Narrow-gap hot wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel

Abstract

The invention provides a narrow-gap hot wire TIG-plasma spray welding hybrid welding method for high-strength wear-resistant steel. The narrow-gap hot wire TIG-plasma spray welding hybrid welding method specifically comprises the following steps that S1, a semi-U-shaped groove is machined in the bottom of one side of a to-be-welded steel plate; s2, a narrow-gap hot wire TIG welding method is adopted, backing welding and filling welding are sequentially conducted on a welding seam, the welding current of a used hot wire TIG welding gun ranges from 100 A to 180 A, the welding voltage ranges from 12 V to 16 V, and the welding speed ranges from 100 mm / min to 150 mm / min; s3, shielded metal arc welding is adopted for cosmetic welding to prepare a weld joint surface corrosion-resistant layer, the welding current of shielded metal arc welding is 70-90 A, the welding voltage is 14-16 V, and the welding speed is 100-120 mm / min; s4, plasma spray welding is adopted for cosmetic welding to prepare a weld joint surface wear-resistant layer, and the welding current of plasma spray welding is 100-110 A; and S5, the surface of the welded joint is covered with heat preservation cotton till the welded joint is cooled to the room temperature. According to the method, efficient welding of the thick-specification wear-resistant steel and the quality and performance of a welding joint are guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of high-strength wear-resistant steel welding processes, and more particularly, to a narrow-gap hot-wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel. Background Art

[0002] With the development of China's national economy and society, the technical level of China's industrial equipment has made great progress; during the construction of a large number of infrastructure such as real estate, bridges, and tunnels, the usage frequency of engineering machinery equipment is very high, and the wear and tear of the equipment is very serious, bringing great losses to the national economy. Therefore, the use of wear-resistant steel in engineering machinery has gradually increased, but there are also some problems in the manufacturing process of high-strength wear-resistant steel: (1) The carbon equivalent of high-strength wear-resistant steel is generally higher than that of ordinary low-alloy high-strength steel, and the weldability is poor, and delayed cracks are likely to occur after welding; (2) Since low-strength matching welding materials are generally used for high-strength wear-resistant steel, the wear resistance of the weld is lower than that of the base metal, and the wear degree of the weld is relatively large during use; (3) The thickness of thick-specification wear-resistant steel plates is relatively large, resulting in a large amount of welding work; a suitable welding process method plays a crucial role in the quality and performance of the welded joint. Single welding methods, such as shielded metal arc welding, gas shielded welding, and submerged arc welding, all have their own advantages and disadvantages. Using a combination of two welding methods can give full play to the advantages of each welding method to a greater extent, improve welding efficiency, and reduce welding costs. However, after adopting a new composite welding method, the corresponding welding process and parameters need to be changed accordingly to ensure the mechanical properties of the welded joint. Summary of the Invention

[0003] In view of the above-mentioned technical problems existing in the use of a single welding method for wear-resistant steel, a narrow-gap hot-wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel is provided to ensure the efficient welding of thick-specification wear-resistant steel and the quality and performance of the welded joint.

[0004] The technical means adopted by the present invention are as follows:

[0005] A narrow-gap hot-wire TIG and plasma spray welding composite welding process for thick-specification high-strength wear-resistant steel, specifically including the following steps:

[0006] S1. Process a semi-U-shaped groove on one side of the steel plate to be welded, and the height of the blunt edge at the bottom of the groove is 1-2 mm; place the grooves of the two steel plates to be welded after grooving opposite to each other to form a weld, and leave a gap of 1-2 mm between the bottom grooves of the two steel plates to be welded; perform preheating treatment on the welding area of the steel plate to be welded before welding.

