阅读说明：本技术 交流用ENi6620镍基焊条及其制备方法与焊接方法 (ENi6620 nickel-based welding rod for alternating current and preparation method and welding method thereof ) 是由 刘杰 蒋勇 陈维富 张克静 杨飞 黄义芳 于 2021-08-06 设计创作，主要内容包括：本发明公开了交流用ENi6620镍基焊条及其制备方法与焊接方法,包括焊芯和裹覆于焊芯表面的药皮,所述药皮组成和含量为：大理石6-10重量份、碳酸锶3-6重量份、萤石6-9重量份、钾冰晶粉2-5重量份、氟硼酸钾0.5-1.5重量份、金红石2-6重量份、电解锰5-8重量份、金属铬25-30重量份、钼铁15-22重量份、钛铁2-5重量份、钨粉3-6重量份、铌铁5-9重量份、纯碱1-3重量份、钛酸钾2-6重量份、氟化稀土1-4重量份、二氧化锆0.5-2.5重量份、稀土硅铁0.5-3.5重量份。采用本方案,其焊条满足GB/T 13814ENi6620技术指标,具有良好的焊接工艺性能和力学性能,特别是-196℃条件下具有良好的低温韧性。(The invention discloses an ENi6620 nickel-based welding rod for alternating current, a preparation method and a welding method thereof, wherein the welding rod comprises a core wire and a coating wrapped on the surface of the core wire, and the coating comprises the following components in percentage by weight: 6-10 parts of marble, 3-6 parts of strontium carbonate, 6-9 parts of fluorite, 2-5 parts of potassium ice crystal powder, 0.5-1.5 parts of potassium fluoborate, 2-6 parts of rutile, 5-8 parts of electrolytic manganese, 25-30 parts of chromium metal, 15-22 parts of ferromolybdenum, 2-5 parts of ferrotitanium, 3-6 parts of tungsten powder, 5-9 parts of ferroniobium, 1-3 parts of calcined soda, 2-6 parts of potassium titanate, 1-4 parts of rare earth fluoride, 0.5-2.5 parts of zirconium dioxide and 0.5-3.5 parts of rare earth ferrosilicon. By adopting the scheme, the welding rod meets the technical index of GB/T13814 ENi6620, has good welding process performance and mechanical property, and particularly has good low-temperature toughness at the temperature of-196 ℃.)

1. The ENi6620 nickel-based welding rod for alternating current comprises a core wire and a coating wrapped on the surface of the core wire, and is characterized in that the coating comprises the following components in percentage by weight: 6-10 parts of marble, 3-6 parts of strontium carbonate, 6-9 parts of fluorite, 2-5 parts of potassium ice crystal powder, 0.5-1.5 parts of potassium fluoborate, 2-6 parts of rutile, 5-8 parts of electrolytic manganese, 25-30 parts of chromium metal, 15-22 parts of ferromolybdenum, 2-5 parts of ferrotitanium, 3-6 parts of tungsten powder, 5-9 parts of ferroniobium, 1-3 parts of calcined soda, 2-6 parts of potassium titanate, 1-4 parts of rare earth fluoride, 0.5-2.5 parts of zirconium dioxide and 0.5-3.5 parts of rare earth ferrosilicon.

2. The nickel-based ENi6620 electrode for alternating current of claim 1, wherein the core wire is a pure nickel core wire.

3. The nickel-based ENi6620 electrode for alternating current as claimed in claim 2, wherein the core wire comprises: less than or equal to 0.10 wt% of C, less than or equal to 0.05 wt% of Mn, less than or equal to 0.15 wt% of Si, less than or equal to 0.020 wt% of P, less than or equal to 0.005 wt% of S, more than or equal to 99.5 wt% of Ni, less than or equal to 0.10 wt% of Fe, and the balance of indispensable impurities.

4. The nickel-based ENi6620 electrode for alternating current of claim 3, wherein the core wire comprises: 0.0045 percent of C, 0.025 percent of Mn, 0.019 percent of Si, 0.0013 percent of P, 0.0010 percent of S, 99.64 percent of Ni, 0.024 percent of Fe and the balance of indispensable impurities.

