Method for straightening titanium alloy tubes

Abstract

The present application relates to the field of titanium alloy precision pipe preparation process, especially to a straightening method of titanium alloy pipe with higher straightening efficiency, comprising the following steps: a, adjusting the angle of the upper straightening roller and the lower straightening roller; b, sending the debugging pipe from the guide inlet between the upper straightening roller and the lower straightening roller; c, then adjusting the upper straightening roller and the lower straightening roller to clamp the debugging pipe; d, after the debugging is completed, loosening the angle locking bolt of the upper straightening roller and the lower straightening roller, adjusting the axis of the upper straightening roller and the lower straightening roller, and making the axis of the upper straightening roller and the lower straightening roller and the center line of the debugging pipe have an included angle range of 60±5°; e, observing the rotation, forward movement and backward movement of the debugging pipe to make the debugging pipe and the straightening roller bear force evenly; f, straightening the titanium alloy pipe; g, after the first straightening is completed, changing the end direction of the titanium alloy pipe, sending the titanium alloy pipe again and completing the second straightening; h, observing the gap between the side wall of the titanium alloy pipe and the ruler.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy precision tube manufacturing process, and in particular to a method for straightening titanium alloy tubes. Background Technology

[0002] Pipe straightening machines eliminate original bends and surface defects in titanium alloy pipes by inducing uniform elastoplastic deformation, thus achieving straightening. During manufacturing and rough machining, titanium alloy pipes are susceptible to various defects due to influencing factors, primarily manifested in variations in cross-sectional roundness, axial straightness, and bending. Inclined roller straightening machines offer unique advantages for straightening circular cross-section pipes. Utilizing full contact between the straightening rollers and the pipe, the pipe rotates and moves axially under the rollers' influence. Through repeated bending during the straightening process, the pipe is ultimately straightened, achieving omnidirectional straightening. Specifically, the upper and lower straightening rollers apply a straightening force to the titanium alloy pipe. Existing straightening solutions suffer from deficiencies in roller adjustment and calibration, leading to suboptimal straightening results and significantly impacting the straightening production process. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a straightening method for titanium alloy tubes that achieves higher straightening efficiency.

[0004] The technical solution adopted by this invention to solve its technical problem is: a straightening method for titanium alloy tubes, including straightening rollers, wherein the straightening rollers include at least one upper straightening roller and at least one lower straightening roller, the axes of the upper straightening roller and the lower straightening roller are intersected, and the method includes the following steps: a) loosening the locking screws of the upper and lower straightening rollers respectively, and adjusting the angle of the upper and lower straightening rollers; b) feeding an adjustment tube into the inlet between the upper and lower straightening rollers, wherein the adjustment tube is fed in while rotating and advancing, and the adjustment tube is fed into the inlet. a) From the initial roller end to the final roller, the centerline of the adjustment tube should be in a straight line; b) Then adjust the upper and lower straightening rollers to clamp the adjustment tube, ensuring that the upper and lower straightening rollers near the inlet and the upper and lower straightening rollers near the outlet are firmly clamped to the adjustment tube, and then tighten the locking screws; c) After adjustment, loosen the angle locking bolts of the upper and lower straightening rollers, and adjust the axes of the upper and lower straightening rollers so that the angle between their axes and the centerline of the adjustment tube is... The range is 60±5°, then tighten the angle locking bolts; e. Adjust the speed of the straightening roller to 20-30 rpm, rotate the forward and reverse switches, and observe the rotation, forward and reverse movement of the test tube to ensure even force on the test tube and the straightening roller; f. Secure the straightening roller, start the switch, and after the test tube is forward and rotated to straighten, use a test ruler to test the bending degree of the test tube. Once the bending degree of the test tube is qualified, proceed with the straightening of the titanium alloy tube; g. Place the titanium alloy tube from the annealing furnace on the feeding platform, guide... The titanium alloy tube is introduced into the inlet between the upper and lower straightening rollers and straightened at a speed of 12-15 rpm. After the first straightening is completed, the end direction of the titanium alloy tube is reversed, and the tube is reinserted for a second straightening. Then, the straightened titanium alloy tube is placed on a test ruler, rolled, and the gap between the tube's sidewall and the ruler is observed. A stainless steel feeler gauge is used for testing; if the maximum gap between the tube and the ruler does not exceed 0.5 mm, the straightening is considered successful. Utilizing the full contact between the straightening rollers and the titanium alloy tube 3, the tube rotates and moves along its axis under the rollers' influence. During the straightening process, it is repeatedly bent and ultimately straightened, achieving omnidirectional straightening. Through the friction between the straightening rollers and the tube, the tube rotates and moves forward, undergoing repeated bending by the straightening rollers, thus achieving straightening.