[0007] S2. Adopt the narrow-gap hot-wire TIG welding method to carry out root welding and filling welding on the weld in sequence. The welding current of the used hot-wire TIG welding torch is 100 - 180 A, the welding voltage is 12 - 16 V, the welding speed is 100 - 150 mm / min, and the oscillation width is 2 - 3 mm;

[0008] S3. On the hot-wire TIG weld bead prepared in S2, carry out capping welding by shielded metal arc welding to prepare the corrosion-resistant layer on the weld surface. The welding current of the shielded metal arc welding is 70 - 90 A, the welding voltage is 14 - 16 V, and the welding speed is 100 - 120 mm / min;

[0009] S4. On the corrosion-resistant layer on the weld surface prepared in S3, carry out capping welding by plasma spray welding to prepare the wear-resistant layer on the weld surface. The welding current of the plasma spray welding is 100 - 110 A, and the flow rates of the ion gas, shielding gas, and powder-feeding gas are all 4 - 7 L / min;

[0010] S5. After welding is completed, cover the surface of the welded joint with heat-insulating cotton until it cools down to room temperature.

[0011] Further, the thickness of the thick-specification high-strength wear-resistant steel is 45 - 65 mm.

[0012] Further, the root radius R of the semi-U-shaped groove is 8 - 10 mm.

[0013] Further, before welding the steel plate to be welded in S1, use an angle grinder to remove the impurities in the area to be welded on the steel plate, and wipe it with industrial alcohol until the area to be welded on the steel plate shows metallic luster.

[0014] Further, use an inert gas as the shielding gas during the process of root welding and filling welding.

[0015] Further, the welding consumables used for root welding and filling welding are JQ.TG50 carbon steel argon arc welding wires. The tensile strength Rm of the welding wire > 490 MPa, and the impact energy Kv2 at -30 °C > 27 J.

[0016] Further, the welding consumables used for shielded metal arc welding are A132 stainless steel electrodes.

[0017] Further, use WC powder and Fe313 iron-based self-fluxing alloy powder as the spray welding powder for plasma spray welding, and both the shielding gas and the powder-feeding gas are argon.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The narrow-gap hot-wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel provided by the present invention uses narrow-gap hot-wire TIG welding for weld root and filling, with a small heat input per unit length of the welding wire and fewer welding passes, which can greatly reduce the probability of welding cracks occurring in the welded joints of thick-specification wear-resistant steel.

[0020] 2. The narrow-gap hot-wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel provided by the present invention. The small heat input of narrow-gap hot-wire TIG welding can also reduce the area of the heat-affected zone and the area where the hardness and wear resistance decrease, and can, to a certain extent, avoid the decrease in the hardness of the welded joint.

[0021] 3. The narrow-gap hot-wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel provided by the present invention can reduce the groove area and welding workload, reduce the time required for the welding process. Compared with the existing welding methods, it can reduce the welding operation time by 30%-50% and reduce the welding cost.

[0022] 4. The narrow-gap hot-wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel provided by the present invention uses shielded metal arc welding with stainless steel electrodes to weld the weld cap to prepare the corrosion-resistant layer, which can form a corrosion-resistant layer with excellent corrosion resistance on the weld surface. Compared with the existing welding methods, the corrosion resistance of the weld after welding using the composite welding method of the present invention can be increased by 50%, greatly enhancing the corrosion resistance of the weld.

[0023] 5. The narrow-gap hot-wire TIG-plasma spray welding composite welding method for high-strength wear-resistant steel provided by the present invention uses plasma spray welding for weld cap welding. The high degree of welding automation can improve the welding efficiency, and can prepare an iron-based WC-reinforced wear-resistant coating with better friction and wear resistance. Compared with the existing welding methods, the friction and wear resistance of the weld after welding using the composite welding method of the present invention is increased by at least 100%. The friction and wear resistance of the prepared wear-resistant coating is much higher than that of the wear-resistant layer of ordinary welding materials, and the hardness can reach up to more than 1000 HV, suitable for use in harsh working environments.

[0024] Based on the above reasons, the present invention can be widely promoted in the field of high-strength wear-resistant steel welding technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1Schematic diagram of the single-sided semi-U groove structure of the present invention.

[0027] Figure 2 Schematic diagram of the process flow of the composite welding method of the present invention.

