An electrode for high-current welding of 10Cr9MoW2VNbBN steel, its coating and cladding metal

Abstract

The present application relates to a welding electrode, its coating and clad metal applicable to the large-current welding of 10Cr9MoW2VNbBN steel, belonging to the technical field of welding consumables; the components of the coating include, by mass parts: 400-450 parts of marble, 200-250 parts of fluorite, 50-90 parts of wollastonite, 40-80 parts of potassium oxide, 250-300 parts of iron powder, 4-8 parts of iron oxide red and 10-15 parts of soda ash; by adding iron powder, since a large amount of heat is required when the iron powder melts, the temperature of the coating and the molten pool can be reduced during welding. In the case where the welding core turns red, the purpose that the welding electrode is applicable to large-current welding can be achieved. At the same time, in the case of high-current welding, the process performance of the welding electrode can be ensured and good mechanical properties of the weld can be obtained.

Description

Technical Field

[0001] The present application relates to the technical field of welding materials, and in particular to a welding rod suitable for high-current welding of 10Cr9MoW2VNbBN steel and its coating and cladding metal. Background Art

[0002] 10Cr9MoW2VNbBN steel is mainly used for high temperature and high pressure parts in thermal power generation equipment. When welding these parts, matching welding rods are required for welding. There are a large number of parts that need to be welded during factory construction, which requires a large welding workload and high labor costs. When the same welding rod is welded with a larger current, a faster melting speed of the welding rod will be obtained. Welders can complete more work tasks in the same unit time by using a larger current welding operation. In order to improve welding efficiency; high current welding is generally used to increase the amount of deposited metal per unit time. At present, the maximum welding current of the 4.0 mm stainless steel welding core welding rod is 140-160A. Poor welding results will occur at higher welding currents. Summary of the invention

[0003] The present application provides a welding rod and its coating and cladding metal suitable for high-current welding of 10Cr9MoW2VNbBN steel, so as to improve the problem that the welding rod has poor welding effect under high welding current.

[0004] During the invention process, the applicant discovered that when the current welding rod is working at a high welding current, the welding core of the welding rod will turn red. After the welding core of the ordinary welding rod turns red, the heat generated by the red welding core will cause part of the powder in the coating to undergo an oxidation-reduction reaction in advance before melting into the molten pool, resulting in a reduction in the effect of the coating entering the molten pool after melting and the coating falling off the welding core, affecting the welder's operation and the mechanical properties of the weld.

[0005] In the first aspect, the present application provides a coating suitable for high-current welding of 10Cr9MoW2VNbBN steel, wherein the components of the coating include, by mass: 400-450 parts of marble, 200-250 parts of fluorite, 50-90 parts of wollastonite, 40-80 parts of potassium oxide, 250-300 parts of iron powder, 4-8 parts of red iron oxide and 10-15 parts of soda ash.

[0006] As an optional embodiment, the ingredients of the coating include, by mass, 410-440 parts of marble, 210-240 parts of fluorite, 60-80 parts of wollastonite, 50-70 parts of potassium oxide, 260-290 parts of iron powder, 5-7 parts of red iron oxide and 11-14 parts of soda ash.

[0007] As an alternative embodiment, the components of the coating by mass parts include: 420-430 parts of marble, 220-230 parts of fluorite, 65-75 parts of wollastonite, 55-65 parts of potassium oxide, 270-280 parts of iron powder, 5.5-6.5 parts of iron oxide red, and 12-13 parts of soda ash.

[0008] As an alternative embodiment, in the marble, the mass ratio of CaCO3 is ≥98%, the mass ratio of S is ≤0.01%, and the mass ratio of P is ≤0.02%; and / or

[0009] In the fluorite, the mass ratio of CaF2 is ≥98%, the mass ratio of SiO2 is ≤1.0%, the mass ratio of C is ≤0.05%, the mass ratio of S is ≤0.01%, and the mass ratio of P is ≤0.02%; and / or

[0010] In the wollastonite, the mass ratio of SiO2 is ≥90.0%, the mass ratio of S is ≤0.02%, and the mass ratio of P is ≤0.02%; and / or

[0011] In the potassium oxide, the mass ratio of KO2 is ≥90%, the mass ratio of S is ≤0.02%, and the mass ratio of P is ≤0.02%; and / or

[0012] In the iron powder, the mass ratio of Fe is ≥97.0%, the mass ratio of Mn is ≤0.40%, the mass ratio of Si is ≤0.20%, the mass ratio of C is ≤0.10%, the mass ratio of S is ≤0.025%, and the mass ratio of P is ≤0.025%; and / or

[0013] In the iron oxide red, the mass ratio of Fe2O3 is ≥99%; and / or

[0014] In the soda ash, the mass ratio of Na2CO3 is ≥99%, and the mass ratio of NaCl is ≤0.70%.

[0015] As an alternative embodiment, the particle size requirement of the marble is: the mass ratio of -40 mesh particles is 100%, and the mass ratio of -150 mesh particles is ≤60%; and / or

[0016] The particle size requirement of the fluorite is: the mass ratio of -40 mesh particles is 100%, and the mass ratio of -150 mesh particles is ≤60%; and / or

[0017] The particle size requirement of the wollastonite is: the mass ratio of -60 mesh particles is 100%; and / or

[0018] The particle size requirement of the potassium oxide is: the mass ratio of -60 mesh particles is 100%; and / or

[0019] The particle size requirement of the iron powder is as follows: the mass percentage of -30 mesh particles is 100%; and / or

[0020] The particle size requirement of the iron oxide red is as follows: the mass percentage of -100 mesh particles is 100%; and / or

[0021] The particle size requirement of the soda ash is as follows: the mass percentage of -100 mesh particles is 100%.

