Gas shielded flux-cored wire for Cr13 series stainless steel surfacing and surfacing method

Abstract

According to the gas-shielded flux-cored wire for Cr13 series stainless steel surfacing and the surfacing method, by optimizing flux-cored wire alloy components and mineral components, the Cr13 petroleum drill rod joint wear-resistant belt gas-shielded flux-cored wire is newly developed, and the single-layer hardness is larger than 57 HRC; the contradictory problem that a traditional wear-resistant welding wire is insufficient in wear resistance and toughness is solved, meanwhile, 7%-15% of austenite is formed in the structure, the wear resistance coefficient of the material is reduced, namely, the wear resistance of the material is improved, and the technology is researched.

Description

Technical Field

[0001] The invention belongs to the technical field of surfacing welding, and in particular relates to a gas-shielded flux-cored welding wire for Cr13 series stainless steel surfacing welding and a surfacing welding method. Background Art

[0002] Oil companies use hardfacing technology to improve the quality of drill pipe, effectively increasing the efficiency and service life of oil drill pipe. The drill pipe joint hardband is essentially an isolation zone with a certain width and thickness along the circumference of the joint. This isolation zone isolates the outer wall of the drill pipe joint from the casing wall or well wall, preventing direct contact between the drill pipe joint and the casing wall or well wall, thereby protecting the drill pipe joint and casing from severe wear. Currently, the toughness of the annular hardband of oil drill pipe used for gas shielded hardfacing is relatively low (experienced V-notch impact toughness greater than 10 J / cm 2 It is beneficial to inhibit the peeling and cracking of the wear-resistant belt. Cracks are easily generated at the overlap of the weld head and tail, and defects such as insufficient wear resistance are the main reasons that limit the application of the wear-resistant belt in drill pipe. Summary of the Invention

[0003] In view of this, the present invention aims to propose a gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing and a surfacing method. By optimizing the alloy composition and mineral composition of the flux-cored welding wire, a new wear-resistant gas-shielded flux-cored welding wire for Cr13 oil drill pipe joints is developed, with a single-layer hardness greater than 57HRC; it solves the contradiction between the wear resistance and insufficient toughness of traditional wear-resistant welding wires, and at the same time, the formation of 7-15% austenite in the structure is conducive to reducing the wear resistance coefficient of the material, that is, improving the wear reduction performance of the material, and the process is studied.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows: A gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing welding comprises the following components by weight: cryolite: 0.2%-1.5%; zirconium silicon powder: 0.1%-0.45%; potassium titanate: 0.1%-1%; ferrotitanium: 1.0%-6%; high-carbon ferrochrome: 20%-35%; titanium carbide: 1.8-11%; graphite: 0.8-7.0%; low-carbon ferrochrome: 40-52%; ferroniobium: 1-8%; ferrovanadium: 1.0-4.0%; ferrosilicon: 1.0%-5.5%; manganese powder: 0.5%-2.5%; ferroboron: 0-1.4%; and the balance is iron powder.

[0005] The main function of adding a certain amount of high-melting-point zirconium-silicon powder is to control the melting point of the welding wire, increase the fluidity of the weld, and make the weld smooth and round, that is, the weld has good roundness; potassium titanate and cryolite mainly play the role of stabilizing the arc.

[0006] Furthermore, the mass ratio of high carbon ferrochrome, titanium carbide and graphite is 1:0.1-0.4:0.05-0.2.

[0007] Furthermore, the mass ratio of titanium carbide to titanium iron is 0.8-1.5 to ensure welding forming and hardness.

[0008] Furthermore, the mass ratio of titanium carbide and ferrotitanium to ferroniobium and ferrovanadium is greater than 0.85.

