Welding rod for nuclear-grade strong irradiation area and preparation method of welding rod

Abstract

The invention provides a welding rod for a nuclear-grade strong irradiation area and a preparation method of the welding rod, and relates to the technical field of welding materials.In the welding rod, powder in the welding rod is composed of calcium carbonate, calcium fluoride, barium fluoride, sodium aluminum fluoride, sodium carbonate, potassium feldspar, titanium dioxide, dehydrated mica, remelted ferrotitanium, remelted ferromolybdenum, silicomanganese powder and nickel powder according to a specific proportion; components of deposited metal formed after the welding rod is welded meet the welding requirements of 508-IIIA (16MND5) and 508-IIIB (18MND5) steel for a nuclear island primary loop at the same time, and after heat treatment is conducted for 40 h at the temperature of 615 DEG C, high strength (Rm is larger than 620 MPa) and high low-temperature impact toughness (AKV is larger than 100 J at the temperature of-30 DEG C) are achieved. In addition, when the welding rod is used for welding, electric arcs are stable, the splashing rate is low, the slag removal rate is high, formed welding seams are attractive, welding defects are few, and good welding manufacturability is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of welding materials, and in particular to a welding rod for use in nuclear-grade strong irradiation areas and a preparation method thereof. Background Art

[0002] The welding rods for 508-ⅢA steel welding in the strong irradiation area of ​​the primary loop of the nuclear island have high requirements for processability and mechanical properties, and also have to have radiation resistance. As the reactor pressure vessel becomes larger and larger, the wall thickness of the reactor pressure vessel is also getting thicker. In order to eliminate the stress generated during the welding process, the post-weld heat treatment time is getting longer and longer. Considering the later repair heat treatment time, it is required that the deposited metal formed by the welding rod after welding still has high strength and high low-temperature impact toughness after 40h heat treatment at 615℃. In addition, in order to ensure the smooth progress of the welding process and the quality of the weld, the welding rod is also required to have good welding processability. However, the existing 508-ⅢA steel welding rods cannot meet the above requirements at the same time. Summary of the invention

[0003] The problem solved by the present invention is at least one of the following: How to obtain a welding rod for 508-ⅢA steel that simultaneously meets the following requirements: (1) the deposited metal formed by the welding rod after welding still has high strength and high low-temperature impact toughness after heat treatment at 615°C for 40 hours; (2) the welding rod has good welding processability.

[0004] In order to solve the above problems, the present invention provides a welding rod for nuclear-grade strong irradiation areas, the welding rod comprises a welding core and a coating, the coating comprises powder and water glass, and the components of the powder include, by weight: calcium carbonate: 38 to 46 parts, calcium fluoride: 19.5 to 20.5 parts, barium fluoride: 0.6 to 1.6 parts, sodium aluminum fluoride: 1.4 to 2.4 parts, soda ash: 0.6 to 1 part, potassium feldspar: 3 to 6 parts, titanium dioxide: 3 to 6 parts, dehydrated mica: 2 to 4 parts, remelted titanium iron: 5 to 8 parts, remelted molybdenum iron: 1.8 to 2.0 parts, silicon manganese powder: 5 to 9 parts, and nickel powder: 2 to 4 parts.

[0005] Optionally, the welding core is a H08HR low alloy steel welding core.

[0006] Optionally, the components of the welding core include, by weight percentage: C: 0.04% to 0.07%, Si: 0.15% to 0.23%, Mn: 0.40% to 0.70%, P: 0 to 0.01%, S: 0 to 0.01%, As: 0 to 0.005%, Sn: 0 to 0.005%, Sb: 0 to 0.005%, B: 0 to 0.0005%, O: 0 to 0.01%, N: 0 to 0.01%, and the balance is Fe and unavoidable impurities.

[0007] Optionally, in the medicine coating, the mass ratio of the water glass to the medicine powder is (4 to 5):20.