[0028] Figure 3 Schematic diagram of the plasma spray welding torch of the present invention. Detailed implementation manners

[0029] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. The following description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0030] As Figures 1-3 shown, a narrow-gap hot wire TIG and plasma spray welding composite welding process for thick-specification high-strength wear-resistant steel proposed by the present invention specifically includes the following steps:

[0031] S1. Machine a semi-U groove on one side of the steel plate to be welded, with the root face height at the bottom of the groove being 1-2 mm; place the grooves of the two steel plates to be welded after grooving opposite to each other to form a weld, and leave a gap of 1-2 mm between the bottom grooves of the two steel plates to be welded; perform preheating treatment on the welding area of the steel plate to be welded, with the preheating temperature being 100-120 °C;

[0032] S2. Adopt the narrow-gap hot wire TIG welding method to perform root welding and filling welding on the weld in sequence. The welding current of the hot wire TIG welding torch used is 100-180 A, the welding voltage is 12-16 V, the welding speed is 100-150 mm / min, and the oscillation width is 2-3 mm;

[0033] S3. On the hot wire TIG weld bead prepared in S2, use shielded metal arc welding to perform capping welding to prepare the corrosion-resistant layer on the weld surface. The welding current of the shielded metal arc welding is 70-90 A, the welding voltage is 14-16 V, and the welding speed is 100-120 mm / min;

[0034] S4. On the corrosion-resistant layer on the weld surface prepared in S3, use plasma spray welding to perform capping welding to prepare the wear-resistant layer on the weld surface. The welding current of the plasma spray welding is 100-110 A, and the flow rates of the ion gas, shielding gas and powder feeding gas are all 4-7 L / min;

[0035] S5. After welding is completed, cover the surface of the welded joint with heat-insulating cotton until it cools down to room temperature, which can reduce the cooling rate of the welded joint and avoid the occurrence of delayed cracks. Inspection can be carried out within 72 hours by observing the surface color of the weld seam and the method of penetrant inspection to ensure that there are no welding defects such as welding cracks and pores near the welded joint.

[0036] Further, the thickness of the thick-specification high-strength wear-resistant steel is 45 - 65 mm.

[0037] Further, the root radius R of the semi-U-shaped groove is 8 - 10 mm.

[0038] Further, in S1, a semi-U-shaped groove is machined by mechanical processing. Before welding the steel plate to be welded, remove oxides, oil stains, rust and other impurities in the area to be welded of the steel plate with an angle grinder, and wipe it with industrial alcohol until the area to be welded of the steel plate shows metallic luster.

[0039] Further, an inert gas is used as the shielding gas during the backing welding and filling welding processes. Preferably, high-purity argon is used as the shielding gas. Before backing welding, blow air into the weld seam for 3 s to fill the bottom of the weld seam with the shielding gas, and then carry out backing welding.

[0040] Further, the welding consumables used for backing welding and filling welding are JQ.TG50 carbon steel argon arc welding wires. The tensile strength Rm of the welding wire is > 490 MPa, and the impact energy Kv2 at -30 °C is > 27 J, having excellent ductility and low-temperature toughness.

[0041] Further, when carrying out filling welding, fill to a distance of 5 - 6 mm from the top of the weld seam.

[0042] Further, the welding consumables used for shielded metal arc welding are A132 stainless steel electrodes, and the specification is small-sized electrodes with a diameter of 3.2 mm.

[0043] Further, WC powder and Fe313 iron-based self-fluxing alloy powder are used as the spray welding powder for plasma spray welding, and both the shielding gas and the powder feeding gas are argon.

[0044] The present invention combines several advanced welding methods such as narrow-gap hot-wire TIG, shielded metal arc welding, and plasma spray welding to prepare wear-resistant steel weld seams with various excellent properties such as the toughness, corrosion resistance, and wear resistance of the weld seam, and an advanced welding process method, which can provide welding technical support for the popularization and application of high-strength wear-resistant steel.

