Welding Local Annealing Residual-Eliminating Equipment for Orthotropic Steel Bridge Deck and Its Using Method

Abstract

The present application relates to a weld local annealing and stress relief device for orthotropic steel bridge decks and a method for using the same. In the present application, the weld local annealing and stress relief device includes a heating temperature control system, a first mounting seat for abutting against the bottom of the orthotropic steel bridge deck plate, and a second mounting seat for abutting against the orthotropic steel bridge longitudinal rib; the second mounting seat is mounted on the first mounting seat; a first driving member for driving the two to move towards the orthotropic steel bridge rib plate is connected to the first mounting seat and the second mounting seat; heating plates are fixedly provided on the mutually facing sides of the first mounting seat and the second mounting seat; the heating temperature control system is electrically connected to the heating plates. The present application also discloses a method for using the device. The device and the method for using the same in the present application enable uniform heating temperature, good effect, convenient use, high adjustability and versatility, reduce the weld residual stress by 75% - 80%, and solve the world problem of repeated cracking in a short period after the repair of in-service bridges.

Description

Technical Field

[0001] This application relates to the technical field of bridge maintenance equipment, and particularly to a local annealing and residual stress elimination device for the welds of orthotropic steel bridge decks and its usage method. Background Art

[0002] An orthotropic steel bridge deck is a structure that jointly bears loads, consisting of longitudinal and transverse stiffeners (longitudinal ribs and transverse ribs) perpendicular to each other and the deck slab. The orthotropic steel bridge deck is one of the important features of modern steel bridges. The orthotropic steel bridge deck structure has the advantages of light self-weight, high stiffness, high load-bearing capacity, and being convenient for factory manufacturing, and is widely used in various large and medium-span bridges.

[0003] The thickness of the deck slab of the orthotropic steel bridge deck is generally 14 - 18 mm, and the longitudinal ribs are usually U-shaped ribs, bulb flat steel ribs or plate ribs, and the thickness of the longitudinal rib plate is generally 6 mm or 8 mm; during manufacturing, the whole bridge is divided into several segments for assembly in the factory. The deck slab is welded and fixedly connected with the longitudinal and transverse ribs. After hoisting, the connection between segments is carried out on the bridge. Usually, all longitudinal fillet welds (such as longitudinal ribs and longitudinal diaphragms) are continuous, and the intersection of transverse ribs or transverse diaphragms with longitudinal welds and the lower flange of longitudinal ribs is cut into an arc-shaped notch to avoid it.

[0004] Since welding is a thermal cycle process of rapid heating and cooling of a local part of the steel, the base metal and deposited metal on both sides of the weld will undergo changes in organization and properties during welding. The weld is restricted by the structure of the body and cannot freely expand and contract thermally. After cooling, a large amount of residual stress is generated at the welding site, accompanied by phenomena such as hydrogen embrittlement, embrittlement, hardening or softening, which reduces the structural performance and strength. Welding residual stress is the initial stress that already exists in the structural cross-section before the structure bears loads. During the service process of the structure, it is superimposed with the working stress caused by other applied loads, which will not only reduce the stiffness and stability of the structure, but also seriously affect the fatigue strength of the structure, the ability to resist stress corrosion cracking and high-temperature creep cracking. The residual stress generated during welding will seriously reduce the load-bearing capacity and fatigue strength of the structure, and even induce cracks leading to catastrophic accidents. The steel bridge deck directly bears the pressure, impact, vibration and shear of vehicle loads as the bridge deck system, and the stress of the bridge deck structure is complex. As the service time of the steel bridge deck increases, fatigue cracking phenomena generally occur, especially the fatigue cracking phenomena at the welds between the deck slab and longitudinal ribs, the welds between transverse diaphragms and longitudinal ribs, and the openings of transverse diaphragms are particularly prominent. It seriously threatens the safety of the bridge structure. Research shows that the fatigue life under the coupling action of welding residual stress and vehicle load stress decreases by 30% - 40%, and the reduction amplitude of fatigue life increases with the increase of residual stress. The residual stress generated by welding is an important factor inducing and accelerating the fatigue cracking of welded joints.

[0005] Post-weld annealing has a good effect on eliminating welding residual stress and hydrogen embrittlement. Post-weld annealing can reduce welding residual stress, improve the weld metal microstructure, thereby enhancing the mechanical properties, corrosion resistance, and fatigue resistance of the weld. During the annealing process, as the martensite structure disappears, carbon, carbides, and hydrogen elements precipitate, dislocation migration occurs, a small amount of plastic deformation takes place, and the grains are evenly distributed, causing changes in the internal structure of the material. This leads to the disappearance of the deformation of internal stress, and the residual stress of the welded joint is reduced and released, showing a uniform distribution. Since the generation of welding residual stress is often accompanied by changes in material properties caused by the welding thermal cycle, heat treatment restores or partially restores the material properties while eliminating residual stress.

