Melting ring for 026Cr18Ni12Mo2N austenitic stainless steel welding and preparation method and application thereof

Abstract

The invention relates to a melting ring for 026Cr18Ni12Mo2N austenitic stainless steel welding and a preparation method and application thereof, and belongs to the technical field of alloy steel welding. The melting ring comprises the following chemical components in percentage by weight: 25 to 27.5 percent of Cr, 1.0 to 1.5 percent of Mo, 0.1 to 0.40 percent of Si, less than or equal to 0.02 percent of Ti, 0.06 to 0.15 percent of Nb and the balance of Fe and inevitable impurities. Through mutual cooperation of the elements, such as Cr, Mo, Si, Ti and Nb, and strict control of the content of each element, a molten ring with excellent performance and a ferrite structure is obtained; the melting ring is used in a welding method or process of 026Cr18Ni12Mo2N austenitic stainless steel, the welding seam structure is obviously refined, and the cracking tendency of the welding seam is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of welding alloy steel, and in particular to a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel, and a preparation method and application thereof. Background Art

[0002] 026Cr18Ni12Mo2N is a typical austenitic stainless steel, which is mainly used to prepare products such as voltage stabilizer electric heating components and electric heating element sleeves. During the welding process, austenitic stainless steel welds are prone to thermal cracks under high temperature conditions, which in turn leads to a decrease in the performance of the welded product and makes subsequent applications impossible. Summary of the invention

[0003] In view of the above analysis, the present invention aims to provide a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel and a preparation method and application thereof, so as to solve the problem of the large cracking tendency of the existing welds.

[0004] On the one hand, the present invention provides a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel, wherein the chemical composition of the melting ring comprises, by weight percentage, Cr: 25-27.5%, Mo: 1.0-1.5%, Si: 0.1-0.40%, Ti: ≤0.02%, Nb: 0.06-0.15%, and the balance is Fe and unavoidable impurities.

[0005] Furthermore, the chemical composition of the melting ring includes Cr: 25-27.2%, Mo: 1.1-1.5%, Si: 0.1-0.30%, Ti: ≤0.02%, and Nb: 0.09-0.15%.

[0006] Further, the impurity element is one or more of C, Mn, S, P and Cu;

[0007] Calculated in weight percentage: C≤0.003%, Mn≤0.20%, S≤0.005%, P≤0.008%, Cu≤0.1%.

[0008] On the other hand, the present invention provides a method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel, comprising the following preparation steps:

[0009] S1: Vacuum induction melting, the materials are prepared according to the composition ratio. When charging, Cr and Fe raw materials are first added, and the vacuum is evacuated to 10-15Pa, and melting begins; after the raw materials are fully melted, the vacuum is further evacuated to 3-5Pa, and the composition is measured by sampling; the vacuum is further evacuated to 0.5-1Pa, and the alloy material is added for refining; the electrode is obtained after casting;

[0010] S2: electroslag remelting;

[0011] S3: Forging;

[0012] S4: hot rolling;

[0013] S5: rods are obtained after solution treatment;

[0014] S6: The rod is machined to obtain a molten ring.

[0015] Further, in step S1, the melting period has a melting time of 90 to 120 minutes and a melting power of 120 kW;

[0016] Refining period ≥40min;

[0017] The pouring temperature is 1440~1480℃.

[0018] Further, in step S3, the heating temperature is 1100-1180°C, the forging deformation ratio is 4-6, the final forging temperature is ≥950°C, and air cooling is performed after forging.

[0019] Further, in step S4, the rolling ratio is ≥5.

[0020] Furthermore, the internal structure of the obtained molten ring is ferrite.

[0021] Furthermore, the tensile strength Rm of the obtained molten ring is ≥430MPa, the yield strength Rp0.2 is ≥260MPa, the elongation after fracture A is ≥20%, and the hardness is ≥150HB.

