Leveling method for large-specification niobium-tungsten alloy thin plate

Abstract

The invention discloses a large-size niobium-tungsten alloy thin plate flattening method, which relates to the technical field of plate processing, and comprises the following steps: selecting high-temperature-resistant plates with the heat-resistant temperature of more than or equal to 1300 DEG C as an upper flattening plate and a lower flattening plate; cleaning and drying the upper leveling plate, the lower leveling plate and the niobium-tungsten alloy thin plate; a lower leveling plate is placed on a vacuum annealing furnace support, and the niobium-tungsten alloy thin plate is placed on the lower leveling plate with the inner concave face facing downwards; and the upper leveling plate is placed above the niobium-tungsten alloy thin plates, the vacuum annealing furnace support is placed in a vacuum annealing furnace after stacking is completed, the vacuum annealing temperature is controlled to be 1250-1450 DEG C, and the upper leveling plate is taken out after heat preservation is conducted for 100-180 min. According to the method, the high-temperature creep effect of a metal material is utilized, the large-specification niobium-tungsten alloy thin plate is placed in the leveling plate, the plate shape tends to be consistent with that of the leveling plate after the plate is subjected to long-time high-temperature creep, and therefore the flatness of the niobium-tungsten alloy thin plate is controlled within the standard range.

Description

Technical Field

[0001] The invention relates to the technical field of plate processing, and in particular to a leveling method for a large-size niobium-tungsten alloy thin plate. Background Art

[0002] Niobium tungsten alloy has low density and high high temperature strength, and is suitable for making liquid rocket engine tail nozzles. With the continuous improvement of rocket engine thrust, the size of rocket engines is getting larger and larger, and the size of niobium tungsten alloy plates required is also increasing, especially the width is increased from 600mm to 1000mm. Since the thickness of niobium tungsten alloy plate is only 0.8mm~2.0mm, and is subject to the large deformation resistance of niobium tungsten alloy during cold rolling, this thin and wide niobium tungsten alloy sheet is easy to show an arc shape during the cold rolling process, and this arc shape still maintains its original shape after vacuum annealing. The niobium tungsten alloy sheet after vacuum annealing is leveled with a leveling machine. Although it can reduce the curvature of the niobium tungsten alloy sheet, the plate rebounds very clearly. The curvature caused by the rebound makes the flatness of the niobium tungsten alloy sheet ≥10%, which far exceeds the requirement of niobium tungsten alloy sheet flatness ≤6% in GJB 8508-2018.

[0003] Since the niobium tungsten alloy thin plate needs to be processed through cutting, molding, welding and other processes before it can be made into a rocket engine tail nozzle, the uneven niobium tungsten alloy plate makes it difficult to accurately control the cutting size during cutting. Due to the obvious springback, molding is also difficult, so that the two welding edges of the niobium tungsten alloy plate cannot be aligned during welding, which is prone to desoldering and low welding strength, making the rocket engine tail nozzle unable to be processed. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for leveling large-sized niobium-tungsten alloy thin plates. The specific technical solution is as follows:

[0005] A large-sized niobium-tungsten alloy thin plate flattening method is used for recrystallization annealing and flattening of a cold-rolled niobium-tungsten alloy thin plate, wherein one side of the niobium-tungsten alloy thin plate forms an inner concave surface. The large-sized niobium-tungsten alloy thin plate flattening method comprises the following steps:

[0006] Step 1: Select high temperature resistant plates with a heat resistance temperature ≥ 1300℃ as the upper and lower leveling plates;

[0007] Step 3: Clean and dry the upper leveling plate, the lower leveling plate and the niobium tungsten alloy thin plate;

[0008] Step 5: placing the lower leveling plate on the support of the vacuum annealing furnace, and placing the niobium-tungsten alloy thin plate with the inner concave surface facing downward on the lower leveling plate;

[0009] Step 7: Place the upper leveling plate on top of the niobium-tungsten alloy thin plate, and after stacking, place the vacuum annealing furnace bracket in the vacuum annealing furnace, control the vacuum annealing temperature to 1250-1450° C., and take it out after keeping it warm for 100-180 minutes.

