A welding method for ultra-high temperature fixing block of gas turbine

Abstract

The present invention discloses a method for welding an ultra-high-temperature fixed block for a gas turbine in the field of aerospace welding technology, comprising the following steps: S1: machining at least two welding bumps on an upper welding workpiece; S3: stacking the upper welding workpiece and the lower welding workpiece and clamping them between the upper welding electrode and the lower welding electrode of a welding fixture; S4: energizing the upper welding electrode and the lower welding electrode and applying welding pressure; and S5: energizing the upper welding electrode and the lower welding electrode for tempering. The present invention achieves multi-bump welding between the upper welding workpiece and the lower welding workpiece, not only enhancing the connection strength between the upper welding workpiece and the lower welding workpiece, but also achieving the advantages of uniform current distribution, uniform weld nuggets, and good welding quality.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace welding, and in particular to a welding method for an ultra-high temperature fixing block of a gas turbine. Background Art

[0002] With the development of economy and the progress of society, the application of welding technology has continued to develop in depth, and the high efficiency and high strength of resistance welding have been more and more widely used in the gas turbine industry.

[0003] Current resistance welding processes include spot welding, seam welding, butt welding, and projection welding. Spot welding involves assembling the workpieces into an overlapping joint and pressing them between two cylindrical electrodes. Resistance heat is used to melt the base metal, forming a weld. Spot welding is primarily used for welding thin plates. Seam welding is similar to spot welding, except that a rotating disc-shaped roller electrode replaces the cylindrical electrode. The workpieces are assembled into an overlapping or butt joint and placed between two roller electrodes. The rollers pressurize the workpieces and rotate, applying power continuously or intermittently to form a continuous weld. Seam welding is primarily used for structures with relatively regular weld seams and sealing requirements, typically with plate thicknesses under 3 mm. Butt welding is a resistance welding method that welds the workpieces together along the entire contact surface. Projection welding is a variation of spot welding, in which a prefabricated raised spot is placed on the workpiece. During projection welding, one or more weld nuggets are formed at the joint.

[0004] Existing projection welding generally adopts the form of single-point welding, which has the disadvantage of low welding strength. When using multi-point projection welding, it is easy to cause poor welding effect due to uneven current concentration and uneven weld nuggets. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a method for welding an ultra-high temperature fixing block of a gas turbine to solve the technical problem of poor welding effect of existing multi-point projection welding.

[0006] The technical solution adopted by the present invention is: a gas turbine ultra-high temperature fixing block welding method, comprising:

[0007] S1: Processing at least two welding convex points on the upper welding workpiece;

[0008] S3: stacking the upper welding workpiece and the lower welding workpiece and clamping them between the upper welding electrode and the lower welding electrode of the welding fixture;

[0009] S4: energizing the upper welding electrode and the lower welding electrode and applying welding pressure;

[0010] S5: energizing the upper welding electrode and the lower welding electrode for tempering.

[0011] Preferably, the welding bumps in S1 are punched out in one time by a stamping die; the stamping die includes an upper pressing plate, a fixed plate, a lower die, a guide column and a punch needle, the lower die is provided with a placement groove for placing the upper welding workpiece, the fixed plate is provided with a stepped positioning hole, the punch needle with a larger upper portion and a smaller lower portion is arranged in the positioning hole, the upper pressing plate and the fixed plate are detachably connected and press the punch needle, and the guide column is arranged between the lower die and the fixed plate to guide the lifting and lowering of the fixed plate.

[0012] Preferably, the parameters of the welding bump in S1 are:

[0013] Bump height H B =1.2±0.15mm;

[0014] Bump diameter D B =2.85±0.10mm;

[0015] Punching diameter D p =2.85±0.10mm;

[0016] Workpiece thickness S B =2.0±0.10mm;

[0017] Punching depth t p =1.75±0.20mm;

[0018] Residual depth t R =S B -t p =0.25±0.10mm.

[0019] Preferably, the number of welding bumps in S1 is 5.

[0020] Preferably, the method further includes S2: first cleaning the upper welding workpiece and the lower welding workpiece with ethanol, then drying at a low temperature, and finally cleaning the welding surface with a laser.

[0021] Preferably, the temperature of the low-temperature drying is 150° C.-180° C.; the laser speed of the laser cleaning is 4000 mm / s, the laser frequency is 50 KHz, and the power is 250 W.