[0006] For a long time, the research and attention to post-weld heat treatment of residual stress at home and abroad have been insufficient. In particular, the lack of relevant equipment for the residual stress of orthotropic steel bridge deck welds and post-weld heat treatment has led to the situation that after the welds of in-service orthotropic steel bridge decks crack, only simple repair welding is carried out without taking necessary measures for detecting and reducing dehydrogenation of post-weld residual stress. As a result, the repaired welds crack rapidly at the repaired positions, directly causing deterioration of the structural strength, reducing the service life of the bridge, and becoming a headache for bridge repair projects at home and abroad.

[0007] In related technologies, an oxyacetylene flame generated by a flame gun is used to locally heat the welding deformation area of the orthotropic steel bridge deck to achieve the purpose of eliminating welding residual deformation. This heat treatment equipment is relatively simple, the heating temperature is difficult to control, and the heating temperature of the local area is not uniform enough, making it difficult to master the heating temperature, and the effect of annealing and eliminating residual stress heat treatment is not good. Especially for in-service orthotropic steel bridge decks, it is very difficult to achieve the purpose of annealing and eliminating residual stress. Summary of the Invention

[0008] In order to improve the local annealing and residual stress elimination effect, convenience, and reliability of the welds of in-service orthotropic steel bridge decks, the present application provides a device and its use method for local annealing and residual stress elimination of the welds of orthotropic steel bridge decks.

[0009] In the first aspect, a device for local annealing and residual stress elimination of the welds of an orthotropic steel bridge deck provided by the present application adopts the following technical solution:

[0010] A device for local annealing and residual stress elimination of the welds of an orthotropic steel bridge deck includes a first mounting seat for abutting against the bottom of the orthotropic steel bridge deck and a second mounting seat for abutting against the orthotropic steel bridge longitudinal rib; one end of the second mounting seat is installed and connected to the first mounting seat;

[0011] A first driving member for driving the two to move towards the direction of the orthotropic steel bridge longitudinal rib is connected to the first mounting seat and the second mounting seat;

[0012] Heating plates are fixedly provided on the sides of the first mounting seat and the second mounting seat facing away from each other.

[0013] The weld local annealing and residual stress elimination device further includes a heating temperature control system, which is electrically connected to the heating plate and is used to control the heating temperature and time of the heating plate.

[0014] The device in this application repairs the disease of fatigue cracking of the longitudinal rib and top plate welds, which most commonly occur in the in-service orthotropic steel bridge deck. When in use, the device is installed at the bottom of the top plate. The first driving member pushes the first mounting seat and the second mounting seat towards the orthotropic steel bridge rib plate and presses against it. The heating plate on the first mounting seat abuts against the bottom of the orthotropic steel bridge top plate, and the heating plate on the first mounting seat abuts against the orthotropic steel bridge rib plate. The heating temperature and heating time of the heating plate are controlled through the heating temperature control system, so as to perform heat treatment on the weld, achieving the effect of eliminating welding residual stress, while improving the weld metal microstructure, thereby improving the mechanical properties, corrosion resistance and fatigue resistance of the weld.

[0015] By adopting the above technical solution, the heating plate can stably and reliably heat a local area, with good controllability, and at the same time the heating temperature is uniform, greatly improving the effect of heat treatment. In addition, the whole device is convenient to use, stable and reliable.

[0016] The heating temperature control system in this application includes a controller, which realizes automatic and precise control of the heating time and heating temperature through a pre-set software control program, with a high degree of automation and high working efficiency. It can also be remotely controlled, saving manpower and being safer. At the same time, for different steel characteristics, various materials can be easily applied through the corresponding selection of the software program, meeting the requirements of multi-function and diversification.

[0017] Optionally, both the first mounting seat and the second mounting seat are in the shape of plates. One end of the second mounting seat is rotatably connected to one end of the first mounting seat through a rotating shaft. At least two first driving members are installed on the first mounting seat and the second mounting seat. The first driving member is a hydraulic rod or an electric push rod. Ear plates corresponding to the first driving members are fixedly provided on the sides of the first mounting seat and the second mounting seat close to each other. One end of the first driving member is pin-connected to the corresponding ear plate, and a magnetic attraction structure is provided at the other end of the first driving member.

[0018] By adopting the above technical solutions, multiple first driving members can stably and reliably push the first mounting seat and the second mounting seat to move. Meanwhile, the magnetic attraction structure at the end of the first driving member is utilized to assist in tightly clamping the first mounting seat and the second mounting seat between two adjacent longitudinal ribs, ensuring the stable and reliable installation of the first mounting seat and the second mounting seat. It can also make the heating plate fit more closely with the orthotropic steel bridge deck and longitudinal ribs, improve the heat conduction efficiency, reduce heat loss, and ensure the heat treatment effect at the same time.

[0019] Optionally, a second driving member for pushing the second mounting seat to swing on the first mounting seat is arranged between the first mounting seat and the second mounting seat.

[0020] By adopting the above technical solutions, the second driving member drives the second mounting seat to swing, adapts to longitudinal ribs of different shapes, and ensures that the heating plate on the second mounting seat fits more closely with the side surface of the longitudinal rib, thereby ensuring the stable and reliable local heating and improving the annealing and defect elimination effect.