[0005] Furthermore, the straightening rollers include 9 upper straightening rollers and 8 lower straightening rollers.

[0006] Furthermore, in step g, the titanium alloy tube has dimensions of Φ8*1.5mm.

[0007] Furthermore, the minimum distance between the corresponding upper and lower straightening rolls ranges from 8.6 to 8.8 mm.

[0008] Furthermore, in step e, after the force on the adjusting tube and the straightening rollers is uniform, the first lower straightening roller, the second upper straightening roller, the second lower straightening roller, and the third upper straightening roller, starting from the inlet, are all moved 2-2.5 mm towards the centerline of the adjusting tube. By applying different bending pressures to each pair of rollers or between each staggered roller, the straightening channel is made to have a slight S-shaped bend. This allows the titanium alloy tube 3 to undergo multiple reverse bending and springback processes during straightening, thereby eliminating the original bend, achieving the straightening purpose, and obtaining a better straightening effect.

[0009] Furthermore, the mass percentages of each component in the titanium alloy pipe are as follows: Al: 1.8~2.5, Zr: 2.0~3.0, C≤0.07, O≤0.13, N≤0.04, H≤0.006, Fe≤0.25, Si≤0.12, and the total of other impurities ≤0.30, with the remainder being titanium.

[0010] The beneficial effects of this invention are as follows: the upper and lower straightening rollers are in close contact with the titanium alloy tube. Through the friction between the straightening rollers and the titanium alloy tube, the tube rotates and moves forward, undergoing repeated bending by the straightening rollers during movement, thus straightening it. By applying different bending amounts to each pair of rollers or each staggered roller, the tube undergoes multiple reverse bending and springback processes during straightening, thereby eliminating the original curvature and achieving the straightening purpose. The improved straightening efficiency of the straightening rollers before straightening significantly increases the straightening efficiency. This invention is particularly suitable for the straightening of titanium alloy tubes. Attached Figure Description

[0011] Figure 1 This is a schematic diagram showing the positional relationship between the upper and lower straightening rollers and the titanium alloy tube in this invention.

[0012] The markings in the diagram are as follows: Upper Straightening Roller 1, First Upper Straightening Roller 11, Second Upper Straightening Roller 12, Third Upper Straightening Roller 13, Fourth Upper Straightening Roller 14, Fifth Upper Straightening Roller 15, Sixth Upper Straightening Roller 16, Seventh Upper Straightening Roller 17, Eighth Upper Straightening Roller 18, Ninth Upper Straightening Roller 19, Lower Straightening Roller 2, First Lower Straightening Roller 21, Second Lower Straightening Roller 22, Third Lower Straightening Roller 23, Fourth Lower Straightening Roller 24, Fifth Lower Straightening Roller 25, Sixth Lower Straightening Roller 26, Seventh Lower Straightening Roller 27, Eighth Lower Straightening Roller 28, Titanium Alloy Tube 3, Inlet 4, Outlet 5. Detailed Implementation

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0014] like Figure 1This diagram illustrates one embodiment of a straightening method for titanium alloy tubes. There are nine upper straightening rollers 1, arranged sequentially from the inlet 4 to the outlet 5: first upper straightening roller 11, second upper straightening roller 12, third upper straightening roller 13, fourth upper straightening roller 14, fifth upper straightening roller 15, sixth upper straightening roller 16, seventh upper straightening roller 17, eighth upper straightening roller 18, and ninth upper straightening roller 19. There are eight lower straightening rollers 2, arranged sequentially from the inlet 4 to the outlet 5: first lower straightening roller 21, second lower straightening roller 22, third lower straightening roller 23, fourth lower straightening roller 24, fifth lower straightening roller 25, sixth lower straightening roller 26, seventh lower straightening roller 27, and eighth lower straightening roller 28. The inlet 4 is formed between the first upper straightening roller 11 and the first lower straightening roller 21. The titanium alloy tube 3 to be straightened, along with the calibration tube, is fed into this inlet 4 to begin the straightening process. The ninth upper straightening roller 19 and the eighth lower straightening roller 28 form an outlet 5, through which the titanium alloy tube 3 to be straightened and the calibration tube exit the straightening process. The axes of the upper straightening roller 1 and the lower straightening roller 2 are intersected to achieve an inclined straightening roller arrangement. This inclined straightening roller arrangement is particularly suitable for straightening tubes with circular cross-sections.

