An annealing and straightening auxiliary device for a titanium alloy ribbed pipe

Abstract

The present invention relates to an annealing and straightening auxiliary device for a titanium alloy ribbed pipe, which comprises a main body support rod, an upper fixed disk, a movable disk, a lower fixed disk, an adjusting screw rod and an adjusting nut; the main body support rod is longitudinally and fixedly connected between the outer circumferences of the upper fixed disk and the lower fixed disk in a circumferentially uniform manner; the movable disk is correspondingly arranged directly below the upper fixed disk and is slidably connected with the main body support rod; the adjusting screw rod is connected between the outer circumferences of the upper fixed disk and the movable disk; the upper and lower ends of the adjusting screw rod are respectively connected with the upper fixed disk and the movable disk through the adjusting nut; the adjusting nut at the upper end of the adjusting screw rod is located above the upper fixed disk, and the adjusting nut at the lower end of the adjusting screw rod is located below the movable disk; a plurality of round holes are correspondingly and uniformly distributed on the movable disk and the lower fixed disk. The present invention is used for straightening and annealing the titanium alloy ribbed pipe, is simple to use and convenient to install, has an ideal straightening effect, and will not damage the height and shape of the convex ribs on the outer surface of the titanium alloy pipe after straightening and annealing.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe heat treatment and straightening, and particularly to an annealing and straightening auxiliary device for a titanium alloy ribbed pipe. Background Art

[0002] The ribs of a titanium alloy ribbed pipe are generally helical with a helix angle of 3°. After the straight ribs are thermally twisted into a helical shape, the overall titanium alloy pipe will form a relatively large bend of 30 mm / m, and dead bends will form at local positions. Due to the convex ribs on the smooth outer surface, a traditional roller straightening machine cannot be used for straightening. The roller straightening machine will damage the convex ribs on the outer surface during the straightening process.

[0003] The existing straightening method is to use a special device to clamp the titanium alloy pipe in a rotating mechanism, heat the titanium pipe to about 500 °C while being energized, and at the same time perform slight stretching straightening on the titanium pipe. After stretching to the required straightness, maintain the state, reduce the current, and wait until it cools down to room temperature. Although this achieves the purpose of straightening, it will have a greater impact on the dimensional accuracy and performance of the titanium alloy pipe. Generally, the dimensional accuracy requirements for such titanium alloy pipes are very strict, and the dimensional tolerance range is very narrow. Although this thermal stretching can straighten, the stretching process will make the circumferential dimension of the titanium alloy pipe smaller. If the original dimensional allowance of the titanium alloy pipe is not reserved enough, it is very easy to cause batch scrapping due to dimensional factors. At the same time, the energized heating temperature during thermal stretching straightening is not much different from the finished product heat treatment temperature of the titanium alloy pipe. After thermal stretching straightening, it will affect the mechanical properties of the finished product. The thermal stretching process cannot maintain a vacuum like the heat treatment process. After the thermal stretching is completed, an oxide layer will form on the inner and outer surfaces of the titanium alloy pipe, and an additional pickling process is required, which will again affect the dimensional accuracy of the titanium alloy pipe. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide an annealing and straightening auxiliary device for a titanium alloy ribbed pipe.

[0005] The technical solution adopted by the present invention is as follows:

[0006] An annealing and straightening auxiliary device for a titanium alloy ribbed pipe proposed by the present invention includes a main support rod, an upper fixed disk, a movable disk, a lower fixed disk, an adjusting screw rod, and an adjusting nut; the main support rod is longitudinally and uniformly connected between the outer circumferences of the upper fixed disk and the lower fixed disk; the movable disk is correspondingly arranged directly below the upper fixed disk and is slidably connected to the main support rod, and can move up and down along the upper region of the main support rod; the adjusting screw rod is connected between the outer circumferences of the upper fixed disk and the movable disk, and the adjusting screw rod and the main support rod are arranged at intervals; the upper and lower ends of the adjusting screw rod are respectively connected to the upper fixed disk and the movable disk through adjusting nuts; the adjusting nut at the upper end of the adjusting screw rod is located above the upper fixed disk, and the adjusting nut at the lower end of the adjusting screw rod is located below the movable disk; a number of circular holes are uniformly distributed in the middle regions of the movable disk and the lower fixed disk in one-to-one correspondence for passing through the titanium alloy ribbed pipe.

[0007] Further, a number of annular reinforcing rib structures are longitudinally and uniformly welded on the part of the main support rod between the movable disk and the lower fixed disk.

[0008] Further, the whole of the auxiliary device is made of 310S stainless steel material.

[0009] Further, the threads of the adjusting screw rod and the adjusting nut are both designed as coarse thread structures.

[0010] Further, the height of the adjusting nut is twice the conventional height.

