Preparation method of nickel-based superalloy rolled bar for gas turbine

Abstract

The invention provides a preparation method of a nickel-based superalloy rolled bar, which comprises the following steps: firstly, carrying out radial forging on a nickel-based superalloy bar billet to obtain a nickel-based superalloy square billet; the nickel-based high-temperature alloy is a GH80A alloy; then, the nickel-based high-temperature alloy square billet obtained in the previous step is heated and subjected to heat preservation, then hot rolling is conducted, cooling is conducted, and a rolled bar is obtained; and finally, the rolled bar obtained in the previous step is subjected to solution treatment, and the nickel-based high-temperature alloy rolled bar is obtained. The 150-200 alloy square billet is rolled into a material through a continuous rolling unit, the processes of square billet heating, hot rolling, cooling and the like are adopted, the finish rolling temperature of the alloy is guaranteed by increasing the rolling starting temperature and high-speed continuous rolling, and compared with the traditional process of rolling the GH80A alloy through a reciprocating rolling mill, the process is more controllable and less affected by human factors, and the production efficiency is improved. And the macrostructure and the mechanical property of the alloy subjected to heat treatment are improved, and the use requirements of blades or bolts of gas turbines of ultra-supercritical thermal power generating units can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of preparing nickel-based high-temperature alloys for gas turbines, and relates to a method for preparing a nickel-based high-temperature alloy rolled bar, and in particular to a method for preparing a nickel-based high-temperature alloy rolled bar for gas turbines. Background Art

[0002] In order to promote the clean and efficient use of fossil energy such as coal, improve coal-fired efficiency and reduce carbon emissions, it is necessary to vigorously develop ultra-supercritical thermal power unit materials. GH80A alloy is based on Ni-Cr, and precipitation strengthening elements such as Al and Ti are added to improve the room temperature and high temperature properties of the alloy. The use temperature can reach 750℃. It has good corrosion resistance and good hot working properties. It is widely used in the preparation of engine bolts and blades for gas turbines or aircraft.

[0003] In order to improve coal combustion efficiency, it is necessary to further increase the steam temperature of the gas turbine of the ultra-supercritical thermal power unit, which puts higher requirements on the durability of the material. The microstructure and performance of the GH80A alloy rolled bars prepared by traditional technology can no longer meet the durability requirements of the new generation of gas turbines.

[0004] Therefore, how to find a more suitable way to further improve the performance of nickel-based high-temperature alloy GH80A alloy, so as to better broaden the depth and breadth of its application, has become one of the focuses of attention of many front-line researchers in the industry. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing a nickel-based high-temperature alloy rolled bar, in particular a method for preparing a nickel-based high-temperature alloy rolled bar for a gas turbine. The nickel-based high-temperature alloy rolled bar prepared by the present invention improves the macrostructure and mechanical properties of the alloy after heat treatment, and has a simple process, mild conditions, good controllability, and is more conducive to industrial-scale production and promotion and application.

[0006] The present invention provides a method for preparing a nickel-based high-temperature alloy rolled bar, comprising the following steps:

[0007] 1) Forging a nickel-based high-temperature alloy rod blank through radial forging to obtain a nickel-based high-temperature alloy square billet;

[0008] The nickel-based high-temperature alloy is GH80A alloy;

[0009] 2) heating and heat-insulating the nickel-based high-temperature alloy billet obtained in the above steps, and then cooling after hot rolling to obtain a rolled rod;

[0010] 3) The rolled rod obtained in the above steps is subjected to a solid solution treatment to obtain a nickel-based high-temperature alloy rolled rod.

[0011] Preferably, the GH80A alloy, measured by element mass content, comprises:

[0012] C: 0.04% ~ 1.0%, Cr: 18% ~ 21%, Al: 1.0% ~ 1.8%, Ti: 1.8% ~ 3.0%, Co ≤ 1.0%, B ≤ 0.008%, Mn ≤ 1.0%, Si ≤ 1.0%, P ≤ 0.02%, S ≤ 0.015%, Cu ≤ 0.2%, Fe ≤ 1.5%, Pb ≤ 20ppm, Bi ≤ 1ppm, Ag ≤ 5ppm and the balance Ni.