5. The ENi6620 nickel-based welding rod for communication according to any one of claims 1 to 4, wherein CaCO 6620 is used in the marble₃The content is more than or equal to 96 percent, and SrCO in strontium carbonate₃Not less than 98.50%, CaF in fluorite₂The content is more than or equal to 96 percent, F in the potassium cryolite is more than or equal to 53.0 percent, Al is more than or equal to 13.0 percent, K is less than or equal to 32.0 percent, and potassium fluoborate KBF₄Not less than 98 percent of rutile TiO₂More than or equal to 92 percent, Mn in electrolytic manganese is more than or equal to 99.5 percent, Cr in metallic chromium is more than or equal to 98 percent, Mo in ferromolybdenum is 45 to 50 percent, Ti in ferrotitanium is 25 to 35 percent, W in tungsten powder is more than or equal to 99 percent, Nb is 45 to 50 percent, NaCl in soda is less than or equal to 0.7 percent, and K in potassium titanate is more than or equal to 98 percent₄TiO₄Not less than 95%, REO not less than 83% in rare earth fluoride, CeO₂Greater than or equal to 45 percent of ZrO in zirconium dioxide₂More than or equal to 95 percent, 45 percent of the rare earth ferrosilicon is more than or equal to 40 percent of Si, 32 percent of the rare earth ferrosilicon is more than or equal to 20 percent of Ce, and 20 percent of the rare earth ferrosilicon is more than or equal to 10 percent of La.

6. The ENi6620 nickel-based welding rod for alternating current according to any one of claims 1 to 4, characterized in that the coating comprises the following components in percentage by weight: 7.5 parts of marble, 4.5 parts of strontium carbonate, 7 parts of fluorite, 3.5 parts of potassium ice crystal powder, 1 part of potassium fluoborate, 3.5 parts of rutile, 6 parts of electrolytic manganese, 27 parts of metallic chromium, 19 parts of ferromolybdenum, 2.5 parts of ferrotitanium, 4 parts of tungsten powder, 7.5 parts of ferroniobium, 1 part of calcined soda, 3 parts of potassium titanate, 1 part of rare earth fluoride, 1 part of zirconium dioxide and 1 part of rare earth ferrosilicon.

7. The ENi6620 nickel-based welding rod for alternating current according to any one of claims 1 to 4, characterized in that the coating comprises the following components in percentage by weight: 6.5 parts of marble, 5.5 parts of strontium carbonate, 8 parts of fluorite, 3 parts of potassium ice crystal powder, 0.8 part of potassium fluoborate, 4 parts of rutile, 7.2 parts of electrolytic manganese, 26.5 parts of chromium metal, 17.5 parts of ferromolybdenum, 3 parts of ferrotitanium, 3.6 parts of tungsten powder, 6.2 parts of ferroniobium, 1.2 parts of soda ash, 3.5 parts of potassium titanate, 1.5 parts of rare earth fluoride, 0.5 part of zirconium dioxide and 1.5 parts of rare earth ferrosilicon.

8. The ENi6620 nickel-based welding rod for alternating current according to any one of claims 1 to 4, characterized in that the coating comprises the following components in percentage by weight: 8 parts of marble, 3 parts of strontium carbonate, 6 parts of fluorite, 4.8 parts of potassium ice crystal powder, 1.2 parts of potassium fluoborate, 4 parts of rutile, 5.5 parts of electrolytic manganese, 25.8 parts of chromium metal, 16 parts of ferromolybdenum, 4 parts of ferrotitanium, 3.2 parts of tungsten powder, 5.8 parts of ferroniobium, 1.6 parts of soda ash, 3.7 parts of potassium titanate, 3 parts of rare earth fluoride, 2 parts of zirconium dioxide and 2.4 parts of rare earth ferrosilicon.

9. The preparation method of the ENi6620 nickel-based welding rod for alternating current according to any one of claims 1 to 8, characterized by comprising the following steps:

(1) stirring the powder of the coating and mixing uniformly;

(2) adding pure potassium water glass with the total component mass of 20-24% and the concentration of 42-43-degree Be' into the stirred coating powder, stirring, uniformly mixing, and then feeding into a welding rod coating press to coat the coating powder on a welding core under the pressure of 14-16 MPa;

(3) baking at low temperature of 85-90 ℃ for 4-6.5 hours and at high temperature of 300-.