[0010] Preferably, tantalum plates or tantalum alloy plates are selected as the upper and lower leveling plates.

[0011] Preferably, the upper and lower leveling plates have a flatness of ≤1%, a surface roughness of ≤1.6 μm, and a single piece weight of ≥200 kg.

[0012] Preferably, the upper and lower leveling plates have the same size, with a length of 1200±2 mm, a width of 1000±2 mm, and a thickness of 8 to 12 mm.

[0013] Preferably, the number of the niobium-tungsten alloy thin plates in step 5 is ≤20, and a plurality of the niobium-tungsten alloy thin plates are aligned and stacked.

[0014] Preferably, step 5 further includes the following steps:

[0015] Step 6: Place a support block made of a high temperature resistant material with a heat resistance temperature ≥ 1300°C on the lower leveling plate, so that the support block is arranged around the niobium tungsten alloy thin plate, wherein the height of the support block is consistent with the stacking thickness of multiple niobium tungsten alloy thin plates.

[0016] Preferably, the high temperature resistant material with a heat resistance temperature ≥ 1300° C. is high temperature structural ceramic.

[0017] Preferably, the number of the support blocks is 8, and the 8 support blocks are respectively arranged at the four corners and the middle of the sides of the lower leveling plate.

[0018] Preferably, the following steps are also included after step 7:

[0019] Step 8: After taking out, the upper and lower leveling plates and the niobium-tungsten alloy thin plate are clamped on a vibration table, and the niobium-tungsten alloy thin plate is continuously vibrated until the niobium-tungsten alloy thin plate is cooled to room temperature.

[0020] Preferably, the vibration mode of the vibration table is up and down vibration.

[0021] The present invention provides a leveling method for large-sized niobium tungsten alloy thin plates. A set of high-temperature resistant leveling plates that can withstand temperatures exceeding 1300°C are designed. The high-temperature creep effect of metal materials is utilized to place the large-sized niobium tungsten alloy thin plates in the leveling plates under high vacuum and high temperature conditions. After a long period of high-temperature creep, the plate shape tends to be consistent with the leveling plates, thereby controlling the flatness of the niobium tungsten alloy thin plates within a standard range to meet the manufacturing requirements of the rocket engine tail nozzle. The problem that the cold-rolled niobium tungsten alloy thin plates cannot be leveled by a leveling machine after recrystallization annealing is successfully solved, thereby achieving smooth subsequent processing of the niobium tungsten alloy thin plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A process flow chart of a method for leveling large-sized niobium-tungsten alloy thin plates provided in an embodiment of the present invention.

[0024] Reference numerals

[0025] 1-upper leveling plate; 2-lower leveling plate; 3-niobium tungsten alloy thin plate; 31-inner concave surface. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition and explanation in the subsequent drawings.

[0028] See also Figure 1 This embodiment provides a large-sized niobium-tungsten alloy thin plate flattening method, which is used for recrystallization annealing and flattening of the niobium-tungsten alloy thin plate 3 after cold rolling, and an inner concave surface 31 is formed on one side of the niobium-tungsten alloy thin plate 3. The large-sized niobium-tungsten alloy thin plate flattening method includes the following steps:

[0029] Step 1: Select high temperature resistant plates with a heat resistance temperature ≥ 1300°C as the upper leveling plate 1 and the lower leveling plate 2.

[0030] Step 3: Clean and dry the upper leveling plate 1, the lower leveling plate 2 and the niobium-tungsten alloy thin plate 3.

[0031] Step 5: Place the lower leveling plate 2 on the support of the vacuum annealing furnace, and place the niobium-tungsten alloy thin plate 3 with its inner concave surface 31 facing downward on the lower leveling plate 2 .

[0032] Step 7: Place the upper leveling plate 1 on the niobium tungsten alloy thin plate 3. After stacking, place the vacuum annealing furnace bracket in the vacuum annealing furnace, control the vacuum annealing temperature to 1250-1450°C, and take it out after keeping it warm for 100-180 minutes.

