Efficient argon arc welding wire for automatic welding of 9Ni steel and preparation method of efficient argon arc welding wire

Abstract

The invention relates to the technical field of welding wire preparation, in particular to an efficient argon arc welding wire for 9Ni steel automatic welding and a preparation method of the efficient argon arc welding wire. The invention discloses a high-efficiency argon arc welding wire for automatic welding of 9Ni steel. The welding wire comprises the following components: less than or equal to 0.03% of C; less than or equal to 0.06% of Si; mn accounts for 0.6%-1.2%, and Cr accounts for 15.2%-16.3%; mo + 1.5 W: 19.0%-22.0% and Mo < = 16.2%; fe: 4.8%-5.6%; 0.2% to 0.8% of Co; 0.06%-0.30% of Ti, 1.6% of Al, 2.1% of Mg and less than or equal to 0.1% of Al; the alloy comprises the following components in percentage by weight: 0.06-0.20% of Ce + 1.2 Y, less than or equal to 0.008% of S + P, less than or equal to 0.003% of O, less than or equal to 0.003% of N, less than or equal to 0.0005% of H and the balance of Ni and unavoidable The welding wire meets the requirement that the gas equivalent C + 10O + 15N is smaller than or equal to 0.09%. The efficient argon arc welding wire for 9Ni steel automatic welding has the advantages that the air hole sensitivity is reduced, a low-melting-point phase is not prone to being formed in weld metal, the hot crack sensitivity is reduced, and the efficient argon arc welding wire is suitable for large-restraint welding occasions.

Description

Technical Field

[0001] The present invention relates to the technical field of welding wire preparation, and in particular to a high-efficiency argon arc welding wire for automatic welding of 9Ni steel and a preparation method thereof. Background Art

[0002] Liquefied natural gas (LNG) is an environmentally friendly, efficient, and convenient clean energy source widely used in transportation, industry, and everyday life. Compared to traditional fossil fuels such as coal and oil, it significantly reduces emissions of carbon and sulfur oxides. LNG distribution is currently characterized by significant regional imbalances, with long distances between production sites and end users, necessitating extensive transportation and storage facilities. Currently, submerged arc horizontal welding is used for girth welds in the construction of large LNG land tanks, offering high efficiency and consistent weld quality.

[0003] However, current general argon arc welding wires still have many defects. For example, Chinese invention patent publication number CN110480208A discloses a nickel-based alloy welding wire for LNG storage tank welding, a preparation method, and a welding process. The composition, by mass percentage, is as follows: Cr: 20.0~23.0%, Mo: 8.0~10.0%, Nb: 3.15~4.15%, Fe≤5.0%, Co≤1.0%, Mn≤0.50%, Al≤0.40%, Ti≤0.40%, Si≤0.50%, C≤0.10%, S≤0.015%, and the rest is Ni. The preparation method includes the following steps: A. Alloy smelting and casting into electrode rods; B. Electroslag remelting; C. Forging and blanking; D. Hot rolling and annealing; E. Pickling and grinding; F. Drawing; G. Dehydrogenation annealing and straightening after hydrogen treatment; H. Coil formation. Welding wires similar to those in this patent all suffer from issues such as high porosity sensitivity, the easy formation of low-melting-point phases in the weld metal, high hot crack susceptibility, and unsuitability for high-constraint welding applications. Summary of the Invention

[0004] In view of this, the present invention aims to provide a high-efficiency argon arc welding wire for automatic welding of 9Ni steel, which is prepared by using a composition of C≤0.03%; Si≤0.06%; Mn: 0.6%~1.2%, Cr: 15.2%~16.3%; Mo+1.5W: 19.0%~22.0% and Mo≤16.2%; Fe: 4.8%~5.6%; Co: 0.2%~0.8%; Ti+1.6Al+2.1Mg: 0.06%~0.30% and Al≤0.1%; Ce+1.2Y: 0.06%~0.20%, S+P≤0.008%, O≤0.003%, N≤0.003% and H≤0.0005%, with the remainder being Ni and unavoidable impurities, thereby solving the problems of high porosity sensitivity, easy formation of low melting point phases in the weld metal, high hot crack sensitivity, and unsuitability for large-constraint welding.

