Method for controlling deformation of small-diameter thick-walled pipe electron beam welding and application thereof

Abstract

The present application relates to a kind of small diameter thick-walled pipe electron beam welding deformation control method and application, belong to electron beam welding technical field.The electron beam welding deformation control method, including small diameter thick-walled pipe is detected to residual magnetism, to be welded surface is polished and rusted, point positioning fixed, alignment;Vacuum pressure reaches 2×10 ‑ 2 Pa after preheating welding;1 / 4 circle is arc position, weld 1 circle, 1 / 2 circle is arc position, stop in 3 / 4 circle position point;Welding speed is 8mm / s-10mm / s, welding accelerating voltage is 110kV-130kV, welding focusing current is 1750mA-1850mA, welding beam is 6mA-10mA;The preheating welding is carried out once welding and secondary welding after;After welding, in vacuum chamber, keep 20min-30min after, the welding deformation of small diameter thick-walled pipe after welding is less than 0.15mm.

Description

Technical Field

[0001] This invention relates to the field of electron beam welding technology, and in particular to a method and application for controlling deformation during electron beam welding of small-diameter thick-walled tubes. Background Technology

[0002] Gears and bearings are key components in the mechanical transmission systems of aircraft engines, helicopters, and other weapon systems. They are used under conditions of high speed, heavy load, complex stress, and drastic changes in conditions, and are directly related to the performance and safety of the weapon systems. Failure will lead to catastrophic accidents.

[0003] The next-generation turboshaft drive system will utilize 16Cr3NiWMoVNbE-manufactured mid- and tail gearboxes, which are key components of the helicopter rotor hub integration. The mid- and tail gearboxes are manufactured by welding gears, shafts, and other components. The 16Cr3NiWMoVNbE structural material is characterized by high alloying, strong hardenability, and high operating temperature. However, the electron beam welding method exhibits strong brittleness and hardness, and a tendency for welding cracks. Furthermore, due to functional requirements, certain gear components require pre-welding carburizing treatment in certain areas before welding. Therefore, the welding deformation must be controlled within 0.15 mm, which is an extremely high requirement.

[0004] Currently, the common method to solve electron beam welding deformation is to perform correction treatment after welding. However, some special structural parts cannot be corrected using traditional methods after welding. For example, some parts have special wear resistance requirements and need to be carburized before welding. If correction treatment is performed after welding, the carburized layer will fall off, directly affecting the service life of the parts.

[0005] Therefore, there is an urgent need for an electron beam welding method that minimizes the deformation of the welded parts and eliminates the need for correction. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a method and application for controlling deformation during electron beam welding of small-diameter thick-walled tubes, in order to solve the problem of large deformation after welding using existing methods.

[0007] On one hand, the present invention provides a method for controlling deformation during electron beam welding of small-diameter thick-walled tubes, comprising the following steps:

[0008] S1: Perform residual magnetism testing on small-diameter thick-walled pipes and grind and remove rust from the surfaces to be welded;

[0009] S2: Position and fix the argon arc welding point of the small-diameter thick-walled pipe to be welded, and then align it;

[0010] S3: Evacuate the vacuum chamber until the vacuum pressure reaches 2×10⁻⁶. -2Preheat welding is performed after Pa; the arc starts at 1 / 4 turn, and welding is performed for 1 turn; the arc ends at 1 / 2 turn, stopping at the 3 / 4 turn position; the welding speed is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 6mA-10mA;

[0011] S4: After the preheating welding, a primary welding and a secondary welding are performed;

[0012] The welding speed of the first welding is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 17mA-25mA; the welding speed of the second welding is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 16mA-23mA.

[0013] S5: After welding, keep in the vacuum chamber for 20-30 minutes, then release the gas and remove from the furnace.

[0014] Furthermore, the diameter of the small-diameter thick-walled tube is 28mm-35mm, and the thickness is 4mm-7mm.

[0015] Furthermore, the small-diameter thick-walled tube has a tensile strength ≥1270MPa, a yield strength ≥1130MPa, and a Rockwell HRC hardness of 36-42.

[0016] Furthermore, the material of the small-diameter thick-walled tube is 16Cr3NiWMoVNbE.

[0017] Furthermore, in step S1, the magnetic flux density of the small-diameter thick-walled tube should be ≤1×10⁻⁶. -4 T.

[0018] Furthermore, the welding speed for the primary and secondary welding is 9 mm / s-10 mm / s.

[0019] Furthermore, the welding acceleration voltage for the primary welding and the secondary welding is 120kV-130kV.