[0021] Optionally, the swing amplitude of the second mounting seat is the included angle range of 90° to 105° between it and the first mounting seat.

[0022] By adopting the above technical solutions, the heating plate on the second mounting seat swings along with the second mounting seat, meeting the different welding angle change requirements for connecting different stiffeners such as U-shaped ribs, I-shaped ribs, and L-shaped ribs. The overall versatility is high and the adjustment is convenient.

[0023] Optionally, the second driving member is also a hydraulic rod or an electric push rod; both ends of the second driving member are respectively connected to the side surfaces of the first mounting seat and the second mounting seat that are close to each other.

[0024] By adopting the above technical solutions, the second driving member can automatically adjust the swing angle of the second mounting seat according to the preset program and parameters, and lock itself after the adjustment is in place, so as to meet the requirements of different longitudinal rib shapes and ensure the stability and reliability of its use.

[0025] Optionally, a first auxiliary mounting seat for abutting against the orthotropic steel bridge diaphragm is fixedly provided at the end of the first mounting seat, and a second auxiliary mounting seat for abutting against the orthotropic steel bridge diaphragm is fixedly provided at the end of the second mounting seat; heating plates are also fixedly provided on the side surfaces of the first auxiliary mounting seat and the second auxiliary mounting seat that face away from the first mounting seat and the second mounting seat.

[0026] By adopting the above technical solutions, the heating plates on the first auxiliary mounting seat and the second auxiliary mounting seat abut against the orthotropic steel bridge diaphragm and heat the related disease areas, meeting the diverse requirements of the equipment of the present application, making its use more extensive, and being able to perform heat treatment on multiple positions simultaneously, with higher working efficiency.

[0027] Optionally, both the first auxiliary mounting seat and the second auxiliary mounting seat are triangular plate bodies, and both the first auxiliary mounting seat and the second auxiliary mounting seat are perpendicular to both the first mounting seat and the second mounting seat at the same time; when the first mounting seat is perpendicular to the second mounting seat, the first auxiliary mounting seat and the second auxiliary mounting seat are butted to form a rectangular plate body structure; a heat preservation board is also installed on one side of the first auxiliary mounting seat or the second auxiliary mounting seat; when the included angle between the first mounting seat and the second mounting seat is an obtuse angle, the heat preservation board can block the gap between the first auxiliary mounting seat and the second auxiliary mounting seat.

[0028] By adopting the above technical solution, the use effects of the first auxiliary mounting seat and the second auxiliary mounting seat are ensured, and at the same time, the interference influence between the two is minimized as much as possible. The heat preservation board is used to improve the heat preservation effect when heating the cross diaphragm.

[0029] Optionally, the heating plate is made of a ceramic electric heating sheet; the first mounting seat, the second mounting seat, the first auxiliary mounting seat and the second auxiliary mounting seat all include a protective shell and a profiled steel skeleton. The protective shell is a sandwich structure and the protective shell is filled with heat-insulating and heat-preserving cotton. The profiled steel skeleton is located inside the protective shell. The heating plate is connected to the profiled steel skeleton through a fixing piece, and a heat-insulating asbestos board is fixedly arranged between the heating plate and the protective shell.

[0030] By adopting the above technical solution, the heating stability and reliability of the heating plate can be effectively improved, heat loss can be reduced, and the effect of annealing and removing residues is ensured.

[0031] Optionally, the weld local annealing and residue removal equipment further includes a mobile power station, and the mobile power station is used to supply energy for heating the heating plate and is electrically connected to the heating temperature control system.

[0032] By adopting the above technical solution, the mobile power station supplies energy for the heating plate, eliminating the need for additional wiring, meeting the use requirements in a power-free field environment, and reducing the use limitations of the entire equipment.

[0033] In a second aspect, the present application also discloses a use method of a weld local annealing and residue removal equipment for an orthotropic steel bridge deck, using the above weld local annealing and residue removal equipment to perform weld local annealing and residue removal treatment on an orthotropic steel bridge deck; the use method of the weld local annealing and residue removal equipment for an orthotropic steel bridge deck includes the following steps:

[0034] S1: Level the surface: Milling or grinding the defective welds on the top plate, diaphragm and rib plate of the orthotropic steel bridge to make their surfaces flat;

[0035] S2: Installation and adjustment of equipment: Install the local annealing and defect elimination equipment for welds at the bottom of the top plate. The first driving member pushes the first mounting seat and the second mounting seat towards the orthotropic steel bridge rib plate and presses them against it. The heating plate on the first mounting seat abuts against the bottom of the orthotropic steel bridge top plate, and the heating plate on the first mounting seat abuts against the orthotropic steel bridge rib plate.

[0036] S3: Heat treatment: Select a suitable temperature control program and parameters, preset the heating temperature and time, and perform heating annealing and defect elimination and dehydrogenation treatment on the welds.

[0037] S4: Detection: After the heat treatment is completed, remove the equipment, and then perform residual stress detection and acceptance.