[0005] To solve the above problems, the present invention provides a high-efficiency argon arc welding wire for automatic welding of 9Ni steel. The welding wire components include: C≤0.03%; Si≤0.06%; Mn: 0.6%-1.2%, Cr: 15.2%-16.3%; Mo+1.5W: 19.0%-22.0% and Mo≤16.2%; Fe: 4.8%-5.6%; Co: 0.2%-0.8%; Ti+1.6Al+2.1Mg: 0.06%-0.30% and Al≤0.1%; Ce+1.2Y: 0.06%-0.20%, S+P≤0.008%, O≤0.003%, N≤0.003% and H≤0.0005%, and the rest is Ni and unavoidable impurities.

[0006] Furthermore, the welding wire satisfies the gas equivalent C+10O+15N≤0.09%.

[0007] A method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel as described in any one of the above, comprising:

[0008] S100, preparing the blank, mixing the components of the welding wire in proportion, and melting them by vacuum melting and electroslag remelting;

[0009] S200, forging treatment, forging temperature is 1020~1250℃;

[0010] S300, hot rolling treatment, the hot rolling temperature is 1000~1250℃, forming hot rolled wire rod;

[0011] S400, solution treatment, keep at 1150-1250℃ for 1-2h and then water cool;

[0012] S500, cleaning the wire rod and degreasing the wire rod;

[0013] S600, drawing process, drawing the wire rod through a wire drawing machine / wire rolling machine to form a welding wire of a preset diameter according to process requirements, and layer winding the welding wire after drawing;

[0014] S700, final processing, final cleaning, drying and packaging of the welding wire.

[0015] Furthermore, in step S200, the forging heating temperature is 1150-1250°C, and the final forging temperature is 1020-1080°C.

[0016] Furthermore, in step S300, the hot rolling heating temperature is 1150-1250°C, and the finishing rolling temperature is 1000-1080°C.

[0017] Furthermore, in step S500, the method of cleaning the disc includes alkali cleaning and acid cleaning, and finally soaking in a soda solution for 3 to 5 minutes to perform acid-base neutralization treatment.

[0018] Further, the alkali washing method comprises:

[0019] Prepare an alkaline degreasing agent, the ingredients of which include: 3-8% sodium hydroxide, 5-8% soda ash, 1-3% sodium citrate, 0.5-1% sodium dodecylbenzene sulfonate, and the remainder is water;

[0020] Use alkaline degreasing agent with a concentration of 15-20%, temperature of 60-80℃, soak for 20-60 minutes, and then ultrasonically clean.

[0021] Further, the pickling method includes:

[0022] Use a mixture of 16-25% nitric acid and 3-8% hydrofluoric acid, soak at a temperature of 40-70°C for 15-25 minutes, and then use high-pressure water to remove residual acid.

[0023] Furthermore, in step S600, the relaxed diameter of the welding wire after layer winding is ≥800 mm, and the warp distance is ≤10 mm.

[0024] Furthermore, in step S700, the final processing method includes:

[0025] S710, a cleaning step, using electrolytic alkaline cleaning and then high-pressure water cleaning;

[0026] S720, drying step, the drying temperature is 80-120° C., and the drying time is 3-10 minutes;

[0027] S730, packaging step, using vacuum packaging.

[0028] Compared with the prior art, the high-efficiency argon arc welding wire for automatic welding of 9Ni steel described in the present invention has the following advantages:

[0029] The advantage of this technical solution is that the welding wire is prepared by using the components of C≤0.03%; Si≤0.06%; Mn: 0.6%~1.2%, Cr: 15.2%~16.3%; Mo+1.5W: 19.0%~22.0% and Mo≤16.2%; Fe: 4.8%~5.6%; Co: 0.2%~0.8%; Ti+1.6Al+2.1Mg: 0.06%~0.30% and Al≤0.1%; Ce+1.2Y: 0.06%~0.20%, S+P≤0.008%, O≤0.003%, N≤0.003% and H≤0.0005%, with the remainder being Ni and unavoidable impurities, thereby reducing the porosity sensitivity, making it difficult for low melting point phases to form in the weld metal, reducing the hot crack sensitivity, and being suitable for large-constraint welding occasions. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below.

[0031] In this disclosure, terms such as "first," "second," "upper," and "lower" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features designated as "first," "second," "upper," and "lower" may explicitly or implicitly include at least one such feature. Furthermore, the technical solutions of various embodiments may be combined, but this must be achievable by persons of ordinary skill in the art. If the technical solutions of various embodiments can be combined, they are within the scope of protection claimed by this disclosure.

[0032] The present invention will be described in detail below with reference to the embodiments.