[0022] Furthermore, the melting ring is used in a 026Cr18Ni12Mo2N austenitic stainless steel welding method.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] 1. The present invention obtains a melting ring with excellent performance and a ferrite structure by combining elements such as Cr, Mo, Si, Ti and Nb, and strictly controlling the content of each element; the melting ring is used in the welding method or process of 026Cr18Ni12Mo2N austenitic stainless steel, the weld structure is significantly refined, and the cracking tendency of the weld is reduced;

[0025] 2. The present invention obtains a melting ring through vacuum induction melting, electroslag remelting, forging, hot rolling, solution treatment and other processes, and has excellent performance, Rm≥430MPa, Rp0.2≥260MPa, A≥20%, and hardness≥150HB;

[0026] 3. The melting ring obtained by the present invention is used in the welding of 026Cr18Ni12Mo2N austenitic stainless steel. During the welding process, a certain amount of ferrite phase is introduced into the austenite, and the weld structure is significantly refined and uniform, thereby improving the overall crack resistance of the weld and the average weld hardness is also slightly higher.

[0027] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0029] Figure 1 This is a physical picture of the melting ring;

[0030] Figure 2 This is the weld structure photo after welding (50×) of the application example;

[0031] Figure 3 This is the weld structure photo after welding (100×) of the application example;

[0032] Figure 4 This is the weld structure photo after welding (200×) of the application example;

[0033] Figure 5 For comparison, the weld structure photo after welding is shown in the application example (50×);

[0034] Figure 6 For comparison, the weld structure photo after welding is shown in the application example (100×);

[0035] Figure 7 For comparison, the weld structure photo after welding is shown in the application example (200×);

[0036] Figure 8 This is the test point diagram of the hardness of the butt joint after welding in the application example;

[0037] Fig. 9 This is a test point diagram of the hardness of the butt joint after welding for comparison application example. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0039] 026Cr18Ni12Mo2N is a typical austenitic stainless steel, which is mainly used to prepare products such as voltage stabilizer electric heating components and electric heating element sleeves. During the welding process, austenitic stainless steel welds are prone to thermal cracks under high temperature conditions, which in turn leads to a decrease in the performance of the welded product and makes subsequent applications impossible.

[0040] The invention provides a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel. The chemical composition of the melting ring comprises, by weight percentage, Cr: 25-27.5%, Mo: 1.0-1.5%, Si: 0.1-0.40%, Ti: ≤0.02%, Nb: 0.06-0.15%, and the balance is Fe and inevitable impurities.

[0041] Compared with the prior art, the present invention obtains a melting ring with excellent performance and a ferrite structure by combining elements such as Cr, Mo, Si, Ti and Nb, and strictly controlling the content of each element; the melting ring is used in the welding method or process of 026Cr18Ni12Mo2N austenitic stainless steel, the weld structure is significantly refined, and the cracking tendency of the weld is reduced.

[0042] The functions of each element are as follows:

[0043] Cr is a key element of ferritic stainless steel (i.e., melting ring, the same below), which can significantly improve the corrosion resistance of the melting ring, especially in an oxidizing environment. In addition, as a strong ferrite forming element, Cr can stabilize the ferrite structure and improve the high temperature strength and oxidation resistance of the melting ring. In summary, the Cr content range is designed to be 25.00-27.50wt%, such as 25.01wt%, 25.09wt%, 25.15wt%, 25.47wt%, 25.56wt%, 25.59wt%, 25.88wt%, 25.95wt%, 26.11wt%, 26.51wt%, 26.66wt%, 26.78wt% or 27.50wt%.

[0044] Mo can enhance the hardness and corrosion resistance of ferritic stainless steel, especially in an environment containing chloride ions. The addition of Mo to high Cr stainless steel can also significantly improve the pitting and crevice corrosion resistance of the melting ring. In summary, the Mo content range is designed to be 1.00-1.50wt%, such as 1.00wt%, 1.13wt%, 1.23wt%, 1.25wt%, 1.33wt%, 1.38wt%, 1.42wt%, 1.45wt% or 1.50wt%.

[0045] Si is also a ferrite-forming element, but too high a silicon content will increase the brittle transition temperature of the molten ring, causing the molten ring to become brittle at low temperatures. An appropriate Si content can improve the fluidity of the molten pool and enhance welding processability. Therefore, the silicon content must be strictly controlled in the design to take into account both welding processability and toughness. In summary, the Si content range is designed to be 0.10-0.40wt%, such as 0.10wt%, 0.15wt%, 0.19wt%, 0.21wt%, 0.28wt%, 0.31wt%, 0.35wt%, 0.39wt% or 0.40wt%.

