A laser welding method for GH3044 high-temperature alloy

Abstract

A GH3044 high-temperature alloy laser welding method belongs to the field of laser welding technology and is suitable for welding thin-walled overlap structures. It can further improve the welding strength of the weld spot and achieve single-sided welding and double-sided forming. The method includes the following steps: sequentially pickling, alcohol cleaning, and drying the surface of the high-temperature alloy to be welded; fixing the high-temperature alloy to be welded on a laser welding turntable to control the welding gap; adjusting the height of the shielding gas and the inclination angle with the weld interface; programming to confirm the welding path, welding starting point, and preheating and slow cooling time; isolating the front and back surfaces of the workpiece to be welded from the air through inert gas during welding; and using a pulsed welding laser to weld the joint to be welded. The present invention adopts a laser pulse slow cooling welding method to overcome defects such as cracks, pores, and surface depressions in high-temperature alloy laser welded joints, and can effectively improve the reliability of high-temperature alloy laser welded joints.

Description

Technical Field

[0001] The invention belongs to the technical field of laser welding, and in particular relates to a laser welding technology applied to GH3044 thin-wall overlap structures. Background Art

[0002] Nickel-based superalloys, with their advantages of high thermal strength, stable structure, and good hot and cold forming properties, are widely used in key welded structural components such as engine combustion chambers and rocket blades. Laser welding of superalloys is prone to forming defects such as dense porosity, arc pits, and cracks due to their high sensitivity to welding heat input. These defects significantly reduce the mechanical properties of the weld and severely impact product quality.

[0003] As the welding structure of high-temperature alloy products becomes increasingly complex and the number of welds increases, the requirements for the internal and external quality and appearance of the welds become higher and higher. Summary of the Invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology and provide a GH3044 high-temperature alloy laser welding method to solve the problems of joint porosity, cracks and surface depressions during GH3044 high-temperature alloy welding in the existing technology, obtain a weld joint with good internal quality, and realize double-sided forming of the weld.

[0005] The technical solution of the present invention is:

[0006] A laser welding method for GH3044 high-temperature alloy, comprising:

[0007] Overlap and fix two high-temperature alloy test plates to be welded, and control the overlap gap;

[0008] The overlapped test plates are welded according to the welding path. The welding process includes arc starting section, welding section, first arc ending section, insulation, and second arc ending section. The power of the arc starting section gradually increases until it reaches the power of the welding section. The power of the welding section is stable. The power of the first arc ending section gradually decreases from the power of the welding section to the power of the insulation section. The power of the insulation section is stable, and the power of the second arc ending section gradually decreases.

[0009] In one possible implementation of the welding method, the test plate material is nickel-based solid solution strengthened high-temperature alloy GH3044; the thickness of the welding test plate is 0.6-1.5 mm.

[0010] In one implementation of the welding method, the overlap gap is within 0.2 mm.

[0011] In one possible implementation of the welding method, before welding, the height of the welding joint and the inclination angle of the weld position surface formed by the shielding gas and the overlapped high-temperature alloy test plates to be welded are adjusted; the laser welding head is perpendicular to the weld joint surface, the overlap surface between the two high-temperature alloy test plates to be welded is the weld joint surface, the height of the laser welding head is adjusted until the defocus amount is 0 mm, the height of the shielding gas nozzle and the inclination angle of the shielding gas nozzle and the weld joint surface are adjusted, the height of the shielding gas nozzle is 3-10 mm from the weld surface, and the inclination angle of the shielding gas nozzle to the vertical direction is 0°-60°.

[0012] In one implementation of the welding method, the welding path is a circle with a diameter of d=Φ4-Φ8.

[0013] In one possible implementation of the welding method, during the entire welding process, the welding speed v = 15 mm / s; the laser power of the welding section = (800-900) × the thickness of the high-temperature alloy test plate to be welded, wherein the thickness of the high-temperature alloy test plate to be welded is the sum of the thicknesses of the two overlapping test plates, and the thicknesses of the two overlapping test plates can be arbitrarily combined within the test plate thickness range of 0.6-1.5 mm.

[0014] In one implementation of the welding method, the arc starting period is:

[0015] The welding time is:

[0016] The time of the first closing arc segment is:

[0017] The time of the insulation section is:

[0018] The time of the second closing arc segment is:

[0019] In one implementation of the welding method, the power of the heat preservation section is: P 保温 =(30-40)%×P, where P is the laser power of the welding section.