10. The welding method of the ENi6620 nickel-based welding rod for alternating current is characterized in that the nickel-based welding rod is subjected to alternating current welding, the welding position is welded vertically upwards, and the linear energy is 10-25 KJ/cm.

Technical Field

The invention relates to the technical field of welding material preparation, in particular to an ENi6620 nickel-based welding rod for alternating current and a preparation method and a welding method thereof.

Background

With the acceleration of global industrialization and informatization processes, the energy demand of countries in the world is increased rapidly, and meanwhile, the problems of energy shortage, coal pollution and the like which seriously restrict the sustainable development of economy are exposed. Natural gas, as a high-quality clean fuel and an important chemical raw material, has become one of three major pillar energy sources in the world today. The status and the role of natural gas in social development are increasingly prominent, and the global production and consumption of natural gas are in a steadily increasing trend. The transportation and storage of the liquefied natural gas require a large number of cryogenic storage tanks (LNG storage tanks), and the working environment requires that the material for manufacturing the LNG storage tanks has good cryogenic toughness and good strength in the cryogenic environment. The 9Ni steel is a medium alloy steel developed by International Nickel company in America, and the structure of the medium alloy steel is martensite and bainite. The steel still has good low-temperature impact toughness, high strength and corrosion resistance when used at extremely low temperature, and has the advantages of less alloy content, large required stress, small thermal expansion rate, good weldability and the like. Currently, 9Ni steel has become the main material for manufacturing large LNG storage tanks.

In recent years, the domestic LNG technology is rapidly developed, the LNG storage tank is automatically designed and built, and the development of the LNG industry greatly improves the requirements on 9Ni steel and welding materials of the 9Ni steel. In LNG engineering applications, manual arc welding with welding rods is the most used, while ENi6620, as a nickel-based welding rod, is the primary choice for the 9Ni steel mating welding material. However, the research on the nickel-based welding rod of the steel for the natural gas storage tank is relatively weak in China, and the matched welding material still depends on the import from abroad for a long time. In order to break through the monopoly of foreign technologies and realize the localization of the 9Ni steel matched welding material, the research and development of the welding material which has good technological properties and meets the requirement of low-temperature toughness has important significance.

CN103769769A discloses a low-hydrogen nickel-based welding electrode for welding 9Ni steel for LNG ships, which consists of a pure nickel core wire and a coating wrapped on the outer surface of the core wire, wherein the coating is prepared from the following components: and (3) marble: 25-35 parts by weight; fluorite: 10-21 parts by weight; 12-28 parts of metallic chromium; 4-10 parts of metal manganese; 8-16 parts of ferromolybdenum; 1-6 parts of ferrotungsten; 7-15 parts of ferrocolumbium; 0-2 parts of organic matters; 0-2 parts of soda ash. CN103978322A also discloses a high-efficiency nickel-based welding rod specially used for ultra-low temperature steel welding of an LNG ship, which comprises a nickel alloy core wire and a coating wrapped on the surface of the core wire, wherein the coating is prepared from the following components: 20-35 parts of marble; 2-7 parts of rutile; 10-25 parts of fluorite; 5-13 parts of metal chromium; 5-10 parts of metal manganese; 6-11 parts of ferromolybdenum; 4-8 parts of ferrotungsten; 3-8 parts of ferrotitanium; 2-8 parts of ferrosilicon; 5.3-9 parts of ferrocolumbium; 0.5-2 parts of sodium carbonate. CN106514049A also discloses a nickel-based welding rod for welding steel for an ultralow temperature container, which comprises a nickel alloy core wire and a coating wrapped on the surface of the core wire, wherein the coating is prepared from the following components: 20-38 parts of marble; 5-8 parts of strontium carbonate; 1-4 parts of potassium feldspar; 3-13 parts of fluorite; 2-10 parts of magnesium fluoride; 3-15 parts of cryolite; 10-20 parts of rutile; 2-7 parts of ferrotitanium; 2-6 parts of aluminum iron; 0.5-2 parts of magnesium-aluminum powder; 4-7 parts of ferromolybdenum; 2-5 parts of ferrocolumbium; 1-3 parts of ferrotungsten. The welding rods of the three patents are used for welding 9Ni steel, and have the following defects: the welding rods disclosed in CN103769769A and CN103978322A have high fluoride content in the coating, high basicity of the coating, and can only be used for direct current reverse connection, and during alternating current welding, the defects of unstable electric arc, poor slag coverage and the like exist. And the 9Ni steel is a material with a larger magnetization tendency, and magnetic blow is easy to generate during direct current welding, which seriously affects the welding quality and causes the defects of incomplete penetration, incomplete fusion, slag inclusion, air holes and the like. The nickel-based welding rod disclosed in CN101745758A can be welded by an ac power supply, and has good welding process and low-temperature toughness, but the welding rod core is a nickel-based alloy core, the core contains high Cr, which can increase resistivity, the core has large resistance, and when the current is large or the second half of the welding rod is in large current, the phenomena of insufficient arc blowing force, red tail end, peeling off of coating, etc. easily occur, which seriously affect the welding operation performance.