[0022] In a second aspect, the present application provides a welding electrode suitable for high-current welding of 10Cr9MoW2VNbBN steel. The welding electrode includes a welding core and a coating. The coating is coated on the welding core, and the coating is the coating described in the first aspect.

[0023] As an optional implementation manner, the composition of the welding core includes, by mass fraction: C: 0.12% - 0.18%, Mn: 0.80% - 1.50%, Si: 0.10% - 0.20%, Cr: 9.00% - 9.50%, Mo: 0.50% - 0.90%, V: 0.20% - 0.30%, Nb: 0.05% - 0.07%, N: 0.001% - 0.01%, B: 0.001 - 0.003%, W: 1.80% - 2.00%, and the balance is Fe and unavoidable impurities.

[0024] As an optional implementation manner, the maximum working current of the welding electrode is greater than 160A; or

[0025] The maximum working current of the welding electrode is 200A.

[0026] In a third aspect, the present application provides a clad metal suitable for high-current welding of 10Cr9MoW2VNbBN steel. The clad metal is obtained by the welding electrode described in the second aspect during the welding process.

[0027] As an optional implementation manner, the composition of the deposited metal includes, by mass fraction: C: 0.08% - 0.15%, Mn: 0.30% - 1.20%, Si: 0.10% - 0.60%, Cr: 8.50% - 9.50%, Mo: 0.30% - 0.70%, V: 0.15% - 0.30%, Nb: 0.02% - 0.07%, N: 0.03% - 0.08%, B: 0.001 - 0.003%, W: 1.50% - 2.00%, K: 0.0001% - 0.0006%, Ca: 0.0001% - 0.001%, and the balance is Fe and unavoidable impurities.

[0028] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0029] The coating provided by the embodiment of the present application can reduce the temperature of the coating and the molten pool during welding by adding iron powder, as a large amount of heat is required when the iron powder melts. When the welding core turns red, the purpose of making the welding rod applicable to high-current welding can be achieved. Meanwhile, in the case of high-current welding, the process performance of the welding rod can be ensured to be good and good mechanical properties of the weld can be obtained. Detailed implementation mode

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0031] Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in the present application can be obtained through market purchase or can be prepared by existing methods.

[0032] The applicant found during the invention process that: when the current welding rod works under high welding current, the welding core of the welding rod will turn red. After the welding core of the ordinary welding rod coating turns red, the heat generated by the red welding core will cause some of the powder in the coating to undergo redox reactions in advance before melting into the molten pool, resulting in a reduction in the effect of the coating melting into the molten pool and the coating falling off from the welding core, affecting the welder's operation and the mechanical properties of the weld. Therefore, it is usually required that a welding rod with a 4.0 mm diameter alloy or stainless steel welding core be welded with a current of 160 A or less. When the same welding rod is welded with a larger current, a faster melting speed of the welding rod can be obtained. The welder will complete more work tasks when welding with a larger current within the same unit time. To improve the welding efficiency, high-current welding is generally adopted to increase the amount of deposited metal per unit time. Currently, the maximum welding current of a welding rod with a 4.0 mm stainless steel welding core is 140 - 160 A. Higher welding currents will result in poor welding effects.

[0033] The redness of the welding core during welding is a physical property of the welding core that is difficult to change. Through research on the coating composition of the welding rod for 10Cr9MoW2VNbBN steel, by adding iron powder to control the molten pool temperature and adding potassium oxide to stabilize the arc, the applicant invented that the maximum welding current of a welding rod with a 4.0 mm diameter alloy welding core is 200 A. When the welding current of the welding rod is 200 A, the temperature of the weld molten pool is moderate, the fluidity of the molten iron is moderate, the arc blow force is stable and concentrated, and the welding operation performance of the welder is good.

[0034] The embodiment of the present application provides a coating suitable for high-current welding of 10Cr9MoW2VNbBN steel. The components of the coating include, by mass: 400-450 parts of marble, 200-250 parts of fluorite, 50-90 parts of wollastonite, 40-80 parts of potassium oxide, 250-300 parts of iron powder, 4-8 parts of iron oxide red, and 10-15 parts of soda ash.

[0035] The function of the iron powder is to reduce the welding heat. A large amount of heat is required when the added iron powder melts. During the welding of the electrode, it can reduce the temperature of the coating and the molten pool, so as to achieve the purpose that the electrode is suitable for high-current welding.

