A kind of boom arm welding test board anti-welding deformation rigidity tool and method

Abstract

The present application relates to excavator structure welding joint fatigue life test technical field, specifically to a kind of rigid tooling and method for preventing welding deformation of boom arm bucket rod welding test plate, the present application supports and raises the height of pressing plate by pad, then makes the pressing plate press down by fastening bolt through through hole and fastening thread hole of sticking plate and bottom plate fastening connection, the outer edge of left test plate and right test plate is pressed to the upper surface of sticking plate by pressing plate, the thickness of sticking plate is greater than the thickness of the portion below left test plate and right test plate of support plate and less than the thickness of bottom plate, so as to avoid the surface of support plate to press the surface of bottom plate;The lower surface of left test plate and right test plate is connected with support plate by tack welding;Rigid tooling fixes the outer edge of welding test plate, and relative displacement near weld is limited by tack welding, and the purpose of rigidly constraining test plate welding deformation can be achieved by the cooperation of the two.

Description

Technical Field

[0001] This invention relates to the field of fatigue life testing technology for welded joints of excavator structural components, specifically to a rigid tooling and method for preventing welding deformation of a boom and stick welding test plate. Background Technology

[0002] Butt welds with backing plates and single-sided bevel fillet welds are the two most common types of welded joints on excavator working devices. These joints are repeatedly subjected to loads during continuous excavator operation until structural cracking occurs, representing typical fatigue fracture. Researchers need to address how to accurately assess the structural service life to prevent premature cracking that could result in warranty losses, while also minimizing material costs. Using fatigue testing to measure the number of cycles (i.e., service life) of these two types of welded joints is an effective way to solve this problem.

[0003] In tensile fatigue life testing, high straightness of the test specimen is required for easy clamping and to prevent additional loads, thus ensuring accurate test results. For fatigue life testing of welded joints, post-weld deformation of the specimen leads to non-compliance with flatness and coaxiality standards, making it difficult to suppress additional loads, which is a problem that needs to be solved.

[0004] For welding deformation control of fatigue specimens with joints, three methods are usually adopted: pre-deformation before welding, rigid fixation during welding, and post-weld straightening.

[0005] Pre-deformation before welding involves predicting the amount of welding deformation in advance and using the opposite deformation to offset the post-weld deformation. However, pre-deformation before welding is only effective for angular deformation and is ineffective for unstable deformation and wave deformation. The length of the welding test plate is relatively long (more than 1000mm), which makes it prone to instability and wave deformation. On the other hand, for butt welds with backing plates and cross joint bevel fillet welds, pre-deformation will cause deviation in the weld root gap, which does not meet the actual requirements.

[0006] Post-weld straightening uses mechanical pressure or flame heating to force the weld deformation to a flat state. However, because fatigue welded test plates are thin and long, weld shrinkage easily leads to instability and deformation, resulting in poor consistency in deformation trends. Among existing straightening methods, mechanical straightening cannot be clamped due to unsuitable spacing and dimensions, while flame straightening only heats the protruding parts, often turning large deformations into wavy shapes, which cannot meet practical requirements.

[0007] Therefore, for butt welds with backing plates and single-sided bevel fillet welds, the technical solution of rigid fixation during welding to prevent welding deformation is mostly adopted. However, the overall thickness of butt welds with backing plates and cross joint bevel fillet welds in the joint area is thicker than that of the plates on both sides, resulting in a large gap between the plates on both sides and the platform. The plates cannot be directly fixed on the welding platform, resulting in poor rigid constraint and poor effect in preventing welding deformation. Summary of the Invention

[0008] The purpose of this invention is to provide a rigid fixture and method for preventing welding deformation of boom stick welding test plates. The method involves supporting and raising the height of the pressure plate using pads, then fastening the plate downwards with bolts passing through through holes and threaded holes in the base plate and mounting plate. The pressure plate presses the outer edges of the left and right test plates against the upper surface of the mounting plate. The thickness of the mounting plate is greater than the thickness of the support plate below the left and right test plates but less than the thickness of the base plate, thus preventing the lower surface of the support plate from pressing against the surface of the base plate. The lower surfaces of the left and right test plates are connected to the support plate via tack welds. The rigid fixture fixes the outer edge of the welding test plate, and the tack welds limit relative displacement near the weld. The two work together to achieve the purpose of rigidly constraining welding deformation of the test plate.

[0009] In a first aspect, the present invention provides a rigid tooling fixture for preventing welding deformation of a boom and stick welding test plate, used to fix the welding test plate of the boom and stick structure. The welding test plate includes a left test plate and a right test plate arranged opposite to each other, with a bevel formed between the left and right test plates for welding. A support plate is provided at the bevel and connected to the lower surfaces of the left and right test plates by tack welding. It includes: The base plate is thicker than the left and right test plates. The mounting plate is symmetrically welded to both sides of the upper surface of the base plate in the width direction. The thickness of the mounting plate is greater than the thickness of the support plate below the left and right test plates and less than the thickness of the base plate. Fastening threaded holes are used to be coaxially opened on the mounting plate and the base plate after the mounting plate welding is completed; The pad block is fixed to the base plate and located outside the plate by means of a pre-machined limiting blind hole and a limiting rod. A bearing groove is formed on the upper surface of the pad block. The distance from the bottom wall of the bearing groove to the lower surface of the pad block is equal to the sum of the thickness of the plate and the thickness of the left and right test plates. The pressure plate includes an mounting end and a pressing end, with a through hole between the mounting end and the pressing end. The mounting end is used to support the bearing groove of the pad, and the pressing end is used to press the left or right test plate against the upper surface of the plate when the fastening bolt passes through the through hole and is fastened to the fastening threaded hole. The thickness of the pressure plate is greater than the thickness of the base plate and less than the sum of the thicknesses of the base plate and the plate.