[0008] Optionally, the water glass is potassium-sodium mixed water glass.

[0009] Optionally, the mass ratio of potassium oxide to sodium oxide in the potassium-sodium mixed water glass is 3:1.

[0010] Optionally, the mass ratio of manganese element to silicon element in the silicon-manganese powder is 3:1.

[0011] The present invention also provides a method for preparing the welding rod for nuclear-grade strong irradiation zone as described above, comprising:

[0012] Step S1, wet-mixing water glass and drug powder in a mass ratio of (4 to 5):20 to obtain a mixture;

[0013] Step S2: Press the mixture and the welding core into welding rods, dry them naturally, and then heat them to obtain welding rods.

[0014] Optionally, in step S2, the temperature of the heating treatment is 380°C to 420°C.

[0015] Optionally, the heating treatment time is 1.5h to 2h.

[0016] The functions of the main components in the powder of the welding rod provided by the present invention are as follows:

[0017] Calcium carbonate: decomposes into CaO (melting point is 2572℃) and CO2 under the action of arc heat. It is a commonly used slag-making and gas-making material in welding rod manufacturing. It can increase the basicity of slag, improve slag removal, and has good P removal, S removal and O and N control capabilities.

[0018] Calcium fluoride: It adjusts the melting point and viscosity of the slag, increases the fluidity of the solvent, and improves the physical properties of the slag, which plays a key role in weld formation and slag removal. It is also the main material for reducing the diffusible hydrogen in the weld.

[0019] Barium fluoride: It is added in conjunction with calcium fluoride and sodium aluminum fluoride, mainly to adjust the melting point of the slag and reduce the diffusible hydrogen; the addition of an appropriate amount of barium fluoride improves the fluidity of the slag, prevents molten iron from dripping during vertical welding, and can obtain good weld formation.

[0020] Sodium aluminum fluoride: combines with hydrogen to form hydrogen fluoride, which reduces the hydrogen content in the weld. During arc welding, the ionized sodium ions can stabilize the arc.

[0021] Titanium dioxide: In the process of slag reaction and solidification of deposited metal, it is conducive to the formation of needle-shaped ferrite nucleation, thereby improving the low-temperature impact toughness of the deposited metal. In addition, titanium dioxide is a good adhesive and plasticizer, which improves the pressure coating performance of welding rods.

[0022] Potassium feldspar: Its main function in the coating is slag formation. Since it contains free substances such as K and Na, it can reduce the arc voltage, stabilize the arc, reduce spatter, and make the weld fine.

[0023] Dehydrated mica: Its main functions in the coating are slag formation and arc stabilization. In addition, its unique layer structure can increase the air permeability of the coating, facilitate moisture discharge and prevent cracks during the drying process.

[0024] Remelting ferrotitanium: After remelting, the Al content of ferrotitanium is reduced (from 8% to 1%), making the arc burn softer, which plays an important role in reducing welding spatter. Ti is a strong deoxidizing element. It is burned while reducing the oxygen content in the deposited metal. A small amount of Ti and N can generate TiN, reducing the activity of N. TiN particles act as crystal nuclei to promote the formation of fine needle-shaped ferrite in the deposited metal, reduce the porosity sensitivity of the deposited metal, and thus improve the low-temperature impact toughness of the deposited metal.

[0025] Remelting ferromolybdenum: After remelting, ferromolybdenum can significantly reduce the content of radiation embrittlement elements such as S, P, O, N, and Cu, and improve the purity of the weld. Mo can play a role in precipitation strengthening in the deposited metal, which can improve the tensile strength; at the same time, it can also significantly change the α phase transformation characteristics, obtain fine needle-shaped ferrite structure, which is conducive to improving the impact toughness of the deposited metal. In addition, Mo has a strong affinity with C, N, and O, and can also clearly inhibit radiation embrittlement.