[0036] The function of marble is to provide slag and gas. Marble (the main component is CaCO3) decomposes to produce CaO and CO2. CO2 enters the molten pool to isolate the molten pool from the air, preventing the molten pool from being oxidized when contacting the air and the high-temperature metal after the molten pool solidifies from being oxidized when contacting the air, and stirring the molten pool. Stirring is beneficial to the oxidation-reduction reaction in the molten pool, the overflow of gas, and the floating of slag. At the same time, it reacts with C in the molten pool to generate twice the amount of CO, CO2 + C = 2CO, and the stirring of the molten pool is more intense, and decarburization will burn out C. When the amount of marble added decreases, the generated CO2 decreases, and the C content in the deposited metal increases, resulting in an increase in mechanical property strength and a decrease in toughness; CaO forms slag with silicon dioxide in the ore in the molten pool to form dicalcium silicate or tricalcium silicate, and the steel slag removes carbon, silicon, and phosphorus from the molten iron. When the amount of marble added decreases, the generated CaO decreases, and the impurity content in the deposited metal increases, resulting in a decrease in mechanical properties. If too much marble is added, on the one hand, it is easy to form a longer sleeve, affecting the welding process. On the other hand, a large amount of CO2 will be generated, with a large blowing force, affecting the welding process.

[0037] The function of fluorite is to improve the fluidity of the molten iron in the molten pool, provide slag and remove hydrogen. Fluorite (the main component is CaF2) decomposes to produce CaO and F. F reacts with the crystal water in the coating and combines with H in the molten pool to form HF, reducing the diffusible hydrogen in the weld, which is beneficial to the crack resistance of the weld. CaO forms slag with SiO2 in the ore to form dicalcium silicate or tricalcium silicate, and the steel slag removes carbon, silicon, and phosphorus from the molten iron, reducing the impurity elements in the weld, purifying the weld, and improving the mechanical properties of the weld.

[0038] Marble and fluorite decompose relatively quickly under high-current conditions, generating a large amount of gas, which easily makes the arc unstable. Adding potassium oxide can play a role in stabilizing the arc, so as to achieve good mechanical properties of the weld under good control of welding operation performance.

[0039] The function of iron oxide red is to promote the oxidation-reduction reaction in the molten pool, accelerate the melting speed of the electrode, and further improve the welding efficiency.

[0040] The silicon element in wollastonite deoxidizes in the molten pool and can also improve the fluidity of the molten iron in the molten pool.

[0041] Soda ash is added as a binder. The combined effect of soda ash and water glass makes the powder viscosity and slippery, which enables the wet welding rod to be produced smoothly.

[0042] The same formula coating welding rod will obtain greater arc blowing force and faster welding rod melting speed when welding with higher current. If the arc blowing force is too small during welding, the arc will be unstable, and defects such as pores will be easily generated in windy outdoor construction; if the arc blowing force is too large during welding, it will cause large spatters, increase the workload of cleaning the weld surface, and too large blowing force will easily cause irregular weld pool and poor weld formation. The above ingredients and ratios can ensure that the arc blowing force of the welding rod is moderate when welding with high current.

[0043] In some embodiments, the ingredients of the coating include, by mass, 410-440 parts of marble, 210-240 parts of fluorite, 60-80 parts of wollastonite, 50-70 parts of potassium oxide, 260-290 parts of iron powder, 5-7 parts of red iron oxide, and 11-14 parts of soda ash.

[0044] In some embodiments, the ingredients of the coating include, by mass, 420-430 parts of marble, 220-230 parts of fluorite, 65-75 parts of wollastonite, 55-65 parts of potassium oxide, 270-280 parts of iron powder, 5.5-6.5 parts of red iron oxide, and 12-13 parts of soda ash.

[0045] In some embodiments, in the marble, the mass fraction of CaCO3 is ≥98%, the mass fraction of S is ≤0.01%, and the mass fraction of P is ≤0.02%; in the fluorite, the mass fraction of CaF2 is ≥98%, the mass fraction of SiO2 is ≤1.0%, the mass fraction of C is ≤0.05%, the mass fraction of S is ≤0.01%, and the mass fraction of P is ≤0.02%; in the wollastonite, the mass fraction of SiO2 is ≥90.0%, the mass fraction of S is ≤0.02%, and the mass fraction of P is ≤0.02%; in the potassium oxide, the mass fraction of KO2 is ≥90%, the mass fraction of S is ≤0.02%, and the mass fraction of P is ≤0.02%; in the iron powder, the mass fraction of Fe is ≥97.0%, the mass fraction of Mn is ≤0.40%, the mass fraction of Si is ≤0.20%, the mass fraction of C is ≤0.10%, the mass fraction of S is ≤0.025%, and the mass fraction of P is ≤0.025%; in the iron oxide red, the mass fraction of Fe2O3 is ≥99%; in the soda ash, the mass fraction of Na2CO3 is ≥99%, and the mass fraction of NaCl is ≤0.70%. The particle size requirements for the marble are as follows: the mass fraction of -40 mesh particles is 100%, and the mass fraction of -150 mesh particles is ≤60%; the particle size requirements for the fluorite are as follows: the mass fraction of -40 mesh particles is 100%, and the mass fraction of -150 mesh particles is ≤60%; the particle size requirements for the wollastonite are as follows: the mass fraction of -60 mesh particles is 100%; the particle size requirements for the potassium oxide are as follows: the mass fraction of -60 mesh particles is 100%; the particle size requirements for the iron powder are as follows: the mass fraction of -30 mesh particles is 100%; the particle size requirements for the iron oxide red are as follows: the mass fraction of -100 mesh particles is 100%; the particle size requirements for the soda ash are as follows: the mass fraction of -100 mesh particles is 100%.

[0046] Based on a general inventive concept, the embodiments of the present application further provide a welding electrode suitable for high-current welding of 10Cr9MoW2VNbBN steel. The welding electrode includes a welding core and a coating, the coating covers the welding core, and the coating is the coating provided above.