[0010] Optionally, it also includes: The base plate has multiple stiffening plates welded to its lower surface, extending along the width of the base plate; the thickness of the stiffening plate is greater than the thickness of the support plate below the left and right test plates and less than the thickness of the base plate; the stiffening plate includes a stiffening plate weld area for connection with the base plate, and the stiffening plate has chamfered ends on both sides in the extending direction of the stiffening plate. The support legs are used to be welded to the corners of the lower surface of the base plate after the stiffening plates are welded; the mounting plate is welded after the support legs are welded; the flatness of the upper surface of the mounting plate is processed with the lower surface of the base plate as a reference; the flatness of the lower surface of the support legs is processed with the upper surface of the mounting plate as a reference.

[0011] Optionally, the length of the fastening bolt is greater than or equal to the sum of the thickness of the base plate and the distance from the bottom wall of the bearing groove to the lower surface of the pad, and less than or equal to the sum of the thickness of the base plate, the distance from the bottom wall of the bearing groove to the lower surface of the pad, and the thickness of the reinforcing plate.

[0012] Optionally, the thickness of the base plate is greater than twice the thickness of the left and right test plates, but less than four times the thickness of the left and right test plates.

[0013] Optionally, the base plate has the following features: The lifting threaded holes are located in the middle of both sides along the length of the base plate; The pad block limiting blind hole is opened on the base plate at the position corresponding to the pad block. The pad block limiting blind hole includes corner pad block limiting blind hole located at each corner of the base plate and side pad block limiting blind hole located at each side plate of the base plate. The base plate fastening threaded holes are spaced apart along the length of the base plate. The base plate fastening threaded holes include end fastening threaded holes located on both sides of the base plate along the length of the base plate and side fastening threaded holes located between the end fastening threaded holes on both sides. The base plate fastening threaded holes are arranged in two rows and are located on both sides of the base plate along the width of the base plate. The distance between the two rows of base plate fastening threaded holes is greater than the total width of the left test plate and the right test plate.

[0014] Optionally, the mounting plate is connected to the base plate via a mounting plate weld area; the mounting plate has the following openings: The fastening threaded holes for the mounting plate are spaced apart along the length of the mounting plate and correspond one by one with the fastening threaded holes for the base plate; the fastening threaded holes for the mounting plate include two end fastening threaded holes located on both sides of the length of the mounting plate and two side fastening threaded holes located between the two end fastening threaded holes on both sides. The second end fastening threaded hole corresponds one to one of the first end fastening threaded holes, with equal diameters and coaxiality; The second side fastening threaded hole corresponds one to the first side fastening threaded hole, with the same diameter and coaxiality.

[0015] Optionally, the pressing end of the pressure plate has a chamfer; the mounting end of the pressure plate has a rounded edge; and the through hole on the pressure plate is clearance-fitted with the fastening bolt.

[0016] Optionally, the pad includes a corner pad located at the corner of the base plate and a side pad located at the side of the base plate; The corner pad has a corner pad groove slope, and the width of the bottom of the corner pad groove slope is greater than the width of the pressure plate; The side pad has a side pad groove slope, and the width of the bottom of the side pad groove slope is greater than the width of the pressure plate.

[0017] Optionally, the welding test plate includes a butt joint test plate assembly with a backing plate or a cross joint assembly; The test plate assembly with backing plate includes a left test plate and a right test plate. The lower surfaces of the left test plate and the right test plate are connected by a backing plate by a tack weld. A bevel is formed in the area between the left test plate and the right test plate above the backing plate. The bevel is used to weld a butt weld. The cross joint assembly includes a left cross test plate and a right cross test plate; a central upright plate is connected between the left cross test plate and the right cross test plate by tack welding. The portion of the central upright plate located above the left and right test plates of the cross is used to weld the upper surfaces of the left and right test plates of the cross to form a bevel fillet weld. The portion of the central upright plate located below the left and right test plates of the cross is used to weld the lower surfaces of the left and right test plates of the cross to form a back fillet weld.