[0009] Nb, Ti, and V are crucial to the formation of carbides in the high-carbon Cr13-based metallographic structure. This invention optimizes the Nb, Ti, and V contents, specifically considering cost-effectiveness and process performance. For example, the price of ferrotitanium is only 1 / 7-9 of that of ferroniobium and 1 / 4-6 of that of ferrovanadium. Therefore, while maintaining process performance, titanium alloy reinforcement is often used, with a requirement for a (titanium carbide + ferrotitanium): (ferroniobium + ferrovanadium) ratio greater than 0.85. This allows for a dispersed distribution of a certain number of fine hard phases, such as TIC and NbC, in the microstructure, improving the hardness and wear resistance of the wear-resistant belt.

[0010] Furthermore, the mass percentage of Ti in the ferrotitanium is greater than 25%.

[0011] Furthermore, the mass percentage of Cr in the high carbon ferrochrome is greater than 64%, and the mass percentage of C is greater than 8%. The mass percentage of Cr in the low-carbon ferrochrome is more than 68%, and the mass percentage of C is less than 0.035%; The mass percentage of Si in ferrosilicon is more than 74%; The mass percentage of V in ferrovanadium is 50%-70%; The mass percentage of Nb in ferroniobium is 60%-70%; The mass percentage of B in ferroboron is more than 20%; The mass percentage of Zr in zirconium silicon powder is 1-2%; The purity of manganese powder, graphite and titanium carbide reaches over 99%.

[0012] Furthermore, the deposited metal of the welding wire includes the following components in weight percentage: C: 0.80%-1.40%; Cr: 11.5%-13.5%; Nb: 0.1%-2.0%; V: 0.1-1.0%; Mn: 0.1%-1%; Si: 0.2%-1.1%; Ti: 0.6-2.0% B: 0-0.1%, Zr: 0-0.04%; Balance Fe.

[0013] Among them, the main role of C is to form a large number of fine and dispersed carbides with Nb, Ti, V, etc. Carbides are the key to improving hardness and wear resistance, but they are also an important reason for restricting the occurrence of cracks.

[0014] The chromium content has a great influence on the metallographic structure of the high-carbon Cr13 series and is the main factor in balancing martensite and austenite. Increasing the chromium content is conducive to the formation of austenite and increases toughness; however, it damages hardness and wear resistance. Therefore, the chromium content must be controlled within a certain range.

[0015] Furthermore, the diameter of the welding wire is 1.6 mm, and the hardness of the deposited metal of the welding wire in the welded state is ≥57 HRc.

[0016] The present invention also provides a surfacing method for the Cr13 stainless steel surfacing gas-shielded flux-cored wire as described above, the method comprising the following steps: (1) using the welding wire to perform gas shielded cladding welding; (2) Slow cooling treatment of welded parts; (3) Cool the weldment to room temperature.

[0017] Furthermore, before step (1), the weldment is preheated, and the preheating temperature is not less than 120°C.

[0018] Furthermore, in step (1), the gas in the gas shield is one or both of carbon dioxide and argon, and the gas flow rate is 20-28 ml / min; the surfacing welding current is 280-400 A, and the welding voltage is 32-38 V; In step (2), the slow cooling rate is 55°C / h-75°C / h.

[0019] Compared with the prior art, the gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing and the surfacing method of the present invention have the following advantages: (1) The microstructure of the gas-shielded flux-cored wire for Cr13 stainless steel surfacing welding described in the present invention is martensite + austenite + carbide, that is, martensite is the main component, 7-15% of austenite, and a certain amount of carbide is distributed on the matrix. This microstructure not only has good process performance, but also has high hardness, high toughness, high wear resistance and good anti-friction properties, which can meet the requirements of surfacing and re-surfacing of petroleum wear-resistant belts.