[0047] In some embodiments, the composition of the welding core, by mass fraction, includes: C: 0.12% - 0.18%, Mn: 0.80% - 1.50%, Si: 0.10% - 0.20%, Cr: 9.00% - 9.50%, Mo: 0.50% - 0.90%, V: 0.20% - 0.30%, Nb: 0.05% - 0.07%, N: 0.001% - 0.01%, B: 0.001 - 0.003%, W: 1.80% - 2.00%, and the balance is Fe and inevitable impurities. Alloying elements are added to this welding core, and its resistance is greater than that of a carbon steel welding core without added alloying elements. When operating at high currents, it is more likely to turn red. For example, when welding with a welding rod of 4.0 mm in diameter using a current above 170 A, the welding core of the welding rod will turn red.

[0048] Generally, the diameters of the welding cores are usually 2.5 mm, 3.2 mm, 4.0 mm, and 5.0 mm. Here, only the manufacturing process of the welding rod with a 4.0 mm welding core is taken as an example. The manufacturing processes of the welding rods with diameters of 2.5 mm, 3.2 mm, and 5.0 mm are the same as that of the 4.0 mm diameter welding rod. When producing the welding rod, the corresponding inner diameter of the mold and the inner diameter of the pipeline need to be adopted according to the outer diameter of the welding core to ensure the smooth production of the welding rod. The specific preparation process is as follows: Mix the coating powder for 15 - 20 minutes. Add 20 - 30% of the total amount of the binder for the coating and stir and mix for 5 - 10 minutes. The diameter of the welding core is 4.0 mm and the length is processed to 400 mm. Feed the mixed powder into the strip press to coat it on the welding core. Bake it at a quasi-low temperature of 50 - 60 °C for 2 - 3 hours, at a low temperature of 80 - 100 °C for 2 - 3 hours, and then at a high temperature of 380 - 400 °C for 1.5 - 2 hours to obtain the welding rod. After the high-temperature baking is completed, cool the welding rod to below 50 °C and then package the welding rod.

[0049] The maximum welding current of the obtained welding rod with a 4.0 mm diameter alloy welding core can reach 200 A. When the welding current of the welding rod is 200 A, the temperature of the weld pool is moderate, the fluidity of the molten iron is moderate, the arc blowing force is stable and concentrated, the welding operation performance of the welder and the mechanical properties of the weld are good, which can improve the production efficiency on the premise of ensuring quality. After popularization and use, it can save energy and shorten the manufacturing period of the equipment.

[0050] Based on a general inventive concept, the embodiments of the present application also provide a cladding metal suitable for high-current welding of 10Cr9MoW2VNbBN steel, and the cladding metal is obtained from the welding rod provided above during the welding process.

[0051] In some embodiments, the composition of the deposited metal by mass fraction includes: C: 0.08% - 0.15%, Mn: 0.30% - 1.20%, Si: 0.10% - 0.60%, Cr: 8.50% - 9.50%, Mo: 0.30% - 0.70%, V: 0.15% - 0.30%, Nb: 0.02% - 0.07%, N: 0.03% - 0.08%, B: 0.001 - 0.003%, W: 1.50% - 2.00%, K: 0.0001% - 0.0006%, Ca: 0.0001% - 0.001%, and the balance is Fe and unavoidable impurities.

[0052] The room temperature tensile strength of the clad metal is 620 MPa - 760 MPa, the room temperature yield strength is 530 MPa - 660 MPa, the room temperature elongation after fracture is 15 - 28%, and the single value of impact at 20 °C is 80 - 120 J.

[0053] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods without specific conditions noted in the following embodiments are generally determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0054] Example 1

[0055] A matching electrode for 10Cr9MoW2VNbBN steel, which is composed of a welding core and a coating covering the surface of the welding core. The composition and content of the coating are as follows: marble: 400 parts by weight, fluorite 210 parts by weight, wollastonite 60 parts by weight, potassium oxide 60 parts by weight, iron powder 255 parts by weight, iron oxide red 5 parts by weight, soda ash 10 parts by weight. It is characterized in that: the marble: CaCO3≥98%, S≤0.01%, P≤0.02%, and the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; fluorite: CaF2≥98%, SiO2≤1.0%, C≤0.05%, S≤0.01%, P≤0.02%, and the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; wollastonite: SiO2≥90.0%, S≤0.02%, P≤0.02%, and the particle size requirements are -60 mesh: 100%. Potassium oxide: KO2≥90%, S≤0.02%, P≤0.02%, and the particle size requirements are -60 mesh: 100%; iron powder: Fe≥97.0%, Mn≤0.40%, Si≤0.20%, C≤0.10%, S≤0.025%, P≤0.025%, and the particle size requirements: -30 mesh: 100%; iron oxide red: Fe2O3≥99%, and the particle size requirements are -100 mesh: 100%; soda ash: Na2CO3≥99%, NaCl≤0.70%, and the particle size requirements are -100 mesh: 100%.

[0056] The diameter of the welding core is 4.0 mm and the length is processed to 400 mm. The chemical composition of the welding core is carbon element 0.18%, manganese element 1.00%, silicon element 0.10%, chromium element 9.50%, molybdenum element 0.90%, vanadium element 0.30%, niobium element 0.06%, nitrogen element 0.005%, boron element 0.001%, tungsten element 2.00%, and the remaining elements are iron element and impurity elements.