[0020] Furthermore, testing revealed that the welding deformation of the small-diameter thick-walled pipe was less than 0.15 mm.

[0021] On the other hand, the present invention provides a method for controlling deformation during electron beam welding of small-diameter thick-walled tubes, which is applied to the welding of gears and gear shafts.

[0022] Furthermore, the weld penetration depth of the parts shall not be less than δ1, and the bottom weld shall not penetrate through; the maximum weld penetration depth shall not be greater than δ1+δ2.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] 1. This invention provides a method for controlling deformation during electron beam welding. The method strictly controls the magnetic flux density of a small-diameter thick-walled tube, fixes and aligns the tube, and then performs preheating welding, primary welding, and secondary welding. The method also controls the welding speed, welding focusing current, welding acceleration voltage, and welding beam current during the welding process, so that the welding deformation of the small-diameter thick-walled tube after welding is less than 0.15 mm.

[0025] 2. The electron beam welding deformation control method of the present invention is applicable to small-diameter thick-walled tubes with a diameter of 28mm-35mm and a thickness of 4mm-7mm. The material of the small-diameter thick-walled tube is 16Cr3NiWMoVNbE, with a tensile strength ≥1270MPa, a yield strength ≥1130MPa, and a Rockwell HRC hardness of 36-42.

[0026] 3. The electron beam welding deformation control method provided by the present invention can be used for welding gears and gear shafts, with small deformation after welding and no cracks.

[0027] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0028] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0029] Figure 1 This is a photograph of the small-diameter thick-walled pipe after welding in Example 1.

[0030] Figure 2 This is a schematic diagram illustrating the fit between the gear and the gear shaft in an application example;

[0031] Figure 3 This is an enlarged view of the welding positions of the gear and gear shaft in the application example;

[0032] Figure 4 This is a schematic diagram showing the welding direction of the gear and gear shaft in an application example;

[0033] In the diagram, 1 is a gear; 2 is a gear shaft; and 3 is a weld. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0035] When welding pipes using electron beam welding technology, the pipes often deform after welding, requiring adjustment through correction. However, when welding gears and gear shafts, the material used is 16Cr3NiWMoVNbE high-strength steel, which requires carburizing during the manufacturing process. If correction is performed, the carburized layer will directly peel off, leading to the failure of the gears and gear shafts.

[0036] Therefore, the present invention provides a method for controlling deformation during electron beam welding of small-diameter thick-walled tubes, comprising the following steps:

[0037] S1: Perform residual magnetism testing on small-diameter thick-walled pipes and grind and remove rust from the surfaces to be welded;

[0038] S2: Position and fix the argon arc welding point of the small-diameter thick-walled pipe to be welded, and then align it;

[0039] S3: Evacuate the vacuum chamber until the vacuum pressure reaches 2×10⁻⁶. -2 Preheat welding is performed after Pa; the arc starts at 1 / 4 turn, and welding is performed for 1 turn; the arc ends at 1 / 2 turn, stopping at the 3 / 4 turn position; the welding speed is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 6mA-10mA;

[0040] S4: After the preheating welding, a primary welding and a secondary welding are performed;

[0041] The welding speed of the first welding is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 17mA-25mA; the welding speed of the second welding is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 16mA-23mA.

[0042] S5: After welding, maintain the vacuum chamber under vacuum for 20-30 minutes, then release the gas and remove the product from the furnace.

[0043] Compared with existing technologies, the electron beam welding deformation control method provided by this invention results in less deformation and no cracks after welding. No traditional correction is required after welding, thus avoiding failure of gears and gear shafts caused by the shedding of the carburized layer. This invention mainly utilizes measures such as the starting position of the circumferential weld, the welding circumferential angle, the arc ending circumferential angle, and multiple welding operations. Furthermore, it controls the welding speed, welding acceleration voltage, welding focusing current, and welding beam current during the welding process. Through these combined effects, the deformation of small-diameter thick-walled tubes after welding can be less than 0.15 mm.

[0044] Specifically, in step S1, the magnetic flux density of the small-diameter thick-walled tube should be ≤1×10⁻⁶. -4 T.

[0045] When using electron beam welding to weld small-diameter thick-walled tubes, the magnetic flux density of the tubes should be ≥1×10⁻⁶. - 4 T, easily induces electron beam deflection during welding, leading to weld misalignment, affecting welding quality, and ultimately resulting in excessive deformation of small-diameter thick-walled tubes. Therefore, this invention first needs to determine the magnetic flux density of the small-diameter thick-walled tube. If it is greater than 1×10 -4 When the temperature reaches T, demagnetization is required to ensure minimal deformation after welding.

