Ultra-long thin nickel-based alloy hot-rolled plate for nuclear power and manufacturing method thereof

Abstract

According to the ultra-long thin nickel-based alloy hot-rolled plate for nuclear power and the manufacturing method thereof, by balancing the composition proportion of the alloy, the high-temperature-resistant strength, the oxidation resistance and the high-temperature lasting creep resistance of the alloy are improved, the performance of the material under the high-temperature service condition is further improved, meanwhile, the preparation process of the alloy is optimized, and the production cost is reduced. The problems of segregation and the like caused by ingot shape expansion can be solved, and the quality risk of materials in the later equipment manufacturing and actual using process is reduced. And the requirements of development of nuclear power equipment on high-temperature-resistant alloy materials with special specifications are met.

Description

Technical Field

[0001] The present invention relates to the field of nickel-based alloys for nuclear power, and particularly to an extra-long thin-specification nickel-based alloy hot-rolled plate for nuclear power and a manufacturing method thereof, which can serve for a long time in a high-temperature environment. Background Art

[0002] Nuclear energy has the advantages of high energy density, low cost, and less greenhouse gas emissions, and is of great significance to optimizing China's energy structure and promoting the sustainable development of energy. The development of nuclear energy technology presents the characteristics of high safety and high efficiency, and the requirements for materials are becoming increasingly stringent. For example, in the steam generator of a modular high-temperature gas-cooled reactor, the temperature of the inlet helium gas is as high as 750°C, so that the working temperature of the components in the inlet chamber of the steam generator and the heat exchange components also reaches 750°C. The service environment of the heat exchange equipment is extremely harsh and requires nickel-based alloys with high high-temperature strength for manufacturing. The composition characteristics of such alloys are that they contain relatively high amounts of elements such as Mo and Nb, and are prone to severe dendritic segregation during solidification, forming some enrichment phases of Cr, Mo, or Nb. It is difficult to control the metallurgical quality, resulting in a decrease in the hot working plasticity of the alloy, and there are generally problems such as poor forgeability, low blooming rate, and easy cracking during rolling. At the same time, the technical indicators required by nuclear power are extremely stringent. At the same time, the characteristics of nuclear power equipment are complex processes and high precision, making the specifications of alloy plates, tubes, bars, etc. required for equipment manufacturing complex, and the manufacturing process is special and the difficulty increases.

[0003] Due to the high content of alloying elements in nickel-based alloys, the internal quality and the difficulty of material deformation are large. For special specifications such as extra-long thin specifications (thickness less than 7 mm) greater than 8 m, there are great difficulties in production. Limited by equipment capabilities, when using hot-rolled steel coils or cold rolling methods for production, there are problems with limited plate width, generally less than 1200 mm. When using the conventional hot rolling method for steel plates, during the deformation process of the steel plate, the temperature drops, resulting in a sharp increase in the deformation resistance, and it is difficult to ensure the target thickness, making it difficult to meet the requirements of existing equipment manufacturing. Therefore, the current solution to such problems is to change the equipment design and splice the steel plates by increasing the welds, which not only increases the manufacturing cost but also poses a risk of welding quality.

[0004] In addition, for the existing high-temperature resistant nickel-based alloys used in nuclear power equipment with a service temperature above 700°C, while considering the long-term creep performance of the material, relatively high high-temperature strength and oxidation resistance are also required, and there are contradictions in material design. At the same time, due to the characteristics of the large-scale nuclear power equipment and the complexity of different reactor types of equipment, the manufacture of ultra-large-sized plates is extremely difficult due to the influence of existing equipment capabilities and material properties, and other methods need to be adopted to meet the equipment manufacturing requirements, which increases the equipment manufacturing cost and the risk.

[0005] Through retrieval, it is found that the research on nickel-based alloys for high-temperature nuclear power applications mainly focuses on the service performance of materials. There is also some research on the preparation of special specification plates, but there is less research on the manufacturing of nickel-based alloy plates with special over-limit specifications and the corresponding material design. There is a break point between the research on high-temperature-resistant nickel-based alloys and the actual preparation process of materials.