[0018] Secondly, the present invention provides a rigid constraint and welding test method for preventing welding deformation of a boom stick welding test plate, which is based on the aforementioned rigid tooling for preventing welding deformation of the boom stick welding test plate. The method includes: The lower surfaces of the left and right test plates are connected to the support plate by tack welding to obtain the workpiece to be welded; Before welding, place the workpiece to be welded on the mounting plate. The left and right test plates are supported on the mounting plates on both sides of the width direction of the base plate. Then, place the mounting end of the pressure plate on the bearing groove of the pad, align the through hole of the pressure plate with the fastening threaded hole on the mounting plate and the base plate, and fasten the fastening bolt through the through hole and fastening threaded hole to press the left and right test plates onto the corresponding upper surface of the mounting plate. Stop rotating when the torque of the fastening bolt reaches the target value. Weld along the bevel between the left and right test plates to form a weld; after welding, use a wet towel to lay the left and right test plates flat to accelerate cooling. During the cooling process, it is necessary to prevent the water in the wet towel from flowing into the area of ​​the preset width near the weld; after the left and right test plates have cooled to room temperature, remove the fastening bolts to release the stiffness constraints of the left and right test plates; cut off the arc start and end areas at both ends of the left and right test plates, and cut the remaining parts into fatigue tensile specimens; the weld must be located at the center between the left and right test plates and perpendicular to the tensile direction of the left and right test plates.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The rigid tooling for preventing welding deformation of the boom stick welding test plate of the present invention includes a base plate, a mounting plate, fastening threaded holes, a pad, and a pressure plate; the thickness of the base plate is greater than that of the left and right test plates to ensure rigidity; the mounting plate is symmetrically welded to both sides of the upper surface of the base plate in the width direction, and the thickness of the mounting plate is greater than the thickness of the support plate below the left and right test plates and less than the thickness of the base plate; the fastening threaded holes are used to be coaxially opened on the mounting plate and the base plate after the mounting plate welding is completed; the pad is fixed to the base plate and located outside the mounting plate through pre-machined limiting blind holes and matching limiting rods. On one side, a bearing groove is formed on the upper surface of the pad; the distance from the bottom wall of the bearing groove to the lower surface of the pad is equal to the sum of the thickness of the mounting plate and the thicknesses of the left and right test plates, thereby ensuring that the left and right test plates can be pressed tightly against the mounting plate; the pressure plate includes an mounting end and a pressing end, with a through hole between the mounting end and the pressing end. The mounting end is used to support the pad on the bearing groove, and the pressing end is used to press the left or right test plate against the upper surface of the mounting plate when the fastening bolt passes through the through hole and is fastened to the fastening threaded hole; the thickness of the pressure plate is greater than the thickness of the base plate and less than the sum of the thicknesses of the base plate and the mounting plate to ensure the constraint effect. This invention first uses pads to support and raise the height of the pressure plate. Then, fastening bolts through through holes and threaded holes in the mounting plate and base plate press the pressure plate down. The pressure plate presses the outer edges of the left and right test plates against the upper surface of the mounting plate. The thickness of the mounting plate is greater than the thickness of the support plate below the left and right test plates but less than the thickness of the base plate, thus preventing the lower surface of the support plate from pressing against the surface of the base plate. The lower surfaces of the left and right test plates are connected to the support plate by tack welds. Rigid fixtures fix the outer edges of the welded test plates, and tack welds limit relative displacement near the weld. The two work together to achieve the purpose of rigidly constraining the welding deformation of the test plates. The rigid fixture for preventing welding deformation of the boom and stick welded test plates of this invention has a significant suppressive effect on the welding deformation that occurs during the welding process of fatigue life test specimens for butt welds with pads and single-sided bevel fillet welds, which are common in the boom and stick structures of excavators. This ensures that the flatness of the test plate after welding meets the requirements of fatigue life testing, eliminating the need for post-weld straightening, avoiding plastic deformation of the weld caused by straightening, and reducing errors in fatigue testing. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the rigid tooling for preventing welding deformation of the boom stick welding test plate provided in an embodiment of the present invention; Figure 2 for Figure 1 A structural diagram from another perspective; Figure 3 for Figure 1 Another structural diagram from a different perspective; Figure 4 A schematic diagram of the pre-welding assembly of a test plate for a butt weld with a backing plate using rigid tooling; Figure 5 A schematic diagram of the pre-welding assembly of a cross-joint single-sided bevel fillet weld test plate using rigid tooling; Figure 6 for Figure 4 Assembly diagram of the test plate for butt weld with backing plate; Figure 7 for Figure 6 A cross-sectional schematic diagram; Figure 8 for Figure 5 Assembly diagram of a test plate for a single-sided bevel fillet weld of a cross joint; Figure 9 for Figure 8 A cross-sectional schematic diagram; Figure 10 for Figure 1 Top view of the midsole plate; Figure 11 for Figure 1 Top view of the center panel; Figure 12 for Figure 1 Top view of the intermediate pressure plate; Figure 13 for Figure 1 Schematic diagram of the structure of the intermediate pad block; Figure 13 (a) is a schematic diagram of the corner pad and the side pad; Figure 13 (b) is a cross-sectional view of the corner pad; Figure 13 (c) is a cross-sectional view of the side pad block; Figure 14 for Figure 1 Schematic diagram of the structure of the central stiffener plate; Figure 15 A schematic diagram of the area where a test plate of a butt weld with a backing plate is subjected to post-weld cold compressing for a rigid fixture. Figure 16 A schematic diagram of the area where a cross-joint single-sided bevel fillet weld test plate, fixed with rigid tooling, is subjected to post-weld cold compress. Figure 17 This is a schematic diagram of post-weld sampling of a butt weld test plate with a backing plate. Figure 18 This is a schematic diagram of the sampling of a test plate after welding a single-sided bevel fillet weld of a cross joint.