[0046] Ti and Nb, as strong carbide and nitride forming elements, can effectively refine grains and enhance the mechanical properties and corrosion resistance of materials. They can form stable carbides or nitrides, reduce the adverse effects of C and N on the performance of the melting ring, and improve high temperature strength. In summary, the Ti content range is designed to be ≤0.02wt%, and the Nb content range is designed to be 0.06-0.15wt%, such as 0.06wt%, 0.094wt%, 0.096wt%, 0.11wt%, 0.13wt% or 0.15wt%.

[0047] Preferably, the chemical composition of the melting ring includes Cr: 25-27.2%, Mo: 1.1-1.5%, Si: 0.1-0.30%, Ti: ≤0.02%, and Nb: 0.09-0.15%.

[0048] Specifically, the impurity element is one or more of C, Mn, S, P and Cu;

[0049] Calculated in weight percentage: C≤0.003%, Mn≤0.20%, S≤0.005%, P≤0.008%, Cu≤0.1%.

[0050] It should be noted that the C element is a key element for solid solution strengthening in steel. Adding C can significantly improve the strength of steel materials, but will reduce plastic toughness. In the present invention, due to the high Cr and Mo contents, excessive C content will lead to the formation of large-sized carbides in the weld. In addition, excessive C content will strongly reduce the Ms point and increase the tendency of residual austenite to form, which is not in line with the idea of ​​introducing ferrite to reduce the tendency of austenitic steel welding cracking.

[0051] Mn is an austenite stabilizing element, and too high a Mn content will also promote the formation of retained austenite. C. Too high a Mn content will promote the formation of austenite and reduce the tendency of ferrite formation.

[0052] S and P are harmful impurities in steel. They will form brittle phases on the grain boundaries, thereby reducing the ductility and impact resistance of the material. At the same time, they will increase the tendency of hot cracking in welded joints. Therefore, the content of S and P must be strictly controlled at an extremely low level.

[0053] Cu can improve the corrosion resistance of the material, especially in acidic and salt spray environments, but a high Cu content will affect the hot working properties of the material, so the Cu content range needs to be controlled within ≤0.10wt%.

[0054] The present invention provides a method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel, comprising the following preparation steps:

[0055] S1: Vacuum induction melting, the materials are prepared according to the composition ratio. When charging, Cr and Fe raw materials are first added, and the vacuum is evacuated to 10-15Pa, and melting begins; after the raw materials are fully melted, the vacuum is further evacuated to 3-5Pa, and the composition is measured by sampling; the vacuum is further evacuated to 0.5-1Pa, and the alloy material is added for refining; the electrode is obtained after casting;

[0056] S2: electroslag remelting;

[0057] S3: Forging;

[0058] S4: hot rolling;

[0059] S5: rods are obtained after solution treatment;

[0060] S6: The rod is machined to obtain a molten ring.

[0061] Compared with the prior art, the present invention obtains rods through vacuum induction melting, electroslag remelting, forging, hot rolling, solution treatment and other processes, and then the rods are processed into pipes by machining, and then sliced ​​to produce melting rings with a thickness of about 0.5 mm. The melting ring has excellent performance, Rm≥430MPa, Rp0.2≥260MPa, A≥20%, and hardness≥150HB; its structure is ferrite, which ensures the strength of the weld and prevents cracking at the weld during use.

[0062] Specifically, in step S1, the melting time of the melting period is 90 to 120 minutes, the melting power is 120 kW; the refining period time is ≥ 40 minutes; and the pouring temperature is 1440 to 1480°C.

[0063] It should be noted that during the hollow smelting process, it is necessary to control the vacuum degree at different times, as well as the melting time, refining time, melting power and pouring temperature. The vacuum induction melting casting electrode is air-cooled after demolding, and then electroslag remelting is carried out. When the smelting is completed, pay attention to the shrinkage compensation time, which should be 3-5 minutes. The electroslag ingot is mechanically peeled, ground, and cut off. Preferably, the head and tail resection amount is 8%-15% to ensure the quality of the electroslag ingot.

[0064] Specifically, in step S3, the heating temperature is 1100-1180°C, the forging deformation ratio is 4-6, the final forging temperature is ≥950°C, and air cooling is performed after forging.