[0006] In view of the above situation, it is urgent to study a nickel-based alloy for long-term use at high temperatures in nuclear power, focusing on higher high-temperature strength, oxidation resistance, and creep rupture properties. At the same time, study the manufacturing process of ultra-long thin plates of this nickel-based alloy to meet the requirements of the development of nuclear power equipment for special specification high-temperature-resistant alloy materials. Summary of the Invention

[0007] Aiming at the defects existing in the prior art, the object of the present invention is to provide an ultra-long thin-specification nickel-based alloy hot-rolled plate for nuclear power and its manufacturing method. By balancing the component ratio of the alloy, the high-temperature strength, oxidation resistance, and high-temperature creep rupture properties of the alloy are improved, and the performance of the material under high-temperature service conditions is also improved. At the same time, the preparation process of the alloy is optimized, which can improve problems such as segregation caused by the expansion of the ingot mold type, and reduce the quality risk of the material in the later equipment manufacturing and actual use process. It meets the requirements of the development of nuclear power equipment for special specification high-temperature-resistant alloy materials.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The first aspect of the present invention provides an ultra-long thin-specification nickel-based alloy hot-rolled plate for nuclear power, including the following chemical components by weight percentage: C: 0.05 - 0.1 wt%, Cr: 20% - 30 wt%, Si ≤ 0.3 wt%, Mn ≤ 0.5 wt%, Ni: 50.0 - 70.0 wt%, Mo: 0.5 - 3.0 wt%, Ti: 0.3 - 1.0 wt%, N: 0.2 - 0.5 wt%, B: 0.001 - 0.006 wt%, P ≤ 0.010 wt%, S ≤ 0.010 wt%, and the rest are Fe and other inevitable impurities.

[0010] Preferably, the chemical components P and S satisfy: P + S ≤ 0.015 wt%.

[0011] Preferably, the ultra-long thin-specification nickel-based alloy hot-rolled plate for nuclear power has a yield strength Rp 0.2 ≥ 224 MPa, a tensile strength R m ≥ 516 MPa, and an elongation A 50％ ≥ 63.5% at a temperature of 700 °C; the ultra-long thin-specification nickel-based alloy hot-rolled plate for nuclear power has a yield strength Rp 0.2 ≥ 200 MPa, a tensile strength R m≥495 MPa, A 50％ ≥85%.

[0012] The second aspect of the present invention provides a manufacturing method of an ultra-long and thin specification nickel-based alloy hot-rolled plate for nuclear power as described in the first aspect of the present invention, comprising the following steps:

[0013] S1, after batching for the ultra-long and thin specification nickel-based alloy hot-rolled plate for nuclear power, a consumable electroslag remelting (ESR) ingot with a thickness greater than 300 mm and a single weight greater than 7 tons is obtained by vacuum induction melting and electroslag remelting;

[0014] S2, homogenization annealing, the ESR ingot is subjected to homogenization annealing at 1190 - 1250 °C for more than 96 h, and then furnace-cooled to below 600 °C and taken out of the furnace for air cooling;

[0015] S3, slab blooming, the annealed ESR ingot is bloomed by forging and hot rolling in sequence to obtain a slab;

[0016] S4, composite rolling, a finished hot-rolled blank is prepared by welding two-layer slabs together, and then the finished hot-rolled blank is heated to 1150 - 1200 °C and rolled. After rolling, heat treatment, separation of the composite plate, and finishing are carried out to obtain the ultra-long and thin specification nickel-based alloy hot-rolled plate for nuclear power.

[0017] Preferably, in step S1, argon protection is adopted during the electroslag remelting process.

[0018] Preferably, in step S2, the holding time is 96 - 120 h.

[0019] Preferably, in step S3, the blooming in the forging process is carried out by the upsetting and drawing method, and the deformation ratio of width and length during forging is ≥20%.

[0020] Preferably, in step S3, the heating temperature during the hot rolling process is 1140 - 1200 °C.

[0021] Preferably, in step S4, during the welding of two-layer slabs, the straight edges are cut by plasma cutting before welding, the four sides are beveled, a separating agent is added in the middle of the slab, and nickel-based alloy welding materials are used for edge welding.

[0022] Preferably, in step S4, during the hot rolling process, the heating temperature is 1150 - 1200 °C, the starting rolling temperature is 1100 - 1150 °C, and the finishing rolling temperature is 900 - 950 °C.

