mo is 0.5~5.0wt%, V is 0.05~2.0wt%, N is 0.2~0.6wt%, Nb is 0.05~0.15wt%, Ce is 0.05~0.1wt%, P≤0.002wt%, S≤0.002wt%, and the rest is Fe.

2. A fully automatic and efficient welding method for repairing high manganese steel frogs, characterized in that: Using the high manganese steel welding wire according to claim 1, the specific steps are: S1: Derusting the steel wire rod that meets the above-mentioned high manganese steel welding wire composition, drawing it, straightening it, cutting it, and cleaning the surface oil stains to obtain the welding wire; S2: Grind and remove oil, rust and other dirt from the frog surface, ensure that the frog surface is smooth and flat, and clamp and fix the frog steel plate; S3: Set welding current, welding voltage, welding speed, and shielding gas according to material properties, determine the frog repair location and path, and perform fully automatic surfacing welding on the frog.

3. A fully automatic and efficient welding method for repairing high manganese steel frogs according to claim 2, characterized in that: The wire was drawn to a diameter of 1.2 mm, with a welding current of 160-250 A, a welding voltage of 16-24 V, a welding speed of 40-60 cm / min, and a wire feeding speed of 6-16 mm / s.

4. A fully automatic and efficient welding method for repairing high manganese steel frogs according to claim 2, characterized in that: During the welding process, pulse current is used to change the traditional current characteristics.

5. A fully automatic and efficient welding method for repairing high manganese steel frogs according to claim 2, characterized in that: The protective gas is 80%-98% Ar+2%-20% CO2.

6. A fully automatic and efficient welding method for repairing high manganese steel frogs according to claim 2, characterized in that: In S3, fully automatic surfacing is performed, and the interlayer temperature is controlled below 100°C.

7. A fully automatic and efficient welding method for repairing high manganese steel frogs according to claim 2, characterized in that: In S3, 4 layers of surfacing are performed, with 3 passes in each layer.

8. A fully automatic and efficient welding method for repairing high manganese steel frogs according to claim 2, characterized in that: The welding equipment includes: ABB robotic arm, Fronius welding machine, Fronius welding gun, and Fronius wire feeder.

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