Disclosure of Invention

The invention aims to solve the technical problems that an arc is unstable, slag is poor in coverage, magnetic blow is easy to generate and the like when a nickel-based welding rod is welded, insufficient arc blowing force is easy to occur when a large current is applied or the rear half part of the welding rod is positioned, the tail end is red, a coating falls off, good low-temperature toughness cannot be kept under the low-temperature condition and the like, and aims to provide an ENi6620 nickel-based welding rod for alternating current and a preparation method and a welding method thereof.

The invention is realized by the following technical scheme:

the ENi6620 nickel-based welding rod for alternating current comprises a core wire and a coating wrapped on the surface of the core wire, wherein the coating comprises the following components in percentage by weight: 6-10 parts of marble, 3-6 parts of strontium carbonate, 6-9 parts of fluorite, 2-5 parts of potassium ice crystal powder, 0.5-1.5 parts of potassium fluoborate, 2-6 parts of rutile, 5-8 parts of electrolytic manganese, 25-30 parts of chromium metal, 15-22 parts of ferromolybdenum, 2-5 parts of ferrotitanium, 3-6 parts of tungsten powder, 5-9 parts of ferroniobium, 1-3 parts of calcined soda, 2-6 parts of potassium titanate, 1-4 parts of rare earth fluoride, 0.5-2.5 parts of zirconium dioxide and 0.5-3.5 parts of rare earth ferrosilicon.

Further optimizing, the welding core is a pure nickel welding core.

Further optimizing, the core wire comprises the following components: less than or equal to 0.10 wt% of C, less than or equal to 0.05 wt% of Mn, less than or equal to 0.15 wt% of Si, less than or equal to 0.020 wt% of P, less than or equal to 0.005 wt% of S, more than or equal to 99.5 wt% of Ni, less than or equal to 0.10 wt% of Fe, and the balance of indispensable impurities.

Further optimizing, the core wire comprises the following components: 0.0045 percent of C, 0.025 percent of Mn, 0.019 percent of Si, 0.0013 percent of P, 0.0010 percent of S, 99.64 percent of Ni, 0.024 percent of Fe and the balance of indispensable impurities.

Further optimized, CaCO in the marble₃The content is more than or equal to 96 percent, and SrCO in strontium carbonate₃Not less than 98.50%, CaF in fluorite₂The content is more than or equal to 96 percent, F in the potassium cryolite is more than or equal to 53.0 percent, Al is more than or equal to 13.0 percent, K is less than or equal to 32.0 percent, and potassium fluoborate KBF₄Not less than 98 percent of rutile TiO₂More than or equal to 92 percent, Mn in electrolytic manganese is more than or equal to 99.5 percent, Cr in metal chromium is more than or equal to 98 percent, Mo in ferromolybdenum is 45 to 50 percent, Ti in ferrotitanium is 25 to 35 percent, W in tungsten powder is more than or equal to 99 percent, niobium45-50 percent of Nb in iron, less than or equal to 0.7 percent of NaCl in soda ash and K in potassium titanate₄TiO₄Not less than 95%, REO not less than 83% in rare earth fluoride, CeO₂Greater than or equal to 45 percent of ZrO in zirconium dioxide₂More than or equal to 95 percent, 45 percent of the rare earth ferrosilicon is more than or equal to 40 percent of Si, 32 percent of the rare earth ferrosilicon is more than or equal to 20 percent of Ce, and 20 percent of the rare earth ferrosilicon is more than or equal to 10 percent of La.