[0045] The high-strength wear-resistant steel narrow-gap hot-wire TIG-plasma spray welding composite welding method provided by the present invention uses narrow-gap hot-wire TIG welding for weld backing and filling, with a small heat input per unit length of the welding wire and fewer welding passes, which can greatly reduce the probability of welding cracks in the welded joints of thick-specification wear-resistant steel. The small heat input of narrow-gap hot-wire TIG welding can also reduce the area of the heat-affected zone and the area where hardness and wear resistance decrease, and can to a certain extent avoid the decrease in the hardness of the welded joint. Using narrow-gap hot-wire TIG welding can reduce the time required for the welding process and lower the welding cost. At the same time, the present invention uses shielded metal arc welding with stainless steel electrodes to weld the weld cap to prepare a corrosion-resistant layer, which can form a corrosion-resistant layer with excellent corrosion resistance on the weld surface and improve the corrosion resistance of the weld. Using plasma spray welding for cap welding, the high degree of welding automation can improve the welding efficiency, and an iron-based WC-reinforced wear-resistant coating with better friction and wear resistance can be prepared. Its friction and wear resistance is much higher than that of the wear-resistant layer of ordinary welding materials, and the hardness can reach up to more than 1500 HV, which is suitable for use in harsh working environments.

[0046] Taking the welding of a 400-mm-long weld between two 45-mm-thick high-strength wear-resistant steel plates as an example, the ordinary V-groove welding method and the composite welding method described in the present invention are respectively used for welding. The time required for welding using the ordinary V-groove welding is about 50 minutes, while using the method of the present invention for welding can shorten the welding operation time by 30%-50%, and the required time is only 25-35 minutes. At the same time, corrosion resistance tests and friction and wear tests are respectively carried out on the welds welded by the two methods. The results show that the weld welded by the ordinary V-groove welding shows rust after about 32 hours in the salt spray corrosion test, while the narrow-gap welded weld of the weld welded by the method of the present invention still does not show rust after 64 hours in the salt spray corrosion test. The present invention can improve the corrosion resistance by 50% compared with the existing welding method. The volume wear rate of the weld surface after welding by the ordinary V-groove welding in the pin-on-disc friction and wear test under dry friction conditions is 3.4×10 -5 mm 3 / (N·m), while the volume wear rate of the wear-resistant layer surface of the weld welded by the method of the present invention in the pin-on-disc friction and wear test under dry friction conditions is about 1.5×10 -5 mm 3 / (N·m), indicating that the present invention significantly improves the friction and wear resistance of the weld after welding compared with the existing welding method.

[0047] Example 1

[0048] This example is applied to the welding of NM500 high-strength wear-resistant steel with a plate thickness of 45 mm. The specific implementation process is as follows:

[0049] S1. Use a machining method to machine a semi-U-shaped groove at the bottom of one side of the steel plate to be welded. The groove form is asFigure 1 As shown in the figure; before welding, use a grinding wheel to clean and polish the groove and the 20 mm area on both sides of the weld until it is bright and free of obvious impurities such as oil stains and rust;

[0050] S2. Fix the steel plate with the groove opened on the workbench and prepare for welding; first, insert the welding torch into the bottom of the weld to be welded, spray high-purity argon shielding gas for 3 s, and then use a welding current of 100 - 120 A for root welding. Root weld two layers, with 2 and 3 passes for each layer respectively; after root welding, carry out filling welding. The welding current is 160 - 180 A, the welding speed is 100 - 150 mm / min, the oscillation width is 2 mm, fill weld 12 - 14 layers, with 2 passes for each layer, and end the filling welding when it is about 5 - 6 mm away from the top; during root welding and filling welding, the shielding gas flow rate is 15 L / min;

[0051] S3. Use A132 manual electrode arc welding to carry out capping welding to prepare the corrosion-resistant layer on the weld surface. The welding current is 90 A, the welding speed is 100 mm / min, the electrode diameter is 3.2 mm, cap weld 1 layer of weld, with 2 passes;

[0052] S4. Use plasma surfacing to carry out capping welding to prepare the wear-resistant layer on the weld surface. Use WC powder and Fe313 iron-based self-fluxing alloy powder as the surfacing powder. The shielding gas and the powder feeding gas are both argon. The welding current is 120 A, and the flow rates of the ion gas, shielding gas, and powder feeding gas are all 4.5 L / min. Cap weld 2 layers of weld, with 2 passes; during plasma surfacing, first spray the iron-based powder through one powder feeding pipe, and at the same time turn on the welding switch for welding. After the arc is struck, the WC powder particles are sprayed through the other powder feeding pipe. The high-temperature plasma arc melts and combines the iron powder and WC powder in the molten pool to form a WC particle-reinforced wear-resistant coating;

[0053] S5. After welding, cover the surface of the welded joint with heat-insulating cotton until it cools to room temperature; perform flaw detection on the weld after 72 h, and the results show that no cracks appear.