[0057] The mixed powder is sent into a strip press to coat it on the welding core. After baking at a quasi-low temperature of 50-60°C for 2-3 hours, at a low temperature of 80-100°C for 2-3 hours, and then at a high temperature of 380-400°C for 1.5-2 hours, the electrode is obtained. After the high-temperature baking is completed, the electrode is cooled to below 50°C, and then the electrode is packaged.

[0058] Welding tests and heat treatments were carried out on this welding electrode. The welding test process was as follows: The preparation of the welding test plate was carried out in accordance with the standard GB / T25774.1-2010 "Inspection of welding consumables - Part 1: Preparation and inspection of specimens for mechanical properties of deposited metal of steels, nickel and nickel alloys". The thickness of the welding test plate was 20 mm, the width was 150 mm, and the length was 400 mm. The preheating temperature of the test plate before welding was 200 °C. The DC reverse connection was used for the welding power source, the welding current was 200 A, the welding voltage was 25 V, the welding speed was 120 mm / min, and the interlayer temperature during the welding process was 250 °C. After the welding of the test plate was completed, the test plate was placed in a heat treatment furnace at 350 °C and kept warm for 2 hours. After the holding time ended, the test plate was taken out and air-cooled; The heat treatment process was as follows: The heat treatment was carried out by putting the test piece into the furnace at room temperature, the heating rate was 100 °C / h, it was kept warm at 760 °C for 2 hours, the cooling rate was 50 °C / h, and it was taken out of the furnace and air-cooled at 300 °C.

[0059] Performance tests were carried out on the samples obtained from the welding tests and heat treatments. The performance tests included: chemical composition analysis tests, tensile tests, and impact tests at 20 °C.

[0060] The composition of the deposited metal obtained by the implementation, in mass fraction, included: carbon element 0.11%, manganese element 0.80%, silicon element 0.20%, chromium element 9.10%, molybdenum element 0.40%, vanadium element 0.20%, niobium element 0.03%, nitrogen element 0.04%, boron element 0.001%, tungsten element 1.90%, potassium element 0.0002%, calcium element 0.0005%, and the remaining elements were iron elements and impurity elements.

[0061] The tensile strength of the deposited metal at room temperature was 720 MPa, the yield strength at room temperature was 590 MPa, the elongation after fracture at room temperature was 20%, and the single values of impact at 20 °C were 90 J, 93 J, and 99 J.

[0062] Example 2

[0063] A welding electrode for 10Cr9MoW2VNbBN steel consists of a welding core and a coating wrapped on the surface of the welding core.

[0064] The composition and content of the coating are as follows: marble: 420 parts by weight, fluorite 215 parts by weight, wollastonite 50 parts by weight, potassium oxide 50 parts by weight, iron powder 250 parts by weight, iron oxide red 5 parts by weight, soda ash 10 parts by weight. It is characterized in that: for the marble: CaCO3≥98%, S≤0.01%, P≤0.02%, and the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; for the fluorite: CaF2≥98%, SiO2≤1.0%, C≤0.05%, S≤0.01%, P≤0.02%, and the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; for the wollastonite: SiO2≥90.0%, S≤0.02%, P≤0.02%, and the particle size requirement is -60 mesh: 100%. For potassium oxide: KO2≥90%, S≤0.02%, P≤0.02%, and the particle size requirement is -60 mesh: 100%; for the iron powder: Fe≥97.0%, Mn≤0.40%, Si≤0.20%, C≤0.10%, S≤0.025%, P≤0.025%, and the particle size requirement: -30 mesh: 100%; for the iron oxide red: Fe2O3≥99%, and the particle size requirement is -100 mesh: 100%; for the soda ash: Na2CO3≥99%, NaCl≤0.70%, and the particle size requirement is -100 mesh: 100%.

[0065] The diameter of the welding core is 4.0 mm and the length is processed to 400 mm. The chemical composition of the welding core is carbon element 0.18%, manganese element 1.00%, silicon element 0.10%, chromium element 9.50%, molybdenum element 0.90%, vanadium element 0.30%, niobium element 0.06%, nitrogen element 0.005%, boron element 0.001%, tungsten element 2.00%, and the remaining elements are iron element and impurity elements.

[0066] The mixed powder is fed into a strip press to coat it on the welding core. It is baked at a quasi-low temperature of 50 - 60°C for 2 - 3 hours, at a low temperature of 80 - 100°C for 2 - 3 hours, and then at a high temperature of 380 - 400°C for 1.5 - 2 hours to obtain the welding electrode. After the high-temperature baking is completed, the welding electrode is cooled to below 50°C, and then the welding electrode is packaged.

[0067] Welding tests and heat treatments were carried out on this welding electrode. The process of the welding test was as follows: The preparation of the welding test plate was carried out in accordance with the standard GB / T25774.1-2010 "Inspection of welding consumables - Part 1: Preparation and inspection of specimens for mechanical properties of deposited metal of steels, nickel and nickel alloys". The thickness of the welding test plate was 20 mm, the width of the test plate was 150 mm, and the length of the test plate was 400 mm. The preheating temperature of the test plate before welding was 200 °C. The direct current reverse connection was used for the welding power supply, the welding current was 200 A, the welding voltage was 25 V, the welding speed was 120 mm / min, and the interlayer temperature during the welding process was 250 °C. After the welding of the test plate was completed, the test plate was placed in a heat treatment furnace at a temperature of 350 °C and kept warm for 2 hours. After the holding time ended, the test plate was taken out and air-cooled. The heat treatment process was as follows: The heat treatment was carried out by putting the test piece into the furnace at room temperature, the heating rate was 100 °C / h, it was kept warm at 760 °C for 2 hours, the cooling rate was 50 °C / h, and it was taken out of the furnace at 300 °C and air-cooled.