[0033] Among them, the upper leveling plate 1 and the lower leveling plate 2 clamp the niobium tungsten alloy thin plate 3 and place it in a vacuum annealing furnace. Under the action of high temperature, the plate undergoes a long period of high-temperature creep, and the plate shape tends to be consistent with the leveling plate, thereby successfully solving the problem that the cold-rolled niobium tungsten alloy thin plate cannot be leveled by a leveling machine after recrystallization annealing, and realizing the subsequent smooth processing of the niobium tungsten alloy thin plate.

[0034] The method for leveling large-sized niobium tungsten alloy thin plates provided in this embodiment designs a set of high-temperature resistant leveling plates that can withstand temperatures exceeding 1300°C. The high-temperature creep effect of metal materials is utilized to place large-sized niobium tungsten alloy thin plates in the leveling plates under high vacuum and high temperature conditions. After a long period of high-temperature creep, the shape of the plates tends to be consistent with the leveling plates, thereby controlling the flatness of the niobium tungsten alloy thin plates within the standard range to meet the manufacturing requirements of the rocket engine tail nozzle. This successfully solves the problem that the cold-rolled niobium tungsten alloy thin plates cannot be leveled by a leveling machine after recrystallization annealing, thereby achieving the subsequent smooth processing of the niobium tungsten alloy thin plates.

[0035] Furthermore, tantalum plates or tantalum alloy plates are selected as the upper leveling plate 1 and the lower leveling plate 2 .

[0036] Furthermore, the flatness of the upper leveling plate 1 and the lower leveling plate 2 is ≤1%, the surface roughness is ≤1.6 μm, and the weight of a single piece is ≥200 kg.

[0037] Furthermore, the upper leveling plate 1 and the lower leveling plate 2 have the same size, with a length of 1200±2 mm, a width of 1000±2 mm, and a thickness of 8 to 12 mm.

[0038] Furthermore, in step 5, the number of the niobium-tungsten alloy thin plates 3 is ≤20, and the plurality of niobium-tungsten alloy thin plates 3 are aligned and stacked.

[0039] Furthermore, after step 5, the following steps are also included:

[0040] Step 6: Place a support block made of a high temperature resistant material with a heat resistance temperature ≥ 1300°C on the lower leveling plate 2, so that the support block is arranged around the niobium tungsten alloy thin plate 3, wherein the height of the support block is consistent with the stacking thickness of multiple niobium tungsten alloy thin plates 3.

[0041] The support block can support the upper leveling plate 1, share the pressure of the niobium-tungsten alloy thin plate 3, and avoid excessive stress on the niobium-tungsten alloy thin plate 3 during high-temperature creep. The height error range of the support block is within 0.05mm.

[0042] Furthermore, the high temperature resistant material with a heat resistance temperature ≥ 1300° C. is a high temperature structural ceramic, specifically, it can be an alumina ceramic, a silicon nitride ceramic or a boron nitride ceramic.

[0043] Furthermore, the number of the support blocks is 8, and the 8 support blocks are respectively arranged at the four corners and the middle of the side of the lower leveling plate 2, so as to effectively share the pressure borne by the niobium tungsten alloy thin plate 3.

[0044] Furthermore, after step 7, the following steps are also included:

[0045] Step 8: After taking out, clamp the upper and lower leveling plates 2 and the niobium-tungsten alloy thin plate 3 on a vibration table, and vibrate continuously until the niobium-tungsten alloy thin plate 3 cools to room temperature.

[0046] Among them, applying vibration during the cooling process of the niobium-tungsten alloy thin plate 3 to room temperature can effectively eliminate residual stress.

[0047] Furthermore, the vibration table is vibrated up and down to avoid dislocation of the niobium-tungsten alloy thin plate 3 .

[0048] Specific examples are provided below. The provided examples may enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0049] Example 1

[0050] The material used for the leveling plate is tantalum plate, which can withstand temperatures ≥1300℃. Its dimensions are: length 1200mm×width 1000mm×thickness 12mm. It is divided into an upper leveling plate and a lower leveling plate, and the two leveling plates have the same dimensions. The flatness of the leveling plate is ≤1%, the surface roughness is ≤1.6μm, and the weight of a single leveling plate is 240kg.