[0022] Preferably, the welding fixture in S3 includes an upper pressure head, an upper welding electrode, a lower welding electrode, a lower pressure head and an insulating positioning block, the insulating positioning block is arranged on the lower pressure head, the insulating positioning block is provided with an upper accommodating groove with the same width as the upper welding electrode and a lower accommodating groove with the same width as the lower welding electrode, the upper accommodating groove is arranged above the lower accommodating groove and is connected to the lower accommodating groove, the upper welding electrode is fixedly connected to the upper pressure head and rises and falls with the upper pressure head.

[0023] Preferably, the upper welding electrode and the lower welding electrode are both made of beryllium cobalt nickel copper with a conductivity of up to 60%.

[0024] Preferably, the welding time of the welding power-on in S4 is 15-25 ms, the welding pressure is 5.8-6.5 MPa, and the welding current is 52-55 KA.

[0025] Preferably, the tempering time of the tempering power supply in S5 is 180-200 ms, and the tempering current is 21-22.5 KA.

[0026] Beneficial effects of the present invention:

[0027] The present invention firstly forms a plurality of welding convex points of the same specification on the upper welding workpiece by a stamping die, then clamps the cleaned upper welding workpiece and the lower welding workpiece between the upper welding electrode and the lower welding electrode of the welding fixture, and then energizes the upper welding workpiece and the lower welding workpiece through the upper welding electrode and the lower welding electrode to weld the upper welding workpiece and the lower welding workpiece into one piece, and finally improves the performance of the upper welding workpiece and the lower welding workpiece after welding by tempering and energizing, thereby achieving better welding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the welding bump structure;

[0029] Figure 2 This is the main view of the welding fixture;

[0030] Figure 3 is a three-dimensional schematic diagram of the welding fixture;

[0031] Figure 4 Schematic diagram of the structure of the stamping die;

[0032] Figure 5 This is a welding diagram.

[0033] Description of reference numerals in the figures:

[0034] 10- Place the workpiece on the welder;

[0035] 20- lower welding workpiece;

[0036] 30-welding bumps;

[0037] 40 - welding fixture; 41 - upper welding electrode; 42 - lower welding electrode; 43 - upper pressure head; 44 - lower pressure head; 45 - insulating positioning block; 46 - upper receiving groove; 47 - lower receiving groove;

[0038] 50-stamping die; 51-upper pressing plate; 52-fixing plate; 53-lower die; 54-guide column; 55-punch needle; 56-locking nut. DETAILED DESCRIPTION

[0039] The following is a further detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention and are not intended to limit the present invention.

[0040] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0042] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0043] Examples, such as Figure 1-Figure 5 As shown, a method for welding an ultra-high temperature fixing block of a gas turbine, the method comprising:

[0044] S1: using a stamping die 50 to stamp out at least two welding bumps 30 of the same specification on the upper welding workpiece 10 at one time.

[0045] Among them, such as Figure 4As shown, the stamping die 50 includes an upper pressing plate 51, a fixed plate 52, a lower die 53, a guide column 54 and a punch 55; the lower die 53 is provided with a placement groove that matches the shape of the upper welding workpiece 10, and the placement groove is used to place the upper welding workpiece 10; a plurality of stepped positioning holes are provided on the fixed plate 52, and the fixed plate 52 is made of Cr12Mo1V1 material, and its hardness reaches HRC58 degrees or more after heat treatment. In order to ensure the hole position accuracy and shape and position accuracy of the positioning holes, an ultra-fine slow wire processing process after heat treatment is adopted, so that the hole position accuracy and shape and position accuracy of the positioning holes are both within 0.001mm. The punch needle 55 is in the shape of a step that is larger at the top and smaller at the bottom, and is set in the positioning hole. The punch needle 55 is made of W18Cr4v material, and its hardness after heat treatment reaches HRC68 degrees or above. In order to ensure that the punch needle 55 does not produce high-temperature annealing during processing (which will reduce the heat treatment performance of the punch needle 55), a circulating water-cooled grinding process is required; in order to increase the wear resistance of the surface of the punch needle 55, the surface of the punch needle 55 is sprayed with precious metals (the surface of the punch needle 55 is titanium-plated) so that the bumps of the finished product are consistent and accurate, providing a strong guarantee for the stability of subsequent welding performance and heat treatment performance. The upper pressure plate 51 and the fixed plate 52 are detachably connected as a whole through the locking nut 56. The upper pressure plate 51 presses the punch needle 55 to limit the upward, downward, left and right movement of the punch needle 55. The guide column 54 is set on the lower mold 53, and the fixed plate 52 is provided with a guide hole that matches the guide column 54. On a hydraulic machine or a punching machine, the fixed plate 52 and the lower mold 53 are moved up and down along the guide column 54 to punch out the welding bump 30 on the upper welding workpiece 10.