[0065] It should be noted that after electroslag remelting, the remelted steel ingot is forged, the heating temperature is 1100-1180°C, and the heating temperature is controlled to be 1100-1180°C, such as 1100°C, 1110°C, 1120°C, 1130°C, 1140°C, 1150°C, 1160°C, 1170°C or 1180°C. The forging deformation ratio is 4-6, such as 4, 5 or 6; the final forging temperature is ≥950°C, air cooling after forging, and the size of the forged billet is 60mm×60mm. After forging, the head and tail are cut off, and the surface is peeled and ground.

[0066] The heating process before forging is the key to improving the homogenization of the remelted ingot. When the heating temperature is too low, the alloy elements cannot diffuse fully. When the heating temperature is too high, overburning is likely to occur, resulting in a coarse structure and affecting the performance of the subsequent melt ring.

[0067] Forging deformation ratio and final forging temperature are key factors affecting the performance of the forged microstructure. When the deformation ratio is too small and the final forging temperature is too high, the grains cannot be fully refined. When the deformation ratio is too large, the finished product size will be insufficient and the equipment capacity will be required. When the final forging temperature is too low, dynamic recrystallization cannot be fully achieved, which can easily lead to uneven microstructure.

[0068] Specifically, in step S4, the rolling ratio is ≥5.

[0069] It should be noted that the hot forged billet is first annealed (650-700℃ for more than 8h, air cooled to room temperature), and then rolled into a rod, with a rolling ratio ≥5, such as 5, 6, 7 or 8. If the rolling ratio is too low, the deformation is insufficient and the material strength is insufficient. If the rolling ratio is too high, it is easy to cause excessive strength and insufficient plastic toughness.

[0070] Specifically, the solution temperature is 870-920°C, the time is ≥1h, and water cooling is performed after the solution.

[0071] It should be noted that after the surface of the rolled bar is polished, a solution treatment is performed, and the solution temperature is 870-920°C, such as 870°C, 880°C, 890°C, 900°C, 910°C or 920°C, and the time is ≥1h, and the solution is cooled by water. If the solution temperature is too low and the holding time is too short, the carbides cannot be fully dissolved, and the remaining large-sized precipitation phase will harm the plastic toughness of the material; if the solution temperature is too high and the holding time is too long, the grains will be too coarse.

[0072] The melting ring of the present invention is used in a 026Cr18Ni12Mo2N austenitic stainless steel welding method. Taking the welding of 026Cr18Ni12Mo2N austenitic stainless steel pipe as an example, the method comprises the following steps:

[0073] (1) Processing 026Cr18Ni12Mo2N austenitic stainless steel into pipes and cutting grooves;

[0074] (2) Argon arc welding is used for welding, using He gas shielded welding, and the ferrite melting ring of the present invention is placed at the groove;

[0075] (3) Welding is performed according to the set welding process parameters.

[0076] Specifically, the welding process parameters are as follows: welding speed 80-100mm / min, pulse current standard welding, welding peak current 120A, proportion time 170-200ms, base current 60A, proportion time 300ms, arc ending current 20A, fall time 5s, and delayed gas supply time 3s.

[0077] Compared with the prior art, the melting ring provided by the present invention is used to weld 026Cr18Ni12Mo2N austenitic stainless steel. During the welding process, a certain amount of ferrite phase is introduced into the austenite, so that the weld structure is significantly refined and uniform, the overall crack resistance of the weld is improved, and the average value of the weld hardness is also slightly higher.

[0078] It should be noted that austenitic stainless steel welds are prone to thermal cracking under high temperature conditions. This is because the austenite structure is highly brittle at high temperatures and has large shrinkage stress during solidification. The ferrite phase has a lower thermal expansion coefficient and can absorb and disperse part of the stress during solidification, reducing stress concentration in the austenite phase, thereby reducing the possibility of crack formation.

[0079] At the same time, the presence of the ferrite phase can provide a crack passivation mechanism during the solidification process, so that the crack is blocked or diverted when it encounters the ferrite phase during the expansion process, thereby reducing the power of crack expansion and reducing the sensitivity to thermal cracks.