[0013] Preferably, the diameter of the nickel-based high-temperature alloy bar blank is 200-250 mm;

[0014] The cross-sectional side length of the nickel-based high-temperature alloy billet is 150 to 200 mm;

[0015] The length of the nickel-based high-temperature alloy square billet is 5000-12000 mm.

[0016] Preferably, the radial forging further includes a surface defect grinding treatment step;

[0017] The heating temperature is 1130-1190°C;

[0018] The heating time is greater than or equal to 3 hours.

[0019] Preferably, the insulation temperature is 1130-1190°C;

[0020] The insulation time is 1 to 4 hours.

[0021] Preferably, the hot rolling includes rough rolling and medium rolling;

[0022] The rough rolling is performed in 4 to 6 passes;

[0023] The intermediate rolling is performed in 2 to 6 passes.

[0024] Preferably, the hot rolling is specifically performed in sequence of rough rolling and intermediate rolling;

[0025] In the rough rolling and intermediate rolling, the deformation of a single pass is ≤20%;

[0026] The hot rolling speed is 1-5 m / s.

[0027] Preferably, the hot rolling temperature is 1130-1190°C;

[0028] The specification of the rolled rod is 60-85 mm;

[0029] The cooling method includes wind cooling or air cooling;

[0030] The cooling is specifically performed on a cooling bed.

[0031] Preferably, the temperature of the solution treatment is 1040-1080°C;

[0032] The solution treatment time is 4 to 8 hours;

[0033] The specific method of the solid solution treatment is to carry out the solid solution treatment while laying the bars flat without stacking them.

[0034] The present invention provides the use of a nickel-based high-temperature alloy rolled bar prepared by the preparation method described in any one of the above technical solutions in a gas turbine.

[0035] The present invention provides a method for preparing a nickel-based high-temperature alloy rolled bar, comprising the following steps: firstly, subjecting a nickel-based high-temperature alloy billet to radial forging to obtain a nickel-based high-temperature alloy billet; the nickel-based high-temperature alloy is a GH80A alloy; then, the nickel-based high-temperature alloy billet obtained in the above steps is heated and insulated, and then hot-rolled and cooled to obtain a rolled bar; finally, the rolled bar obtained in the above steps is subjected to a solid solution treatment to obtain a nickel-based high-temperature alloy rolled bar. Compared with the prior art, the present invention provides a method for preparing a nickel-based high-temperature alloy rolled bar with specific steps. The present invention adopts GH80A alloy 150-200 billets to be rolled into products by a continuous rolling mill, and the rolling process mainly adopts billet heating, hot rolling and cooling. The process ensures the final rolling temperature of the alloy by increasing the start rolling temperature and high-speed continuous rolling, which is more controllable than the traditional reciprocating rolling mill GH80A alloy rolling process, is less affected by human factors, and improves the macrostructure and mechanical properties of the alloy after heat treatment. The method for preparing a nickel-based high-temperature alloy rolled bar provided by the invention is a method for preparing a nickel-based high-temperature alloy rolled bar for a gas turbine, and can meet the use requirements of gas turbine blades or bolts of an ultra-supercritical thermal power unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 These are low-magnification test results of the heat-treated state of the nickel-based high-temperature alloy rolled bars prepared by the process of the present invention and the nickel-based high-temperature alloy rolled bars prepared by the conventional process. DETAILED DESCRIPTION

[0037] In order to further understand the present invention, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0039] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably uses industrial purity or conventional purity in the field of nickel-based high-temperature alloy preparation.