[0046] Preferably, Figure 1 As shown, the number of welding bumps 30 on the upper welding workpiece 10 is 5; and the parameters of the welding bumps 30 are:

[0047] Bump height H B =1.2±0.15mm;

[0048] Bump diameter D B =2.85±0.10mm;

[0049] Punching diameter D p =2.85±0.10mm;

[0050] Workpiece thickness S B =2.0±0.10mm;

[0051] Punching depth t p =1.75±0.20mm;

[0052] Residual depth t R =S B -t p=0.25±0.10mm; the welding protrusion 30 that exceeds the above parameter range is prone to uneven weld nugget size.

[0053] S2: First, clean the upper welding workpiece 10 and the lower welding workpiece 20 with ethanol, then dry the ethanol on the upper welding workpiece 10 and the lower welding workpiece 20 at a low temperature of 150°C-180°C, and finally clean the welding surface with a laser; wherein the laser cleaning laser speed is 4000 mm / s, the laser frequency is 50 kHz, and the power is 250 W.

[0054] S3: If Figure 5 As shown, the upper welding workpiece 10 and the lower welding workpiece 20 are stacked and clamped between the upper welding electrode 41 and the lower welding electrode 42 of the welding fixture 40.

[0055] Among them, such as Figure 2 、 Figure 3 As shown, the welding fixture 40 includes an upper pressing head 43, an upper welding electrode 41, a lower welding electrode 42, a lower pressing head 44, and an insulating positioning block 45. The insulating positioning block 45 is movably mounted on the lower pressing head 44. The insulating positioning block 45 is provided with an upper receiving groove 46 and a lower receiving groove 47. The upper receiving groove 46 is disposed above and communicates with the lower receiving groove 47. The width of the upper receiving groove 46 is equal to that of the upper welding workpiece 10 and the upper welding electrode 41, and the width of the lower receiving groove 47 is equal to that of the lower welding workpiece 20 and the lower welding electrode 42. This allows the current to be more concentratedly distributed on each welding bump 30, resulting in a uniform weld nugget and better welding quality. The upper welding electrode 41 is fixedly connected to the upper pressing head 43 and rises and falls with the upper pressing head 43 to apply welding pressure to the upper welding workpiece 10 and the lower welding workpiece 20.

[0056] Preferably, the upper welding electrode 41 and the lower welding electrode 42 are both made of beryllium cobalt nickel copper with a conductivity as high as 60%.

[0057] S4: The upper welding electrode 41 and the lower welding electrode 42 are energized and welding pressure is applied to instantly release a strong current in the contact area of ​​the welding bump 30. The welding current passes through the welding bump 30, and as the welding power is applied, the welding bump 30 begins to melt to form a molten core; under the action of the welding pressure, a real contact point appears between the contact surfaces of the upper welding workpiece 10 and the lower welding workpiece 20, the molten core continues to grow, and the atoms at the contact position of the upper welding workpiece 10 and the lower welding workpiece 20 are continuously activated to form a molten core.

[0058] Among them, the welding time of welding power is 15-25ms, the welding pressure is 5.8-6.5Mpa, and the welding current is 52-55KA.

[0059] S5: Tempering and electrifying the upper welding electrode 41 and the lower welding electrode 42 to reduce the hardness of the welded workpiece and increase the toughness.

[0060] Among them, the tempering time of tempering power is 180-200ms, and the tempering current is 21-22.5KA.

[0061] Compared with the prior art, this application has at least the following beneficial technical effects:

[0062] 1. This application utilizes a dedicated stamping die 50 to simultaneously stamp multiple weld bumps 30 on a welded workpiece 10. Furthermore, the structure of the stamping die 50 is flexible and adaptable in terms of material selection, and the heat treatment of the material is relatively easy and flexible, requiring no special operator requirements. The stamping die 50 is simple in structure and easy to maintain. The punching pin 55 is detachably mounted on the fixed plate 52. When the punching pin 55 breaks or wears out, it can be quickly and efficiently replaced without the need for specialized personnel, ensuring production efficiency, reducing manufacturing costs, and shortening the production cycle.