[0038] This application is used for local annealing heat treatment of the welded seams of orthotropic steel bridge decks. Through the heating plates in the relevant equipment, the outer side of the heating plates is completely attached to the outer side of the rib plate and the weld toes on the upper left and right sides with the flattest and most uniform force. Compared with the existing technology, this achieves uniform annealing heat treatment of the butt welds of the rib plates, thereby more uniformly eliminating the welding residual stress. The relevant equipment in this application is convenient for installation and disassembly, has a high degree of automation, good heating and heat preservation effects; the entire equipment is portable, reusable, and reduces the production cost; the method in this application is beneficial to complete the post-weld annealing of orthotropic steel bridge decks, can shorten the construction period, save construction costs, effectively connect the construction processes, conform to the concept of green construction, has strong practicability, and the key technologies of the annealing process have the advantages of high stress elimination rate and simple operation.

[0039] In summary, this application includes at least one of the following beneficial technical effects:

[0040] 1. In this application, the outer side of the heating plate is completely attached to the outer side of the rib plate and the weld toes on the upper left and right sides with the flattest and most uniform force, which can uniformly perform annealing heat treatment on the butt welds of the rib plates, thereby more uniformly eliminating the welding residual stress.

[0041] 2. In this application, the structures of the first mounting seat, the second mounting seat, the first auxiliary mounting seat, and the second auxiliary mounting seat are optimized. Through the heat preservation structure design, the heating during temperature rise can be heat-preserved. During the heat treatment process, the heat loss is delayed, the uneven temperature gradient is reduced, and it is ensured to accurately follow the predetermined annealing process, saving costs and improving the heat treatment effect.

[0042] 3. The heating plate in this application uses a ceramic electric heating sheet, with uniform heating, stable and reliable.

[0043] 4. The relevant equipment in this application is convenient for installation and disassembly, enabling local annealing treatment in-situ on the existing bridge site, with good heating and heat preservation effects; the entire equipment is portable and reusable, reducing production costs; the construction period in its process method is short, saving construction costs; especially for local annealing heat treatment of the welded seams of orthotropic steel bridge decks in service, the residual stress of the welds is reduced by 75% - 80%, the phenomenon of hydrogen embrittlement is basically eliminated, the effect of eliminating residues is obvious, the fatigue performance of the welded joints is improved, and the world problem of repeated cracking in the short term after the repair of existing bridges is solved, which has extremely high practical significance and economic value.

[0044] 5. The heating temperature control system in this application includes a controller, which realizes automatic and precise control of the heating time and heating temperature through a pre-set software control program, with high automation and high working efficiency.

[0045] 6. With the automatic control of the heating temperature control system in this application, it can be remotely controlled, saving manpower and being safer; at the same time, for different steel characteristics, it can easily achieve the application of a variety of materials through the corresponding selection of software programs, meeting the multi-functional and diversified needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic structural diagram of the usage state of the equipment for eliminating residues by local annealing of welds in this application.

[0047] Figure 2 It is a schematic partial installation structural diagram of the equipment for eliminating residues by local annealing of welds in this application.

[0048] Figure 3 It is a three-dimensional structural diagram of the first mounting seat, the second mounting seat, the first auxiliary mounting seat and the second auxiliary mounting seat in this application.

[0049] Figure 4 It is a three-dimensional structural diagram of the first mounting seat, the second mounting seat, the first auxiliary mounting seat and the second auxiliary mounting seat from another perspective in this application.

[0050] Figure 5 It is a schematic structural diagram of the equipment in this application when used for U-shaped ribs.

[0051] Figure 6 It is a schematic structural diagram of the equipment in this application when used for bulb flat steel ribs.

[0052] Figure 7 It is a schematic internal structural diagram of the first mounting seat, the second mounting seat, the first auxiliary mounting seat and the second auxiliary mounting seat in this application.

[0053] Figure 8 It is a diagram showing the change of longitudinal residual stress before and after annealing in this application.

[0054] Figure 9 It is the diagram of the change in the transverse residual stress before and after annealing in this application.

[0055] In the figure:

[0056] 10. Mobile power station;

[0057] 20. Heating temperature control system;

[0058] 30. First mounting seat; 31. Ear plate; 32. First auxiliary mounting seat; 33. Protection housing; 34. Section steel skeleton; 35. Heat insulation and thermal insulation cotton; 36. Fixing part; 37. Heat insulation asbestos board;

[0059] 40. Second mounting seat; 41. Second auxiliary mounting seat;

[0060] 50. Heating plate;

[0061] 60. First driving part;

[0062] 70. Second driving part;

[0063] 80. Top plate;

[0064] 90. Longitudinal rib;

[0065] 100. Rotating shaft;

[0066] 101. Thermal insulation board. Detailed implementation manners

[0067] The following further elaborates on this application in conjunction with the attached Figure 1 - attached Figure 9 , with further detailed description.

[0068] In this application, aiming at the current dilemma that a large number of cracks appear in the in-service orthotropic steel bridge deck but are difficult to repair, post-weld heating and heat preservation are carried out on the welds of the orthotropic steel bridge deck, ultimately achieving the effects of reducing residual stress and dehydrogenation.