[0040] The present invention provides a method for preparing a nickel-based high-temperature alloy rolled bar, comprising the following steps:

[0041] 1) Forging a nickel-based high-temperature alloy rod blank through radial forging to obtain a nickel-based high-temperature alloy square billet;

[0042] The nickel-based high-temperature alloy is GH80A alloy;

[0043] 2) heating and heat-insulating the nickel-based high-temperature alloy billet obtained in the above steps, and then cooling after hot rolling to obtain a rolled rod;

[0044] 3) The rolled rod obtained in the above steps is subjected to a solid solution treatment to obtain a nickel-based high-temperature alloy rolled rod.

[0045] The invention firstly subjects a nickel-based high-temperature alloy rod blank to radial forging to obtain a nickel-based high-temperature alloy square billet.

[0046] The nickel-based high-temperature alloy is GH80A alloy.

[0047] In the present invention, the GH80A alloy preferably includes, by element mass content:

[0048] C: 0.04% to 1.0%, Cr: 18% to 21%, Al: 1.0% to 1.8%, Ti: 1.8% to 3.0%, Co≤1.0%, B≤0.008%, Mn≤1.0%, Si≤1.0%, P≤0.02%, S≤0.015%, Cu≤0.2%, Fe≤1.5%, Pb≤20ppm, Bi≤1ppm, Ag≤5ppm and the balance Ni, more preferably C: 0.1% to 0.8%, Cr: 18.5% to 20.5%, Al: 1.15% to 1.65%, Ti: 2.0% to 2.7%, Co≤1.0%, B≤0.008%, Mn≤1 .0%, Si≤1.0%, P≤0.02%, S≤0.015%, Cu≤0.2%, Fe≤1.5%, Pb≤20ppm, Bi≤1ppm, Ag≤5ppm and the balance Ni, more preferably C: 0.3%~0.6%, Cr: 19%~20%, Al: 1.3%~1.5%, Ti: 2.3%~2.4%, Co≤1.0%, B≤0.008%, Mn≤1.0%, Si≤1.0%, P≤0.02%, S≤0.015%, Cu≤0.2%, Fe≤1.5%, Pb≤20ppm, Bi≤1ppm, Ag≤5ppm and the balance Ni.

[0049] In the present invention, the diameter of the nickel-based high-temperature alloy rod blank is preferably 200-250 mm, more preferably 210-240 mm, and more preferably 220-230 mm.

[0050] In the present invention, the cross-sectional side length of the nickel-based high-temperature alloy billet is preferably 150 to 200 mm, more preferably 160 to 190 mm, and even more preferably 170 to 180 mm.

[0051] In the present invention, the length of the nickel-based high-temperature alloy billet is preferably 5000-12000 mm, more preferably 6500-10500 mm, and more preferably 8000-900 mm.

[0052] In the present invention, the radial forging preferably further includes a surface defect grinding treatment step.

[0053] The present invention further heats and keeps the nickel-based high-temperature alloy billet obtained in the above steps, and then cools it after hot rolling to obtain a rolled rod.

[0054] In the present invention, the heating temperature is preferably 1130-1190°C, more preferably 1140-1180°C, and even more preferably 1150-1170°C.

[0055] In the present invention, the heating time is preferably greater than or equal to 3 hours.

[0056] In the present invention, the insulation temperature is preferably 1130-1190°C, more preferably 1140-1180°C, and more preferably 1150-1170°C.

[0057] In the present invention, the insulation time is preferably 1 to 4 hours, more preferably 1.5 to 3.5 hours, and more preferably 2 to 3 hours.

[0058] In the present invention, the hot rolling preferably includes rough rolling and medium rolling.

[0059] In the present invention, the rough rolling is preferably performed in 4 to 6 passes, more preferably in 3 to 5 passes.

[0060] In the present invention, the intermediate rolling is preferably performed 2 to 6 times, more preferably 3 to 4 times.

[0061] In the present invention, the hot rolling is preferably performed in sequence of rough rolling and intermediate rolling.

[0062] In the present invention, in the rough rolling and intermediate rolling, the deformation amount of a single pass is preferably ≤20%.

[0063] In the present invention, the hot rolling speed is preferably 1 to 5 m / s, more preferably 2 to 4 m / s.