[0026] Silicon manganese powder is added to the coating as a deoxidizer and alloying element. It can be rapidly oxidized at high temperatures to generate oxides and silicates. These substances can absorb impurities and gases generated during welding, effectively preventing the formation of pores and inclusions in the weld, thereby improving the low-temperature impact toughness of the deposited metal.

[0027] Compared with the related art, in the present invention, the powder in the welding rod is composed of calcium carbonate, calcium fluoride, barium fluoride, sodium aluminum fluoride, soda ash, potassium feldspar, titanium dioxide, dehydrated mica, remelted ferrotitanium, remelted ferromolybdenum, silicon manganese powder and nickel powder in a specific ratio, wherein the components such as calcium carbonate, calcium fluoride, barium fluoride, sodium aluminum fluoride and remelted ferrotitanium work together to ensure that the welding rod has good welding processability; the components such as titanium dioxide, remelted ferrotitanium, remelted ferromolybdenum, silicon manganese powder, nickel powder work together to ensure that the deposited metal formed after the welding rod has high low-temperature impact toughness. In addition, remelted ferromolybdenum can also ensure that the deposited metal formed after the welding rod has high tensile strength. The components of the deposited metal formed after the welding rod provided by the present invention meet the welding requirements of 508-ⅢA steel, and after heat treatment at 615°C for 40h, it has high strength and high low-temperature impact toughness. In addition, when welding with this electrode, the arc is more stable, the spatter rate is lower, the slag removal rate is higher, the weld formation is more beautiful, there are fewer welding defects, and it has better welding processability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a schematic flow chart of a method for preparing welding rods for nuclear-grade strong irradiation areas according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0030] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0031] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0032] An embodiment of the present invention provides a welding rod for nuclear-grade strong irradiation areas, the welding rod comprising a welding core and a coating, the coating comprising powder and water glass, and the components of the powder comprising, by weight: calcium carbonate: 38 to 46 parts, calcium fluoride: 19.5 to 20.5 parts, barium fluoride: 0.6 to 1.6 parts, sodium aluminum fluoride: 1.4 to 2.4 parts, soda ash: 0.6 to 1 part, potassium feldspar: 3 to 6 parts, titanium dioxide: 3 to 6 parts, dehydrated mica: 2 to 4 parts, remelted titanium iron: 5 to 8 parts, remelted molybdenum iron: 1.8 to 2.0 parts, silicon manganese powder: 5 to 9 parts, and nickel powder: 2 to 4 parts.

[0033] In the embodiment of the present invention, the powder in the welding rod is composed of calcium carbonate, calcium fluoride, barium fluoride, sodium aluminum fluoride, soda ash, potassium feldspar, titanium dioxide, dehydrated mica, remelted ferrotitanium, remelted ferromolybdenum, silicon manganese powder and nickel powder in a specific ratio, wherein the components such as calcium carbonate, calcium fluoride, barium fluoride, sodium aluminum fluoride and remelted ferrotitanium work together to ensure that the welding rod has good welding processability; the components such as titanium dioxide, remelted ferrotitanium, remelted ferromolybdenum, silicon manganese powder, nickel powder work together to ensure that the deposited metal formed after the welding rod has high low-temperature impact toughness. In addition, remelted ferromolybdenum can also ensure that the deposited metal formed after the welding rod has high tensile strength. The components of the deposited metal formed after the welding rod provided in the embodiment of the present invention meet the welding requirements of 508-ⅢA steel, and after heat treatment at 615°C for 40h, it has high strength and high low-temperature impact toughness. In addition, when welding with this electrode, the arc is more stable, the spatter rate is lower, the slag removal rate is higher, the weld formation is more beautiful, there are fewer welding defects, and it has better welding processability.