[0023] Preferably, in step S4, the deformation amount of the first pass of hot rolling is 2 - 5%, the deformation amount of the middle passes is ≥10%, and the deformation amount of the finishing pass is 5 - 10%.

[0024] Preferably, in the step S4, the thickness of the ultra-long and thin nickel-based alloy hot-rolled plate for nuclear power is ≤7 mm, and the length >10 m.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. By balancing the component ratio of the alloy, controlling the content of C element in the alloy, and improving the high-temperature instantaneous strength of the alloy, at the same time, alloying elements such as Mo are added to improve the high-temperature resistance strength and oxidation resistance of the alloy; at the same time, by adding appropriate amounts of elements such as Cr and Ti, the anti-creep and oxidation resistance of the alloy matrix under long-term high-temperature use conditions are improved, which can meet the requirements of long-term service at temperatures above 700°C;

[0027] 2. A certain content of N element is added to the present invention to improve the strength of the material under high-temperature service conditions; trace elements such as B are added, which can improve the high-temperature strength and high-temperature creep resistance of the material, and at the same time improve the workability of the alloy, and can also greatly improve the service performance of the material under long-term high-temperature service conditions;

[0028] 3. The manufacturing method of the present invention can improve problems such as segregation caused by the expansion of the ingot type through electroslag ingot remelting, homogenization process, and hot deformation process of ultra-long and thin steel plates, and at the same time ensure the internal structure and plate shape and size of the thin steel plates, reducing the quality risks of the material in the later equipment manufacturing and actual use processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic flow chart of the manufacturing method of the ultra-long and thin nickel-based alloy hot-rolled plate for nuclear power of the present invention;

[0030] Figure 2 is a schematic diagram of the welding and blanking method during the blank grouping process of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form.

[0032] Existing high-temperature resistant nickel-based alloys for nuclear power equipment with service temperatures above 700°C have contradictions in material design. While considering the long-term creep performance of the material, high-temperature strength and oxidation resistance are also required. At the same time, due to the characteristics of the large-scale nuclear power equipment and the complexity of equipment in different reactor types, it is extremely difficult to manufacture plates of extreme specifications due to the influence of existing equipment capabilities and material properties. Other methods need to be adopted to meet the equipment manufacturing requirements, which increases the equipment manufacturing cost and risk. Therefore, the present invention balances the component ratio of the alloy, improves the high-temperature strength, oxidation resistance and high-temperature creep performance of the alloy, also improves the performance of the material under high-temperature service conditions, optimizes the alloy preparation process, improves problems such as segregation caused by the enlargement of the ingot type, and reduces the quality risk of the material in the later equipment manufacturing and actual use process, and can meet the requirements of the development of nuclear power equipment for special specification high-temperature resistant alloy materials.

[0033] The hot-rolled plate of ultra-long and thin specification nickel-based alloy for nuclear power provided by the present invention comprises the following chemical components by weight percentage: C: 0.05 - 0.1 wt%, Cr: 20% - 30 wt%, Si ≤ 0.3 wt%, Mn ≤ 0.5 wt%, Ni: 50.0 - 70.0 wt%, Mo: 0.5 - 3.0 wt%, Ti: 0.3 - 1.0 wt%, N: 0.2 - 0.5 wt%, B: 0.001 - 0.006 wt%, P ≤ 0.010 wt%, S ≤ 0.010 wt%, and the rest are Fe and other inevitable impurities.

[0034] Among them, the chemical components P and S satisfy: P + S ≤ 0.015 wt%.

[0035] The principle of the composition design of the hot-rolled plate of ultra-long and thin specification nickel-based alloy for nuclear power of the present invention is as follows:

[0036] The alloy of the present invention is a nickel-chromium-iron-based alloy. Ni is the basic element for austenitization and is very stable in an oxidation environment. Adding a higher content of Cr element, on the one hand, Cr can greatly improve the oxidation resistance of the material in the Ni-Cr austenite solid solution. Secondly, considering the long-term high-temperature service conditions of the invented alloy, the high-temperature passivation film formed by Cr is very stable and can improve the oxidation resistance of the alloy surface. However, the content of Cr should not be too high, otherwise it will affect the processing performance of the material and cause difficulties in the production such as rolling of the alloy. Therefore, the content of Cr is controlled between 20% and 30 wt%.