[0021] Numbering on the map: 1. Base plate; 2. Mounting plate; 3. Support leg; 4. Rib plate; 5. Pressure plate; 6. Spacer block; 7. Limiting bar; 8. Fastening bolt; 9. Test plate assembly with spacer plate; 10. Cross joint assembly; 11. Lifting threaded hole; 12. Corner pad limit blind hole; 15. Side pad limit blind hole; 13. One end fastening threaded hole; 14. One side fastening threaded hole; 21. End fastening threaded hole two; 22. Side fastening threaded hole two; 23. Weld area of ​​the plate; 41. Chamfer at the end of the stiffening slab; 42. Weld area of ​​the stiffening slab; 51. Rounded corners on the edge of the pressure plate; 52. Through hole; 53. Chamfer on the pressure plate; 61. Corner pad; 62. Side pad; 611. Inclined surface of the corner pad groove; 612. Bottom of the corner pad groove; 621. Inclined surface of the side pad groove; 622. Bottom of the side pad groove; 91. Left test plate; 92. Right test plate; 93. Backing plate; 94. Butt weld; 101. Test plate on the left side of the cross; 102. Test plate on the right side of the cross; 103. Centered upright plate; 104. Bevel fillet weld; 105. Back fillet weld. Detailed Implementation

[0022] It should be noted that: The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0023] This embodiment introduces a rigid tooling for preventing welding deformation of boom stick welding test plates. It can be matched with special structures such as butt welds with backing plates or cross joint welds. With the corresponding assembly specifications and usage methods, the welding deformation of the welding test plates can be controlled, thereby meeting the flatness and coaxiality requirements of the specimens during fatigue testing.

[0024] Specifically, the rigid fixture includes a base plate 1, a mounting plate 2, support legs 3, stiffening plates 4, pressure plates 5, pads 6, limiting rods 7, and fastening bolts 8, as shown below. Figures 1 to 3 As shown, the mounting plate 2, stiffening plate 4, and support leg 3 are welded to the corresponding positions on the upper and lower surfaces of the base plate 1, respectively.

[0025] The welding test plate includes a left test plate and a right test plate arranged opposite to each other, with a bevel formed between the left and right test plates for welding. A support plate is provided at the bevel, which is connected to the lower surfaces of the left and right test plates by tack welding. Specifically, combined with... Figure 4 and Figure 5 The assembly method of the rigid tooling and the welding test plate includes two types of assembly methods: butt weld with backing plate and cross joint single-sided bevel fillet weld.

[0026] The test plate assembly 9 with a backing plate includes a left test plate 91 and a right test plate 92. A backing plate 93, serving as a support plate, is tack welded to the lower surfaces of the left test plate 91 and the right test plate 92. A butt bevel is formed between the left test plate 91 and the right test plate 92, above the backing plate 93. This butt bevel is used to weld a butt weld 94. The material and weld joint morphology are the same as those of the excavator structural component being tested. Figure 6 and Figure 7 As shown, the thickness of the test plate 91 on the left side of the docking and the test plate 92 on the right side of the docking are equal, denoted as T. 09 For medium-thick plates, the thickness of the mating pad 93 is denoted as T. 93 .

[0027] The cross-joint assembly 10 includes a left cross test plate 101 and a right cross test plate 102; a central upright plate 103 serving as a support plate is connected between the left cross test plate 101 and the right cross test plate 102 by tack welding; the portion of the central upright plate 103 above the left cross test plate 101 and the right cross test plate 102 is used to weld a bevel fillet weld 104 to the upper surfaces of the left cross test plate 101 and the right cross test plate 102; the portion of the central upright plate 103 below the left cross test plate 101 and the right cross test plate 102 is used to weld a back fillet weld 105 to the lower surfaces of the left cross test plate 101 and the right cross test plate 102. Figure 8 and Figure 9 As shown, the material and weld joint morphology are the same as those of the excavator structural component being tested. The thickness of the test plate 101 on the left side of the cross and the test plate 102 on the right side of the cross are equal, denoted as T. 10 The plate is of medium thickness. The distance between the bottom end of the central upright plate 103 and the lower surface of the test plate 101 on the left side of the cross is denoted as S. 103 .

[0028] Combination Figure 4 and Figure 10 The base plate 1 is made of low-alloy high-strength structural steel, and the plate thickness T1 ranges from 2T to 1. 09 2T 10} ≤ T1 ≤ max{4T 09 4T 10The base plate 1 is provided with a lifting threaded hole 11, a pad block limiting blind hole, and a base plate fastening threaded hole; the lifting threaded hole 11 is opened in the middle of both sides in the length direction of the base plate 1; the pad block limiting blind hole is opened on the base plate 1 at the position corresponding to the pad block 6, and the pad block limiting blind hole includes corner pad block limiting blind hole 12 located at each corner of the base plate 1 and side pad block limiting blind hole 15 located at each side plate of the base plate 1; the base plate fastening threaded hole is arranged at intervals along the length direction of the base plate 1, and the base plate fastening threaded hole includes end fastening threaded hole 13 located on both sides in the length direction of the base plate 1 and side fastening threaded hole 14 located between the end fastening threaded holes 13 on both sides; the base plate fastening threaded hole has two rows and is located on both sides in the width direction of the base plate 1 respectively; the distance between the two rows of base plate fastening threaded holes is greater than the total width of the left test plate and the right test plate. Specifically, there are two lifting threaded holes 11, which are centered in the width direction of the base plate 1 and are processed after welding. The lifting threaded holes 11 in this embodiment make transportation and lifting convenient and solve the problem of heavy tooling that is inconvenient to transport.