[0046] In step S2, the small-diameter thick-walled tube to be welded is fixed by manual argon arc welding using a "stop-lock bottom" type tubular butt welding method. The tube is then placed in the vacuum chamber of the electron beam welding equipment and aligned using a dial indicator. The tail of the tube is then pressed with a live center, ready for subsequent welding.

[0047] In step S3, by controlling the welding start position, welding circumference angle and arc termination circumference angle, and performing preheating welding, the welding process involves both preheating and welding, which is equivalent to including the preheating process in the welding process. This can reduce a separate preheating process and improve the welding production efficiency of the component.

[0048] In step S4, the combination of primary and secondary welding can reduce the deformation of small-diameter thick-walled pipes during the welding process, controlling the deformation to within 0.15mm.

[0049] The primary goal of the first welding process is to achieve weld penetration and weld quality. The primary goal of the second welding process is to correct the weld shape.

[0050] In both primary and secondary welding, the welding speed used is 8mm / s-10mm / s, and the welding acceleration voltage is 110kV-130kV. When the welding speed is lower than 8mm / s, the welding time will be prolonged, and the heat input to the small-diameter thick-walled tube will gradually increase, resulting in greater welding deformation. When the welding speed is higher than 10mm / s, welding cracks are more likely to occur during welding, causing the welding quality of the small-diameter thick-walled tube to fail to meet the quality requirements.

[0051] For example, the welding speed of the primary welding and the secondary welding can be 8 mm / s, 9 mm / s or 10 mm / s.

[0052] Preferably, the welding speed for the first and second welding is 10 mm / s.

[0053] Similarly, when the welding acceleration voltage is below 110kV, the welding heat input gradually increases, leading to excessive welding deformation. When the welding acceleration voltage is above 130kV, welding cracks are easily generated during the welding process, causing small-diameter thick-walled pipes to be scrapped.

[0054] For example, the welding acceleration voltage can be 110kV, 120kV or 130kV.

[0055] Preferably, the welding acceleration voltage is 120 kV.

[0056] Under these conditions, a matching relationship for the welding beam can be formed simultaneously. According to the line energy relationship q=UI / v, with the acceleration voltage U and welding speed v determined, the welding beam I is proportional to the line energy q. Depending on the welding thickness and welding quality requirements, the welding beam I has a minimum and a maximum value, which is the size of the welding window of the welding beam I in welding terminology.

[0057] Similarly, the welding current is to ensure that the welding penetration reaches the required depth. If the welding current is too small, the weld will not penetrate. If the welding current is too large, the weld will burn through, weld beads will be generated, the internal quality of the weld will be unqualified, and the shrinkage and deformation of the parts will be large.

[0058] When the welding current is 6mA-10mA, it serves the purpose of preheating and sealing, ensuring the smooth progress of subsequent welding. When the welding current for the first welding is 17mA-25mA, it ensures that the welding quality and weld penetration of small-diameter thick-walled pipes meet the requirements. When the welding current for the second welding is 16mA-23mA, it ensures the correction of welding deformation.

[0059] Specifically, the diameter of the small-diameter thick-walled tube is 28mm-35mm, and the thickness is 4mm-7mm.

[0060] This invention is applicable to small-diameter, thick-walled products or parts, such as pipes, where the thickness and diameter specifications are matched. When the pipe diameter is greater than 35mm, the rigidity of the pipe is enhanced, so it is not easy to deform after welding, the welding process is easy to control, and the welding difficulty is reduced accordingly. When the pipe diameter is less than 28mm and has a certain thickness, electron beam welding is not suitable, as the welding quality and the amount of welding deformation are difficult to control.

[0061] Specifically, the small-diameter thick-walled tube has a tensile strength ≥1270MPa, a yield strength ≥1130MPa, and a Rockwell HRC hardness of 36-42.

[0062] Specifically, the small-diameter thick-walled tube is made of 16Cr3NiWMoVNbE, which has the characteristics of ultra-high strength, high alloying, strong hardenability and poor weldability.

[0063] In step S5, after the secondary welding is completed, the surface temperature of the weld and the area near the weld of the small-diameter thick-walled pipe will reach 900℃-700℃. After being kept in a vacuum for 20min-30min, it is taken out of the furnace to prevent the weld from cracking and reduce the occurrence of deformation, thus ensuring the welding quality.