[0037] C in nickel-based alloys plays a crucial role in improving the material strength. To enhance the high-temperature strength of the material, the C content is controlled to be higher than 0.05 wt%, but a relatively high C content will form various types of carbides during subsequent processing and heat treatment, affecting the processing performance of the material. Therefore, in this invention, the carbon content is controlled at a relatively low level, within the range of 0.05 - 0.1 wt%. To improve the high-temperature strength of this alloy, a certain amount of N is added in this invention. N in austenite has a good solution strengthening effect and can play a role in substituting Ni and strengthening other alloys to a certain extent, but the addition of N should not be too high, as it will affect the plasticity of the alloy and increase the risk of other defects in the steel. Therefore, in this invention, its content is controlled within the range of 0.2 - 0.5 wt%.

[0038] A certain amount of Mo and Ti are added to the nickel-based alloy to further improve the high-temperature strength and, at the same time, improve the long-term service performance such as high-temperature oxidation resistance of the alloy. To improve the grain boundary stability and strength of the alloy and enhance the processing ability of the material, a small amount of B element is added. The addition of B can improve the high-temperature strength of the alloy. This type of element generally aggregates at grain boundaries and between dendrites in the alloy. Appropriate combined addition can significantly improve the high-temperature strength of the material. At the same time, the addition of this type of element can improve the morphology of inclusions in the alloy, improve the overall high-temperature oxidation resistance of the material, and also improve the stability of the surface oxide layer, enhancing the oxidation ability of the material in a dynamic oxidation environment. However, if this type of element is added in excess, it will cause a rapid decline in the plastic toughness of the material, affecting the processing performance of the material. Therefore, in this invention, B is controlled within the range of 0.001 - 0.006 wt%. The contents of impurity elements such as P and S are also controlled in the alloy. A relatively high P will greatly reduce the welding performance of the material.

[0039] The above-mentioned ultra-long and thin-gauge nickel-based alloy hot-rolled plate for nuclear power has a yield strength Rp 0.2 ≥224 MPa, a tensile strength R m ≥516 MPa, and an elongation A 50％ ≥63.5% at a temperature of 700 °C; the ultra-long and thin-gauge nickel-based alloy hot-rolled plate for nuclear power has a yield strength Rp 0.2 ≥200 MPa, a tensile strength R m ≥495 MPa, and an elongation A 50％ ≥85% at a temperature of 800 °C.

[0040] Combined with Figure 1 shown, this invention also provides a manufacturing method for the ultra-long and thin-gauge nickel-based alloy hot-rolled plate for nuclear power, including the following steps:

[0041] S1, after proportioning according to the ultra-long and thin-gauge nickel-based alloy hot-rolled plate for nuclear power, a consumable electroslag remelting ingot with a thickness greater than 300 mm and a single weight greater than 7 tons is obtained by vacuum induction melting and electroslag remelting;

[0042] Specifically, according to the above-mentioned batching of ultra-long and thin nickel-based alloy hot-rolled plates for nuclear power, production is carried out by means of vacuum induction + electroslag remelting, pouring into flat electrodes for plate preparation, and then carrying out electroslag remelting and smelting under argon protection to smelt into electroslag flat ingots with a thickness greater than 300 mm and a single weight greater than 7 tons.

[0043] S2, homogenization annealing, subject the electroslag flat ingot to homogenization annealing at 1190 - 1250 °C, hold for more than 96 h, and then cool in the furnace to below 600 °C and then take out of the furnace for air cooling;

[0044] Specifically, to reduce element segregation in the alloy, the electroslag flat ingot prepared above is subjected to homogenization annealing, where the annealing process is: the annealing temperature is 1190 - 1250 °C, the annealing time is ≥96 h, and then cool in the furnace to below 600 °C and then take out of the furnace for air cooling.

[0045] S3, slab blooming, subject the annealed electroslag flat ingot to forging and hot rolling in sequence for blooming to obtain a slab;

[0046] Specifically, the annealed electroslag flat ingot is prepared into a slab by means of a forging + hot rolling combined blooming process; among them, forging blooming adopts the upsetting and drawing method, and the width and length deformation ratio ≥20%, and the purpose of forging blooming is to break the as-cast structure and allow multi-directional deformation; the heating temperature during hot rolling blooming is 1140 - 1200 °C, and conventional hot rolling models are used for rolling, and its purpose is to ensure the dimensional uniformity and surface quality of the subsequent finished rolling billets.