[0064] In the present invention, the hot rolling temperature is preferably 1130-1190°C, more preferably 1140-1180°C, and even more preferably 1150-1170°C.

[0065] In the present invention, the specification of the rolled rod is preferably 60 to 85 mm, more preferably 65 to 80 mm, and more preferably 70 to 75 mm. Specifically, the rolled rod is preferably a cylindrical rod, and its specification is the diameter of the circular cross section of the rod.

[0066] In the present invention, the cooling method preferably includes wind cooling or air cooling.

[0067] In the present invention, the cooling is preferably performed on a cooling bed.

[0068] In the present invention, the rolled rod obtained in the above steps is finally subjected to solid solution treatment to obtain a nickel-based high-temperature alloy rolled rod.

[0069] In the present invention, the temperature of the solution treatment is preferably 1040-1080°C, more preferably 1045-1075°C, more preferably 1050-1070°C, and more preferably 1055-1065°C.

[0070] In the present invention, the solution treatment time is preferably 4 to 8 hours, more preferably 4.5 to 7.5 hours, more preferably 5 to 7 hours, and more preferably 5.5 to 6.5 hours.

[0071] In the present invention, the specific method of the solid solution treatment is preferably to carry out the solid solution treatment on the bars while laying them flat without stacking them.

[0072] The present invention also provides the use of the nickel-based high-temperature alloy rolled bar prepared by the preparation method described in any one of the above technical solutions in a gas turbine.

[0073] The present invention is to complete and refine the overall technical solution, better improve the macrostructure of the nickel-based high-temperature alloy rolled bar, and further improve the mechanical properties of the nickel-based high-temperature alloy. The preparation method of the nickel-based high-temperature alloy rolled bar for gas turbines may specifically include the following contents:

[0074] The invention provides a method for preparing a nickel-based high-temperature alloy rolled bar for a gas turbine. The method adopts GH80A alloy 150-200 square billets to be rolled into bars by a continuous rolling mill. The rolling process mainly involves square billet preparation, square billet heating, hot rolling and cooling.

[0075] The chemical composition range of the GH80A alloy is as follows: C: 0.04% to 1.0%, Cr: 18% to 21%, Al: 1.0% to 1.8%, Ti: 1.8% to 3.0%, Co≤1.0%, B≤0.008%, Mn≤1.0%, Si≤1.0%, P≤0.02%, S≤0.015%, Cu≤0.2%, Fe≤1.5%, Pb≤20ppm, Bi≤1ppm, Ag≤5ppm, and Ni is the remainder.

[0076] The following steps are involved:

[0077] Step 1: Billet preparation: To prevent billet from being out of square, a radial forging machine is used to prepare 150-200 billets with a length of 5000-12000 mm;

[0078] Step 2: After the surface defects of the square billet prepared in step 1 are repaired, the surface defects are ground and then heated at a temperature of 1130-1190° C. for a heating time of ≥3 h and a holding time of ≥2 h;

[0079] Step 3: The billet heated in step 2 is taken out of the furnace for hot rolling. The hot rolling includes rough rolling and intermediate rolling. The rough rolling is performed for 4 to 6 passes and the intermediate rolling is performed for 1 to 4 passes. The deformation of each pass is controlled to be ≤20%. The rolling speed is controlled to be 1 to 5 m / s. The specification of the rolled bar is 60 to 85 mm.

[0080] Step 4: The rolled bar that has been hot-rolled in step 4 is spread out on a cooling bed for air cooling or wind cooling.

[0081] Step 5: The rod is solution treated at a solution temperature of 1040-1080°C.

[0082] See Table 1, which shows the aging room temperature tensile properties of the nickel-based high-temperature alloy rolled bars for gas turbines prepared in the present invention.