[0054] Example 2

[0055] This example is applied to the welding of NM500 high-strength wear-resistant steel with a plate thickness of 55 mm. The specific implementation process is as follows:

[0056] S1. Use mechanical processing methods to machine a semi-U-shaped groove at the bottom of one side of the steel plate to be welded. The groove form is as Figure 1 shown in the figure; before welding, use a grinding wheel to clean and polish the groove and the 20 mm area on both sides of the weld until it is bright and free of obvious impurities such as oil stains and rust;

[0057] S2. Fix the steel plate with the prepared groove on the workbench for welding; pre - insert the welding torch into the bottom position of the weld to be welded. After spraying high - purity argon shielding gas for 3 s, carry out root welding with a welding current of 100 - 120 A. Carry out two layers of root welding, with the number of passes for each layer being 2 and 3 respectively. After root welding, carry out filling welding with a welding current of 160 - 180 A, a welding speed of 100 - 150 mm / min, a swing width of 2 mm. Carry out 15 - 17 layers of filling welding, with 2 passes for each layer. End the filling welding when it is about 5 - 6 mm away from the top. During root welding and filling welding, the shielding gas flow rate is 15 L / min;

[0058] S3. Use A132 manual electrode arc welding to carry out capping welding to prepare the corrosion - resistant layer on the weld surface. The welding current is 80 A, the welding speed is 100 mm / min, the electrode diameter is 3.2 mm. Carry out 1 layer of capping welding with 2 passes;

[0059] S4. Use plasma spray welding to carry out capping welding to prepare the wear - resistant layer on the weld surface. Use WC powder and Fe313 iron - based self - fluxing alloy powder as the spray - welding powder. Both the shielding gas and the powder - feeding gas are argon. The welding current is 110 A, and the flow rates of the ion gas, shielding gas, and powder - feeding gas are all 4.5 L / min. Carry out 2 layers of capping welding with 2 passes. During plasma spray welding, first spray the iron - based powder through one powder - feeding pipe, and at the same time turn on the welding switch for welding. After the arc is struck, the WC powder particles are sprayed through the other powder - feeding pipe. The high - temperature plasma arc melts and combines the iron powder and WC powder in the molten pool to form a WC particle - reinforced wear - resistant coating;

[0060] S5. After welding, cover the surface of the welded joint with heat - insulating cotton until it cools to room temperature; after 72 h, conduct flaw detection on the weld. The results show that no cracks appear.

[0061] Example 3

[0062] This example is applied to the welding of NM500 high - strength wear - resistant steel with a plate thickness of 65 mm. The specific implementation process is as follows:

[0063] S1. Use mechanical processing methods to machine a semi - U - shaped groove at the bottom of one side of the steel plate to be welded. The groove form is as Figure 1 shown; before welding, use a grinding wheel to clean and polish the groove and the 20 - mm area on both sides of the weld until it is bright and free of obvious oil stains, rust and other impurities;

[0064] S2. Fix the grooved steel plate on the workbench for welding preparation; pre-insert the welding torch into the bottom position of the weld to be welded, spray high-purity argon shielding gas for 3 s, and then perform root welding with a welding current of 100 - 120 A. Perform two layers of root welding, with 2 and 3 passes for each layer respectively; after root welding, perform filling welding. The welding current is 160 - 180 A, the welding speed is 100 - 150 mm / min, the oscillation width is 2 mm, perform 19 - 21 layers of filling welding, with 2 passes for each layer, and end the filling welding when it is about 5 - 6 mm away from the top; during the root welding and filling welding processes, the shielding gas flow rate is 15 L / min;

[0065] S3. Use A132 manual electrode arc welding to perform capping welding to prepare the corrosion-resistant layer on the weld surface. The welding current is 70 A, the welding speed is 100 mm / min, the electrode diameter is 3.2 mm, perform 1 layer of capping welding on the weld, with 2 passes;