[0020] (2) The gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing of the present invention achieves hardness matching with carbides by optimizing the carbon content in the welding wire; improves wear resistance and toughness, and improves the stability of the surfacing material by optimizing the alloy content of the welding wire; and optimizes the mineral and compound components to achieve good process performance, especially reduced spatter and porosity. Ultimately, it not only achieves good process performance, but also has high hardness and high crack resistance. The hardness of the deposited metal in the welded state is greater than or equal to 57HRc; the V-notch impact toughness is greater than 10 J / cm 2 The results of on-site drill pipe surface surfacing tests show that no cracks were generated at the end-to-end overlap of the circular weld when preheated to above 120°C, fully meeting practical requirements after operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 This is a real picture after surfacing welding using the welding wire in Example 1; Figure 2 This is a physical picture after surfacing welding using the welding wire in Comparative Example 1; Figure 3 This is a real picture after surfacing welding using the welding wire in Comparative Example 2; Figure 4 This is a real picture after surfacing welding using the welding wire in Comparative Example 3; Figure 5 This is the metallographic structure diagram of Example 1 after welding. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] In the following examples, each component satisfies the following conditions: The mass percentage of Cr in the high carbon ferrochrome is more than 64%, and the mass percentage of C is more than 8%; The mass percentage of Cr in the low-carbon ferrochrome is more than 68%, and the mass percentage of C is less than 0.035%; The mass percentage of Si in ferrosilicon is more than 74%; The mass percentage of Ti in ferrotitanium is more than 25%; The mass percentage of V in ferrovanadium is 50%-70%; The mass percentage of Nb in ferroniobium is 60%-70%; The mass percentage of B in ferroboron is more than 20%; The mass percentage of Zr in zirconium silicon powder is 1-2%; The purity of manganese powder, graphite and titanium carbide reaches over 99%.

[0025] Example 1 Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 12g; zirconium silicon powder: 4g; potassium titanate: 1g; ferrotitanium: 60g; high carbon ferrochrome: 200g; titanium carbide: 70g; graphite: 40g; low carbon ferrochrome: 480g; ferroniobium: 76g; ferrovanadium: 12g; ferrosilicon: 30g; manganese powder: 15g, and the remainder is iron powder, totaling 1000 grams of powder.

[0026] High carbon ferrochrome: titanium carbide: graphite = 20:7:4 = 1:0.35:0.2; Titanium carbide: titanium iron = 70:60 = 1.17; (Titanium carbide + titanium iron): (niobium iron + vanadium iron) = (70 + 60): (76 + 12) = 1.48.

[0027] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.5 mm, a width of 14 mm, and a filling rate of 26%.

[0028] Example 2 Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 2g; zirconium silicon powder: 3g; potassium titanate: 5g; ferrotitanium: 42g; high carbon ferrochrome: 300g; titanium carbide: 50g; graphite: 56g; low carbon ferrochrome: 425g; ferroniobium: 20g; ferrovanadium: 30g; ferrosilicon: 50g; manganese powder 9g; ferroboron: 8g; the remainder is iron powder, totaling 1000 grams of powder.

[0029] High carbon ferrochrome: titanium carbide: graphite = 300:50:56 = 1:0.17:0.19; Titanium carbide: titanium iron = 50:42 = 1.19; (Titanium carbide + titanium iron): (niobium iron + vanadium iron) = (50 + 42): (20 + 30) = 1.84.

[0030] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.4 mm, a width of 14 mm, and a filling rate of 26%.

[0031] Example 3 Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 8g; zirconium silicon powder: 2g; potassium titanate: 4g; ferrotitanium: 35g; high carbon ferrochrome: 320g; titanium carbide: 43g; graphite: 40g; low carbon ferrochrome: 465g; ferroniobium: 12g; ferrovanadium: 20g; ferrosilicon: 35g; manganese powder: 16g; the remainder is iron powder, totaling 1000 grams of powder.

[0032] High carbon ferrochrome: titanium carbide: graphite = 320:43:40 = 1:0.134:0.125; Titanium carbide: titanium iron = 43:35 = 1.23; (Titanium carbide + titanium iron): (niobium iron + vanadium iron) = (43 + 35): (20 + 12) = 2.44.

[0033] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.4 mm, a width of 14 mm, and a filling rate of 26%.