[0080] The addition of ferrite can also improve the mechanical properties of the weld, especially under high temperature and complex stress conditions. In addition, during the welding process, austenitic stainless steel is prone to chromium carbide precipitation in the heat-affected zone, leading to intergranular corrosion. The ferrite phase can reduce this sensitization phenomenon to a certain extent, homogenize the weld structure, reduce the inhomogeneity of the chemical composition, and thus improve the overall intergranular corrosion resistance and hardness of the weld.

[0081] Therefore, a certain amount of ferrite structure (provided by the melting ring) is introduced into the austenitic stainless steel weld to improve the welding performance of austenitic steel. The introduction of the ferrite phase needs to strictly control its content, which is generally achieved through suitable welding materials and welding processes (for example, by using the ferrite type melting ring provided by the present invention, and the welding process parameters provided by the present invention as mentioned above). Selecting appropriate welding materials is the basis for controlling the content of ferrite phase in the weld, and the ratio of alloy elements in the welding material directly affects the phase structure of the weld metal. Based on the results of comprehensive consideration of welding quality, mechanical properties, corrosion resistance and other factors, the volume fraction of the ferrite phase in the austenitic stainless steel weld is usually controlled at about 5%-12% to achieve the best effect. Too high a ferrite content may cause the weld to be too hard, reducing its toughness and machinability; while too low a ferrite content may not be able to effectively play its improvement role.

[0082] In order to more clearly describe the present invention, it is further illustrated by the following examples and comparative examples.

[0083] Example 1

[0084] The method for preparing the melting ring comprises the following steps:

[0085] S1: Vacuum induction melting: 1) Add Cr and Fe raw materials, evacuate to 10Pa, and send electricity for melting; 2) After the raw materials are fully melted, further evacuate to 4Pa, take samples to measure the composition. The entire melting period takes about 100 minutes; 3) Further evacuate to 0.5Pa, add alloy materials for alloying treatment, and refine for 50 minutes; 4) After refining, electrode casting is carried out, and the casting temperature is 1460℃.

[0086] S2: Electroslag remelting: After the electrode is demoulded, it is air-cooled, and then electroslag remelting is carried out. After the smelting is completed, the shrinkage is supplemented for 3-5 minutes. The electroslag ingot is mechanically peeled and ground, and 10% of the head and tail are cut off.

[0087] S3: Forging: The electroslag ingot is heated and kept at 1180℃, the forging deformation ratio is 6, air-cooled after forging, and the size of the forged billet is 60mm×60mm. After forging, the head is cut off by 5%, the tail is cut off by 15%, and the surface is peeled and ground.

[0088] S4: Hot rolling: The billet is first annealed (680°C for 8 hours, air-cooled to room temperature), and then rolled into rods with a rolling ratio of 6.

[0089] S5: Solution treatment: solution temperature is 900℃, keep warm for 1h after through-heat treatment, water cool after solution treatment, and obtain the melting ring after processing.

[0090] Example 2-3

[0091] The preparation process of Examples 2 and 3 is substantially the same as that of Example 1, except that the composition of the melting ring is different, as shown in Table 1.

[0092] Table 1 Chemical composition of the examples (wt%)

[0093] element C Si Mn Mo Nb Example 1 0.0012 0.21 0.050 1.23 0.11 Example 2 0.0005 0.19 0.0035 1.41 0.096 Example 3 0.0006 0.19 0.0032 1.12 0.094 element Cr Ti Cu S p Example 1 25.59 0.005 0.023 0.0024 0.005 Example 2 27.2 0.0023 0.0026 0.0020 0.005 Example 3 25.2 0.0022 0.0024 0.0020 0.005

[0094] Comparative Example 1

[0095] The preparation process of Comparative Example 1 is substantially the same as that of Example 1, except that the S and P elements in Comparative Example 1 exceed the standard, with the S content being 0.023% and the P content being 0.018%.

[0096] Performance Testing

[0097] The above-mentioned Examples 1-3 and Comparative Example 1 were subjected to performance tests, mainly including tensile strength, yield strength, elongation after fracture and hardness at room temperature. The test results are shown in Table 2.

[0098] Table 2 Performance test results

[0099]

[0100] Combined with Examples 1-3 and Comparative Examples 1-3 and with reference to Table 1 and with Figure 1 It can be seen that the melting ring obtained by the embodiment of the present invention has excellent comprehensive performance, the internal structure is ferrite, the tensile strength Rm ≥ 500MPa, the yield strength Rp0.2 ≥ 390MPa, the elongation after fracture A ≥ 35%, and the hardness ≥ 160HB. The melting ring obtained by the present invention can be used in the 026Cr18Ni12Mo2N austenitic stainless steel welding method to ensure that no cracks are generated during and after the welding process.