[0029] There are 8 blind holes 12 for corner pads, located on the outer side of the corner pad 61, which are machined before welding; there are 4 threaded holes 13 for end fastening, which are machined after welding, with a threaded hole spacing L along the length of the base plate 1. 013 The range of values ​​for is max{L 09 +5mm, L 10 +5mm}≤L 013 ≤max{ L 09 +15mm, L 10 +15mm}; Side fastening threaded holes 14, machined after welding, 6 in total, with threaded hole spacing W in the width direction of the base plate 1. 014 The range of values ​​for W is max{W 09 +5mm, W 10 +5mm} ≤W 014 ≤ max{W 09 +10mm, W 10 +10mm}; Side pad block limiting blind holes 15, a total of 12, are processed before welding.

[0030] Combination Figure 5 and Figure 11Two mounting plates 2 are provided, symmetrically welded to both sides of the upper surface of the base plate 1 in the width direction. The thickness of the mounting plate 2 is greater than the thickness of the support plate below the left and right test plates and less than the thickness of the base plate 1. The mounting plate 2 is connected to the base plate 1 through the mounting plate weld area 23, with a circumferential fillet weld. The mounting plate 2 is provided with mounting plate fastening threaded holes. The mounting plate fastening threaded holes are spaced apart along the length direction of the mounting plate 2 and correspond one-to-one with the fastening threaded holes of the base plate. The mounting plate fastening threaded holes include end fastening threaded holes 21 located on both sides of the mounting plate 2 in the length direction and side fastening threaded holes 22 located between the end fastening threaded holes 21 on both sides. The end fastening threaded holes 21 correspond one-to-one with the end fastening threaded holes 13, with equal diameters and coaxiality. The side fastening threaded holes 22 correspond one-to-one with the side fastening threaded holes 14, with equal diameters and coaxiality. Specifically, the mounting plate 2 can enhance the rigidity of the base plate 1 and reserve space for the welding joint. The thickness T2 of the mounting plate 2 has a range of maximum value {T...} 93 , S 103 <T2<T1, the material of the mounting plate 2 is low-alloy high-strength structural steel. The end fastening threaded hole 21 is equal to and coaxial with the end fastening threaded hole 13 of the test plate, that is, M21=M13. Both are uniformly drilled after welding. The side fastening threaded hole 22 is equal to and coaxial with the side fastening threaded hole 14, that is, M22=M14. It is also uniformly drilled after welding. The distance S from the center of the fastening threaded hole of the mounting plate to the inner boundary of the mounting plate 2 is... 22 .

[0031] Combination Figure 5 and Figure 12 Ten pressure plates 5 are provided to restrain welding deformation during welding. Each pressure plate 5 includes an mounting end and a pressing end, with a through hole 52 between them. The mounting end is used to support the bearing groove of the pad 6, and the pressing end is used to press the left or right test plate against the upper surface of the plate 2 when the fastening bolt 8 passes through the through hole 52 and is fastened to the fastening threaded hole. The thickness of the pressure plate 5 is greater than the thickness of the base plate 1 but less than the sum of the thicknesses of the base plate 1 and the plate 2. The thickness T5 of the pressure plate 5 is in the range T1 < T5 < T1 + T2. The pressure plate 5 is made of 45 steel in a quenched and tempered state to ensure sufficient rigidity. The pressure plate 5 has a chamfer 53 at its pressing end, which increases the contact area between the pressure plate 5 and the plate 2 when the bolt is tightened; the mounting end of the pressure plate 5 has a rounded edge 51 to eliminate burrs and facilitate bolt installation and tightening. The through hole 52 on the pressure plate 5 is clearance-fitted with the fastening bolt 8, and the width of the pressure plate 5 is denoted as W5. The fastening bolt 8 is used to mate with the fastening threaded hole; the length of the fastening bolt 8 is greater than or equal to the sum of the thickness of the base plate 1 and the distance from the bottom wall of the bearing groove to the lower surface of the pad 6, and less than or equal to the sum of the thickness of the base plate 1, the distance from the bottom wall of the bearing groove to the lower surface of the pad 6, and the thickness of the reinforcing plate 4. Specifically, the bolt length L8 of the fastening bolt 8 is in the range of T1+S. 62 ≤L8≤T1+S 62 +T4.