[0064] The method for controlling deformation during electron beam welding of small-diameter thick-walled tubes described in this invention can be used for welding gears and gear shafts, resulting in minimal deformation. Specifically, the weld penetration depth must be no less than δ1, and the bottom weld must not penetrate the weld. The maximum weld penetration depth cannot exceed δ1 + δ2. δ1 represents the effective contact surface thickness during welding, and the weld penetration depth must exceed this dimension. δ2 represents the thickness during bottom welding assembly, and the weld penetration depth must not exceed δ1 + δ2; otherwise, the welding quality and the amount of part deformation will be affected.

[0065] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0066] Example 1

[0067] A method for controlling deformation during electron beam welding of small-diameter thick-walled tubes, characterized by comprising the following steps:

[0068] S1: Perform residual magnetism testing on small-diameter thick-walled tubes; the magnetic flux density should be ≤1×10⁻⁶. -4 T, grind and remove rust from the surface to be welded;

[0069] The small-diameter thick-walled tube has a diameter of 30mm and a thickness of 5mm; the material is 16Cr3NiWM oVNbE; its tensile strength is ≥1270MPa, yield strength is ≥1130MPa, and Rockwell HRC hardness is 36-42.

[0070] S2: The small-diameter thick-walled tube to be welded is fixed by manual argon arc welding using the "stop-lock bottom" type tubular butt welding method, and placed in the vacuum chamber of the electron beam welding equipment. The part is then aligned by dial indicator using a three-jaw chuck. The tail of the part is clamped with a live center, ready for subsequent welding.

[0071] S3: Evacuate the vacuum chamber until the vacuum pressure reaches 2×10⁻⁶. -2 Preheat welding is performed after Pa; 1 / 4 turn is the arc starting position, weld 1 turn, 1 / 2 turn is the arc ending position, and stop at the 3 / 4 turn position; welding speed is 10mm / s, welding acceleration voltage is 120kV, welding focusing current is 1815mA, and welding beam current is 10mA.

[0072] S4: After the preheating welding, a primary welding and a secondary welding are performed;

[0073] The welding speed of the first welding is 10 mm / s, the welding acceleration voltage is 120 kV, the welding focusing current is 1815 mA, and the welding beam current is 18.5 mA; the welding speed of the second welding is 10 mm / s, the welding acceleration voltage is 120 kV, the welding focusing current is 1815 mA, and the welding beam current is 17.5 mA.

[0074] S5: After welding, maintain the vacuum chamber under vacuum for 30 minutes, then release the gas and remove the product from the furnace.

[0075] Examples 2-5

[0076] The preparation processes of Examples 2-5 are largely the same as those of Example 1, with the differences shown in Table 1.

[0077] Table 1. Parameters during the welding process in Examples 1-5

[0078]

[0079]

[0080] Comparative Examples 1-4

[0081] The preparation processes of Comparative Examples 1-4 are largely the same as those of Example 1, with the differences shown in Table 2.

[0082] Table 2 Parameters during the welding process of Comparative Examples 1-4

[0083]

[0084] Size inspection

[0085] Deformation and crack detection were performed on the small-diameter thick-walled tubes of Examples 1-5 and Comparative Examples 1-4 after welding. The results are shown in Table 3.

[0086] Table 3 Detection Results

[0087]

[0088]

[0089] Referring to Examples 1-5 and Comparative Examples 1-4, and in conjunction with Tables 1-3 and... Figure 1 It can be seen that when the welding methods provided in Examples 1-5 are used, the deformation of the small-diameter thick-walled tubes after welding is less than 0.15 mm, and no cracks are generated.

[0090] Application Example 1

[0091] The gear 1 and gear shaft 2 are welded using the welding method provided in Example 1. The material of gear 1 and gear shaft 2 is 16Cr3NiWMoVNbE. Figure 1 and Figure 2 The outer diameter of the weld 3 between gear 1 and gear shaft 2 is 30mm, the wall thickness of gear 1 is 5mm, and the thickness of gear shaft 2 is 7mm.

[0092] The steps of its electron beam welding method are as follows:

[0093] S1: Perform residual magnetism testing on gear 1 and gear shaft 2. Use a magnetometer to check the magnetic flux density at the welding location for each part. The magnetic flux density should not exceed 1×10⁻⁶. -4 T; if greater than 1×10 -4 When T is reached, demagnetization is required until the magnetic flux density of the parts meets the requirements. Then, the surface to be welded and the surrounding 20mm area are ground and rusted. After that, the surface to be welded and the surrounding area are wiped with acetone using a non-woven cloth.