[0034] Comparative Example 1: The content of titanium carbide and graphite exceeds the standard and the ratio is inconsistent Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 12g; zirconium silicon powder: 4g; potassium titanate: 1g; ferrotitanium: 60g; high carbon ferrochrome: 200g; titanium carbide: 18g; graphite: 92g; low carbon ferrochrome: 480g; ferroniobium: 76g; ferrovanadium: 12g; ferrosilicon: 30g; manganese powder: 15g, the remainder is iron powder, a total of 1000 grams of powder.

[0035] High carbon ferrochrome: titanium carbide: graphite = 200:18:92 = 1:0.09:0.46; Titanium carbide: titanium iron = 18:60 = 0.3; (Titanium carbide + titanium iron): (niobium iron + vanadium iron) = (18 + 60): (76 + 12) = 0.89.

[0036] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.5 mm, a width of 14 mm, and a filling rate of 26%.

[0037] Comparative Example 2: The ratio of high carbon ferrochrome, titanium carbide and graphite is inconsistent Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 12g; zirconium silicon powder: 4g; potassium titanate: 1g; ferrotitanium: 60g; high carbon ferrochrome: 200g; titanium carbide: 102g; graphite: 8g; low carbon ferrochrome: 480g; ferroniobium: 76g; ferrovanadium: 12g; ferrosilicon: 30g; manganese powder 15g, the rest is iron powder, totaling 1000 grams of powder.

[0038] High carbon ferrochrome: titanium carbide: graphite = 200:102:8 = 1:0.51:0.04; Titanium carbide: titanium iron = 102:60 = 1.7; (Titanium carbide + titanium iron): (niobium iron + vanadium iron) = (102 + 60): (76 + 12) = 1.84.

[0039] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.5 mm, a width of 14 mm, and a filling rate of 26%.

[0040] Comparative Example 3: Lack of zirconium silicon powder Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 12g; potassium titanate: 1g; ferrotitanium: 60g; high carbon ferrochrome: 200g; titanium carbide: 70g; graphite: 40g; low carbon ferrochrome: 480g; ferroniobium: 76g; ferrovanadium: 12g; ferrosilicon: 30g; manganese powder: 15g, and the rest is iron powder, totaling 1000 grams of powder.

[0041] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.5 mm, a width of 14 mm, and a filling rate of 26%.

[0042] Comparative Example 4: Titanium iron content exceeds the standard and the proportion is inconsistent Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 12g; zirconium silicon powder: 4g; potassium titanate: 1g; ferrotitanium: 110g; high carbon ferrochrome: 200g; titanium carbide: 20g; graphite: 40g; low carbon ferrochrome: 480g; ferroniobium: 76g; ferrovanadium: 12g; ferrosilicon: 30g; manganese powder 15g, the remainder is iron powder, a total of 1000 grams of powder.

[0043] High carbon ferrochrome: titanium carbide: graphite = 200:20:40 = 1:0.1:0.2; Titanium carbide: titanium iron = 20:110 = 1:5.5 = 0.18; (Titanium carbide + titanium iron): (niobium iron + vanadium iron) = (20 + 110): (76 + 12) = 1.48.

[0044] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.5 mm, a width of 14 mm, and a filling rate of 26%.

[0045] Comparative Example 5 (Titanium Carbide + Ferro-Titanium): (Ferroniobium + Ferro-Vanadium) ratio is too low Cr13 series stainless steel cladding gas shielded flux-cored welding wire includes the following components: Cryolite: 12g; zirconium silicon powder: 4g; potassium titanate: 1g; ferrotitanium: 30g; high carbon ferrochrome: 200g; titanium carbide: 40g; graphite: 40g; low carbon ferrochrome: 480g; ferroniobium: 106g; ferrovanadium: 42g; ferrosilicon: 30g; manganese powder: 15g, the remainder is iron powder, totaling 1000 grams of powder.

[0046] High carbon ferrochrome: titanium carbide: graphite = 200:40:40 = 1:0.2:0.2; Titanium carbide: titanium iron = 40:30 = 1.33; (Titanium carbide + ferrotitanium): (ferrovanadium + ferroniobium) = 70:148 = 0.47.