[0020] In one possible implementation of the welding method, during the welding process, the front shielding gas at the weld position of the high-temperature alloy test plate to be welded is He gas, and the back shielding gas is Ar gas, the gas flow rate is 15-20 L / min, and the pre-welding and post-welding blowing times must not be less than 3s.

[0021] In one possible implementation of the welding method, during the welding process, a pulse welding laser is used to weld the joint to be welded; the pulse welding laser frequency is 800-1200 Hz, and the pulse width is 5-7 ms.

[0022] In summary, this application has at least the following beneficial technical effects:

[0023] The present invention implements a GH3044 high-temperature alloy laser welding method, which adopts preheating (preheating in the arc starting section) and segmented slow cooling (i.e., the first arc closing section, the heat preservation section, and the second arc closing section of the present application) to avoid the problem of surface depression at the arc closing point and achieve good forming of the lap weld; on the other hand, laser pulse welding is used to reduce welding heat input and reduce the tendency of high-temperature alloys to crack; at the same time, based on the difference in the front and back side environments during welding, different types of inert gas protection are used on the front and back sides during the welding process to achieve good protection of the front and back sides of the weld and improve the welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flowchart of the steps of a laser welding method for GH3044 high-temperature alloy according to the present invention;

[0025] Figure 2 This is a graph showing the laser power changing with time in the present invention. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions and advantages of the present invention more clear, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0027] Example 1

[0028] The test plate material is GH3044, thickness is 0.8+0.8mm, and the joint form is lap welding. The specific steps are as follows:

[0029] (1) Pickle the surface of the high-temperature alloy to be welded to remove the surface oxides of the high-temperature alloy to be welded, and use alcohol to clean the surface oil of the workpiece. After completion, dry it.

[0030] (2) The GH3044 alloy to be overlapped is fixed on the welding turntable using a special tool, and the overlap gap is 0.1 mm.

[0031] (3) Adjust the height of the welding joint and the inclination angle of the shielding gas and the weld surface; the laser welding head is perpendicular to the weld joint surface, the laser welding head height defocus is 0mm, the shielding gas nozzle height is 7mm from the weld surface, and the shielding gas nozzle inclination angle is 50°.

[0032] (4) The welding path of the entire welding process is a circle with a diameter of d = Φ7, the welding speed v = 15 mm / s, and the welding process is divided into five sections: arc starting section - welding section - first arc closing section - insulation section - second arc closing section.

[0033] Steady-state welding time of welding section:

[0034] Time of arc starting section, first arc closing section (arc closing 1), second arc closing section (arc closing 2), and holding section:

[0035]

[0036]

[0037]

[0038]

[0039] Total welding process time: T 总 =T 起弧 +T P +T 收弧1 +T 保温 +T 收弧2 =3120ms

[0040] The power of the arc starting section: gradually increases from 0 to the power of the welding section;

[0041] The laser power in the welding section is P = 1400W and is stable;

[0042] The power of the first arc closing section: the laser power gradually decreases from the welding section to the heat preservation section;

[0043] Power of insulation section: P 保温 =35%×P=500W

[0044] The power of the second arc closing section: the power of the insulation section gradually decreases to 0.

[0045] (5) During welding, the front shielding gas of the product is He gas, the back shielding gas is Ar gas, the gas flow rate is 15L / min, and the pre-blow time before welding and the post-blow time after welding are 5s.

[0046] (6) Pulse welding laser frequency is 1000 Hz and pulse width is 6 ms.

[0047] When welding is performed according to the method of this embodiment, the surface of the obtained weld spot is smooth and free of spatter, the weld is well formed, the front side is silvery white or slightly yellow, and the back side is silvery white. The weld is formed on both sides, and there are no defects such as cracks, inclusions, and unfused welds inside the weld.

[0048] Example 2

[0049] The test plate material is GH3044, thickness is 1.2+1.2mm, and the joint form is lap welding. The specific steps are as follows:

[0050] (1) Pickle the surface of the high-temperature alloy to be welded to remove the surface oxides of the high-temperature alloy to be welded, and use alcohol to clean the surface oil of the workpiece. After completion, dry it.

[0051] (2) The GH3044 alloy to be overlapped is fixed on the welding turntable using a special tool, and the overlap gap is 0.15 mm.