[0083] Table 1

[0084]

[0085] The above content of the present invention provides a method for preparing nickel-based high-temperature alloy rolled bars for gas turbines. The present invention adopts GH80A alloy 150-200 square billets to be rolled into products through a continuous rolling mill, and the rolling process mainly adopts square billet heating, hot rolling and cooling. This process ensures the final rolling temperature of the alloy by increasing the starting rolling temperature and high-speed continuous rolling. Compared with the traditional reciprocating rolling mill process for rolling GH80A alloy, it is more controllable and less affected by human factors, and improves the macrostructure and mechanical properties of the alloy after heat treatment. The preparation method of nickel-based high-temperature alloy rolled bars provided by the present invention is a preparation method of nickel-based high-temperature alloy rolled bars for gas turbines, which can meet the use requirements of gas turbine blades or bolts of ultra-supercritical thermal power units.

[0086] In order to further illustrate the present invention, a method for preparing a nickel-based high-temperature alloy rolled bar provided by the present invention is described in detail below in combination with examples. However, it should be understood that these examples are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following examples.

[0087] Example 1

[0088] Chemical composition of Φ250mm rod: C: 0.05%, Cr: 19%, Al: 1.3%, Ti: 2.5%, Co 0.05%, B0.005%, Mn 0.001%, Si0.001%, P0.004%, S 0.0009%, Cu 0.02%, Fe 1.0%, Pb 10ppm, Bi0.5ppm, Ag 1ppm, Ni balance. After fine forging, the billet is opened into a 150*150*6000mm square billet; after the surface of the square billet is cleaned, it is heated in a roller hearth heating furnace, heated to 1190℃ for 4 hours and kept warm for 2 hours, and rolled to Φ80mm bars in a continuous rolling unit for rough rolling (4 passes) and intermediate rolling (2 passes). The rolling speed is controlled at 3m / s without deceleration. After the bar is air-cooled on the cooling bed, it is segmented and then solution treated. Solution treatment: heated to 1060℃ with the furnace and kept warm for 8 hours and air-cooled.

[0089] Take samples for low-magnification inspection and key performance inspection. The low-magnification results are shown in Figure 1 , Figure 1 The results of low-power detection of the heat-treated nickel-based high-temperature alloy rolled bars prepared by the process of the present invention and the nickel-based high-temperature alloy rolled bars prepared by the conventional process are shown in the figure above. The figure below shows the nickel-based high-temperature alloy rolled bars prepared by the process of the present invention.

[0090] The key mechanical property indicators are shown in Table 2, which is a comparison of the mechanical property results of the nickel-based high-temperature alloy rolled bars prepared by the process of the present invention and the nickel-based high-temperature alloy rolled bars prepared by the conventional process.

[0091] Table 2

[0092]

[0093]

[0094] Example 2

[0095] Chemical composition of Φ200mm rod: C: 0.055%, Cr: 19.2%, Al: 1.4%, Ti: 2.3%, Co 0.07%, B0.006%, Mn 0.011%, Si0.002%, P0.003%, S 0.001%, Cu 0.01%, Fe 1.2%, Pb 10ppm, Bi0.5ppm, Ag 1ppm, Ni balance. After fine forging, the billet is opened into a 130*130*8000mm square billet; after the surface of the square billet is cleaned, it is heated in a roller hearth heating furnace, heated to 1130℃ for 4 hours and kept warm for 2 hours, and rolled to Φ65mm bars in a continuous rolling unit for rough rolling (4 passes) and intermediate rolling (4 passes). The rolling speed is controlled at 4m / s without deceleration. After the bar is air-cooled on the cooling bed, it is segmented and then solution treated. Solution treatment: heated to 1080℃ with the furnace and kept warm for 8 hours and air-cooled.

[0096] Sampling is carried out for low-magnification inspection and key performance inspection. The low-magnification results are Figure 1 The key mechanical properties are shown in Table 2.