[0033] A high-efficiency argon arc welding wire for automatic welding of 9Ni steel, comprising the following components: C ≤ 0.03%; Si ≤ 0.06%; Mn: 0.6% to 1.2%, Cr: 15.2% to 16.3%; Mo + 1.5W: 19.0% to 22.0% and Mo ≤ 16.2%; Fe: 4.8% to 5.6%; Co: 0.2% to 0.8%; Ti + 1.6Al + 2.1Mg: 0.06% to 0.30% and Al ≤ 0.1%; Ce + 1.2Y: 0.06% to 0.20%, S + P ≤ 0.008%, O ≤ 0.003%, N ≤ 0.003%, and H ≤ 0.0005%, with the remainder being Ni and unavoidable impurities. The welding wire satisfies a gas equivalent of C + 10O + 15N ≤ 0.09%.

[0034] The main ideas for preparing welding wire using the above components are as follows:

[0035] (1) Use comprehensive gas control technology to reduce porosity sensitivity. By controlling the gas equivalent of the weld metal (C+10O+15N), the generation of porosity can be reduced from the source; the carbon content of the welding wire can be controlled to reduce CO porosity sensitivity; Ti, Al, and Mg composite degassing technology can be used to reduce CO and N2 porosity sensitivity; rare earth Ce and Y can be used to remove hydrogen and reduce hydrogen porosity sensitivity.

[0036] (2) Use multiple approaches to reduce the hot crack sensitivity of weld metals, including raw material control, rare earth purification, and segregation reduction. By controlling S and P and using rare earths La and Ce to fix S and P, the formation of low-melting-point phases is reduced, reducing the hot crack sensitivity. Controlling the Si content, reducing segregation, and avoiding the formation of low-melting-point second phases further reduce the hot crack sensitivity.

[0037] (3) Improve the comprehensive mechanical properties of the weld metal through multi-element synergistic strengthening and toughening technology. Through the synergistic effect of W and Mo, segregation is reduced, the weld metal is strengthened and the low-temperature toughness of the weld metal is improved. Adding appropriate amounts of Cr and Fe can strengthen the weld metal while avoiding the formation of harmful second phases and maintaining good low-temperature toughness. Adding a certain amount of Mn and Co can strengthen the weld metal and improve the low-temperature toughness.

[0038] In order to better illustrate the technical approach of this patent, the main functions of each component are described in detail below.

[0039] C: It forms carbides with elements such as Cr, Mo and W, significantly reducing the plasticity and toughness of the weld metal. However, excessive C increases the sensitivity to porosity and should be controlled below 0.03%.

[0040] Si: Although it can play a certain role in solid solution strengthening, if the content is too high, it is easy to segregate between dendrites and form low-melting-point compounds. When the constraint is large, the weld is prone to cracking. It should be controlled below 0.06%.

[0041] Cr: It is an important strengthening element. When the Cr content is less than 15.2%, the strength of the weld metal is low. When the Cr content is greater than 16.3%, carbides and brittle second phases are easily formed, which deteriorates the low-temperature toughness.

[0042] Mn: It has a certain solid solution strengthening effect. At the same time, combined with low melting point elements such as S, it can reduce hot crack sensitivity. When Mn content is less than 0.6%, the weld metal strength is low. When the Mn content exceeds 1.2%, a large amount of second phase precipitates, reducing the plasticity and low-temperature toughness of the weld metal.

[0043] W and Mo: They are important strengthening elements, with W having a greater strengthening effect than Mo. When the Mo content exceeds 16.2%, it is prone to segregation, forming a brittle second phase and deteriorating low-temperature toughness. When the Mo+1.5W content is less than 19.0%, the strength of the weld metal is insufficient. When the Mo+1.5W content exceeds 22%, W and Mo tend to segregate between dendrites, forming a large amount of brittle second phase, which reduces the toughness and plasticity of the weld metal.

[0044] Fe: An important strengthening element. When Fe is less than 4.8%, the strength of the weld metal is insufficient; when Fe is greater than 5.6%, it tends to segregate between dendrites, increasing the sensitivity to hot cracking.

[0045] Co: It can strengthen the weld metal and improve low-temperature toughness. When Co is less than 0.2%, the weld metal strength is insufficient and the low-temperature toughness is low. When Co exceeds 0.8%, the beneficial effect is not significantly increased, but due to its high price, it will significantly increase the cost.

[0046] Ti, Al, and Mg: All are strong deoxidizing and denitrifying elements. They can also protect C from oxidation, significantly reducing the porosity sensitivity of the weld metal while improving its strength, plasticity, and low-temperature toughness. When Ti+1.6Al+2.1Mg is less than 0.06%, the above beneficial effects are insufficient. When Ti+1.6Al+2.1Mg is greater than 0.12%, a large amount of non-metallic inclusions and brittle second phases are generated, seriously deteriorating the low-temperature toughness of the weld metal. When Ti+1.6Al+2.1Mg: 0.06% to 0.3% and Al ≤ 0.1%, the weld metal has low porosity sensitivity and good plasticity and low-temperature toughness.