[0034] In some embodiments of the present invention, the welding core is a H08HR low alloy steel welding core, and the components of the welding core include, by weight percentage: C: 0.04% to 0.07%, Si: 0.15% to 0.23%, Mn: 0.40% to 0.70%, P: 0 to 0.01%, S: 0 to 0.01%, As: 0 to 0.005%, Sn: 0 to 0.005%, Sb: 0 to 0.005%, B: 0 to 0.0005%, O: 0 to 0.01%, N: 0 to 0.01%, and the balance is Fe and unavoidable impurities.

[0035] In some embodiments of the present invention, in the medicine coating, the mass ratio of the water glass to the medicine powder is (4 to 5): 20. Exemplarily, the water glass is a potassium-sodium mixed water glass, and the mass ratio of potassium oxide to sodium oxide in the potassium-sodium mixed water glass is 3:1.

[0036] In some embodiments of the present invention, the mass ratio of manganese element to silicon element in the silicon-manganese powder is 3:1.

[0037] like Figure 1 As shown, the embodiment of the present invention also provides a method for preparing the welding rod for nuclear-grade strong irradiation zone as described above, comprising:

[0038] Step S1, wet-mixing water glass and drug powder in a mass ratio of (4 to 5):20 to obtain a mixture;

[0039] Step S2: Press the mixture and the welding core into welding rods, dry them naturally, and then heat them to obtain welding rods.

[0040] In some embodiments of the present invention, in step S2, the temperature of the heating treatment is 380° C. to 420° C., and the time of the heating treatment is 1.5 h to 2 h.

[0041] The present invention is further described below in conjunction with specific embodiments. In the embodiments of the present invention, the manufacturer of the water glass used is Baoding Runfeng Industrial Co., Ltd., and the product model is YKN 2.9M (3:1); the manufacturer of the remelted ferrotitanium used is Jinzhou Huiren New Material Technology Co., Ltd., and the product model is TT4008; the manufacturer of the remelted ferromolybdenum used is Jinzhou Huiren New Material Technology Co., Ltd., and the product model is MI6508;

[0042] Example 1

[0043] A1. Wet-mix water glass and medicine powder in a mass ratio of 5:20 to obtain a mixture; wherein, in parts by weight, the components of the medicine powder include: 45 parts of calcium carbonate, 20 parts of calcium fluoride, 0.6 parts of barium fluoride, 1.4 parts of sodium aluminum fluoride, 1 part of soda ash, 6 parts of potassium feldspar, 4 parts of titanium dioxide, 4 parts of dehydrated mica, 6 parts of remelted ferrotitanium FeTi40, 1.9 parts of remelted ferromolybdenum FeMo65, 8 parts of silicon manganese powder, and 2.1 parts of nickel powder; the water glass is a potassium-sodium mixed water glass, in which the mass ratio of potassium oxide to sodium oxide is 3:1, and the mass ratio of manganese element to silicon element in the silicon manganese powder is 3:1.

[0044] A2. The mixture and welding core are pressed into welding rods, and after natural drying, they are heated to obtain welding rods; wherein the heating temperature is 400°C and the time is 2h; the components of the welding core include: C: 0.06%, Si: 0.19%, Mn: 0.55%, P: 0.005%, S: 0.005%, As: 0.003%, Sn: 0.003%, Sb: 0.003%, B: 0.0002%, O: 0.005%, N: 0.005%, and the balance is Fe and unavoidable impurities.

[0045] A3. The welding rod is used for welding 508-ⅢA steel to obtain a welded part. After testing, the components of the deposited metal in the welded part include: C: 0.048%, Si: 0.32%, Mn: 1.49%, P: 0.005%, S: 0.002%, Cr: 0.03%, Ni: 0.82%, Mo: 0.46%, O: 0.0278%, N: 0.0149%, and the balance is Fe and unavoidable impurities.

[0046] Example 2

[0047] The difference from Example 1 is that in step A1, the components of the medicinal powder include, by weight: calcium carbonate: 45 parts, calcium fluoride: 20 parts, barium fluoride: 0.6 parts, sodium aluminum fluoride: 1.4 parts, soda ash: 1 part, potassium feldspar: 5 parts, titanium dioxide: 4 parts, dehydrated mica: 4 parts, remelted titanium iron FeTi40: 6 parts, remelted molybdenum iron FeMo65: 1.9 parts, silicon manganese powder: 8 parts, and nickel powder: 2.1 parts.