[0097] Example 3

[0098] Chemical composition of Φ200mm rod: C: 0.065%, Cr: 19.5%, Al: 1.6%, Ti: 2.6%, Co 0.08%, B0.006%, Mn 0.013%, Si0.012%, P0.0053%, S 0.0014%, Cu0.015%, Fe 1.1%, Pb10ppm, Bi0.5ppm, Ag 1ppm, Ni balance. After fine forging, the billet is opened into a 180*180*7000mm square billet; after the surface of the square billet is cleaned, it is heated in a roller hearth heating furnace, heated to 1160℃ for 4h and kept warm for 2h, and rolled to Φ70mm bars in a continuous rolling unit for rough rolling (6 passes) and intermediate rolling (4 passes). The rolling speed is controlled at 4m / s without deceleration. After the bar is air-cooled on the cooling bed, it is segmented and then solution treated. Solution treatment: heated to 1055℃ with the furnace and kept warm for 6h and air-cooled.

[0099] Sampling is carried out for low-magnification inspection and key performance inspection. The low-magnification results are Figure 1 The key mechanical properties are shown in Table 2.

[0100] The above is a detailed introduction to the preparation method of a nickel-based high-temperature alloy rolled bar for a gas turbine provided by the present invention. The principle and implementation method of the present invention are explained in this article using specific examples. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing a nickel-based high-temperature alloy rolled bar, characterized in that: The following steps are involved: 1) Forging a nickel-based high-temperature alloy rod blank through radial forging to obtain a nickel-based high-temperature alloy square billet; The nickel-based high-temperature alloy is GH80A alloy; 2) heating and heat-insulating the nickel-based high-temperature alloy billet obtained in the above steps, and then cooling after hot rolling to obtain a rolled rod; 3) The rolled rod obtained in the above steps is subjected to a solid solution treatment to obtain a nickel-based high-temperature alloy rolled rod.

2. The preparation method according to claim 1, characterized in that: The GH80A alloy, measured by element mass content, includes: C: 0.04% ~ 1.0%, Cr: 18% ~ 21%, Al: 1.0% ~ 1.8%, Ti: 1.8% ~ 3.0%, Co ≤ 1.0%, B ≤ 0.008%, Mn ≤ 1.0%, Si ≤ 1.0%, P ≤ 0.02%, S ≤ 0.015%, Cu ≤ 0.2%, Fe ≤ 1.5%, Pb ≤ 20ppm, Bi ≤ 1ppm, Ag ≤ 5ppm and the balance Ni.

3. The preparation method according to claim 1, characterized in that: The diameter of the nickel-based high-temperature alloy rod blank is 200-250 mm; The cross-sectional side length of the nickel-based high-temperature alloy billet is 150 to 200 mm; The length of the nickel-based high-temperature alloy square billet is 5000-12000 mm.

4. The preparation method according to claim 1, characterized in that: The radial forging also includes a surface defect grinding treatment step; The heating temperature is 1130-1190°C; The heating time is greater than or equal to 3 hours.

5. The preparation method according to claim 1, characterized in that: The insulation temperature is 1130-1190°C; The insulation time is 1 to 4 hours.

6. The preparation method according to claim 1, characterized in that: The hot rolling includes rough rolling and medium rolling; The rough rolling is performed in 4 to 6 passes; The intermediate rolling is performed in 2 to 6 passes.

7. The preparation method according to claim 1, characterized in that: The hot rolling specifically comprises rough rolling and intermediate rolling in sequence; In the rough rolling and intermediate rolling, the deformation of a single pass is ≤20%; The hot rolling speed is 1-5 m / s.

8. The preparation method according to claim 1, characterized in that: The hot rolling temperature is 1130-1190°C; The specification of the rolled rod is 60-85 mm; The cooling method includes wind cooling or air cooling; The cooling is specifically performed on a cooling bed.

9. The preparation method according to claim 1, characterized in that: The temperature of the solution treatment is 1040-1080°C; The solution treatment time is 4 to 8 hours; The specific method of the solid solution treatment is to carry out the solid solution treatment while laying the bars flat without stacking them.

10. Use of the nickel-based high-temperature alloy rolled bar prepared by the preparation method according to any one of claims 1 to 9 in a gas turbine.

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