[0068] Performance tests were carried out on the samples obtained from the welding tests and heat treatments. The performance tests included: chemical composition analysis tests, tensile tests, and impact tests at 20 °C.

[0069] The composition of the deposited metal obtained by the implementation, in terms of mass fraction, included: carbon element 0.11%, manganese element 0.79%, silicon element 0.22%, chromium element 9.11%, molybdenum element 0.42%, vanadium element 0.22%, niobium element 0.04%, nitrogen element 0.03%, boron element 0.001%, tungsten element 1.88%, potassium element 0.0003%, calcium element 0.0006%, and the remaining elements were iron elements and impurity elements.

[0070] The tensile strength of the deposited metal at room temperature was 710 MPa, the yield strength at room temperature was 585 MPa, the elongation after fracture at room temperature was 21%, and the single values of the impact at 20 °C were 97 J, 103 J, and 106 J.

[0071] Example 3

[0072] A matching electrode for 10Cr9MoW2VNbBN steel, which consists of a welding core and a coating wrapped on the surface of the welding core. The composition and content of the coating are as follows: marble: 435 parts by weight, fluorite 220 parts by weight, wollastonite 75 parts by weight, potassium oxide 65 parts by weight, iron powder 270 parts by weight, iron oxide red 5 parts by weight, soda ash 10 parts by weight. It is characterized in that: the marble: CaCO3≥98%, S≤0.01%, P≤0.02%, and the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; fluorite: CaF2≥98%, SiO2≤1.0%, C≤0.05%, S≤0.01%, P≤0.02%, and the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; wollastonite: SiO2≥90.0%, S≤0.02%, P≤0.02%, and the particle size requirements are -60 mesh: 100%. Potassium oxide: KO2≥90%, S≤0.02%, P≤0.02%, and the particle size requirements are -60 mesh: 100%; iron powder: Fe≥97.0%, Mn≤0.40%, Si≤0.20%, C≤0.10%, S≤0.025%, P≤0.025%, and the particle size requirements: -30 mesh: 100%; iron oxide red: Fe2O3≥99%, and the particle size requirements are -100 mesh: 100%; soda ash: Na2CO3≥99%, NaCl≤0.70%, and the particle size requirements are -100 mesh: 100%.

[0073] The diameter of the welding core is 4.0 mm and the length is processed to 400 mm. The chemical composition of the welding core is carbon element 0.18%, manganese element 1.00%, silicon element 0.10%, chromium element 9.50%, molybdenum element 0.90%, vanadium element 0.30%, niobium element 0.06%, nitrogen element 0.005%, boron element 0.001%, tungsten element 2.00%, and the remaining elements are iron element and impurity elements.

[0074] The mixed powder is sent into a strip press to wrap it on the welding core. After baking at a quasi-low temperature of 50-60°C for 2-3 hours, at a low temperature of 80-100°C for 2-3 hours, and then at a high temperature of 380-400°C for 1.5-2 hours, the electrode is obtained. After the high-temperature baking is completed, the electrode is cooled to below 50°C, and then the electrode is packaged.

[0075] Welding tests and heat treatments were carried out on this welding electrode. The welding test process was as follows: The preparation of the welding test plate was in accordance with the standard GB / T 25774.1-2010 "Inspection of welding consumables - Part 1: Preparation and inspection of specimens for mechanical properties of deposited metal of steels, nickel and nickel alloys". The thickness of the welding test plate was 20 mm, the width was 150 mm, and the length was 400 mm. Before welding, the preheating temperature of the test plate was 200 °C. The DC reverse connection was used for the welding power source, the welding current was 200 A, the welding voltage was 25 V, the welding speed was 120 mm / min, and the interpass temperature during the welding process was 250 °C. After the welding of the test plate was completed, the test plate was placed in a heat treatment furnace at 350 °C and kept warm for 2 hours. After the holding time ended, the test plate was taken out and air-cooled. The heat treatment process was as follows: The heat treatment was carried out by putting the material into the furnace at room temperature, the heating rate was 100 °C / h, it was kept warm at 760 °C for 2 hours, the cooling rate was 50 °C / h, and it was taken out of the furnace at 300 °C and air-cooled.

[0076] Performance tests were carried out on the samples obtained from the welding tests and heat treatments. The performance tests included: chemical composition analysis tests, tensile tests, and impact tests at 20 °C.

[0077] The composition of the obtained clad metal in terms of mass fraction included: carbon element 0.12%, manganese element 0.90%, silicon element 0.25%, chromium element 9.15%, molybdenum element 0.48%, vanadium element 0.22%, niobium element 0.04%, nitrogen element 0.04%, boron element 0.001%, tungsten element 1.85%, potassium element 0.0002%, calcium element 0.0007%, and the remaining elements were iron elements and impurity elements.