[0011] The present invention has the following beneficial effects compared with the prior art:

[0012] The present invention applies a longitudinal tension to the bent ribbed pipe in advance. Under the action of the tension, the bent ribbed pipe is slightly straightened; while maintaining the tension, the device is placed in a pit furnace for vacuum annealing; during the annealing heating process, using the characteristic that the thermal expansion coefficient of the device is larger than that of the titanium alloy, calculate the linear expansion lengths of the two, reasonably consider the factors of outer diameter reduction and wall thickness thinning due to the difference in linear expansion length, and reserve a certain margin for the outer diameter and wall thickness of the original titanium alloy ribbed pipe in advance. During the heating and heat preservation processes of the pit furnace, the titanium alloy ribbed pipes with large bends and dead bends are stretched and straightened; during the subsequent furnace cooling process, the forced elongation difference part of the titanium alloy ribbed pipe is retained, and with the slow temperature drop, a certain tension effect can still be maintained until it is completely cooled to room temperature, and finally a titanium alloy ribbed pipe meeting the performance and straightness is obtained. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the overall structure of an annealing and straightening auxiliary device for a titanium alloy ribbed pipe proposed by the present invention.

[0014] Figure 2 is Figure 1 the front view structural schematic diagram of

[0015] Among them, the reference numerals in the drawings are: 1 - main body support rod; 2 - lower fixed disk; 3 - annular reinforcing rib structure; 4 - movable disk; 5 - adjusting screw; 6 - upper fixed disk; 7 - adjusting nut. Specific embodiments

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] It should be noted that in the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating that the device or component must have a specific orientation, be constructed and operated in a specific orientation.

[0018] Referring to the attached Figure 1-2 , the specific structure of an embodiment of an annealing and straightening auxiliary device for a titanium alloy ribbed tube proposed by the present invention is given. The auxiliary device includes four main body support rods 1, a lower fixed disk 2, an annular reinforcing rib structure 3, a movable disk 4, four adjusting screws 5, an upper fixed disk 6 and an adjusting nut 7.

[0019] Among them, the four main body support rods 1 are longitudinally fixedly connected in a circumferentially distributed manner between the outer circumferences of the upper fixed disk 6 and the lower fixed disk 2, and their lower ends all penetrate through the lower fixed disk 2; the movable disk 4 is correspondingly arranged directly below the upper fixed disk 6, and its outer circumference is slidably connected to the four main body support rods 1 respectively; the movable disk 4 can move up and down a certain distance along the upper region of the main body support rod 1; the adjusting screws 5 are circumferentially distributed and connected between the outer circumferences of the upper fixed disk 6 and the movable disk 4, and the four adjusting screws 5 and the four main body support rods 1 are arranged at intervals; the upper end of the adjusting screw 5 is inserted into the movable hole reserved on the outer circumference of the upper fixed disk 6, and the lower end is threadedly connected to the threaded hole reserved on the outer circumference of the movable disk 4; adjusting nuts 7 are respectively connected to the upper and lower ends of the adjusting screw, and the adjusting nut 7 at the upper end of the adjusting screw is located above the upper fixed disk 6, and the adjusting nut 7 at the lower end of the adjusting screw 5 is located below the movable disk 4. The function of the upper fixed disk 6 is to bear the pre-tightening force of the four adjusting screws 5 and maintain the stability of the structure under high temperature conditions.

[0020] The thread of the adjusting screw rod 5 and the adjusting nut 7 are both designed as coarse thread structures. First, it ensures the stability of the position. Second, it ensures that the thread will not deform under high-temperature stress. And to prevent the internal thread of the adjusting nut 7 from deforming under high-temperature conditions, the height of the adjusting nut 7 is designed to be twice the conventional height, so as to reduce the stress on each internal thread under high-temperature conditions and prevent the internal thread from deforming.

[0021] In the middle regions of the movable plate 4 and the lower fixed plate 2, a number of through-round holes are evenly arranged in a one-to-one correspondence for passing through the titanium alloy ribbed pipes. After the upper and lower ends of the titanium alloy ribbed pipes are respectively inserted into the corresponding round holes, waist-shaped holes are radially cut in the parts above the movable plate 4 and below the lower fixed plate 2, and then pins are respectively used to pass through the waist-shaped holes to fix the upper and lower ends respectively. When the movable plate 4 is adjusted to move upward and a certain pulling force is applied to the upper end of the titanium alloy ribbed pipe through the pin, the pin at the lower end and the lower fixed plate 2 fix the lower end of the titanium alloy ribbed pipe and can withstand the pulling force at high temperature without being broken. This device can install more than 10 titanium alloy ribbed pipes at the same time, which can greatly improve the production efficiency.

[0022] When the movable plate 4 moves upward at normal temperature, the movable plate 4 drives the pin to slightly straighten the bent titanium alloy ribbed pipe in advance. During the high-temperature vacuum annealing process at 700°C for 2 hours, the absolute elongation of this device will stretch the titanium alloy ribbed pipe by another section. During the subsequent slow cooling process, the stretched and straightened state is retained, so as to achieve the purpose of annealing + straightening. The size data of the original titanium pipe is different from the size data required by the final technical conditions, and the difference between the two needs to be considered in advance.