[0015] Specifically, the second upper straightening roller 12, the third upper straightening roller 13, the fourth upper straightening roller 14, the fifth upper straightening roller 15, and the sixth upper straightening roller 16 are arranged alternately with the second lower straightening roller 22, the third lower straightening roller 23, the fourth lower straightening roller 24, and the fifth lower straightening roller 25, forming an alternating roller configuration. The first lower straightening roller 21 is positioned directly below the first upper straightening roller 11, the sixth lower straightening roller 26 is positioned directly below the seventh upper straightening roller 17, the seventh lower straightening roller 27 is positioned directly below the eighth upper straightening roller 18, and the eighth lower straightening roller 28 is positioned directly below the ninth upper straightening roller 19.

[0016] For titanium alloy tube 3, a Φ32mm thick titanium tube with a wall thickness of 4mm is rolled into a Φ8mm thick tube with a wall thickness of 1.5mm through 4-5 passes. Afterwards, it undergoes sandblasting, polishing, pickling, and cleaning, and then enters a vacuum chamber furnace for annealing. The temperature is raised to 750℃ at a rate of 3-5℃ / min, held for 2 hours, and then cooled under vacuum in the furnace to obtain titanium alloy tube 3. During rolling, extrusion, drawing, annealing heat treatment, cooling, and various processing processes, titanium alloy tube 3 undergoes bending or torsional deformation due to external forces, temperature changes, and fluctuations in internal forces. This is mainly manifested in changes in the roundness of the tube's cross-section, straightness along the axial direction, and other aspects. To eliminate defects in titanium alloy tube 3 and improve its precision, it needs to be straightened on a straightening machine. The straightening machine in this scheme eliminates the original bending and surface defects of titanium alloy tube 3 by inducing uniform elastoplastic deformation, thus achieving the purpose of straightening. The mass percentages of each component in the titanium alloy pipe are as follows: Al: 1.8~2.5, Zr: 2.0~3.0, C≤0.07, O≤0.13, N≤0.04, H≤0.006, Fe≤0.25, Si≤0.12, and the total of other impurities ≤0.30, with the remainder being titanium.

[0017] The following two examples illustrate the corresponding steps of this solution.

[0018] Example 1

[0019] In this embodiment, the straightening of the titanium alloy tube 3 is carried out according to the following steps:

[0020] 1. Loosen the locking screws on both sides of the top surface of the 17 straightening rollers (9 upper straightening rollers 1 and 8 lower straightening rollers 2) using a special tool. Adjust the 9 rollers of the upper straightening rollers 1 with a manual wheel so that their distance from the reference surface is 20mm. Then adjust the horizontal distance of the 8 rollers of the lower straightening rollers 2 counterclockwise so that their distance from the corresponding upper straightening rollers 1 is 8.6-8.8mm.

[0021] 2. Manually and slowly feed the Φ8*1.5mm special adjustment tube through the inlet 4, rotating and advancing at the same time, from the initial rollers of the inlet 4, namely the first upper straightening roller 11 and the first lower straightening roller 21, to the end rollers, namely the ninth upper straightening roller 19 and the eighth lower straightening roller 28, so that the center line of the adjustment tube is on a straight line.

[0022] 3. Adjust each of the lower straightening rollers 2 by rotating the manual wheel clockwise until the eight rollers of the lower straightening rollers 2 and the nine rollers of the upper straightening rollers 1 clamp the adjustment tube together. Then, rotate the adjustment tube slightly by hand. In particular, ensure that the first upper straightening roller 11 and the first lower straightening roller 21 near the inlet 4, as well as the ninth upper straightening roller 19 and the eighth lower straightening roller 28 near the outlet 5, are clamped tightly to the adjustment tube.

[0023] 4. Loosen the angle locking bolts of the 17 straightening rollers. Without affecting the surface quality, tilt them as much as possible to increase the contact area between the straightening rollers and the titanium tube. Initially adjust the tilt angle of the straightening rollers to 60°. Use a special wrench to tighten the straightening rollers so that they do not wobble.

[0024] 5. Adjust the speed of the straightening roller to 20 rpm, rotate the forward and reverse switches, and observe the rotation and forward and reverse movement of the test tube to ensure that the test tube and the straightening roller are subjected to uniform force.

[0025] 6. Stop the machine, loosen the fastening bolts, and use the manual wheel to apply pressure to adjust the center distance of the straightening rollers. Move the first lower straightening roller 21, the second upper straightening roller 12, the second lower straightening roller 22, and the third upper straightening roller 13 2.2mm towards the center line of the adjustment tube. This will make the straightening channel have a slight S-shaped bend, so that the titanium alloy tube 3 can undergo multiple reverse bending and springback processes during straightening, thereby eliminating the original bend and achieving the purpose of straightening, resulting in a better straightening effect.