[0047] S4, composite rolling, use double-layer slab welding to form a finished hot-rolled billet, then heat the finished hot-rolled billet to 1150 - 1200 °C and then carry out rolling, and after rolling, carry out heat treatment, composite plate separation, and finishing to obtain an ultra-long and thin nickel-based alloy hot-rolled plate for nuclear power.

[0048] For ultra-long and thin steel plates with a limit specification of thickness ≤7 mm, length greater than 10 m, and width ≥1200 mm, in order to ensure the reliability of steel plate deformation, reduce the rolling mill load, improve the plate shape and surface quality, and improve the internal structure of the steel plate, hot rolling deformation adopts a composite rolling process, and preliminary rolling blooming + grinding and cutting + welding and blanking are carried out before finished hot rolling.

[0049] Use the slab obtained in step S3 and form a finished hot-rolled billet by double-layer slab welding. Before welding, use plasma cutting to straighten the edges, bevel the four sides, add a separating agent in the middle of the slab, and use nickel-based alloy welding materials for edge welding; among them, the welding and blanking method is as Figure 2 shown, and the marked pore positions are for exhausting gas during subsequent hot rolling.

[0050] The obtained finished hot-rolled billets are heated to 1150 - 1200 °C and then rolled. To ensure the original structure of the steel plate during rolling, the starting rolling temperature ≤ 1160 °C, preferably 1100 - 1150 °C, and the finishing rolling temperature ≥ 900 °C, preferably 900 - 950 °C; The rolling strategy for rolling ultra-long thin steel plates is a rolling strategy of small deformation + large deformation + medium and small degree of deformation. The requirements for the amount of deformation in the rolling strategy are: the amount of deformation in the first pass is 2 - 5%; the amount of deformation in the intermediate passes ≥ 10%; the amount of deformation in the finishing pass is 5 - 10%. Among them, the purpose of the small deformation in the first pass is to eliminate the non-uniformity of the billet and ensure the uniformity and stability of different parts of the billet in subsequent deformations; ensuring a certain amount of deformation in the intermediate passes aims to ensure the degree of deformation and the tissue uniformity in the thickness direction of the steel plate; the use of medium and small degree of deformation in the finishing pass aims to ensure the shape of the ultra-long thin steel plate, and at the same time, a certain amount of deformation is required to control the finishing structure and eliminate the deformed structure.

[0051] The rolled composite billets are processed through heat treatment, composite plate separation, finishing and other processes to obtain ultra-long thin nickel-based alloy hot-rolled plates for nuclear power with a thickness ≤ 7 mm, a length greater than 10 m, and a width ≥ 1200 mm.

[0052] The following further illustrates the ultra-long thin nickel-based alloy hot-rolled plates for nuclear power and their manufacturing methods of the present invention with specific examples;

[0053] In Examples A1 - A4, the chemical composition formulations shown in Table 1 are used. To facilitate comparison of the effects of the present invention, two commonly used high-temperature-resistant nickel-based alloys B1 and B2 with component systems are selected as comparative examples for reference.

[0054] Table 1 Chemical Compositions of Examples and Comparative Examples (wt%)

[0055]

[0056] Examples A1 - A4 are smelted according to the components shown in Table 1. The specific preparation process is as follows:

[0057] 1) Smelting: Prepared by a vacuum induction + electroslag remelting process. During electroslag remelting, argon protection is used to obtain an electroslag flat ingot with a thickness ≥ 400 mm and a single weight ≥ 7 tons.

[0058] 2) Homogenization annealing: The annealing temperature is 1190 - 1250 °C, the holding time is 96 h - 120 h, and it is cooled in the furnace to below 600 °C and then taken out of the furnace for air cooling.