[0069] Based on the detection of the residual stress of the fillet welds of the orthotropic steel bridge deck, this application conducts a large number of modeling and full-scale bridge tests on the reasons for fatigue cracking at the welds between the top plate and the longitudinal ribs, between the diaphragm and the longitudinal ribs, and at the openings of the diaphragm. Through analysis, research, detection, and inspection, it is finally confirmed that the transverse residual stress as high as 200 MPa after welding induces the generation of cracks in the initial defects of the welds under the side effect of the vehicle operation stress; meanwhile, the longitudinal welding residual stress as high as 400 MPa (which has exceeded the yield strength of the base metal) is the main reason for the rapid propagation of cracks.

[0070] After it is clear that welding residual stress is the main cause of weld fatigue cracking, a large amount of research and development has been carried out on various stress-relieving technologies, and it is finally confirmed that post-weld heat treatment of the weld is the best method for stress relief and dehydrogenation. On this basis, relevant equipment for local heating and annealing of orthotropic steel bridge deck welds to reduce weld residual stress and dehydrogenation is developed, filling the technical equipment gap at home and abroad for post-weld heat treatment of welding repairs for diseases of in-service orthotropic steel bridge decks. After the relevant equipment and methods in this application are used for crack repair of actual bridges, the effect is good. The detected post-weld residual longitudinal stress is reduced from an average of 400 MPa to about 120 MPa, and the transverse residual stress is reduced from 150 MPa to within 100 MPa. No delayed cracks caused by hydrogen-induced embrittlement occur, achieving good social and economic benefits.

[0071] Specifically, referring to Figure 1 and Figure 2 As shown, in this embodiment, the local annealing stress-relieving equipment for orthotropic steel bridge deck welds includes a mobile power station 10, a heating temperature control system 20, a first mounting seat 30 for abutting against the bottom of the orthotropic steel bridge deck 80, and a second mounting seat 40 for abutting against the orthotropic steel bridge longitudinal rib 90; one end of the second mounting seat 40 is installed and connected to the first mounting seat 30, and heating plates 50 are fixedly provided on the mutually facing sides of the first mounting seat 30 and the second mounting seat 40; the heating temperature control system 20 is electrically connected to the heating plates 50 and is used to control the heating temperature and time of the heating plates 50. The heating temperature control system 20 controls the heating temperature and time of the heating plates 50 through the magnitude of voltage, current, and energization time. Temperature sensors can be arranged on the heating plates 50 to provide real-time feedback on the actual temperature of the heating plates 50. The mobile power station 10 is used to supply energy for heating the heating plates 50 and is electrically connected to the heating temperature control system 20. In this way, when the whole equipment operates in the field environment, there is no need to additionally set up wires, thus meeting the use requirements of complex working conditions and reducing the use limitations of the whole equipment.

[0072] Referring to Figure 3 and Figure 4As shown, both the first mounting seat 30 and the second mounting seat 40 are plate bodies. One end of the second mounting seat 40 is rotatably connected to one end of the first mounting seat 30 through a rotating shaft 100. A first driving member 60 for driving both of them to move in the direction of the orthotropic steel bridge longitudinal rib 90 is connected to the first mounting seat 30 and the second mounting seat 40. There are at least two first driving members 60 mounted on the first mounting seat 30 and the second mounting seat 40. In this embodiment, preferably, there are two first driving members 60 mounted on the first mounting seat 30 and the second mounting seat 40, and the four first driving members 60 are distributed in a rectangular array. The first driving member 60 is a hydraulic rod or an electric push rod. An ear plate 31 corresponding to each first driving member 60 is fixedly provided on the side surface of the first mounting seat 30 close to the second mounting seat 40. One end of the first driving member 60 is pin-connected to the corresponding ear plate 31, and a magnetic attraction structure is arranged at the other end of the first driving member 60. The magnetic attraction structure can be an electromagnet or a permanent magnet. The above-mentioned multiple first driving members 60 can stably and reliably push the first mounting seat 30 and the second mounting seat 40 to move. At the same time, the magnetic attraction structure at the end of the first driving member 60 is used to assist in tightly clamping the first mounting seat 30 and the second mounting seat 40 between two adjacent longitudinal ribs 90, ensuring the stable and reliable installation of the first mounting seat 30 and the second mounting seat 40, and also enabling the heating plate 50 to fit more closely with the orthotropic steel bridge top plate 80 and the longitudinal rib 90, improving the heat conduction efficiency, reducing heat loss, and ensuring the heat treatment effect at the same time.

[0073] Referring to Figure 3 and Figure 4 As shown, a second driving member 70 for pushing the second mounting seat 40 to swing on the first mounting seat 30 is arranged between the first mounting seat 30 and the second mounting seat 40. The swing amplitude of the second mounting seat 40 is the included angle range of 90° to 105° between it and the first mounting seat 30. Combining Figure 5 and Figure 6 As shown, the second driving member 70 drives the second mounting seat 40 to swing, adapts to longitudinal ribs 90 of different shapes, and ensures that the heating plate 50 on the second mounting seat 40 fits more closely with the side surface of the longitudinal rib 90, thereby ensuring the stable and reliable local heating and improving the heat treatment effect. The heating plate 50 on the second mounting seat 40 swings within the above angle range as the second mounting seat 40 swings, which can meet the different welding angle change requirements for connecting different stiffeners such as U-shaped ribs, I-shaped ribs, L-shaped ribs, etc. The overall versatility is high and the adjustment is convenient.