[0052] (3) Adjust the height of the welding joint and the inclination angle of the shielding gas and the weld surface; the laser welding head is perpendicular to the weld joint surface, the laser welding head height defocus is 0mm, the shielding gas nozzle height is 7mm from the weld surface, and the shielding gas nozzle inclination angle is 50°.

[0053] (4) The welding path is a circle with a diameter of d = Φ7, the welding speed v = 15 mm / s, and the welding process is divided into five sections: arc starting section - welding section - first arc closing section - insulation section - second arc closing section.

[0054] Steady-state welding time of welding section:

[0055] Time of arc starting section, first arc closing section (arc closing 1), second arc closing section (arc closing 2), and holding section:

[0056]

[0057]

[0058]

[0059]

[0060] Total welding process time: T 总 =T 起弧 +T P +T 收弧1 +T 保温 +T 收弧2 =3120ms

[0061] The power of the arc starting section: gradually increases from 0 to the power of the welding section;

[0062] The laser power in the welding section is P = 1800W and is stable;

[0063] The power of the first arc closing section: the laser power gradually decreases from the welding section to the heat preservation section;

[0064] Power of insulation section: P 保温 =35%×P=630W

[0065] The power of the second arc closing section: the power of the insulation section gradually decreases to 0.

[0066] (5) During welding, the front shielding gas of the product is He gas, the back shielding gas is Ar gas, the gas flow rate is 15L / min, and the pre-blow time before welding and the post-blow time after welding are 5s.

[0067] (6) Pulse welding laser frequency is 1000 Hz and pulse width is 6 ms.

[0068] When welding is performed according to the method of this embodiment, the surface of the obtained weld spot is smooth and free of spatter, the weld is well formed, the front side is silvery white or slightly yellow, and the back side is silvery white. The weld is formed on both sides, and there are no defects such as cracks, inclusions, and unfused welds inside the weld.

[0069] Example 3

[0070] The test plate material is GH3044, thickness 1+1mm, and the joint form is lap welding. The specific steps are as follows:

[0071] (1) Pickle the surface of the high-temperature alloy to be welded to remove the surface oxides of the high-temperature alloy to be welded, and use alcohol to clean the surface oil of the workpiece. After completion, dry it.

[0072] (2) The GH3044 alloy to be overlapped is fixed on the welding turntable using a special tool, and the overlap gap is 0.1 mm.

[0073] (3) Adjust the height of the welding joint and the inclination angle of the shielding gas and the weld surface; the laser welding head is perpendicular to the weld joint surface, the laser welding head height defocus is 0mm, the shielding gas nozzle height is 7mm from the weld surface, and the shielding gas nozzle inclination angle is 45°.

[0074] (4) The welding path is a circle with a diameter of d = Φ5, the welding speed v = 15 mm / s, and the welding process is divided into five sections: arc starting section - welding section - first arc closing section - insulation section - second arc closing section.

[0075] Steady-state welding time of welding section:

[0076] Time of arc starting section, first arc closing section (arc closing 1), second arc closing section (arc closing 2), and holding section:

[0077]

[0078]

[0079]

[0080]

[0081] Total welding process time: T 总 =T 起弧 +T 100％ +T收弧1 +T 保温 +T 收弧2 =1860ms

[0082] The power of the arc starting section: gradually increases from 0 to the power of the welding section;

[0083] The laser power in the welding section is P = 1600W and is stable;

[0084] The power of the first arc closing section: the laser power gradually decreases from the welding section to the heat preservation section;

[0085] Power of insulation section: P 保温 =35%×P=560W

[0086] The power of the second arc closing section: the power of the insulation section gradually decreases to 0.

[0087] (5) During welding, the front shielding gas of the product is He gas, the back shielding gas is Ar gas, the gas flow rate is 15L / min, and the pre-blow time before welding and the post-blow time after welding are 5s.

[0088] (6) Pulse welding laser frequency is 1000 Hz and pulse width is 6 ms.

[0089] When welding is performed according to the method of this embodiment, the surface of the obtained weld spot is smooth and free of spatter, the weld is well formed, the front side is silvery white or slightly yellow, and the back side is silvery white. The weld is formed on both sides, and there are no defects such as cracks, inclusions, and unfused welds inside the weld.