[0094] S2: The gear 1 and gear shaft 2 are fixed by manual argon arc welding using a "stop-lock bottom" type tubular docking method. The parts are then placed in the vacuum chamber of the electron beam welding equipment and aligned by a dial indicator using a three-jaw chuck. The tail of the parts is clamped by a live center.

[0095] S3: Evacuate the vacuum chamber until the vacuum pressure reaches 2×10⁻⁶. -2 Preheat welding is performed after Pa;

[0096] Reference Figure 3The welding process path is as follows: point A on the circumference is the electron beam arc initiation position. Along the clockwise direction, arc AB is the electron beam arc initiation segment. Point B is the maximum electron beam current. Weld one revolution in the clockwise direction. Returning to point B is the electron beam arc termination point. Arc segment BCD is the electron beam termination segment. Point D is when the electron beam current decreases to 0. The part rotates 3 / 4 revolutions along the circumferential arc DABC and stops rotating at point C. The welding speed is 10 mm / s, the welding acceleration voltage is 120 kV, the welding focusing current is 1815 mA, and the welding beam current is 10 mA.

[0097] S4: After the preheating welding, a primary welding and a secondary welding are performed;

[0098] The welding speed for a single weld is 10 mm / s, the welding acceleration voltage is 120 kV, the welding focusing current is 1815 mA, and the welding beam current is 18.5 mA; the weld penetration depth is not less than δ1 ( Figure 3 Furthermore, the weld must not penetrate the bottom weld, and the maximum weld penetration depth must not exceed δ1 + δ2. Figure 3 The secondary welding process involves a welding speed of 10 mm / s, a welding acceleration voltage of 120 kV, a welding focusing current of 1815 mA, and a welding beam current of 17.5 mA.

[0099] S5: After welding, maintain the vacuum chamber for 30 minutes, then release the gas and remove the furnace to complete the welding.

[0100] The deformation was measured after welding, and the deformation was 0.108 mm, with no cracks.

[0101] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling deformation during electron beam welding of 16Cr3NiWMoVNbE small-diameter thick-walled tubes, characterized in that, Includes the following steps: S1: Perform residual magnetism testing on the small-diameter thick-walled tube and grind and remove rust from the surface to be welded; the magnetic flux density of the small-diameter thick-walled tube should be ≤1×10⁻⁶. -4 T; The material of the small-diameter thick-walled tube is 16Cr3NiWMoVNbE; The diameter of the small-diameter thick-walled tube is 28mm-35mm, and the thickness is 4mm-7mm; S2: The small-diameter thick-walled pipe to be welded is positioned and fixed by argon arc welding using a stop-lock bottom type tubular butt welding method, and then aligned. S3: Evacuate the vacuum chamber until the vacuum pressure reaches 2×10⁻⁶. -2 Preheat welding is performed after Pa; the arc starts at 1 / 4 turn, and welding is performed for 1 turn; the arc ends at 1 / 2 turn, stopping at the 3 / 4 turn position; the welding speed is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 6mA-10mA; S4: After the preheating welding, a primary welding and a secondary welding are performed; The welding speed of the first welding is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 17mA-25mA; the welding speed of the second welding is 8mm / s-10mm / s, the welding acceleration voltage is 110kV-130kV, the welding focusing current is 1750mA-1850mA, and the welding beam current is 16mA-23mA. S5: After welding, keep it in the vacuum chamber for 20-30 minutes, then release the gas and remove it from the furnace. The welding deformation of small-diameter thick-walled pipes is less than 0.15mm.

2. The method for controlling deformation during electron beam welding of small-diameter thick-walled tubes according to claim 1, characterized in that, The small-diameter thick-walled tube has a tensile strength ≥1270MPa, a yield strength ≥1130MPa, and a Rockwell HRC hardness of 36-42.

3. The method for controlling deformation during electron beam welding of small-diameter thick-walled tubes according to claim 1, characterized in that, The welding speed for the first and second welding processes is 9 mm / s to 10 mm / s.

4. The method for controlling deformation during electron beam welding of small-diameter thick-walled tubes according to claim 1, characterized in that, The welding acceleration voltage for the primary and secondary welding is 120kV-130kV.

5. The application of the method for controlling deformation during electron beam welding of small-diameter thick-walled tubes according to any one of claims 1-4 in the welding of gears and gear shafts.

6. The application according to claim 5, characterized in that, The weld penetration depth of the parts shall not be less than δ1, and the maximum weld penetration depth shall not be greater than δ1+δ2; δ1 represents the effective contact surface thickness during welding; δ2 represents the thickness during lock bottom assembly.

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