[0074] In this embodiment, the second driving member 70 is also a hydraulic rod or an electric push rod; both ends of the second driving member 70 are respectively connected to the adjacent sides of the first mounting seat 30 and the second mounting seat 40. The second driving member 70 can automatically adjust the swing angle of the second mounting seat 40 according to preset programs and parameters, and lock itself after the adjustment is in place, so as to meet the requirements of different longitudinal rib 90 shapes and ensure the stability and reliability of its use.

[0075] Referring to Figure 3 and Figure 4 As shown, a first auxiliary mounting seat 32 for abutting against the orthotropic steel bridge diaphragm is fixedly provided at the end of the first mounting seat 30, and a second auxiliary mounting seat 41 for abutting against the orthotropic steel bridge diaphragm is fixedly provided at the end of the second mounting seat 40; heating plates 50 are also fixedly provided on the sides of the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41 facing away from the first mounting seat 30 and the second mounting seat 40. Further, both the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41 are triangular plate bodies, and both the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41 are perpendicular to both the first mounting seat 30 and the second mounting seat 40 at the same time; when the first mounting seat 30 is perpendicular to the second mounting seat 40, the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41 are butted to form a rectangular plate body structure; a heat preservation plate 101 is also installed on one side of the first auxiliary mounting seat 32 or the second auxiliary mounting seat 41, and the heat preservation plate 101 is fixed to one of the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41 by screws. For example, a part of the heat preservation plate 101 is fixed to the first auxiliary mounting seat 32 by screws, and another part of the heat preservation plate 101 extends out of the first auxiliary mounting seat 32 towards the direction of the second auxiliary mounting seat 41, and there is a small gap between the side surface of the heat preservation plate 101 and the side surface of the second auxiliary mounting seat 41; when the second auxiliary mounting seat 41 swings with the first mounting seat 30, the side surface of the heat preservation plate 101 is opposite to the side surface of the second auxiliary mounting seat 41 and there is slight friction or no friction between them; when the included angle between the first mounting seat 30 and the second mounting seat 30 is obtuse, the heat preservation plate 101 can block the gap between the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41. The heating plates 50 on the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41 abut against the orthotropic steel bridge diaphragm, heat the relevant disease areas, make its use range wider, and can perform heat treatment on multiple positions at the same time, with higher working efficiency.

[0076] The heating plate 50 in this embodiment is made of a customized ceramic electric heating sheet, and its length, width and angle are designed and customized according to the annealing and heat preservation requirements of the steel bridge deck; Referring to Figure 7As shown, in the present application, the first mounting seat 30, the second mounting seat 40, the first auxiliary mounting seat 32 and the second auxiliary mounting seat 41 all include a protective housing 33 and a profiled steel skeleton 34. The protective housing 33 is made of a steel plate with a thickness of 1 to 2 mm. The protective housing 33 is a sandwich structure and is filled with heat-insulating and heat-preserving cotton 35 inside. The thickness of the heat-insulating and heat-preserving cotton 35 is 10 to 20 mm. The profiled steel skeleton 34 is located inside the protective housing 33. The heating plate 50 is connected to the profiled steel skeleton 34 through a fixing member 36, and a heat-insulating asbestos board 37 is fixedly arranged between the heating plate 50 and the protective housing 33. The fixing member 36 can be a bolt, a rivet or a countersunk screw. Such a multi-layer heat-preserving structure has a good heat-preserving effect, can effectively improve the heating stability and reliability of the heating plate 50, reduce heat loss, and ensure the effect of heat treatment.

[0077] The present application also discloses a method for using a welding seam local annealing and defect elimination device for an orthotropic steel bridge deck. The welding seam local annealing and defect elimination device for the orthotropic steel bridge deck is used for the local annealing and defect elimination treatment of the welding seam of the orthotropic steel bridge deck. The method for using the welding seam local annealing and defect elimination device for the orthotropic steel bridge deck includes the following steps:

[0078] S1: Surface leveling: Milling or grinding the disease welding seams of the top plate 80, the partition plate and the rib plate of the orthotropic steel bridge to make their surfaces flat.

[0079] S2: Equipment installation and adjustment: Install the welding seam local annealing and defect elimination device at the bottom of the top plate 80. The first driving member 60 pushes the first mounting seat 30 and the second mounting seat 40 towards the rib plate of the orthotropic steel bridge and presses them against it. The heating plate 50 on the first mounting seat 30 abuts against the bottom of the top plate 80 of the orthotropic steel bridge, and the heating plate 50 on the first mounting seat 30 abuts against the rib plate of the orthotropic steel bridge.