[0078] The tensile strength of the deposited metal at room temperature was 700 MPa, the yield strength at room temperature was 570 MPa, the elongation after fracture at room temperature was 22%, and the single values of the impact at 20 °C were 88 J, 81 J, and 76 J.

[0079] Comparative Example 1

[0080] A matching electrode for 10Cr9MoW2VNbBN steel, which is composed of a welding core and a coating covering the surface of the welding core. The composition and content of the coating are as follows: marble: 350 parts by weight, fluorite 220 parts by weight, wollastonite 75 parts by weight, potassium oxide 65 parts by weight, iron powder 270 parts by weight, iron oxide red 5 parts by weight, soda ash 10 parts by weight. It is characterized in that: the marble: CaCO3≥98%, S≤0.01%, P≤0.02%, the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; fluorite: CaF2≥98%, SiO2≤1.0%, C≤0.05%, S≤0.01%, P≤0.02%, the particle size requirements are: -40 mesh: ≥100%, -150 mesh: ≤60%; wollastonite: SiO2≥90.0%, S≤0.02%, P≤0.02%, the particle size requirement is -60 mesh: 100%. Potassium oxide: KO2≥90%, S≤0.02%, P≤0.02%, the particle size requirement is -60 mesh: 100%; iron powder: Fe≥97.0%, Mn≤0.40%, Si≤0.20%, C≤0.10%, S≤0.025%, P≤0.025%, the particle size requirement: -30 mesh: 100%; iron oxide red: Fe2O3≥99%, the particle size requirement is -100 mesh: 100%; soda ash: Na2CO3≥99%, NaCl≤0.70%, the particle size requirement is -100 mesh: 100%.

[0081] The diameter of the welding core is 4.0 mm and the length is processed to 400 mm. The chemical composition of the welding core is carbon element 0.18%, manganese element 1.00%, silicon element 0.10%, chromium element 9.50%, molybdenum element 0.90%, vanadium element 0.30%, niobium element 0.06%, nitrogen element 0.005%, boron element 0.001%, tungsten element 2.00%, and the remaining elements are iron element and impurity elements.

[0082] The mixed powder is sent into a strip press to coat it on the welding core. After baking at a quasi-low temperature of 50-60°C for 2-3 hours, at a low temperature of 80-100°C for 2-3 hours, and then at a high temperature of 380-400°C for 1.5-2 hours, the electrode is obtained. After the high-temperature baking is completed, the electrode is cooled to below 50°C and then the electrode is packaged.

[0083] Welding tests and heat treatments were carried out on this welding electrode. The welding test process was as follows: The preparation of the welding test plate was carried out in accordance with the standard GB / T 25774.1-2010 "Inspection of welding consumables - Part 1: Preparation and inspection of specimens for mechanical properties of deposited metal of steels, nickel and nickel alloys". The thickness of the welding test plate was 20 mm, the width of the test plate was 150 mm, and the length of the test plate was 400 mm. The preheating temperature of the test plate before welding was 200 °C. The DC reverse connection was used for the welding power supply, the welding current was 200 A, the welding voltage was 25 V, the welding speed was 120 mm / min, and the interlayer temperature during the welding process was 250 °C. After the welding of the test plate was completed, the test plate was placed in a heat treatment furnace at a temperature of 350 °C and kept warm for 2 hours. After the insulation time ended, the test plate was taken out and air-cooled; The heat treatment process was as follows: The heat treatment was carried out by putting the test piece into the furnace at room temperature, the heating rate was 100 °C / h, it was kept warm at 760 °C for 2 hours, the cooling rate was 50 °C / h, and it was taken out of the furnace and air-cooled at 300 °C.

[0084] Performance tests were carried out on the samples obtained from the welding tests and heat treatments. The performance tests included: chemical composition analysis tests, tensile tests, and impact tests at 20 °C.

[0085] The composition of the deposited metal obtained by the implementation, in terms of mass fraction, included: carbon element 0.15%, manganese element 0.90%, silicon element 0.25%, chromium element 9.15%, molybdenum element 0.48%, vanadium element 0.22%, niobium element 0.04%, nitrogen element 0.05%, boron element 0.001%, tungsten element 1.85%, potassium element 0.0002%, calcium element 0.0003%, and the remaining elements were iron elements and impurity elements.

[0086] The tensile strength of the deposited metal at room temperature was 740 MPa, the yield strength at room temperature was 630 MPa, the elongation after fracture at room temperature was 18%, and the single values of impact at 20 °C were 38 J, 44 J, and 31 J.

[0087] It can be seen from the above embodiments that the welding electrode prepared by the method provided in the embodiments of the present application for welding 10Cr9MoW2VNbBN steel can meet the mechanical property technical requirements of the matching welding electrode for 10Cr9MoW2VNbBN steel. It should be noted that the mechanical property technical requirements of the matching welding electrode for 10Cr9MoW2VNbBN steel are as follows: the tensile strength of the deposited metal at room temperature is greater than or equal to 620 MPa, the yield strength at room temperature is greater than or equal to 530 MPa, the elongation after fracture at room temperature ≥ 15, and the impact at 20 °C ≥ 27 J; Through the comparison between Comparative Example 1 and Example 3, it can be obtained that when the addition amount of marble reaches a certain amount, especially when it is 400 - 450 parts by mass, the comprehensive mechanical properties of the weld are better.