[0051] Place the lower leveling plate on the vacuum annealing furnace support, and place the concave side of the niobium tungsten alloy sheet toward the lower leveling plate. Place 20 large-sized cold-rolled niobium tungsten alloy sheets. After the large-sized cold-rolled niobium tungsten alloy sheets are neatly stacked, cover the upper leveling plate on the niobium tungsten alloy sheets. See the schematic diagram of leveling large-sized niobium tungsten alloy sheets for details. Figure 1 Before loading into the furnace, the leveling plate and niobium-tungsten alloy sheet must be cleaned and free of oil and dirt on the surface.

[0052] The stacked leveling plates and cold-rolled niobium-tungsten alloy thin plates were placed in a vacuum annealing furnace at a vacuum annealing temperature of 1350°C for 120 minutes. The vacuum annealed and leveled niobium-tungsten alloy thin plates were placed on a testing platform for flatness testing, and the flatness was 3.2%, meeting the requirements.

[0053] Example 2

[0054] The material used for the leveling plate is tantalum plate, which can withstand temperatures ≥1300℃. Its dimensions are: length 1200mm×width 1000mm×thickness 12mm. It is divided into an upper leveling plate and a lower leveling plate, and the two leveling plates have the same dimensions. The flatness of the leveling plate is ≤1%, the surface roughness is ≤1.6μm, and the weight of a single leveling plate is 240kg.

[0055] Place the lower leveling plate on the vacuum annealing furnace support, and place the concave side of the niobium tungsten alloy sheet toward the lower leveling plate. Place 20 large-sized cold-rolled niobium tungsten alloy sheets. After the large-sized cold-rolled niobium tungsten alloy sheets are neatly stacked, cover the upper leveling plate on the niobium tungsten alloy sheets. See the schematic diagram of leveling large-sized niobium tungsten alloy sheets for details. Figure 1 Before loading into the furnace, the leveling plate and niobium-tungsten alloy sheet must be cleaned and free of oil and dirt on the surface.

[0056] The stacked leveling plates and cold-rolled niobium-tungsten alloy thin plates were placed in a vacuum annealing furnace at a vacuum annealing temperature of 1350°C for 180 minutes. The vacuum annealed and leveled niobium-tungsten alloy thin plates were placed on a testing platform for flatness testing, and the flatness was 2.8%, meeting the requirements.

[0057] Example 3

[0058] The material used for the leveling plate is tantalum plate, which can withstand temperatures ≥1300℃. Its dimensions are: length 1200mm×width 1000mm×thickness 12mm. It is divided into an upper leveling plate and a lower leveling plate, and the two leveling plates have the same dimensions. The flatness of the leveling plate is ≤1%, the surface roughness is ≤1.6μm, and the weight of a single leveling plate is 240kg.

[0059] Place the lower leveling plate on the vacuum annealing furnace support, and place the concave side of the niobium tungsten alloy sheet toward the lower leveling plate. Place 10 large-sized cold-rolled niobium tungsten alloy sheets. After the large-sized cold-rolled niobium tungsten alloy sheets are neatly stacked, cover the upper leveling plate on the niobium tungsten alloy sheets. See the schematic diagram of leveling large-sized niobium tungsten alloy sheets for details. Figure 1 Before loading into the furnace, the leveling plate and niobium-tungsten alloy sheet must be cleaned and free of oil and dirt on the surface.

[0060] The stacked leveling plates and cold-rolled niobium-tungsten alloy thin plates were placed in a vacuum annealing furnace at a vacuum annealing temperature of 1300°C for 120 minutes. The vacuum annealed and leveled niobium-tungsten alloy thin plates were placed on a testing platform for flatness testing, and the flatness was 3.0%, meeting the requirements.

[0061] Example 4

[0062] The material used for the leveling plate is tantalum plate, which can withstand temperatures ≥1300℃. Its dimensions are: length 1200mm×width 1000mm×thickness 12mm. It is divided into an upper leveling plate and a lower leveling plate, and the two leveling plates have the same dimensions. The flatness of the leveling plate is ≤1%, the surface roughness is ≤1.6μm, and the weight of a single leveling plate is 240kg.