[0101] Application Examples

[0102] Application Example: The ferrite melting ring of Example 1 is selected to weld 026Cr18Ni12Mo2N austenitic stainless steel; the comparative application example is 026Cr18Ni12Mo2N austenitic stainless steel welded without using the melting ring.

[0103] Specific process:

[0104] (1) Processing 026Cr18Ni12Mo2N austenitic stainless steel into pipes and cutting grooves;

[0105] (2) Argon arc welding is used for welding, using He gas shielded welding, and the ferrite melting ring of the present invention is placed at the groove, with a thickness of 0.5 mm;

[0106] (3) Welding was performed with the set welding process parameters, the specific process was as follows: welding speed 90 mm / min, pulse current standard welding, welding peak current 120 A, proportion time 170-200 ms, base current 60 A, proportion time 300 ms, arc ending current 20 A, fall time 5 s, and delayed gas supply time 3 s.

[0107] Table 3 Performance test results after welding

[0108]

[0109] Combined with comparative application examples and application examples Figure 2-9 It can be seen that the ferrite melting ring provided in Example 1 of the present invention is used to weld 026Cr18Ni12Mo2N austenitic stainless steel. Compared with not using a melting ring, at the same multiple, the weld structure of 026Cr18Ni12Mo2N austenitic stainless steel is significantly refined after welding with the ferrite melting ring, and the average weld hardness is also slightly higher.

[0110] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel, characterized in that: The chemical composition of the melting ring includes, by weight percentage, Cr: 25-27.5%, Mo: 1.0-1.5%, Si: 0.1-0.40%, Ti: ≤0.02%, Nb: 0.06-0.15%, and the remainder is Fe and unavoidable impurities.

2. The melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel according to claim 1, characterized in that: The chemical composition of the melting ring includes Cr: 25-27.2%, Mo: 1.1-1.5%, Si: 0.1-0.30%, Ti: ≤0.02%, and Nb: 0.09-0.15%.

3. The melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel according to claim 1 or 2, characterized in that: The impurity element is one or more of C, Mn, S, P and Cu; Calculated in weight percentage: C≤0.003%, Mn≤0.20%, S≤0.005%, P≤0.008%, Cu≤0.1%.

4. A method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following preparation steps: S1: Vacuum induction melting, the materials are prepared according to the composition ratio. When charging, Cr and Fe raw materials are first added, and the vacuum is evacuated to 10-15Pa, and melting begins; after the raw materials are fully melted, the vacuum is further evacuated to 3-5Pa, and the composition is measured by sampling; the vacuum is further evacuated to 0.5-1Pa, and the alloy material is added for refining; the electrode is obtained after casting; S2: electroslag remelting; S3: Forging; S4: hot rolling; S5: rods are obtained after solution treatment; S6: The rod is machined to obtain a molten ring.

5. The method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel according to claim 4, characterized in that: In step S1, the melting period is 90 to 120 minutes, and the melting power is 120 kW; Refining period ≥40min; The pouring temperature is 1440~1480℃.

6. The method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel according to claim 4, characterized in that: In step S3, the heating temperature is 1100-1180°C, the forging deformation ratio is 4-6, the final forging temperature is ≥950°C, and air cooling is performed after forging.

7. The method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel according to claim 4, characterized in that: In step S4, the rolling ratio is ≥5.

8. The method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel according to claim 4, characterized in that: The internal structure of the obtained molten ring is ferrite.

9. The method for preparing a melting ring for welding 026Cr18Ni12Mo2N austenitic stainless steel according to claim 4, characterized in that: The obtained molten ring has a tensile strength Rm≥430MPa, a yield strength Rp0.2≥260MPa, an elongation after fracture A≥20%, and a hardness≥150HB.

10. The melting ring according to any one of claims 1 to 3 or the melting ring obtained by the preparation method according to any one of claims 4 to 9 is used in a 026Cr18Ni12Mo2N austenitic stainless steel welding method.

Images