[0059] 3) Slab cogging: Different processes of forging + hot rolling are used for combined cogging. The purpose of forging cogging is to break the as-cast structure and enable multi-directional deformation. Hot rolling cogging ensures the dimensional uniformity and surface quality of the billets for subsequent finished product rolling. Forging is carried out by upsetting + drawing out, and the width and length deformation ratios are ≥20%. The heating temperature for hot rolling cogging is between 1140 and 1200 °C, and conventional hot rolling models are used for rolling; finally, slabs are obtained.

[0060] 4) Slab assembling: To ensure the shape and dimensional uniformity of extra-long thin-gauge difficult-to-deform nickel-based alloys, double-layer slab welding is used to prepare the finished hot-rolled billets. Before welding, plasma cutting is used to cut the straight edges, bevels are made around the edges, a separating agent is added in the middle of the slabs, and nickel-based alloy welding materials are used for edge welding. The schematic diagram of the welding and assembling method is as Figure 1 shown:

[0061] 5) Composite rolling: The above-mentioned finished hot-rolled billets are subjected to composite rolling. The rolling process is as follows: heating temperature is 1150 - 1200 °C; starting rolling temperature is 1100 - 1150 °C, and final rolling temperature is 900 - 950 °C; the pass deformation amounts are respectively: initial pass: 3%; intermediate passes: 15 - 20%; final rolling pass: 10%.

[0062] After composite rolling, composite hot-rolled plates with a rolling specification of 10*2000*10000 mm are obtained. After rolling, heat treatment, separation of the composite plates, and finishing, nickel-based alloy hot-rolled plates with a specification of 5*2000*10000 mm for nuclear power use with extra-long thin gauges are obtained.

[0063] Production process of the control example: Vacuum induction + electroslag remelting process is used to die-cast steel ingots according to the same process. Forging cogging is carried out conventionally without homogenization annealing. Since the hot-rolled steel plates are not welded and assembled, the specification is 8*1800*9000 mm. The heat treatment and finishing processes of the control alloy and the invention alloy are carried out according to processes similar to the standards.

[0064] The alloys of the above-mentioned examples and control examples are subjected to performance testing. The high-temperature tensile properties are shown in Table 2, the oxidation resistance properties are shown in Table 3, and the high-temperature creep properties are shown in Table 4.

[0065] Table 2 High-temperature tensile properties of the alloys in the examples and comparative examples

[0066]

[0067] Table 3 Oxidation resistance properties of the alloys in the examples and comparative examples

[0068]

[0069] Table 4 High-temperature creep properties of the alloys in the examples and comparative examples

[0070]

[0071]

[0072] Combined with Tables 2 - 4, it can be seen that for the ultra - long and thin - gauge nickel - based alloy hot - rolled plates prepared in the embodiments of the present invention, at 700 °C, the yield strength Rp 0.2 is between 224 and 255 MPa, the tensile strength R m is between 516 and 574 MPa, and the elongation A 50％ is between 63.5 and 75.0%; at 800 °C, the yield strength Rp 0.2 is between 203 and 229 MPa, the tensile strength R m is between 495 and 548 MPa, and the elongation A 50％ is between 85.0 and 95.5%; the average oxidation rate at 600 °C for 300 h is ≤0.010 g / m 2 ·h, and the average oxidation rate at 800 °C for 300 h is ≤0.012 g / m 2 ·h; the 10,000 - h creep rupture strength at 700 °C is 128 - 155 MPa, and the 10,000 - h creep rupture strength at 800 °C is 52 - 66 MPa. Thus, it can be seen that the high - temperature instantaneous tensile strength of the alloy in the embodiments of the present invention is significantly higher than that of the control alloy B1, and is generally equivalent to that of the control alloy B2. In terms of high - temperature oxidation performance, the alloy of the present invention still has good high - temperature oxidation resistance at 800 °C, and its high - temperature oxidation resistance is better than that of the control alloy B1 and is equivalent to that of the control alloy B2. From the perspective of high - temperature long - term performance, the alloys of the present invention are significantly superior to the control alloys.