[0032] Combination Figure 5 and Figure 13 Ten pads 6 are provided to support the pressure plate 5. They are made of 45 steel in a quenched and tempered state to ensure sufficient rigidity. The pads 6 are fixed to the base plate 1 and located outside the plate 2 through pre-machined limiting blind holes and limiting rods 7. A bearing groove is formed on the upper surface of the pad 6. The distance from the bottom wall of the bearing groove to the lower surface of the pad 6 is equal to the sum of the thickness of the plate 2 and the thicknesses of the left and right test plates. The pads 6 include corner pads 61 located at the corners of the base plate 1 and side pads 62 located on the sides of the base plate 1. The corner pads 61 have a corner pad groove slope 611, and the width of the bottom 612 of the corner pad groove slope 611 is greater than the width of the pressure plate 5. The side pads 62 have a side pad groove slope 621, and the width of the bottom 622 of the side pad groove slope 621 is greater than the width of the pressure plate 5. The bottom width of the corner pad recess 612 is denoted as W. 612 The distance between the bottom of the corner pad groove 612 and the bottom surface of the pad 6 is denoted as S. 61 The bottom width of the side pad recess 622 is denoted as W. 622 The distance between the bottom of the corner pad groove 622 and the bottom surface of the pad 6 is denoted as S. 62 The width of the bottom of the groove in the pad block is within the range of W5+1mm≤W 612 W 622 ≤W5+2mm, the distance from the bottom of the groove of the pad block to the bottom surface is S. 61 = S 62 =T2+T 09 Or S 61 = S 62 =T2+T 10 .

[0033] Combination Figure 14 The four stiffening plates 4 enhance the rigidity of the base plate 1. The thickness T4 of the stiffening plates 4 has a maximum value range of T. 93 , S 103} < T4 < T1, such as Figure 14As shown, the material is low-alloy high-strength structural steel. The lower surface of the base plate 1 is welded with multiple stiffening plates 4 extending along the width direction of the base plate 1. The thickness of the stiffening plate 4 is greater than the thickness of the support plate below the left and right test plates and less than the thickness of the base plate 1. The stiffening plate 4 includes a stiffening plate weld area 42 for connecting with the base plate 1 and a circumferential fillet weld. The two sides of the stiffening plate 4 in the extending direction are formed with stiffening plate end chamfers 41. Specifically, a total of 20 limiting rods 7 are provided. The limiting rods 7 are used to restrict the horizontal sliding of the pad 6 during the fastening process. The diameter D7 of the limiting rod 7 is in the range of 4mm ≤D7<min{M12, M15}. The diameter of the corner pad limiting blind hole 12 is M12; the diameter of the side pad limiting blind hole 15 is M15. The limiting rod 7 is made of structural steel.

[0034] There are four support legs 3 in total, made of structural steel and in a cuboid shape. The support legs 3 are used to weld to the corners of the lower surface of the base plate 1 after the stiffening plates 4 are welded; the mounting plate 2 is welded after the support legs 3 are welded; the flatness of the lower surface of the support legs 3 is processed with the upper surface of the mounting plate 2 as a reference.

[0035] Specifically, the welding requirements during the manufacturing process of the rigid tooling are as follows: the mounting plate 2, stiffening plate 4, and support leg 3 are welded to corresponding positions on the upper and lower surfaces of the base plate 1. After the assembly is completed, the stiffening plate 4 is welded to the lower surface of the base plate 1 first, then the support leg 3 is welded to the lower surface of the base plate 1, and finally the mounting plate 2 is welded to the upper surface of the base plate 1. The machining requirements during the manufacturing process of the rigid tooling are as follows: first, the flatness of the upper surface of the mounting plate 2 is machined using the lower surface of the base plate 1 as a reference; then, the lower surface of the support leg 3 is machined using the machined surface of the mounting plate 2 as a reference to ensure the parallelism between the surface of the mounting plate 2 and the lower surface of the support leg 3. Subsequently, through holes are drilled and threads are machined at designated locations.

[0036] The rigid restraint method for preventing welding deformation of the welding test plate: Step 1: Assemble the welding test plate. The welding test plate is either a butt joint test plate assembly 9 with a backing plate or a cross joint assembly 10. The back of the butt joint test plate assembly 9 with a backing plate or the cross joint assembly 10 is tack welded to the inside of the bevel. This includes two types: tack welding and intermittent tack welding. This increases the structural rigidity of the test plate assembly and ensures that the tack weld will not break due to restraint stress during the welding process. Step 2: Bolt tightening. Before welding, fasten the test plate assembly 9 with backing plate or the cross joint assembly 10 to the upper surface of the plate 2 using the rigid tooling's fastening bolts 8, pressure plate 5, and shim 6. See [link / details]. Figure 4 and Figure 5The fastening bolt 8 is tightened to a fixed torque. The bearing groove of the pad 6 mates with the lower surface of the pressure plate 5. Limiting rods 7 are provided on both sides of the pad 6 to prevent the pressure plate 5 from sliding against the pad 6 during the tightening or loosening of the fastening bolt 8. The limiting rods 7 are inserted into the inner clearance fit of the corner pad limiting blind hole 12 or the side pad limiting blind hole 15. In this embodiment, the pressure plate 5 is designed to prevent slippage by using a grooved pad 6 in conjunction with the limiting rods 7 to limit the rotation of the pressure plate 5 with the fastening bolt 8 during tightening and loosening.