[0080] S3: Heat treatment: Select a suitable temperature control program and parameters, preset the heating temperature and time, and perform heating annealing and defect elimination and dehydrogenation treatment on the welding seam.

[0081] S4: Detection: After the heat treatment is completed, remove the equipment, and then perform residual stress detection and acceptance.

[0082] The implementation principle is as follows: The equipment in this application repairs the disease of fatigue cracking of the weld between the longitudinal rib 90 and the top plate 80, which is the most common in the in-service orthotropic steel bridge deck. When in use, the equipment is installed at the bottom of the top plate 80. The first driving member 60 pushes the first mounting seat 30 and the second mounting seat 40 towards the orthotropic steel bridge rib plate and holds them against it. The heating plate 50 on the first mounting seat 30 abuts against the bottom of the orthotropic steel bridge top plate 80, and the heating plate 50 on the first mounting seat 30 abuts against the orthotropic steel bridge rib plate. The heating temperature and heating time of the heating plate 50 are controlled by the heating temperature control system 20, so as to perform heat treatment on the weld, eliminate the welding residual stress, improve the weld metal microstructure, and thus improve the mechanical properties, corrosion resistance and fatigue resistance of the weld.

[0083] Referring to Table 1, during the annealing process, since the peak temperature of the annealing process is 600 °C and the base metal does not undergo austenite phase transformation, and martensite is a supersaturated solid solution of carbon in α-Fe. As the annealing process proceeds, element diffusion and element combination cause carbon and carbides to precipitate at the α-Fe grain boundaries, and the supersaturated state of carbon in α-Fe disappears, forming a mixed structure of α-Fe and carbides, that is, bainite structure. During the annealing process, as the martensite structure disappears, carbon and carbides precipitate, dislocation migration, a small amount of plastic deformation, and uniform distribution of grains occur, the internal structure of the material changes, the deformation of the internal stress disappears, and the residual stress of the welded joint is reduced and released and shows a uniform distribution.

[0084] Serial number Annealing temperature / °C Insulation time / min Maximum heating rate °C / h Maximum cooling rate °C / h 1 600～620 25 220 280 2 550～570 180 220 280 3 500～520 360 220 280

[0085] Table 1

[0086] This application is used for local annealing heat treatment of the welded seams of the in-service orthotropic steel bridge deck. Through the heating plate in the relevant equipment, the outer side of the heating plate is completely attached to the outside of the rib plate and the weld corners on the left and right above with the flattest and most uniform force. Compared with the existing technology, this achieves uniform annealing heat treatment of the butt welds of the rib plates, thereby more uniformly eliminating the welding residual stress; the relevant equipment in this application is convenient for installation and disassembly, has a high degree of automation, good heating and heat preservation effects; the whole equipment is easy to carry, can be reused, and reduces the production cost; the method in this application is conducive to completing the post-weld annealing of the orthotropic steel bridge deck, can shorten the construction period, save construction costs, effectively connect the construction processes, conforms to the concept of green construction, has strong practicability, and the key technologies of the annealing process have the advantages of high stress elimination rate and simple operation.

[0087] Referring to Figure 8 and Figure 9As shown in the test data graph of the residual stress change before and after annealing obtained from thousands of actual bridge experiments, in this application, after the process treatment of automatic heating, heat preservation, and cooling of the weld at the repair location, the transverse residual stress of the weld at the repair location is reduced by 75%, and the longitudinal residual stress is reduced by more than 80%. The phenomenon of hydrogen embrittlement is basically eliminated, and the effect of eliminating residues is obvious, solving the world problem of repeated cracking in a short period after the repair of in-service bridges.

[0088] The heating temperature control system in this application includes a controller, which realizes automatic and precise control of the heating time and heating temperature through a pre-set software control program. It has a high degree of automation and high working efficiency. It can also be remotely controlled, saving manpower and being safer. At the same time, for different steel characteristics, various materials can be easily applied through the corresponding selection of software programs. For example, for orthotropic steel bridge deck materials 350, 370, 420, 620, etc. with different yield strengths, software programs with corresponding different heating temperatures and heating times are set. Thus, according to the pre-obtained steel bridge material model, the corresponding automatic temperature control program can be quickly selected to meet the requirements of multi-function and diversification.