[0048] After testing, the components of the deposited metal in the weldment in Example 2 include: C: 0.054%, Si: 0.33%, Mn: 1.48%, P: 0.006%, S: 0.002%, Cr: 0.03%, Ni: 0.84%, Mo: 0.46%, O: 0.0265%, N: 0.0135%, and the remainder is Fe and unavoidable impurities.

[0049] Example 3

[0050] The difference from Example 1 is that in step A1, the components of the medicinal powder include, by weight: calcium carbonate: 45 parts, calcium fluoride: 20 parts, barium fluoride: 1.6 parts, sodium aluminum fluoride: 2.4 parts, soda ash: 1 part, potassium feldspar: 4 parts, titanium dioxide: 4 parts, dehydrated mica: 3 parts, remelted titanium iron FeTi40: 5.6 parts, remelted molybdenum iron FeMo65: 2 parts, silicon manganese powder: 8.2 parts, and nickel powder: 2.2 parts.

[0051] After testing, the components of the deposited metal in the weldment in Example 3 include: C: 0.056%, Si: 0.34%, Mn: 1.51%, P: 0.006%, S: 0.002%, Cr: 0.04%, Ni: 0.83%, Mo: 0.48%, O: 0.0270%, N: 0.0126%, and the remainder is Fe and unavoidable impurities.

[0052] Comparative Example 1

[0053] The difference from Example 1 is that in step A1, the components of the medicinal powder include, by weight: calcium carbonate: 46 parts, calcium fluoride: 22 parts, soda ash: 1 part, potassium feldspar: 6 parts, titanium dioxide: 4 parts, dehydrated mica: 4 parts, remelted titanium iron FeTi40: 6 parts, remelted molybdenum iron FeMo65: 1.9 parts, silicon manganese powder: 8 parts, and nickel powder: 2.1 parts.

[0054] Comparative Example 2

[0055] The difference from Example 1 is that in step A1, the components of the medicinal powder include, by weight: calcium carbonate: 45 parts, calcium fluoride: 20 parts, barium fluoride: 0.6 parts, sodium aluminum fluoride: 1.4 parts, soda ash: 1 part, potassium feldspar: 6 parts, titanium dioxide: 4 parts, dehydrated mica: 4 parts, remelted titanium iron FeTi40: 4 parts, remelted molybdenum iron FeMo65: 1.9 parts, silicon manganese powder: 8 parts, and nickel powder: 2.1 parts.

[0056] Comparative Example 3

[0057] The difference from Example 1 is that in step A1, the components of the medicinal powder include, by weight: calcium carbonate: 45 parts, calcium fluoride: 20 parts, barium fluoride: 0.6 parts, sodium aluminum fluoride: 1.4 parts, soda ash: 1 part, potassium feldspar: 6 parts, titanium dioxide: 4 parts, dehydrated mica: 4 parts, remelted titanium iron FeTi40: 6 parts, remelted molybdenum iron FeMo65: 1.6 parts, silicon manganese powder: 8 parts, and nickel powder: 2.1 parts.

[0058] Comparative Example 4

[0059] The difference from Example 1 is that in step A1, the components of the medicinal powder include, by weight: calcium carbonate: 45 parts, calcium fluoride: 20 parts, barium fluoride: 0.6 parts, sodium aluminum fluoride: 1.4 parts, soda ash: 1 part, potassium feldspar: 6 parts, titanium dioxide: 4 parts, dehydrated mica: 4 parts, ordinary ferrotitanium FeTi30-A: 6 parts, ordinary ferromolybdenum FeMo60-A: 1.9 parts, silicon manganese powder: 8 parts, and nickel powder: 2.1 parts.