[0047] The above-mentioned welding wire powder was wrapped with a steel strip to produce a flux-cored welding wire with a diameter of 1.6 mm. The steel strip was made of ordinary carbon steel H08A with a thickness of 0.5 mm, a width of 14 mm, and a filling rate of 26%.

[0048] When the ratio of (titanium carbide + ferrotitanium): (ferroniobium + ferrovanadium) is too low, the welding powder costs about RMB 10 more per kilogram than in Example 1, which is about RMB 3,000 more expensive per ton of welding wire, resulting in a low cost-performance ratio.

[0049] The mass percentages of the main alloy components of the deposited metal in the flux-cored welding wires in the above embodiments and comparative examples are shown in Table 1 below.

[0050] Table 1 Mass percentage of main alloy components in cladding materials (wt%)

[0051] 1. The welding wires of the above embodiments and comparative examples were used for on-site drill pipe surface surfacing test. The results are as follows: Figure 1-4 shown.

[0052] The results after welding of Examples 1-3 are the same. Figure 1 As shown in the actual picture of Example 1 after welding, the content of each component, the ratio of high carbon ferrochrome, titanium carbide and graphite, and the ratio of titanium carbide and ferrotitanium in Examples 1-3 all meet the requirements, the weld is well formed, and there is no defect on the surface after welding.

[0053] Comparative Example 1: High carbon ferrochrome: titanium carbide: graphite = 1:0.09:0.46, the actual picture after welding is as follows Figure 2 As shown, the welding smoke is large, the wire drawing is not smooth, and there are cracks on the roller surface after welding.

[0054] Comparative Example 2: High carbon ferrochrome: titanium carbide: graphite = 1:0.51:0.04, the actual picture after welding is as follows Figure 3 As shown in the figure, the welding spatter is large, the weld surface spread is poor, and pores are generated.

[0055] Comparative Example 3 Compared with Example 1, the zirconium silicon powder was removed and the surface Figure 4 As shown, the weld is not round, has poor forming, poor wettability, and is easy to fall off after being put on the machine.

[0056] Compared with Example 1, in Comparative Example 4, the titanium carbide: ferrotitanium = 1:5.5, the ferrotitanium content is too high, resulting in serious ferrotitanium burning and low hardness after welding, which is 54.9HRC. However, the process performance is good, as shown in Table 2.

[0057] The performance of the welding wire obtained in Comparative Example 5 is slightly different from that in Example 1, but it is expensive and not suitable for mass production.

[0058] 2. Based on the good welding process of Examples 1-3 and Comparative Example 4, surfacing samples can be produced, that is, the surfacing samples do not produce defects such as slag inclusions, pores, and cracks. Next, the flux-cored wires of Examples 1-3 and Comparative Example 4 were used to perform gas shielded surfacing welding on a test plate with a length × width × height = 200 mm × 400 mm × 30 mm. The surfacing sample was welded in accordance with YB / T4326-2013, with a single-side surfacing thickness of 15 mm. The specific surfacing welding process is as follows: (1) Preheat the sample to 150°C; (2) Gas shielded cladding was performed using the flux-cored wires in Examples 1-3 and Comparative Example 4. The cladding parameters were as follows: Protective gas: carbon dioxide; Gas flow rate: 22ml / min; Welding current I: 360A; Welding voltage U: 33V; (3) Slowly cool the welded specimen at a rate of 60°C / h to room temperature; Figure 5 The metallographic structure after welding in Example 1 is martensite, of which austenite is about 10%, and a certain amount of carbide is precipitated between the dendrites.

[0059] The metallographic structures of Examples 2-3 and Comparative Example 4 after surfacing treatment are also martensite and 7-15% austenite.

[0060] Impact specimens were prepared on the cover layer of the test plate according to the specimen and measurement requirements shown in YB / T4326-2013 and tested. The results are shown in Table 2 below.

[0061] Table 2 Some mechanical properties of cladding materials at different temperatures

[0062] It can be seen that compared with Example 1, in Comparative Example 4, the ratio of titanium carbide to ferrotitanium is 1:5.5, and the ferrotitanium content is too high, resulting in a low hardness after welding of 54.9 HRC.