Further optimizing, the composition and the content of the coating are as follows: 7.5 parts of marble, 4.5 parts of strontium carbonate, 7 parts of fluorite, 3.5 parts of potassium ice crystal powder, 1 part of potassium fluoborate, 3.5 parts of rutile, 6 parts of electrolytic manganese, 27 parts of metallic chromium, 19 parts of ferromolybdenum, 2.5 parts of ferrotitanium, 4 parts of tungsten powder, 7.5 parts of ferroniobium, 1 part of calcined soda, 3 parts of potassium titanate, 1 part of rare earth fluoride, 1 part of zirconium dioxide and 1 part of rare earth ferrosilicon.

Further optimizing, the composition and the content of the coating are as follows: 6.5 parts of marble, 5.5 parts of strontium carbonate, 8 parts of fluorite, 3 parts of potassium ice crystal powder, 0.8 part of potassium fluoborate, 4 parts of rutile, 7.2 parts of electrolytic manganese, 26.5 parts of chromium metal, 17.5 parts of ferromolybdenum, 3 parts of ferrotitanium, 3.6 parts of tungsten powder, 6.2 parts of ferroniobium, 1.2 parts of soda ash, 3.5 parts of potassium titanate, 1.5 parts of rare earth fluoride, 0.5 part of zirconium dioxide and 1.5 parts of rare earth ferrosilicon.

Further optimizing, the composition and the content of the coating are as follows: 8 parts of marble, 3 parts of strontium carbonate, 6 parts of fluorite, 4.8 parts of potassium ice crystal powder, 1.2 parts of potassium fluoborate, 4 parts of rutile, 5.5 parts of electrolytic manganese, 25.8 parts of chromium metal, 16 parts of ferromolybdenum, 4 parts of ferrotitanium, 3.2 parts of tungsten powder, 5.8 parts of ferroniobium, 1.6 parts of soda ash, 3.7 parts of potassium titanate, 3 parts of rare earth fluoride, 2 parts of zirconium dioxide and 2.4 parts of rare earth ferrosilicon.

Further optimizing, the preparation method of the ENi6620 nickel-based welding rod for alternating current comprises the following steps:

(1) stirring the powder of the coating and mixing uniformly;

(2) adding pure potassium water glass with the total component mass of 20-24% and the concentration of 42-43-degree Be' into the stirred coating powder, stirring, uniformly mixing, and then feeding into a welding rod coating press to coat the coating powder on a welding core under the pressure of 14-16 MPa;

(3) baking at low temperature of 85-90 ℃ for 4-6.5 hours and at high temperature of 300-.

The stirring time of the stirring is equal to or more than 30 min.

And further optimizing the welding method of the ENi6620 nickel-based welding rod for alternating current, wherein the nickel-based welding rod is subjected to alternating current welding, the welding position is welded vertically upwards, and the linear energy is 10-25 KJ/cm.

Further optimizing, the welding method adopts the ENi6620 nickel-based welding rod for alternating current, and the welding rod is matched with 9Ni steel for use.

Further optimizing, the welding method has the advantages that the tensile strength of normal-temperature deposited metal is more than or equal to 620Mpa, the yield strength is more than or equal to 350Mpa, the elongation is more than or equal to 32 percent, and the impact toughness at the temperature of 196 ℃ is good.

Further optimizing, the mass ratio of the coating to the welding rod is 25-30: 100, the mass ratio of the medicinal powder to the binder is 100: 20 to 24.