[0060] Experimental example

[0061] The processability of Examples 1 to 3 and Comparative Examples 1 and 4 during the welding process was recorded, and the results are shown in Table 1. It can be seen from Table 1 that, compared with Comparative Examples 1 and 4, the welding processability of Examples 1 to 3 is better.

[0062] Table 1

[0063]

[0064] After the welded parts prepared in Examples 1 to 3 and Comparative Examples 2 to 3 were heat treated at 615°C for 40 hours, the strength and low-temperature impact toughness of the deposited metal were tested. The results are shown in Table 2. It can be seen from Table 2 that compared with Comparative Example 2, the low-temperature impact toughness of the deposited metal of the welded parts prepared in Examples 1 to 3 was higher after the heat treatment at 615°C for 40 hours; compared with Comparative Example 3, the strength and low-temperature impact toughness of the deposited metal of the welded parts prepared in Examples 1 to 3 were higher after the heat treatment at 615°C for 40 hours.

[0065] Table 2

[0066]

[0067]

[0068] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A welding rod for nuclear grade strong irradiation area, characterized in that: The invention comprises a welding core and a coating, wherein the coating comprises powder and water glass. The powder comprises, by weight, 38 to 46 parts of calcium carbonate, 19.5 to 20.5 parts of calcium fluoride, 0.6 to 1.6 parts of barium fluoride, 1.4 to 2.4 parts of sodium aluminum fluoride, 0.6 to 1 parts of soda ash, 3 to 6 parts of potassium feldspar, 3 to 6 parts of titanium dioxide, 2 to 4 parts of dehydrated mica, 5 to 8 parts of remelted ferrotitanium, 1.8 to 2.0 parts of remelted ferromolybdenum, 5 to 9 parts of silicon manganese powder and 2 to 4 parts of nickel powder.

2. The welding rod for nuclear grade strong irradiation area according to claim 1, characterized in that: The welding core is a H08HR low alloy steel welding core.

3. The welding rod for nuclear grade strong irradiation area according to claim 2, characterized in that: Measured in percentage by weight, the components of the welding core include: C: 0.04% to 0.07%, Si: 0.15% to 0.23%, Mn: 0.40% to 0.70%, P: 0 to 0.01%, S: 0 to 0.01%, As: 0 to 0.005%, Sn: 0 to 0.005%, Sb: 0 to 0.005%, B: 0 to 0.0005%, O: 0 to 0.01%, N: 0 to 0.01%, and the balance is Fe and unavoidable impurities.

4. The welding rod for nuclear grade strong irradiation area according to claim 1, characterized in that: In the medicine coating, the mass ratio of the water glass to the medicine powder is (4 to 5):

20.

5. The welding rod for nuclear grade strong irradiation area according to claim 1, characterized in that: The water glass is potassium-sodium mixed water glass.

6. The welding rod for nuclear grade strong irradiation area according to claim 5, characterized in that: The mass ratio of potassium oxide to sodium oxide in the potassium-sodium mixed water glass is 3:

1.

7. The welding rod for nuclear grade strong irradiation area according to claim 1, characterized in that: The mass ratio of manganese element to silicon element in the silicon-manganese powder is 3:

1.

8. A method for preparing a welding rod for nuclear grade strong irradiation zone according to any one of claims 1 to 7, characterized in that: include: Step S1, wet-mixing water glass and drug powder in a mass ratio of (4 to 5):20 to obtain a mixture; Step S2: Press the mixture and the welding core into welding rods, dry them naturally, and then heat them to obtain welding rods.

9. The method for preparing a welding rod for a nuclear grade strong irradiation zone according to claim 8, characterized in that: In the step S2, the temperature of the heating treatment is 380°C to 420°C.

10. The method for preparing a welding rod for nuclear grade strong irradiation zone according to claim 9, characterized in that: The heating treatment time is 1.5h to 2h.

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