[0063] Examples 1-3 all meet the requirements of this application: the ratio of high-carbon ferrochrome, titanium carbide, and graphite is 1:0.1-0.4:0.05-0.2, and the ratio of titanium carbide to ferrotitanium is 0.8-1.5. Furthermore, 0.1-0.45% white zirconium silicon powder is added. Therefore, both processability and mechanical properties are excellent.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing, characterized by: The welding wire comprises the following components by weight percentage: cryolite: 0.2%-1.5%; zirconium silicon powder: 0.1%-0.45%; potassium titanate: 0.1%-1%; ferrotitanium: 1.0%-6%; high carbon ferrochrome: 20%-35%; titanium carbide: 1.8-11%; graphite: 0.8-7.0%; low carbon ferrochrome: 40-52%; ferroniobium: 1-8%; ferrovanadium: 1.0-4.0%; ferrosilicon: 1.0%-5.5%; manganese powder: 0.5%-2.5%; Ferroboron: 0-1.4%; the balance is iron powder.

2. The gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing according to claim 1, characterized in that: The mass ratio of high carbon ferrochrome, titanium carbide and graphite is 1:0.1-0.4:0.05-0.2; The mass ratio of titanium carbide to ferrotitanium is 0.8-1.

5.

3. The gas-shielded flux-cored welding wire for Cr13 series stainless steel surfacing welding according to claim 1, characterized in that: The mass ratio of titanium carbide and ferrotitanium to ferroniobium and ferrovanadium is >0.

85.

4. The gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing according to claim 3, characterized in that: The mass percentage of Ti in ferrotitanium is more than 25%.

5. The gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing according to claim 1, characterized in that: The mass percentage of Cr in the high carbon ferrochrome is more than 64%, and the mass percentage of C is more than 8%; The mass percentage of Cr in the low-carbon ferrochrome is more than 68%, and the mass percentage of C is less than 0.035%; The mass percentage of Si in ferrosilicon is more than 74%; The mass percentage of V in ferrovanadium is 50%-70%; The mass percentage of Nb in ferroniobium is 60%-70%; The mass percentage of B in ferroboron is more than 20%; The mass percentage of Zr in zirconium silicon powder is 1-2%; The purity of manganese powder, graphite and titanium carbide reaches over 99%.

6. The gas-shielded flux-cored welding wire for Cr13 series stainless steel surfacing welding according to claim 1, characterized in that: The deposited metal of the welding wire includes the following components in weight percentage: C：0.80%-1.40%； Cr：11.5%-13.5%； Nb: 0.1%-2.0%; V：0.1-1.0%； Mn: 0.1%-1%; Si: 0.2%-1.1%; Ti: 0.6-2.0% B：0-0.1%， Zr：0-0.04%； Balance Fe.

7. The gas-shielded flux-cored welding wire for Cr13 stainless steel surfacing according to claim 1, characterized in that: The diameter of the welding wire is 1.6 mm, and the hardness of the deposited metal of the welding wire in the welded state is ≥57 HRc.

8. A surfacing method for a Cr13 stainless steel surfacing gas-shielded flux-cored wire according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: (1) using the welding wire to perform gas shielded cladding welding; (2) Slow cooling treatment of welded parts; (3) Cool the weldment to room temperature.

9. The surfacing welding method of the gas-shielded flux-cored welding wire for Cr13 series stainless steel surfacing according to claim 8, characterized in that: Before step (1), the weldment is also preheated, and the preheating temperature is not less than 120°C.

10. The surfacing welding method of a gas-shielded flux-cored welding wire for Cr13 series stainless steel surfacing according to claim 8, characterized in that: In step (1), the gas in the gas shield is one or both of carbon dioxide and argon, and the gas flow rate is 20-28 ml / min; the surfacing welding current is 280-400 A, and the welding voltage is 32-38 V; In step (2), the slow cooling rate is 55°C / h-75°C / h.

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