[0063] 2. The present application uses a welding fixture 40 to weld the upper welding workpiece 10 and the lower welding workpiece 20, which can make the current more concentratedly distributed on each welding convex point 30, making the weld nugget uniform and achieving better welding quality.

[0064] 3. The present invention realizes multi-convex point welding between the upper welding workpiece 10 and the lower welding workpiece 20, which not only enhances the connection strength between the upper welding workpiece 10 and the lower welding workpiece 20, but also has the advantages of uniform current distribution, uniform weld nugget and good welding quality.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for welding an ultra-high temperature fixing block of a gas turbine, characterized in that: include: S1: processing at least two welding protrusions (30) on the upper welding workpiece (10); S3: stacking the upper welding workpiece (10) and the lower welding workpiece (20) and clamping them between the upper welding electrode (41) and the lower welding electrode (42) of the welding fixture (40); S4: electrifying the upper welding electrode (41) and the lower welding electrode (42) and applying welding pressure; S5: conducting tempering and electrifying on the upper welding electrode (41) and the lower welding electrode (42); Among them, the parameters of the welding bump (30) are: Bump height H B =1.2±0.15mm; Bump diameter D B =2.85±0.10mm; Punching diameter D p =2.85±0.10mm; Workpiece thickness S B =2.0±0.10mm; Punching depth t p =1.75±0.20mm; Residual depth t R =S B -t p =0.25±0.10mm.

2. A gas turbine ultra-high temperature fixing block welding method according to claim 1, characterized in that: The welding convex point (30) in the S1 is punched out by a punching die (50) at one time; the punching die (50) comprises an upper pressing plate (51), a fixing plate (52), a lower die (53), a guide column (54) and a punching needle (55); the lower die (53) is provided with a placement groove for placing the upper welding workpiece (10); the fixing plate (52) is provided with a stepped positioning hole; the punching needle (55) which is larger at the top and smaller at the bottom is arranged in the positioning hole; the upper pressing plate (51) and the fixing plate (52) are detachably connected and press the punching needle (55); the guide column (54) is arranged between the lower die (53) and the fixing plate (52) and is used to guide the lifting and lowering of the fixing plate (52).

3. A gas turbine ultra-high temperature fixing block welding method according to claim 1, characterized in that: The number of the welding bumps (30) in S1 is 5.

4. A gas turbine ultra-high temperature fixing block welding method according to claim 1, characterized in that: The method further comprises S2: first cleaning the upper welding workpiece (10) and the lower welding workpiece (20) with ethanol, then drying at a low temperature, and finally cleaning the welding surface with a laser.

5. A gas turbine ultra-high temperature fixing block welding method according to claim 4, characterized in that: The temperature of the low-temperature drying is 150° C.-180° C.; the laser speed of the laser cleaning is 4000 mm / s, the laser frequency is 50 KHz, and the power is 250 W.

6. A gas turbine ultra-high temperature fixing block welding method according to claim 1, characterized in that: The welding fixture (40) in S3 includes an upper pressure head (43), an upper welding electrode (41), a lower welding electrode (42), a lower pressure head (44) and an insulating positioning block (45). The insulating positioning block (45) is arranged on the lower pressure head (44). The insulating positioning block (45) is provided with an upper accommodating groove (46) with the same width as the upper welding electrode (41) and a lower accommodating groove (47) with the same width as the lower welding electrode (42). The upper accommodating groove (46) is arranged above the lower accommodating groove (47) and is connected to the lower accommodating groove (47). The upper welding electrode (41) is fixedly connected to the upper pressure head (43) and rises and falls with the upper pressure head (43).

7. A gas turbine ultra-high temperature fixing block welding method according to claim 6, characterized in that: The upper welding electrode (41) and the lower welding electrode (42) are both made of beryllium cobalt nickel copper with a conductivity of up to 60%.

8. The method for welding an ultra-high temperature fixing block of a gas turbine according to claim 1, characterized in that: The welding time of the welding power-on in S4 is 15-25ms, the welding pressure is 5.8-6.5Mpa, and the welding current is 52-55KA.

9. The method for welding an ultra-high temperature fixing block of a gas turbine according to claim 1, characterized in that: The tempering time of the tempering power supply in S5 is 180-200ms, and the tempering current is 21-22.5KA.

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