[0088] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the description of the said range has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the description of the range from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0089] In addition, in the description of the specification of the present application, terms such as "including" and "comprising" mean "including but not limited to". In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this text, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may mean: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B may be singular or plural. In this text, "at least one" means one or more, and "a plurality" means two or more. "At least one kind", "at least one of the following items (pieces)" or similar expressions refer to any combination of these items, including any combination of single item (piece) or plural items (pieces). For example, "at least one of a, b, or c", or, "at least one of a, b, and c" can both mean: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0090] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. An electrode suitable for high-current welding of 10Cr9MoW2VNbBN steel, characterized in that, The welding electrode includes a welding core and a coating, the coating covers the welding core, and the components of the coating include, by mass parts: 410 - 440 parts of marble, 210 - 240 parts of fluorite, 60 - 80 parts of wollastonite, 50 - 70 parts of potassium oxide, 260 - 290 parts of iron powder, 5 - 7 parts of iron oxide red, and 11 - 14 parts of soda ash; In the marble, the mass proportion of CaCO3 ≥ 98%, the mass proportion of S ≤ 0.01%, and the mass proportion of P ≤ 0.02%; In the fluorite, the mass proportion of CaF2 ≥ 98%, the mass proportion of SiO2 ≤ 1.0%, the mass proportion of C ≤ 0.05%, the mass proportion of S ≤ 0.01%, and the mass proportion of P ≤ 0.02%; The particle size requirement of the marble is: the mass proportion of -40 mesh particles is 100%, and the mass proportion of -150 mesh particles ≤ 60%; The particle size requirement of the fluorite is: the mass proportion of -40 mesh particles is 100%, and the mass proportion of -150 mesh particles ≤ 60%; The maximum working current of the welding electrode is 200 A, and the diameter of the welding core is 4.0 mm.

2. The electrode applicable to the large-current welding of 10Cr9MoW2VNbBN steel according to claim 1, characterized in that, The components of the coating include, by mass parts: 420 - 430 parts of marble, 220 - 230 parts of fluorite, 65 - 75 parts of wollastonite, 55 - 65 parts of potassium oxide, 270 - 280 parts of iron powder, 5.5 - 6.5 parts of iron oxide red, and 12 - 13 parts of soda ash.

3. The welding electrode applicable to the high - current welding of 10Cr9MoW2VNbBN steel according to any one of claims 1 to 2, characterized in that In the wollastonite, the mass proportion of SiO2 ≥ 90.0%, the mass proportion of S ≤ 0.02%, and the mass proportion of P ≤ 0.02%; and / or In the potassium oxide, the mass proportion of KO2 ≥ 90%, the mass proportion of S ≤ 0.02%, and the mass proportion of P ≤ 0.02%; and / or In the iron powder, the mass proportion of Fe ≥ 97.0%, the mass proportion of Mn ≤ 0.40%, the mass proportion of Si ≤ 0.20%, the mass proportion of C ≤ 0.10%, the mass proportion of S ≤ 0.025%, and the mass proportion of P ≤ 0.025%; and / or In the iron oxide red, the mass proportion of Fe2O3 ≥ 99%; and / or In the soda ash, the mass proportion of Na2CO3 ≥ 99%, and the mass proportion of NaCl ≤ 0.70%.

4. The welding electrode applicable to the high - current welding of 10Cr9MoW2VNbBN steel according to any one of claims 1 to 2, characterized in that The particle size requirement of the wollastonite is: the mass proportion of -60 mesh particles is 100%; and / or The particle size requirement of the potassium oxide is: the mass proportion of -60 mesh particles is 100%; and / or The particle size requirement of the iron powder is: the mass proportion of -30 mesh particles is 100%; and / or The particle size requirement of the iron oxide red is: the mass proportion of -100 mesh particles is 100%; and / or The particle size requirement of the soda ash is: the mass proportion of -100 mesh particles is 100%.

5. The welding electrode applicable to the high-current welding of 10Cr9MoW2VNbBN steel according to claim 1, characterized in that, The composition of the welding core by mass fraction includes: C: 0.12% - 0.18%, Mn: 0.80% - 1.50%, Si: 0.10% - 0.20%, Cr: 9.00% - 9.50%, Mo: 0.50% - 0.90%, V: 0.20% - 0.30%, Nb: 0.05% - 0.07%, N: 0.001% - 0.01%, B: 0.001 - 0.003%, W: 1.80% - 2.00%, and the balance is Fe and unavoidable impurities.

6. A cladding metal applicable to high-current welding of 10Cr9MoW2VNbBN steel, characterized in that, The cladded metal is obtained during welding with the welding electrode according to any one of claims 1 to 5.

7. The clad metal applicable to the large-current welding of 10Cr9MoW2VNbBN steel according to claim 6, characterized in that, The composition of the deposited metal by mass fraction includes: C: 0.08% - 0.15%, Mn: 0.30% - 1.20%, Si: 0.10% - 0.60%, Cr: 8.50% - 9.50%, Mo: 0.30% - 0.70%, V: 0.15% - 0.30%, Nb: 0.02% - 0.07%, N: 0.03% - 0.08%, B: 0.001 - 0.003%, W: 1.50% - 2.00%, K: 0.0001% - 0.0006%, Ca: 0.0001% - 0.001%, and the balance is Fe and unavoidable impurities.