The main functions of the components in the medicinal powder are as follows:

and (3) marble: the marble has the main functions of slagging and gas making, protects a welding seam from being oxidized and nitrided by air, can improve the alkalinity of slag, improve the purity of deposited metal, reduce the amount of impurities, adjust the melting point and viscosity of the slag, and adjust the interfacial tension and surface tension of the slag and metal, and improve slag removal.

Strontium carbonate: its effect is similar with the marble, and the gas making slagging increases the activity of slag, can make the even cover of sediment on the welding seam surface, possesses two advantages simultaneously: the moisture absorption resistance is stronger than that of marble; the pyrolysis temperature is higher than marble and therefore provides better protection to the weld pool. Strontium carbonate produces less carbon dioxide than calcium carbonate in the same amount, and reduces the oxygen potential under the same conditions.

Fluorite: the melting point and viscosity of the slag are adjusted, the fluidity of the slag is increased, the physical property of the slag is improved, the slag plays a key role in weld forming, slag removal and the like, and the slag is also a main material for reducing diffusible hydrogen in a weld, but harmful gas hydrogen fluoride can be decomposed in the welding process, so that electric arc instability can be caused, and the proportion should be reasonably controlled.

Potassium ice crystal powder: the method mainly has the effects of slagging, regulating the viscosity and the surface tension of slag and reducing the sensitivity of air holes.

Potassium fluoroborate: improve the coating pressing property, slag thinning, molten pool fluidity and electric arc stability.

Rutile: the rutile mainly has the effects of stabilizing arc and slagging, and can adjust the melting point, viscosity, surface tension and fluidity of molten slag, improve weld formation and reduce splashing. Plays a key role in weld forming and electric arc stability.

Electrolytic manganese: the addition of manganese element can play roles of desulfurization and deoxidation, and can also transit manganese element to the welding line, thereby improving the welding line strength.

Metallic chromium: the chromium element is transited into the welding seam, so that the requirement of deposited metal components is met, the welding seam has excellent normal temperature and high temperature oxidation resistance, and the corrosion resistance is improved. Meanwhile, M23C6 type carbide can be formed, which has better carbide strengthening effect in the matrix and solid solution strengthening effect.

Ferromolybdenum: molybdenum element is transited into the welding seam to meet the requirement of deposited metal components, the molybdenum can obviously improve the strength of the welding seam metal and has the function of refining crystal grains, the proper ferromolybdenum adding amount can improve the strength, hardness and thermal stability of the welding seam, but the excessive molybdenum iron can influence the toughness of the welding seam metal.

Titanium iron: the main functions are deoxidation and denitrification, and nitrogen holes are avoided.

Tungsten powder: tungsten element is transited into the welding seam to meet the requirement of deposited metal components.

Ferrocolumbium: and niobium element is transited into the welding seam to meet the requirement of deposited metal components. Nb is a strong carbide former, and forms a stable carbide NbC, which is extremely stable. However, as the Nb content increases, the elongation decreases due to the increase in the volume ratio of NbFe2, and too high a Nb content significantly decreases the toughness of the deposited metal.

Soda ash: lubrication, improving the press coating performance of the welding rod and ensuring that the surface of the welding rod is smooth and beautiful.

Potassium titanate: the main function is to improve the welding process performance of the welding rod, and simultaneously, the method is beneficial to improving the press coating performance of the welding rod and stabilizing the welding arc. The content is too much, the moisture absorption of the coating is increased, the content is lower, and the improvement of the welding manufacturability of the welding rod is not obvious.

Rare earth fluoride: the method has the main effects of thinning slag, purifying the welding seam, improving the fluidity of the slag and improving the low-temperature impact toughness of the welding seam metal. Decomposing into rare earth and fluorine atoms at high temperature to generate rare earth sulfide and rare earth oxide floating in slag. The method can obviously reduce the S content and the oxygen content of the weld metal, improve the shape of inclusions in the weld, ensure that the inclusions are distributed in a fine spherical and dispersed manner, and play an obvious role in purifying and deteriorating the weld metal. Is beneficial to improving the low-temperature impact toughness of the welding seam.

Zirconium dioxide: the chemical change is generated in the welding process, the thermal expansion coefficient of the slag is changed, and the slag removal of the welding seam is facilitated.