[0063] Place the lower leveling plate on the vacuum annealing furnace support, and place the concave side of the niobium tungsten alloy sheet toward the lower leveling plate. Place 10 large-sized cold-rolled niobium tungsten alloy sheets. After the large-sized cold-rolled niobium tungsten alloy sheets are neatly stacked, cover the upper leveling plate on the niobium tungsten alloy sheets. See the schematic diagram of leveling large-sized niobium tungsten alloy sheets for details. Figure 1 Before loading into the furnace, the leveling plate and niobium-tungsten alloy sheet must be cleaned and free of oil and dirt on the surface.

[0064] The stacked leveling plates and cold-rolled niobium-tungsten alloy thin plates were placed in a vacuum annealing furnace at a vacuum annealing temperature of 1300°C for 180 minutes. The vacuum annealed and leveled niobium-tungsten alloy thin plates were placed on a testing platform for flatness testing, and the flatness was 2.8%, meeting the requirements.

[0065] Comparative Example 1

[0066] The material used for the leveling plate is tantalum plate, which can withstand temperatures ≥1300℃. Its dimensions are: length 1200mm×width 1000mm×thickness 12mm. It is divided into an upper leveling plate and a lower leveling plate, and the two leveling plates have the same dimensions. The flatness of the leveling plate is ≤1%, the surface roughness is ≤1.6μm, and the weight of a single leveling plate is 240kg.

[0067] Place the lower leveling plate on the support of the vacuum annealing furnace, and place the concave side of the niobium tungsten alloy sheet toward the lower leveling plate. Place 30 large-sized cold-rolled niobium tungsten alloy sheets. After the large-sized cold-rolled niobium tungsten alloy sheets are neatly stacked, cover the upper leveling plate on the niobium tungsten alloy sheets. See the schematic diagram of leveling large-sized niobium tungsten alloy sheets for details. Figure 1 Before loading into the furnace, the leveling plate and niobium-tungsten alloy sheet must be cleaned and free of oil and dirt on the surface.

[0068] The stacked leveling plates and cold-rolled niobium-tungsten alloy thin plates were placed in a vacuum annealing furnace at a vacuum annealing temperature of 1350°C for 180 minutes. The vacuum annealed and leveled niobium-tungsten alloy thin plates were placed on a testing platform for flatness testing, and the flatness was 8%, which did not meet the requirements.

[0069] Comparative Example 2

[0070] The material used for the leveling plate is tantalum plate, which can withstand temperatures ≥1300℃. Its dimensions are: length 1200mm×width 1000mm×thickness 12mm. It is divided into an upper leveling plate and a lower leveling plate, and the two leveling plates have the same dimensions. The flatness of the leveling plate is ≤1%, the surface roughness is ≤1.6μm, and the weight of a single leveling plate is 240kg.

[0071] Place the lower leveling plate on the vacuum annealing furnace support, and place the concave side of the niobium tungsten alloy sheet toward the lower leveling plate. Place 20 large-sized cold-rolled niobium tungsten alloy sheets. After the large-sized cold-rolled niobium tungsten alloy sheets are neatly stacked, cover the upper leveling plate on the niobium tungsten alloy sheets. See the schematic diagram of leveling large-sized niobium tungsten alloy sheets for details. Figure 1 Before loading into the furnace, the leveling plate and niobium-tungsten alloy sheet must be cleaned and free of oil and dirt on the surface.

[0072] The stacked leveling plates and cold-rolled niobium-tungsten alloy thin plates were placed in a vacuum annealing furnace at a vacuum annealing temperature of 1200°C for 180 minutes. The vacuum annealed and leveled niobium-tungsten alloy thin plates were placed on a testing platform for flatness testing, and the flatness was 10%, which did not meet the requirements.