[0089] The embodiments of this specific implementation manner are all preferred embodiments of this application, and do not limit the protection scope of this application accordingly. The same components are represented by the same reference numerals. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A local annealing and residual removal equipment for welds of orthotropic steel bridge decks, characterized in that: It comprises a first mounting seat (30) for abutting against the bottom of an orthotropic steel bridge top plate (80) and a second mounting seat (40) for abutting against a longitudinal rib (90) of the orthotropic steel bridge; one end of the second mounting seat (40) is mounted and connected to the first mounting seat (30); The first mounting seat (30) and the second mounting seat (40) are connected to a first driving member (60) for driving the two to move toward the orthotropic steel bridge longitudinal rib (90); A heating plate (50) is fixedly provided on the side surfaces of the first mounting seat (30) and the second mounting seat (40) facing away from each other; The weld local annealing and residual removal equipment further comprises a heating temperature control system (20), wherein the heating temperature control system (20) is electrically connected to the heating plate (50) and is used to control the heating temperature and time of the heating plate (50); The first mounting seat (30) and the second mounting seat (40) are both plate-shaped, and one end of the second mounting seat (40) is rotatably connected to one end of the first mounting seat (30) via a rotating shaft (100); a second driving member (70) is provided between the first mounting seat (30) and the second mounting seat (40) for driving the second mounting seat (40) to swing on the first mounting seat (30); A first auxiliary mounting seat (32) for abutting against the orthotropic steel bridge diaphragm is fixedly provided at the end of the first mounting seat (30), and a second auxiliary mounting seat (41) for abutting against the orthotropic steel bridge diaphragm is fixedly provided at the end of the second mounting seat (40); the heating plate (50) is also fixedly provided on the side surfaces of the first auxiliary mounting seat (32) and the second auxiliary mounting seat (41) facing away from the first mounting seat (30) and the second mounting seat (40); The first auxiliary mounting seat (32) and the second auxiliary mounting seat (41) are both triangular plates, and the first auxiliary mounting seat (32) and the second auxiliary mounting seat (41) are both perpendicular to the first mounting seat (30) and the second mounting seat (40); when the first mounting seat (30) and the second mounting seat (40) are perpendicular, the first auxiliary mounting seat (32) and the second auxiliary mounting seat (41) are relatively connected to form a rectangular plate structure; a heat preservation plate (101) is also installed on one side of the first auxiliary mounting seat (32) or the second auxiliary mounting seat (41); when the angle between the first mounting seat (30) and the second mounting seat (40) is an obtuse angle, the heat preservation plate (101) can block the gap between the first auxiliary mounting seat (32) and the second auxiliary mounting seat (41).

2. The local annealing and residual removal equipment for welds of orthotropic steel bridge decks according to claim 1 is characterized in that: There are at least two first driving members (60) installed on the first mounting seat (30) and the second mounting seat (40), and the first driving member (60) is a hydraulic rod or an electric push rod; an ear plate (31) corresponding to the first driving member (60) is fixed on the side surface of the first mounting seat (30) and the second mounting seat (40) close to each other, and one end of the first driving member (60) is pinned to the corresponding ear plate (31), and the other end of the first driving member (60) is provided with a magnetic attraction structure.

3. The local annealing and residual removal equipment for welds of orthotropic steel bridge decks according to claim 1 or 2, characterized in that: The swing amplitude of the second mounting seat (40) is within the angle range of 90° to 105° between the second mounting seat (40) and the first mounting seat (30).

4. The local annealing and residual removal equipment for welds of orthotropic steel bridge decks according to claim 1 or 2, characterized in that: The second driving member (70) is a hydraulic rod or an electric push rod; the two ends of the second driving member (70) are respectively connected to the side surfaces of the first mounting seat (30) and the second mounting seat (40) that are close to each other.

5. The local annealing and residual removal equipment for welds of orthotropic steel bridge decks according to claim 1 is characterized in that: The heating plate (50) is made of a ceramic electronic heating plate; the first mounting seat (30), the second mounting seat (40), the first auxiliary mounting seat (32) and the second auxiliary mounting seat (41) all include a protective shell (33) and a steel frame (34); the protective shell (33) is a sandwich structure and is filled with heat-insulating cotton (35); the steel frame (34) is located in the protective shell (33); the heating plate (50) is connected to the steel frame (34) via a fastening member (36) and a heat-insulating asbestos board (37) is fixed between the heating plate (50) and the protective shell (33).

6. The local annealing and residual removal equipment for welds of orthotropic steel bridge decks according to claim 1 is characterized in that: The weld local annealing and residual removal equipment also includes a mobile power station (10), wherein the mobile power station (10) is used to supply energy and heat the heating plate (50) and is electrically connected to the heating temperature control system (20).

7. A method for using a local annealing and residual removal device for welds of orthotropic steel bridge decks, characterized in that: The local annealing and residual removal equipment for welds as described in any one of claims 1 to 6 is used to perform local annealing and residual removal treatment for welds; the method of use comprises the following steps: S1: Smoothing the surface: milling or grinding the top plate (80), diaphragm and rib plate defect welds of the orthotropic steel bridge to make the surface smooth; S2: Installing and adjusting the equipment: installing the weld local annealing and residual removal equipment on the bottom of the top plate (80), the first driving member (60) pushes the first mounting seat (30) and the second mounting seat (40) to move toward the orthotropic steel bridge rib plate and hold it; the heating plate (50) on the first mounting seat (30) abuts against the bottom of the orthotropic steel bridge top plate (80), and the heating plate (50) on the first mounting seat (30) abuts against the orthotropic steel bridge rib plate; S3: Heat treatment: Select appropriate temperature control program and parameters, preset heating temperature and time, and perform heating annealing, residual dehydrogenation treatment on the weld; S4: Inspection: After the heat treatment is completed, the equipment is dismantled and then residual stress detection and acceptance are carried out.

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