[0090] Examples 4-6

[0091] The test plate material is GH3044, thickness 1+1mm, and the joint form is lap welding. The specific steps are as follows:

[0092] (1) Pickle the surface of the high-temperature alloy to be welded to remove the surface oxides of the high-temperature alloy to be welded, and use alcohol to clean the surface oil of the workpiece. After completion, dry it.

[0093] (2) The GH3044 alloy to be overlapped is fixed on the welding turntable using a special tool, and the overlap gap is 0.1 mm.

[0094] (3) Adjust the height of the welding joint and the inclination angle of the shielding gas and the weld surface; the laser welding head is perpendicular to the weld joint surface, the laser welding head height defocus is 0mm, the shielding gas nozzle height is 7mm from the weld surface, and the shielding gas nozzle inclination angle is 45°.

[0095] (4) The welding path is a circle with a diameter of d = Φ5, the welding speed v = 15 mm / s, and the welding process is divided into five sections: arc starting section - welding section - first arc closing section - insulation section - second arc closing section.

[0096] Power of insulation section: P 保温 =35%×P=560W

[0097] (5) During welding, the front shielding gas of the product is He gas, the back shielding gas is Ar gas, the gas flow rate is 15L / min, and the pre-blow time before welding and the post-blow time after welding are 5s.

[0098] (6) Pulse welding laser frequency is 1000 Hz and pulse width is 6 ms.

[0099] The only difference between Examples 4-6 is that the time of arc starting section-welding section-first arc closing section-heat holding section-second arc closing section is different.

[0100] In Example 4, the steady-state welding time of the welding section is:

[0101] Time of arc starting section, first arc closing section (arc closing 1), second arc closing section (arc closing 2), and holding section:

[0102]

[0103]

[0104]

[0105]

[0106] Total welding process time: T 总 =T 起弧 +T 100％ +T 收弧1 +T 保温 +T 收弧2 =2042ms.

[0107] In Example 5, the steady-state welding time of the welding section is:

[0108] Time of arc starting section, first arc closing section (arc closing 1), second arc closing section (arc closing 2), and holding section:

[0109]

[0110]

[0111]

[0112]

[0113] Total welding process time: T 总 =T 起弧 +T 100％ +T收弧1 +T 保温 +T 收弧2 =2007ms.

[0114] In Example 6, the steady-state welding time of the welding section is:

[0115] Time of arc starting section, first arc closing section (arc closing 1), second arc closing section (arc closing 2), and holding section:

[0116]

[0117]

[0118]

[0119]

[0120] Total welding process time: T 总 =T 起弧 +T 100％ +T 收弧1 +T 保温 +T 收弧2 =1810ms.

[0121] According to the method of this embodiment, welding was performed. Examples 4-6 all obtained welds with smooth surfaces and no spatter. The welds were well formed, with the front side being silvery white or slightly yellow and the back side being silvery white. The welds were all formed on both sides, and there were no defects such as cracks, inclusions, and unfused welds inside the welds.

[0122] Examples 7-8

[0123] The only difference between Example 7-8 and Example 5 is that the laser power of the welding section is different.

[0124] In Example 7, the laser power of the welding section is P = 1660W, which is stable; the power of the heat preservation section is P 保温 =35%×P=580W.

[0125] In Example 8, the laser power of the welding section is P = 1750W, which is stable; the power of the heat preservation section is P 保温 =35%×P=610W.

[0126] Examples 9-10

[0127] The only difference between Example 9-10 and Example 5 is that the power of the heat preservation section is different.

[0128] In Example 9, the power of the heat preservation section: P 保温 =30%×P=480W.

[0129] In Example 10, the power of the heat preservation section: P 保温 =40%×P=640W.

[0130] Examples 11-12

[0131] The only difference from Example 5 is that in Example 11, the height of the laser welding head is adjusted until the defocus amount is -2. In Example 12, the height of the laser welding head is adjusted until the defocus amount is +2.

[0132] The weld seams of the high-temperature alloy test plates obtained in the above examples were tested, and the test results are shown in Table 1.

[0133] Table 1 Test results

[0134]

[0135]

[0136] According to Table 1, in Examples 4-6, the time for each part of the arc starting section-welding section-first arc closing section-insulation section-second arc closing section is different, and welds with smooth surfaces and no spatter can be obtained. The welds are well formed, with the front side being silvery white or slightly yellowish and the back side being silvery white. The welds are formed on both sides, and there are no defects such as cracks, inclusions, and unfused welds inside the welds.