Rare earth silicon iron: as a deoxidizer, and the rare earth elements are transited into the weld metal, and the deoxidizer has the functions of deoxidizing and purifying the weld. The addition of rare earth element into deposited metal can obviously reduce the sulfur content of weld metal, inhibit the liquid crack of deposited metal, refine crystal grains and contribute to the low-temperature impact toughness of weld.

Pure potassium water glass: as a binder, silicon oxide is provided in the slag, so that the viscosity of the molten slag can be adjusted, the slag can be well covered, and the weld bead forming is improved. Compared with potassium-sodium water glass, pure potassium water glass has more remarkable effect on improving the arc stability of the alternating current arc.

In the present invention, "-" unless otherwise specified, the symbol is a mass percentage.

The invention realizes the aim of the invention by organically combining the components of the coating and matching the coating with the pure nickel core wires, and the core wires can be purchased from the market and are all commercially available products.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention discloses an ENi6620 welding rod for alternating current, which has the advantages of stable electric arc, small splashing, good slag removal, attractive weld forming and other excellent welding process performances, and good all-position welding operation performance.

(2) In the invention, the coating adopts CaO-SrO-CaF₂-SiO₂-TiO₂-ZrO₂Slag system, high basicity of coating. Through a large number of tests, the ratio of the marble, fluorite, strontium carbonate, rutile and potassium ice powder in the coating of the welding rod is adjusted, so that good technological properties can be obtained.

(3) According to the invention, strontium carbonate is adopted to replace part of calcium carbonate, under the same condition, carbon dioxide generated by decomposition of strontium carbonate is less, the oxidizing property of welding atmosphere is smaller, the transition of alloy elements is facilitated, electric arc is softer, welding spatter is effectively improved, and the loss of the alloy elements caused by spatter is reduced.

(4) In the invention, the elpasolite has stronger slag-thinning effect compared with fluorite, and the cryolite contains low ionization potential K ions, so that the arc stability of the alternating current arc can be improved.

(5) In the invention, the metal manganese, the rare earth ferrosilicon and the ferrotitanium are added into the coating composition for combined deoxidation, so that alloy transition can be ensured.

(6) According to the invention, the rare earth fluoride and the rare earth ferrosilicon are added in a composite form, so that the transition of rare earth elements is facilitated, the introduction of the rare earth elements can purify a welding line, the purity of the welding line is improved, and the mechanical property, especially the low-temperature impact toughness, of the welding line is improved.

(7) In the invention, the pure nickel rod wire is adopted to replace the alloy wire, so that the problems of red coating, cracking and falling off are solved.

(8) In the invention, the welding rod is used for welding 9Ni steel, alternating current welding is adopted, vertical upward welding is adopted, the welding heat input is 10-25KJ/cm, the tensile strength of normal-temperature deposited metal is not less than 620Mpa, the yield strength is not less than 350Mpa, the elongation is not less than 32%, and the impact toughness at the temperature of 196 ℃ is good. The welding rod has good welding process performance, stable electric arc, small splashing, good slag removal, beautiful welding line formation and good all-position welding operation performance. The preparation method is simple and convenient to operate.

(9) The invention is mainly used for welding Ni 9% (UNSK81340) steel, the weld metal has the same linear expansion coefficient with the steel, and can also be used for welding dissimilar steel and difficult-to-weld alloy.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not used as limitations of the present invention.

Example 1

Taking 100Kg of pure nickel core wire rod wire, wherein the core wire comprises the following components in percentage by weight: 0.0045% of C, 0.025% of Mn, 0.019% of Si, 0.0013% of P, 0.0010% of S, 99.64% of Ni, 0.024% of Fe, and the balance of indispensable impurities.

Taking a coating, wherein the coating comprises the following components in parts by mass in terms of the mass percentage of the medicinal powder in the welding rod:

7.5 parts of marble, 4.5kg of strontium carbonate, 7kg of fluorite, 3.5kg of potassium ice crystal powder, 1kg of potassium fluoborate, 3.5kg of rutile, 6kg of electrolytic manganese, 27kg of metallic chromium, 19kg of ferromolybdenum, 2.5kg of ferrotitanium, 4kg of tungsten powder, 7.5kg of ferroniobium, 1kg of soda ash, 3kg of potassium titanate, 1kg of rare earth fluoride, 1kg of zirconium dioxide and 1kg of rare earth ferrosilicon.