[0026] 7. Secure the straightening rollers, turn on the switch, and rotate the adjustment tube forward to straighten it. Then, use a dedicated 3-meter ruler to test the curvature.

[0027] 8. Place the titanium alloy tube 3, which has just come out of the annealing furnace (within 24 hours), on the feeding platform and feed it into the straightening machine with the above 17 straightening rollers. Straighten it at a rate of 20 revolutions per minute. After completion, change the end direction of the titanium alloy tube 3, that is, feed the tail end of the titanium alloy tube 3 into the straightening machine first for secondary straightening.

[0028] 9. Place the straightened titanium alloy pipe 3 on a dedicated 3-meter straightedge, roll it carefully, observe the gap between it and the straightedge, and use a stainless steel feeler gauge to check. If the maximum gap does not exceed 0.5mm, the straightening is qualified.

[0029] Using the straightening method described above, a total of 50 titanium alloy pipes were used, and 49 of them passed the straightening test.

[0030] Example 2

[0031] In this embodiment, the straightening of the titanium alloy tube 3 is carried out according to the following steps:

[0032] 1. Loosen the locking screws on both sides of the top surface of the slant straightening machine with 17 straightening rollers (9 upper straightening rollers 1 and 8 lower straightening rollers 2) using a special tool. Adjust the 9 rollers of upper straightening roller 1 with a manual wheel so that their distance from the reference surface is 21mm. Then adjust the horizontal distance of the 8 rollers of lower straightening roller 2 counterclockwise so that their distance from the corresponding upper straightening roller 1 is 8.7-8.9mm.

[0033] 2. Manually and slowly feed the Φ8*1.5mm special adjustment tube through the inlet 4, rotating and advancing it at the same time, from the initial rollers (i.e., the first upper straightening roller 11 and the first lower straightening roller 21) of the inlet 4 to the end rollers (i.e., the ninth upper straightening roller 19 and the eighth lower straightening roller 28), so that the center line of the adjustment tube is on a straight line;

[0034] 3. Adjust each of the lower straightening rollers 2 by rotating the manual wheel clockwise until the eight rollers of the lower straightening rollers 2 and the nine rollers of the upper straightening rollers 1 clamp the adjustment tube together. Then, rotate the tube slightly by hand. In particular, ensure that the first upper straightening roller 11 and the first lower straightening roller 21 near the inlet 4, as well as the ninth upper straightening roller 19 and the eighth lower straightening roller 28 near the outlet 5, are clamped tightly to the adjustment tube.

[0035] 4. Loosen the angle locking bolts of the 17 straightening rollers. Without affecting the surface quality, tilt them as much as possible to increase the contact area between the straightening rollers and the titanium tube. Initially adjust the tilt angle of the straightening rollers to 65°. Use a special wrench to tighten the straightening rollers so that they do not wobble.

[0036] 5. Adjust the speed of the straightening roller to 30 rpm, rotate the forward and reverse switches, and observe the rotation and forward and reverse movement of the test tube to ensure that the test tube and the straightening roller are subjected to uniform force.

[0037] 6. Stop the machine, loosen the fastening bolts, and use the manual wheel to apply pressure to adjust the center distance of the straightening rollers, so that the first lower straightening roller 21, the second upper straightening roller 12, the second lower straightening roller 22 and the third upper straightening roller 13 all move 2.4mm towards the center line of the adjustment tube. The straightening channel has a slight S-shaped bend, so that the titanium alloy tube 3 can be subjected to multiple reverse bending and springback processes during straightening, thereby eliminating the original bend, achieving the purpose of straightening and obtaining a better straightening effect.

[0038] 7. Secure the straightening rollers, turn on the switch, and rotate the adjustment tube forward to straighten it. Then, use a dedicated 3-meter ruler to test the curvature.

[0039] 8. Place the titanium alloy tube 3, which has just come out of the annealing furnace (within 24 hours), on the feeding platform and feed it into the straightening machine with the above 17 straightening rollers. Straighten it at a speed of 30 revolutions per minute. After completion, change the direction of the end of the titanium alloy tube 3, that is, feed the tail end of the titanium alloy tube 3 into the straightening machine first for secondary straightening.

[0040] 9. Place the straightened titanium alloy pipe 3 on a dedicated 3-meter straightedge, roll it carefully, and observe the gap between the titanium alloy pipe 3 and the straightedge. Use a stainless steel feeler gauge to check the gap. If the maximum gap does not exceed 0.5mm, the straightening is qualified.