[0137] In Examples 5, 7-8, the laser power of the welding section is different, and all of them can obtain a smooth surface without spatter, a well-formed weld, a silvery white or slightly yellowish weld on the front side and a silvery white weld on the back side. The welds are double-sided formed, and there are no cracks, inclusions, unfused defects, etc. inside the welds.

[0138] In Examples 5, 9-10, the power of the insulation section is different, the surface of the weld is smooth and spatter-free, the weld is well formed, the front is silvery white or slightly yellow, and the back is silvery white. The welds are double-sided formed, and there are no cracks, inclusions, unfused defects, etc. inside the welds.

[0139] In Examples 5, 11-12, the defocus amounts are different. When the defocus amount is -2 or +2, the surface of the weld is smooth and spatter-free, and the weld is well-formed, but there are porosity defects inside the weld. When the defocus amount is 0, the surface of the weld is smooth and spatter-free, and the weld is well-formed. The front side is silvery white or slightly yellow, and the back side is silvery white. The welds are double-sided formed, and there are no cracks, inclusions, unfused defects, etc. inside the weld.

[0140] Although the present invention is disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A laser welding method for GH3044 high temperature alloy, characterized by: include Overlap and fix two high-temperature alloy test plates to be welded, and control the overlap gap; The overlapped test plates were welded according to the welding path. The welding process included arc starting section, welding section, first arc ending section, heat preservation section, and second arc ending section. The power of the arc starting section was gradually increased until it reached the power of the welding section. The power of the welding section was stable. The power of the first arc ending section was gradually reduced from the power of the welding section to the power of the heat preservation section. The power of the heat preservation section was stable. The power of the second arc ending section was gradually reduced. The arc starting time is: ; The welding time is: ; The time of the first closing arc segment is: ; The time of the insulation section is: ; The time of the second closing arc segment is: .

2. The laser welding method for GH3044 high temperature alloy according to claim 1, characterized in that: The test plate material is nickel-based solid solution strengthened high temperature alloy GH3044; the thickness of the welding test plate is 0.6-1.5 mm.

3. The laser welding method for GH3044 high temperature alloy according to claim 1, characterized in that: The overlap gap is within 0.2 mm.

4. The laser welding method for GH3044 high temperature alloy according to claim 1, characterized in that: Before welding, adjust the height of the welding joint and the inclination angle of the welding seam formed by the shielding gas and the overlapped high-temperature alloy test plates to be welded; The laser welding head is perpendicular to the weld joint surface. The overlapping surface between the two high-temperature alloy test plates to be welded is the weld joint surface. Adjust the height of the laser welding head until the defocus amount is 0mm. Adjust the height of the shielding gas nozzle and the inclination angle between the shielding gas nozzle and the weld joint surface. The height of the shielding gas nozzle is 3-10mm from the weld surface, and the inclination angle of the shielding gas nozzle to the vertical direction is 0°-60°.

5. The laser welding method for GH3044 high temperature alloy according to claim 1, characterized in that: The welding path is a circle with a diameter of d=Φ4-Φ8.

6. The laser welding method for GH3044 high temperature alloy according to claim 1, characterized in that: During the entire welding process, the welding speed v=15mm / s; The laser power of the welding section = (800-900) × the thickness of the high-temperature alloy test plate to be welded, where the thickness of the high-temperature alloy test plate to be welded is the sum of the thicknesses of the two overlapping test plates, and the thicknesses of the two overlapping test plates can be arbitrarily combined within the test plate thickness range of 0.6-1.5 mm.

7. A laser welding method for GH3044 high temperature alloy according to any one of claims 1 to 6, characterized in that: The power of the insulation section is: , where P is the laser power in the welding section.

8. The laser welding method for GH3044 high temperature alloy according to claim 1, characterized in that: During the welding process, the front shielding gas at the weld position of the high-temperature alloy test plate to be welded is He gas, and the back shielding gas is Ar gas, with a gas flow rate of 15-20 L / min. The pre-welding and post-welding blowing times must not be less than 3s.

9. The laser welding method for GH3044 high temperature alloy according to claim 1, characterized in that: During the welding process, a pulse welding laser is used to weld the joint to be welded; The pulse welding laser frequency is 800-1200Hz and the pulse width is 5-7ms.

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