Mixing the above components, adding pure potassium water glass 22% of the total weight of the medicinal powder, and stirring at 20 deg.C with Baume concentration of 42-43 ° Be for 10-15 min. The welding wire is coated on a core wire on oil pressure type welding rod production equipment by using a conventional process. Then baking at the low temperature of 85-90 ℃ for 4-6.5 hours and at the high temperature of 300-.

When the welding rod (alternating current) obtained in the embodiment is used for a welding test, the electric arc is stable, the splashing is small, the slag removal is good, the molten pool is clear and regular, and the welding seam is attractive in appearance.

Vertical upward welding is adopted, and the welding heat input is 10-25 KJ/cm.

The deposited metal comprises the following chemical components:

c: 0.017 wt%, Mn: 2.23 wt%, Si: 0.20 wt%, S: 0.0056 wt%, P: 0.0035 wt%, Cr: 13.27 wt%, Ni: 70.46 wt%, Mo: 6.43 wt%, Cu: 0.027 wt%, Nb 0.95 wt%, Fe 3.70 wt%, W1.45 wt%, Ta 0.013 wt%, and the balance 0.12 wt%.

The deposited metal has the following mechanical properties:

mechanical property of deposited metal of welding rod

Example 2

The present example is the same as example 1 except that the weight of each component in the coating is different.

The weight of each component in the coating in the embodiment is as follows: 6.5kg of marble, 5.5kg of strontium carbonate, 8kg of fluorite, 3kg of potassium ice crystal powder, 0.8kg of potassium fluoborate, 4kg of rutile, 7.2kg of electrolytic manganese, 26.5kg of metallic chromium, 17.5kg of ferromolybdenum, 3kg of ferrotitanium, 3.6kg of tungsten powder, 6.2kg of ferroniobium, 1.2kg of soda ash, 3.5kg of potassium titanate, 1.5kg of rare earth fluoride, 0.5kg of zirconium dioxide and 1.5kg of rare earth ferrosilicon.

The weld deposit metal obtained after welding comprises the following chemical components:

c: 0.014 wt%, Mn: 2.44 wt%, Si: 0.23 wt%, S: 0.0054 wt%, P: 0.0032 wt%, Cr: 13.07 wt%, Ni: 71.53 wt%, Mo: 5.95 wt%, Cu: 0.022 wt%, Nb 0.88 wt%, Fe 4.51 wt%, W1.31 wt%, Ta 0.015 wt%, and the balance 0.13 wt%.

The deposited metal has the following mechanical properties:

mechanical property of deposited metal of welding rod

Example 3

The present example is the same as example 1 except that the weight of each component in the coating is different.

The weight of each component in the coating in the embodiment is as follows: 8kg of marble, 3kg of strontium carbonate, 6kg of fluorite, 4.8kg of potassium ice crystal powder, 1.2kg of potassium fluoborate, 4kg of rutile, 5.5kg of electrolytic manganese, 25.8kg of metallic chromium, 16kg of ferromolybdenum, 4kg of ferrotitanium, 3.2kg of tungsten powder, 5.8kg of ferroniobium, 1.6kg of soda ash, 3.7kg of potassium titanate, 3kg of rare earth fluoride, 2kg of zirconium dioxide and 2.4kg of rare earth ferrosilicon.

The weld deposit metal obtained after welding comprises the following chemical components:

c: 0.016 wt%, Mn: 2.25 wt%, Si: 0.26 wt%, S: 0.0064 wt%, P: 0.0038 wt%, Cr: 13.19 wt%, Ni: 71.61 wt%, Mo: 5.65 wt%, Cu: 0.018 wt%, Nb 0.91 wt%, Fe 3.90 wt%, W1.33 wt%, Ta 0.011 wt%, and the balance 0.11 wt%.

The deposited metal has the following mechanical properties:

mechanical property of deposited metal of welding rod

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.