[0047] Ce and Y: Their primary function is to purify the weld metal, improving low-temperature toughness while reducing hot crack susceptibility. When Ce+1.2Y is less than 0.06%, these beneficial effects are insufficient. When Ce+1.2Y exceeds 0.2%, non-metallic inclusions increase, reducing the weld metal's plasticity and low-temperature toughness.

[0048] S, P: impurity elements that can significantly increase the hot crack sensitivity of the weld metal. S+P should be controlled below 0.008%.

[0049] O, N, H: These are all impurity elements. Excessive content will significantly reduce the strength, plasticity, and low-temperature toughness of the weld metal, while significantly increasing porosity sensitivity. O should be controlled to ≤ 0.003%, N ≤ 0.003%, H ≤ 0.001%, and C+10O+15N ≤ 0.09%.

[0050] Compared with the prior art, the welding wire prepared by the above technical solution does not contain components such as Cu, Si, and Nb, limits the impurity elements S and P, reduces the porosity sensitivity, is not easily formed in the weld metal, reduces the sensitivity to thermal cracks, and is suitable for large-constraint welding occasions.

[0051] A method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel as described in any one of the above, comprising:

[0052] S100, preparing the blank, mixing the components of the welding wire in proportion, and melting them by vacuum melting and electroslag remelting;

[0053] S200, forging treatment, the forging temperature is 1020~1250℃, preferably, the forging heating temperature is 1150~1250℃, the final forging temperature is 1020~1080℃, and the single hammer deformation is ≤10%;

[0054] S300, hot rolling treatment, the hot rolling temperature is 1000-1250° C., preferably, the hot rolling heating temperature is 1150-1250° C., and the final rolling temperature is 1000-1080° C., to form a hot-rolled wire rod;

[0055] S400, solution treatment, keep the temperature at 1150-1250℃ for 1-2h to fully dissolve the carbides and the second phase, and then water cool;

[0056] S500, cleaning the wire rod, degreasing and cleaning the wire rod, the cleaning method includes alkali cleaning and acid cleaning, and finally soaking in a soda solution for 3 to 5 minutes for acid-base neutralization treatment to prevent further corrosion by residual acid;

[0057] Alkaline cleaning methods include:

[0058] Prepare an alkaline degreasing agent, the ingredients of which include: 3-8% sodium hydroxide, 5-8% soda ash, 1-3% sodium citrate, 0.5-1% sodium dodecylbenzene sulfonate, and the remainder is water;

[0059] Use alkaline degreasing agent with a concentration of 15-20%, temperature of 60-80℃, soak for 20-60 minutes, and then ultrasonically clean.

[0060] Pickling methods include:

[0061] Use a mixture of 16-25% nitric acid and 3-8% hydrofluoric acid, soak at a temperature of 40-70°C for 15-25 minutes, and then use high-pressure water to remove residual acid.

[0062] S600, drawing process, drawing the wire rod through a wire drawing machine / wire rolling machine to form a welding wire of a preset diameter according to the process requirements. After drawing, the welding wire is layered and wound. After layer winding, the relaxed diameter of the welding wire is ≥800mm and the warp distance is ≤10mm.

[0063] S700, final treatment, final cleaning, drying and packaging of welding wire. Final treatment methods include:

[0064] S710, a cleaning step, using electrolytic alkaline cleaning and then high-pressure water cleaning;

[0065] S720, drying step, the drying temperature is 80-120° C., and the drying time is 3-10 minutes;

[0066] S730, packaging step, using vacuum packaging.

[0067] The present invention is illustrated below using specific examples. In this example, three ingots with the compositions of the examples were prepared by vacuum melting and electroslag remelting. These ingots were then reduced to Φ1.1 mm by forging, hot rolling, and drawing on a straight wire drawing machine. The welding wires of the examples were then alkali-washed, high-pressure-water-washed, and dried. The specific compositions are shown in Table 1.