[0041] Using the straightening method described above, a total of 50 titanium alloy pipes were used, and 48 of them passed the straightening test.

[0042] As can be seen from the above two embodiments, the straightening qualification rate of this solution can reach over 95%, and it effectively enables the titanium alloy pipe 3 to undergo multiple reverse bending and springback processes during straightening, thereby eliminating the original bending, achieving the purpose of straightening, and obtaining a better straightening effect.

Claims

1. A method for straightening titanium alloy pipes, comprising straightening rollers, said straightening rollers comprising at least one upper straightening roller (1) and at least one lower straightening roller (2), wherein the axis of the upper straightening roller (1) and the axis of the lower straightening roller (2) are arranged to intersect each other, characterized in that, Includes the following steps: a. Loosen the locking screws of the upper straightening roller (1) and the lower straightening roller (2) respectively, and adjust the angle of the upper straightening roller (1) and the lower straightening roller (2); b. The test tube is fed into the inlet (4) between the upper straightening roller (1) and the lower straightening roller (2). The test tube is fed in while rotating and moving forward. The test tube passes through the initial roller end at the inlet (4) to the end roller. The center line of the test tube is on a straight line. c. Then adjust the upper straightening roller (1) and the lower straightening roller (2) so that the upper straightening roller (1) and the lower straightening roller (2) clamp the debugging tube. Ensure that the upper straightening roller (1) and the lower straightening roller (2) near the inlet (4) and the upper straightening roller (1) and the lower straightening roller (2) near the outlet (5) are clamped to the debugging tube, and then tighten the locking screw. d. After the debugging is completed, loosen the angle locking bolts of the upper straightening roller (1) and the lower straightening roller (2), adjust the axis of the upper straightening roller (1) and the axis of the lower straightening roller (2) so that the angle between the axis of the upper straightening roller (1) and the axis of the lower straightening roller (2) and the center line of the debugging tube is within the range of 60±5°, and then tighten the angle locking bolts. e. Adjust the speed of the straightening roller to 20-30 rpm, rotate the forward and reverse switches, and observe the rotation, forward and reverse movement of the adjustment tube to ensure that the adjustment tube and the straightening roller are subjected to uniform force. f. Secure the straightening rollers, turn on the switch, and straighten the test tube by rotating it forward. Then, use a test ruler to test the curvature of the test tube. Once the curvature of the test tube is qualified, straighten the titanium alloy tube (3). g. Place the titanium alloy tube (3) from the annealing furnace on the feeding platform and guide it into the inlet (4) between the upper straightening roller (1) and the lower straightening roller (2). Straighten it at a speed of 20 to 30 revolutions per minute. After completing the first straightening, change the direction of the end of the titanium alloy tube (3) and feed the titanium alloy tube (3) back in to complete the second straightening. h. Place the straightened titanium alloy tube (3) on the test ruler, roll the titanium alloy tube (3) and observe the gap between the side wall of the titanium alloy tube (3) and the ruler. During this period, insert a stainless steel feeler gauge to check. If the maximum gap between the titanium alloy tube and the ruler does not exceed 0.5mm, the straightening is qualified.

2. The straightening method for titanium alloy tubing as described in claim 1, characterized in that: The straightening rollers include 9 upper straightening rollers (1) and 8 lower straightening rollers (2).

3. The straightening method for titanium alloy tubing as described in claim 2, characterized in that: In step g, the titanium alloy tube (3) has a size specification of Φ8*1.5mm.

4. The straightening method for titanium alloy tubing as described in claim 3, characterized in that: The minimum distance between the corresponding matching upper straightening roller (1) and lower straightening roller (2) is 8.6 to 8.8 mm.

5. The straightening method for titanium alloy tubing as described in claim 4, characterized in that: In step e, after the adjustment tube and the straightening roller are subjected to uniform force, the first lower straightening roller (21), the second upper straightening roller (12), the second lower straightening roller (22) and the third upper straightening roller (13) starting from the inlet (4) are all moved 2 to 2.5 mm towards the center line of the adjustment tube.

6. The method for straightening titanium alloy tubing as described in any one of claims 1 to 5, characterized in that: The mass percentages of each component in the titanium alloy pipe (3) are as follows: Al: 1.8~2.5, Zr: 2.0~3.0, C ≤0.07, O≤0.13, N ≤0.04, H≤0.006, Fe≤0.25, Si≤0.12, and the total of other impurities ≤0.30, with the remainder being titanium.

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