[0073] In summary, the alloy of the present invention can be used for high - temperature components with temperatures above 700 °C under high - temperature working conditions in nuclear power. Due to its excellent high - temperature strength and creep rupture performance compared with existing heat - resistant nickel - based alloys, it can solve the problem of long - term use failure under actual complex use conditions. The ultra - long and thin - gauge nickel - based alloy hot - rolled plates for nuclear power of the present invention can reduce welds for equipment manufacturing, reduce the safety risks in nuclear power working conditions, and at the same time, reduce manufacturing costs and shorten the manufacturing cycle. In addition, the alloy of the present invention realizes ingot making through vacuum induction + electroslag remelting, through homogenization treatment, and through the method of welding and assembling blanks for hot rolling of finished plates, uniform and reliable internal structures can be obtained. At the same time, it can improve the plate shape and dimensional uniformity of ultra - long and thin - gauge difficult - to - deform alloy plates, reduce manufacturing and use risks. Its successful design and development will bring huge social and economic benefits to the application of high - performance special alloys in China.

[0074] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered by the scope of the claims of the present invention.

Claims

1. An extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications, characterized in that, It includes the following chemical components by weight percentage: C: 0.05 - 0.1 wt%, Cr: 20% - 30 wt%, Si ≤ 0.3 wt%, Mn ≤ 0.5 wt%, Ni: 50.0 - 70.0 wt%, Mo: 0.5 - 3.0 wt%, Ti: 0.3 - 1.0 wt%, N: 0.2 - 0.5 wt%, B: 0.001 - 0.006 wt%, P ≤ 0.010 wt%, S ≤ 0.010 wt%, and the balance is Fe and other inevitable impurities.

2. The extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 1, characterized in that, The chemical components P and S satisfy: P + S ≤ 0.015 wt%.

3. The extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 2, characterized in that, The hot-rolled nickel-based alloy sheet with extra-long and thin specification for nuclear power applications has a yield strength Rp 0.2 ≥224 MPa, a tensile strength R m ≥516 MPa, and an A 50％ ≥63.5% at a temperature of 700°C; the hot-rolled nickel-based alloy sheet with extra-long and thin specification for nuclear power applications has a yield strength Rp 0.2 ≥200 MPa, a tensile strength R m ≥495 MPa, and an A 50％ ≥85% at a temperature of 800°C.

4. A manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to any one of claims 1 to 3, characterized in that, It includes the following steps: S1, After batching according to the ultra-long and thin specification nickel-based alloy hot-rolled plate for nuclear power, use vacuum induction melting and electroslag remelting to obtain an electroslag flat ingot with a thickness greater than 300 mm and a single weight greater than 7 tons; S2, Homogenization annealing, subject the electroslag flat ingot to homogenization annealing at 1190 - 1250 °C, keep it warm for more than 96 h, and then cool it in the furnace to below 600 °C and then take it out for air cooling; S3, Slab blooming, subject the annealed electroslag flat ingot to forging and hot rolling in sequence for blooming to obtain a slab; S4, Composite rolling, use double-layer slab welding to form a finished hot-rolled blank, then heat the finished hot-rolled blank to 1150 - 1200 °C and then carry out rolling, and after rolling, carry out heat treatment, composite plate separation, and finishing to obtain the ultra-long and thin specification nickel-based alloy hot-rolled plate for nuclear power.

5. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S1, argon protection is adopted during the electroslag remelting process.

6. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S2, the holding time is 96 - 120 h.

7. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S3, in the forging process, the upsetting and drawing method is adopted for blooming, and the deformation ratio of width and length during forging ≥ 20%.

8. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S3, the heating temperature during the hot rolling process is 1140 - 1200 °C.

9. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S4, during the double-layer slab welding process, before welding, use plasma cutting to cut the straight edge, bevel the four sides, add a separating agent in the middle of the slab, and use nickel-based alloy welding materials for edge welding.

10. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S4, during the hot rolling process, the heating temperature is 1150 - 1200 °C, the starting rolling temperature is 1100 - 1150 °C, and the finishing rolling temperature is 900 - 950 °C.

11. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S4, the initial pass deformation amount of the hot rolling is 2 - 5%, the deformation amount of the middle pass ≥ 10%, and the deformation amount of the finishing pass is 5 - 10%.

12. The manufacturing method of the extra-long and thin nickel-based alloy hot-rolled plate for nuclear power applications according to claim 4, characterized in that, In the step S4, the thickness of the ultra-long and thin specification nickel-based alloy hot-rolled plate for nuclear power ≤ 7 mm, and the length > 10 m.

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