[0073] Principle description:

[0074] The upper leveling plate 1 and the lower leveling plate 2 clamp the niobium tungsten alloy thin plate 3 and place it in a vacuum annealing furnace. Under the action of high temperature, the plate undergoes a long period of high-temperature creep, and the plate shape tends to be consistent with the leveling plate, thereby successfully solving the problem that the cold-rolled niobium tungsten alloy thin plate cannot be leveled by a leveling machine after recrystallization annealing, and realizing the subsequent smooth processing of the niobium tungsten alloy thin plate.

[0075] The principles and implementation methods of the present invention are described herein using specific examples, and the description of the above embodiments is only used to help understand the method and core ideas of the present invention. The above are only preferred implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention, which should be within the protection scope of the present invention.

Claims

1. A method for leveling large-sized niobium-tungsten alloy thin plates, characterized in that: Used for recrystallization annealing and leveling of a cold-rolled niobium-tungsten alloy thin plate (3), wherein one side of the niobium-tungsten alloy thin plate (3) forms an inner concave surface (31), and the leveling method of a large-size niobium-tungsten alloy thin plate comprises the following steps: S1: Select high temperature resistant plates with a heat resistance temperature of ≥1300°C as the upper leveling plate (1) and the lower leveling plate (2); S3: cleaning and drying the upper leveling plate (1), the lower leveling plate (2) and the niobium-tungsten alloy thin plate (3); S5: placing the lower leveling plate (2) on a vacuum annealing furnace support, and placing the niobium-tungsten alloy thin plate (3) with its inner concave surface (31) facing downward on the lower leveling plate (2); S7: placing the upper leveling plate (1) on top of the niobium-tungsten alloy thin plate (3), placing the vacuum annealing furnace support in the vacuum annealing furnace after stacking, controlling the vacuum annealing temperature to be 1250-1450° C., and taking it out after keeping the temperature for 100-180 minutes.

2. The large-size niobium-tungsten alloy thin plate leveling method according to claim 1 is characterized in that: Tantalum plates or tantalum alloy plates are selected as the upper leveling plate (1) and the lower leveling plate (2).

3. The large-size niobium-tungsten alloy thin plate leveling method according to claim 1 is characterized in that: The upper leveling plate (1) and the lower leveling plate (2) have a flatness of ≤1%, a surface roughness of ≤1.6 μm, and a single piece weight of ≥200 kg.

4. The large-size niobium-tungsten alloy thin plate leveling method according to claim 1 is characterized in that: The upper leveling plate (1) and the lower leveling plate (2) have the same size, with a length of (1200±2) mm, a width of (1000±2) mm, and a thickness of 8 to 12 mm.

5. The large-size niobium-tungsten alloy thin plate leveling method according to claim 4 is characterized in that: In step S5, the number of the niobium-tungsten alloy thin plates (3) is ≤20, and a plurality of the niobium-tungsten alloy thin plates (3) are aligned and stacked.

6. The method for leveling large-sized niobium-tungsten alloy thin plates according to claim 5, characterized in that: After step S5, the following steps are also included: S6: placing a support block made of a high temperature resistant material with a heat resistance temperature ≥ 1300°C on the lower leveling plate (2), so that the support block is arranged around the niobium tungsten alloy thin plate (3), wherein the height of the support block is consistent with the stacking thickness of multiple niobium tungsten alloy thin plates (3).

7. The large-size niobium-tungsten alloy thin plate leveling method according to claim 6 is characterized in that: The high temperature resistant material with a heat resistance temperature of ≥1300°C is high temperature structural ceramics.

8. The method for leveling large-sized niobium-tungsten alloy thin plates according to claim 6, characterized in that: The number of the support blocks is 8, and the 8 support blocks are respectively arranged at the four corners and the middle of the side of the lower straightening plate (2).

9. The large-size niobium-tungsten alloy thin plate leveling method according to claim 1 is characterized in that: After step S7, the following steps are also included: S8: After being taken out, the upper and lower leveling plates (2) and the niobium-tungsten alloy thin plate (3) are clamped on a vibration table and continuously vibrated until the niobium-tungsten alloy thin plate (3) is cooled to room temperature.

10. The method for leveling large-sized niobium-tungsten alloy thin plates according to claim 9, characterized in that: The vibration mode of the vibration table is up and down vibration.

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