[0023] A number of annular reinforcing rib structures 3 are longitudinally and evenly welded on the part of the main support rod 1 located between the movable plate 4 and the lower fixed plate 2. In this embodiment, the number of the annular reinforcing rib structures 3 is seven. By drilling holes at the connection positions corresponding to the four main support rods 1, and then connecting them to the main support rod 1 by welding on the overall structure; by adding intermediate reinforcing ribs at a certain distance, the structural stability of the device is maintained to ensure that the device does not deform at normal temperature and high temperature.

[0024] In this embodiment, the whole of the auxiliary device is made of 310S stainless steel material. 310S stainless steel is austenitic chromium-nickel stainless steel, which has good oxidation resistance, corrosion resistance, creep strength and good high-temperature resistance. It has high strength and creep strength at high temperature and begins to soften at 800°C, while the actual use temperature of this device is up to 700°C at most, which can effectively meet the high-temperature strength requirements of the heat treatment temperature.

[0025] The working principle of the present invention is as follows: By using an existing vacuum annealing furnace, while ensuring the performance of the ribbed tube after torsion through vacuum annealing heat treatment, an auxiliary device is fabricated. A longitudinal tension is applied to the bent ribbed tube in advance. Under the action of the tension, the bent ribbed tube is slightly straightened. While maintaining the tension, the device inserted into the ribbed tube is placed in a pit furnace for vacuum annealing. During the annealing heating process, taking advantage of the characteristic that the coefficient of thermal expansion of the device material is larger than that of the titanium alloy, the linear expansion lengths of both are calculated. Considering reasonably the factors such as the reduction of the outer diameter and the thinning of the wall thickness due to the difference in linear expansion length, a certain margin is reserved in advance for the outer diameter and wall thickness of the original titanium alloy ribbed tube. During the heating and holding processes in the pit furnace, the titanium alloy ribbed tube with large bends and dead bends is stretched and straightened. During the subsequent furnace cooling process, the forced elongation difference part of the titanium alloy ribbed tube is retained. As the temperature slowly drops, a certain tension effect can still be maintained until it is completely cooled to room temperature, and finally a titanium alloy ribbed tube meeting the performance and straightness requirements is obtained.

[0026] This method principle can be applied to special-shaped parts, such as V-shaped titanium parts, S-shaped titanium parts, etc., which cannot be straightened by roller straightening, for annealing and straightening, and has promotional value. The annealing and straightening operations can be completed at one time, without occupying additional space, reducing the production process, saving time costs and production costs, which is extremely beneficial to production organization and can ensure the smooth progress of production.

[0027] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An annealing and straightening auxiliary device for a titanium alloy ribbed pipe, characterized in that: The auxiliary device includes a main body support rod, an upper fixing disk, a movable disk, a lower fixing disk, an adjusting screw rod and an adjusting nut; the main body support rod is longitudinally and fixedly connected between the outer circumferences of the upper fixing disk and the lower fixing disk in a circumferentially uniform manner; the movable disk is correspondingly arranged directly below the upper fixing disk and is slidably connected to the main body support rod, and can move up and down along the upper region of the main body support rod; the adjusting screw rod is connected between the outer circumferences of the upper fixing disk and the movable disk, and the adjusting screw rod and the main body support rod are arranged at intervals; the upper and lower ends of the adjusting screw rod are respectively connected to the upper fixing disk and the movable disk through adjusting nuts; the adjusting nut at the upper end of the adjusting screw rod is located above the upper fixing disk, and the adjusting nut at the lower end of the adjusting screw rod is located below the movable disk; a number of circular holes are uniformly distributed in the middle regions of the movable disk and the lower fixing disk in a one-to-one correspondence for passing through the titanium alloy ribbed pipe; After the upper and lower ends of the titanium alloy ribbed pipe are respectively inserted into the corresponding circular holes, waist-shaped holes are radially cut in the parts above the movable disk and below the lower fixing disk, and then pins are respectively used to pass through the waist-shaped holes to fix the upper and lower ends respectively. After adjusting the movable disk to move upward and applying a certain pulling force to the upper end of the titanium alloy ribbed pipe through the pin, the pin at the lower end and the lower fixing disk fix the lower end of the titanium alloy ribbed pipe and can bear the pulling force at high temperature without being pulled off.

2. The annealing and straightening auxiliary device for a titanium alloy ribbed pipe according to claim 1, wherein: A number of annular reinforcing rib structures are longitudinally and uniformly welded on the part of the main body support rod between the movable disk and the lower fixing disk.

3. The annealing and straightening auxiliary device for a titanium alloy ribbed pipe according to claim 1, wherein: The whole of the auxiliary device is made of 310S stainless steel material.

4. An annealing and straightening auxiliary device for a titanium alloy ribbed pipe according to claim 1, characterized in that: The threads of the adjusting screw rod and the adjusting nut are both designed as coarse thread structures.

5. The annealing and straightening auxiliary device for a titanium alloy ribbed pipe according to claim 1, wherein: The height of the adjusting nut is twice the conventional height.

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