[0066] S4. Use plasma spray welding to perform capping welding to prepare the wear-resistant layer on the weld surface. Use WC powder and Fe313 iron-based self-fluxing alloy powder as the spray welding powder, and both the shielding gas and the powder feeding gas are argon. The welding current is 100 A, and the flow rates of the ion gas, shielding gas, and powder feeding gas are all 4.5 L / min. Perform 2 layers of capping welding on the weld, with 2 passes; during plasma spray welding, first spray the iron-based powder through one powder feeding pipe, and at the same time turn on the welding switch for welding. After the arc is struck, spray WC powder particles through the other powder feeding pipe. The high-temperature plasma arc melts and combines the iron powder and WC powder in the molten pool to form a WC particle-reinforced wear-resistant coating;

[0067] S5. After welding is completed, cover the surface of the welded joint with heat-insulating cotton until it cools to room temperature; perform flaw detection on the weld after 72 h, and the results show that no cracks appear.

[0068] The main welding process parameters used in Examples 1 - 3 are shown in Table 1. Different welding currents are used for different steel plate thicknesses because the greater the steel plate thickness, the greater the welding stress during welding. A smaller welding current needs to be used to reduce the heat input and avoid generating welding cracks.

[0069] Table 1 Welding process parameters of Examples 1 - 3

[0070]

[0071] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding composite welding method, characterized in that: The specific steps include: S1. A semi-U-shaped groove is processed on one side of the steel plate to be welded, and the height of the blunt edge of the groove bottom is 1-2mm; the grooves of the two steel plates to be welded are placed opposite to each other to form a weld, and a gap of 1-2mm is left between the grooves at the bottom of the two steel plates to be welded; the welding area of ​​the steel plate to be welded is preheated before welding; S2. Use narrow gap hot wire TIG welding method, perform base welding and filler welding in the weld in sequence, the hot wire TIG welding gun used has a welding current of 100-180A, a welding voltage of 12-16V, a welding speed of 100-150mm / min, and a swing width of 2-3mm; S3. On the hot wire TIG weld prepared in S2, arc welding is used to perform cap welding to prepare a corrosion-resistant layer on the weld surface. The arc welding current is 70-90A, the welding voltage is 14-16V, and the welding speed is 100-120mm / min. S4. On the corrosion-resistant layer on the weld surface prepared in S3, plasma spray welding is used to perform cap welding to prepare a wear-resistant layer on the weld surface. The welding current of the plasma spray welding is 100-110A, and the flow rates of the ion gas, shielding gas and powder feeding gas are all 4-7L / min. S5. After welding is completed, use insulation cotton to cover the surface of the weld joint until it cools to room temperature.

2. The high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding hybrid welding method according to claim 1 is characterized in that: Thick gauge high strength wear resistant steel has a thickness of 45-65mm.

3. The high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding hybrid welding method according to claim 1 is characterized in that: The root radius R of the semi-U-shaped groove is 8-10mm.

4. The high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding hybrid welding method according to claim 1 is characterized in that: Before welding, the steel plates to be welded in S1 were cleaned of impurities in the area to be welded by an angle grinder, and industrial alcohol was used to wipe the area to be welded until the metallic luster was exposed.

5. The high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding hybrid welding method according to claim 1 is characterized in that: Inert gas is used as shielding gas during root welding and filler welding.

6. The high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding hybrid welding method according to claim 1 is characterized in that: The welding materials used for base welding and filling welding are JQ.TG50 carbon steel argon arc welding wire, the tensile strength of the welding wire is Rm>490MPa, and the impact energy Kv2 at -30℃ is>27J.

7. The high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding hybrid welding method according to claim 1 is characterized in that: The welding material used for arc welding is A132 stainless steel electrode.

8. The high-strength wear-resistant steel narrow gap hot wire TIG-plasma spray welding hybrid welding method according to claim 1 is characterized in that: Plasma spray welding uses WC powder and Fe313 iron-based self-fluxing alloy powder as spray welding powder, and the shielding gas and powder feeding gas are both argon.

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