[0068] Table 1

[0069]

[0070] The example welding wire was deposited and matched with 9Ni steel for vertical butt welding of test plates. The welding parameters used are shown in Table 2, the mechanical properties of the deposited metal are shown in Table 3, and the mechanical properties of the joint are shown in Table 4. The results showed that the example welding wire produced a stable arc in the vertical welding position, with good weld formation, moderate deposited metal strength, excellent toughness of the deposited metal and the joint at -196°C, and no cracks were observed in the joint after forward, reverse, and lateral bends of 180°. Crack testing was conducted according to the GB / T 41107.2 T-joint weld crack test method, and no cracks were observed. Defect analysis of the example weld joints in the vertical welding position was performed according to GB / T 13298 and flaw detection was performed according to GB / T 3323. The results are shown in Table 5. All joints were free of defects such as pores, slag inclusions, lack of fusion, or cracks, and all achieved a flaw detection grade of Class I. The welding efficiency was compared with that of an electric welding rod, as shown in Table 5, which showed that the efficiency was nearly three times that of the rod.

[0071] Table 2

[0072]

[0073] Table 3

[0074]

[0075] Table 4

[0076]

[0077] Table 5

[0078]

[0079] The welding wire proposed in the present invention has good welding processability, and the matching 9Ni steel joint has no welding defects such as pores, lack of fusion, and cracks. The welding efficiency is much higher than that of welding rods. The deposited metal and the welded joint have moderate strength and excellent low-temperature toughness, which can meet the requirements of efficient and high-quality welding of large 9Ni steel storage tanks.

[0080] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A high-efficiency argon arc welding wire for automatic welding of 9Ni steel, characterized in that: The welding wire components include: C≤0.03%; Si≤0.06%; Mn: 0.6%~1.2%, Cr: 15.2%~16.3%; Mo+1.5W: 19.0%~22.0% and Mo≤16.2%; Fe: 4.8%~5.6%; Co: 0.2%~0.8%; Ti+1.6Al+2.1Mg: 0.06%~0.30% and Al≤0.1%; Ce+1.2Y: 0.06%~0.20%, S+P≤0.008%, O≤0.003%, N≤0.003% and H≤0.0005%, and the rest are Ni and unavoidable impurities.

2. The high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 1, characterized in that: The welding wire satisfies a gas equivalent of C+10O+15N≤0.09%.

3. A method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel as claimed in claim 1 or 2, characterized in that: include: S100, preparing the blank, mixing the components of the welding wire in proportion, and melting them by vacuum melting and electroslag remelting; S200, forging treatment, forging temperature is 1020~1250℃; S300, hot rolling treatment, the hot rolling temperature is 1000~1250℃, forming hot rolled wire rod; S400, solution treatment, keep at 1150-1250℃ for 1-2h and then water cool; S500, cleaning the wire rod and degreasing the wire rod; S600, drawing process, drawing the wire rod through a wire drawing machine / wire rolling machine to form a welding wire of a preset diameter according to process requirements, and layer winding the welding wire after drawing; S700, final processing, final cleaning, drying and packaging of the welding wire.

4. The method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 3, characterized in that: In step S200, the forging heating temperature is 1150-1250°C, and the final forging temperature is 1020-1080°C.

5. The method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 3, characterized in that: In step S300, the hot rolling heating temperature is 1150-1250°C, and the finishing rolling temperature is 1000-1080°C.

6. The method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 3, characterized in that: In step S500, the method of cleaning the disc includes alkali cleaning and acid cleaning, and finally soaking in a soda solution for 3 to 5 minutes to perform acid-base neutralization treatment.

7. The method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 6, characterized in that: Alkaline cleaning methods include: Prepare an alkaline degreasing agent, the ingredients of which include: 3-8% sodium hydroxide, 5-8% soda ash, 1-3% sodium citrate, 0.5-1% sodium dodecylbenzene sulfonate, and the remainder is water; Use alkaline degreasing agent with a concentration of 15-20%, temperature of 60-80℃, soak for 20-60 minutes, and then ultrasonically clean.

8. The method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 6, characterized in that: Pickling methods include: Use a mixture of 16-25% nitric acid and 3-8% hydrofluoric acid, soak at a temperature of 40-70°C for 15-25 minutes, and then use high-pressure water to remove residual acid.

9. The method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 3, characterized in that: In step S600, the relaxed diameter of the welding wire after layer winding is ≥800 mm, and the warp distance is ≤10 mm.

10. The method for preparing a high-efficiency argon arc welding wire for automatic welding of 9Ni steel according to claim 3, characterized in that: In step S700, the final processing method includes: S710, a cleaning step, using electrolytic alkaline cleaning and then high-pressure water cleaning; S720, drying step, the drying temperature is 80-120° C., and the drying time is 3-10 minutes; S730, packaging step, using vacuum packaging.

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