[0037] In this embodiment, the rigid fixture fixes the outer edge of the welding test plate, and the tack weld restricts the relative displacement near the weld. The two work together to achieve the goal of rigidly constraining the welding deformation of the test plate. The rigid constraint fixture uses a combination of multiple high-strength fastening bolts 8 and pressure plates 5 as a fastening constraint to the welding test plate. The height of the pads 6 of the pressure plate 5 is adjusted according to the thickness of the mounting plate 2 and the welding test plate to ensure sufficient contact area between the pressure plate 5 and the welding test plate. The pressure plate 5 and the main body of the fixture are both designed with reinforced materials and structures, including a base plate, mounting plate, and stiffening plates.

[0038] Step 3: Robot welding. Weld along the bevel between the left and right test plates to form a weld. Start welding from the end of the weld, first weld the root pass and then fill and cover the pass. Keep the automatic welding parameters unchanged until the arc is extinguished at the other end of the weld. Welding is not allowed to stop in the middle to ensure that the weld surface is uniform and consistent.

[0039] Step 4: Rapid cooling. After welding, apply a damp towel to the surfaces to accelerate cooling. The towel should be applied to the surfaces of the left and right test plates. Figure 15 and Figure 16 As shown, during the cooling process, it is necessary to prevent water from the wet towel from flowing into the area with a width of D9 or D10 near the weld. In this embodiment, rapid cooling is achieved after welding by setting a cold compress zone on the upper surface of the welded test plate and laying a wet towel in the cold compress zone to accelerate the post-weld cooling process of the test plate.

[0040] Step 5: After the left and right test plates have cooled to room temperature, remove the fastening bolts 8 to release the stiffness constraints on the left and right test plates.

[0041] Step Six: Cut off the arc initiation and termination areas at both ends of the left and right test plates, and cut the remaining parts into fatigue tensile specimens; the weld must be located at the center between the left and right test plates and perpendicular to the tensile direction of the left and right test plates, see... Figure 17 and Figure 18 .

[0042] The rigid constraint method for preventing welding deformation of the tensile welded test plate described in this embodiment has a significant suppressive effect on welding deformation that commonly occurs during the welding process of fatigue life test specimens for butt welds with backing plates and single-sided bevel fillet welds in excavator booms and stick structures. This ensures that the flatness of the test plate after welding meets the requirements of fatigue life testing, eliminating the need for post-weld straightening, avoiding plastic deformation of the weld caused by straightening, and reducing errors in fatigue testing.

[0043] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A rigid tooling for preventing welding deformation of a boom and stick welding test plate, used to fix the welding test plate of the boom and stick structure, the welding test plate comprising a left test plate and a right test plate arranged opposite to each other, a bevel for welding being formed between the left and right test plates, and a support plate provided at the bevel for connection to the lower surfaces of the left and right test plates by tack welding; characterized in that, include: The base plate (1) is thicker than the left and right test plates; The mounting plate (2) is symmetrically welded to both sides of the upper surface of the base plate (1) in the width direction. The thickness of the mounting plate (2) is greater than the thickness of the support plate located below the left test plate and the right test plate and less than the thickness of the base plate (1). Fastening threaded holes are used to be coaxially opened on the plate (2) and the base plate (1) after the welding of the plate (2) is completed; The pad (6) is fixed to the base plate (1) and located outside the plate (2) by a pre-processed limiting blind hole and a limiting rod (7). A bearing groove is formed on the upper surface of the pad (6). The distance from the bottom wall of the bearing groove to the lower surface of the pad (6) is equal to the sum of the thickness of the plate (2) and the thickness of the left test plate and the right test plate. The pressure plate (5) includes an installation end and a pressing end, with a through hole (52) between the installation end and the pressing end. The installation end is used to support the bearing groove of the pad (6), and the pressing end is used to press the left or right test plate onto the upper surface of the plate (2) when the fastening bolt (8) passes through the through hole (52) and is fastened to the fastening thread hole. The thickness of the pressure plate (5) is greater than the thickness of the base plate (1) and less than the sum of the thicknesses of the base plate (1) and the plate (2).

2. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 1, characterized in that, Also includes: The bottom plate (1) has multiple stiffening plates (4) welded to its lower surface, extending along the width direction of the bottom plate (1); the thickness of the stiffening plate (4) is greater than the thickness of the support plate below the left and right test plates and less than the thickness of the bottom plate (1); the stiffening plate (4) includes a stiffening plate weld area (42) for connecting with the bottom plate (1), and the two sides of the stiffening plate (4) in the extension direction are formed with stiffening plate end chamfers (41). The support leg (3) is used to be welded to each corner of the lower surface of the base plate (1) after the stiffening plate (4) is welded; the mounting plate (2) is welded after the support leg (3) is welded; the flatness of the upper surface of the mounting plate (2) is processed with the lower surface of the base plate (1) as the reference; the flatness of the lower surface of the support leg (3) is processed with the upper surface of the mounting plate (2) as the reference.

3. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 2, characterized in that, The length of the fastening bolt (8) is greater than or equal to the sum of the thickness of the base plate (1) and the distance from the bottom wall of the bearing groove to the lower surface of the pad (6), and less than or equal to the sum of the thickness of the base plate (1), the distance from the bottom wall of the bearing groove to the lower surface of the pad (6), and the thickness of the stiffening plate (4).

4. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 1, characterized in that, The thickness of the base plate (1) is greater than twice the thickness of the left test plate and the right test plate, and less than four times the thickness of the left test plate and the right test plate.

5. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 1, characterized in that, The base plate (1) has the following openings: The lifting threaded hole (11) is opened in the middle of both sides of the base plate (1) along its length; The pad block limiting blind hole is opened on the base plate (1) at the position corresponding to the pad block (6). The pad block limiting blind hole includes corner pad block limiting blind hole (12) located at each corner of the base plate (1) and side pad block limiting blind hole (15) located at each side plate of the base plate (1). The base plate fastening threaded holes are spaced apart along the length direction of the base plate (1). The base plate fastening threaded holes include end fastening threaded holes (13) located on both sides of the length direction of the base plate (1) and side fastening threaded holes (14) located between the end fastening threaded holes (13) on both sides. The base plate fastening threaded holes are arranged in two rows and are located on both sides of the width direction of the base plate (1). The distance between the two rows of base plate fastening threaded holes is greater than the total width of the left test plate and the right test plate.

6. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 4, characterized in that, The mounting plate (2) is connected to the base plate (1) through the mounting plate weld area (23); the mounting plate (2) has the following openings: The fastening threaded holes of the plate are spaced apart along the length direction of the plate (2) and correspond one by one with the fastening threaded holes of the base plate; the fastening threaded holes of the plate include the end fastening threaded holes (21) located on both sides of the length direction of the plate (2) and the side fastening threaded holes (22) located between the end fastening threaded holes (21) on both sides. The end fastening threaded hole two (21) corresponds one to the end fastening threaded hole one (13), with equal diameter and coaxiality; The second side fastening threaded hole (22) corresponds to the first side fastening threaded hole (14) one by one, with the same diameter and coaxiality.

7. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 1, characterized in that, The pressure plate (5) has a chamfer (53) at the pressing end; the pressure plate (5) has a rounded edge (51) at the mounting end; and the through hole (52) on the pressure plate (5) is clearance-fitted with the fastening bolt (8).

8. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 1, characterized in that, The pad (6) includes a corner pad (61) located at the corner of the base plate (1) and a side pad (62) located on the side of the base plate (1). The corner pad (61) has a corner pad groove inclined surface (611), and the width of the bottom (612) of the corner pad groove of the corner pad groove inclined surface (611) is greater than the width of the pressure plate (5); The side pad (62) has a side pad groove inclined surface (621), and the width of the bottom (622) of the side pad groove inclined surface (621) is greater than the width of the pressure plate (5).

9. The rigid tooling for preventing welding deformation of the boom stick welding test plate according to claim 1, characterized in that, The welding test plate includes a butt test plate assembly with a backing plate (9) or a cross joint assembly (10). The test plate assembly (9) with backing plate includes a left test plate (91) and a right test plate (92). The lower surfaces of the left test plate (91) and the right test plate (92) are connected by a backing plate (93) by tack welding. A butt bevel is formed between the left test plate (91) and the right test plate (92) above the backing plate (93). The butt bevel is used to weld a butt weld (94). The cross joint assembly (10) includes a left cross test plate (101) and a right cross test plate (102); a centering plate (103) is connected between the left cross test plate (101) and the right cross test plate (102) by tack welding. The portion of the central upright plate (103) above the left side test plate (101) and the right side test plate (102) of the cross is used to weld the upper surfaces of the left side test plate (101) and the right side test plate (102) of the cross to form a bevel fillet weld. The portion of the central upright plate (103) located below the left cross test plate (101) and the right cross test plate (102) is used to weld the lower surfaces of the left cross test plate (101) and the right cross test plate (102) to form a back fillet weld.

10. A rigid constraint and welding test method for preventing welding deformation of a boom stick welding test plate, characterized in that, The method is carried out using the rigid tooling for preventing welding deformation of the boom stick welding test plate according to any one of claims 1-9, and the method includes: The lower surfaces of the left and right test plates are connected to the support plate by tack welding to obtain the workpiece to be welded; Before welding, place the workpiece to be welded on the plate (2). The left test plate and the right test plate are supported on the plate (2) on both sides of the width direction of the base plate (1). Then, place the mounting end of the pressure plate (5) on the bearing groove of the pad (6) so that the through hole (52) of the pressure plate (5) is aligned with the fastening thread hole on the plate (2) and the base plate (1). Pass the fastening bolt (8) through the through hole (52) and fasten it to the fastening thread hole to press the left test plate and the right test plate onto the corresponding plate (2) upper surface. Stop rotating when the torque of the fastening bolt (8) reaches the target value. Weld along the bevel between the left and right test plates to form a weld; after welding, use a wet towel to lay the left and right test plates flat to accelerate cooling. During the cooling process, it is necessary to prevent the water in the wet towel from flowing into the area of ​​the preset width near the weld; after the left and right test plates have cooled to room temperature, remove the fastening bolts (8) to release the stiffness constraint of the left and right test plates; cut off the arc start and end areas at both ends of the left and right test plates, and cut the remaining parts into fatigue tensile specimens; the weld should be located at the center between the left and right test plates and perpendicular to the tensile direction of the left and right test plates.

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