440 results about "Welding residual stress" patented technology

The invention relates to a method for measuring welding residual stress-a partial layer-by-layer blind hole removing method for measuring the residual stress on the basis of a blind hole method, which proposes to measure the residual stress in a component by using the partial layer-by-layer blind hole removing method. After materials of certain depth on both the front side and the opposite side of a component to be measured are partially removed, the blind hole method is used for measuring the residual stress. The method is a semi-destructive residual stress measuring method, can be used for carrying out multi-point measurement and measuring the residual stress in the component with severe stress change and has convenient operation and high measuring efficiency. Proved by a thick plate carbon steel welding residual stress measuring test, the method has more accurate measuring results.

The invention relates to the technical field of welding, in particular to a method for controlling deformation of a nickel-based ageing-strengthening high-temperature alloy casing welding assembly, and a piece of technological equipment of the method. According to the method, the welding deformation is controlled by using rigid limit of materials with close linear expansion coefficients, a tooling structure that can meet rigid supporting requirements during welding as well as control and eliminate residual stress deformation during welding is adopted, after an inner ring and eight T-shaped supporting plate components form an eight-diagram structure, a heat treatment process at the temperature of 550 DEG C for eliminating stress is additionally performed so as to reduce residual stress between the inner ring and the roots of the supporting plates before electron beam welding; after all welding processes are completed, a vacuum solution treatment process at the temperature of 970 DEG C is additionally performed, and a double aging treatment process at the temperature of 720 DEG C and 620 DEG C is further additionally performed to completely eliminate residual internal stress after welding so as to achieve service performance. According to the invention, the problems that the conventional combustion engine can not control fatigue crack, and requirements on the reliability and the service life of the combustion engine can not be met are solved; by adopting the novel welding technology method and the technological equipment, the investment is small, the operation is simple and the engineering application is facilitated.

The invention belongs to the technical field of metal plate forming, and relates to a wall board creep age forming method based on finite element mould profile rebound compensation. By the wall board creep age forming method, a finite element method is used for determining a mould profile, technological tests and mould repairing times are largely reduced, appearance control of formed parts can be realized, and forming precision is improved; according to the data through analog computation of forming process and rebound process of a formed piece, the mould profile is compensated, revised and optimized, so that rebound parts are the same as or close to the appearance of an ideal formed piece, and automatic optimization to the mould appearance during a creep age forming process is realized. The forming method can be applicable to various wallboard structures; except for overall wallboard parts, the forming method can be used for welding overall wallboards; welding residual stress can be effectively reduced, stress corrosion resistance capability is enhanced, and service lives of parts are prolonged.

The invention relates to an ultrasonic assisted laser electric arc composite welding method of an aluminum alloy. On the basis of carrying out a welding scheme by combining TIG electric arc welding and laser welding, ultrasonic vibration pressure is introduced into a welding seam, wherein a designed vibration head is in direct contact with the welding seam, so that ultrasonic resources can be more sufficiently utilized, and gas in the welding seam can be rapidly escaped; most of gas in the welding seam is removed so that welding seam gas pore defects are reduced or avoided; tissue crystal grains of the welding seam are remarkably refined by utilizing cavitation effect and acoustic streaming effect caused by the fact that ultrasonic waves are transmitted in liquid, and furthermore, tissue alloy elements of the welding seam are more uniform, segregation is reduced, the strength and corrosion resistance performance of the welding seam are improved, and the performance of a welding connector is improved; and welding residual stress is effectively eliminated or reduced and the strength and corrosion resistance performance of the connector are enhanced, so that the efficient welding of the aluminum alloy is realized.

The invention provides a welding microcell performance test based residual stress detection method, which comprises the following steps of: carrying out a micro-compression-shear test on a welding microcell so as to obtain a load-displacement curve of the welding microcell, establishing a 3D (three-dimensional) finite element model of a micro-compression-shear test process, and carrying out a finite element reverse backstepping method based on an improved Gurson model so as to obtain a true stress-strain relation of the welding microcell; computing the welding residual stress, wherein in the process of carrying out computing on a welding temperature field, the influence of the mechanical property of the welding microcell on the change of the temperature field is not considered; and after the welding temperature field is obtained, in the process of carrying out computing on a welding stress field, taking normal-temperature mechanical property parameters (when the temperature of a weldment is reduced according to the true stress-strain relation of the welding microcell) into a welding computing model, and then obtaining the welding residual stress through computing. The accuracy of the method disclosed by the invention is higher than that of a result obtained by using a residual stress computing method which is implemented through not considering the mechanical property of the welding microcell.

A catalytic converter assembly welding method for a vehicle exhaust system uses incremental part welding and includes the following steps of welding a front cone, a carrier shell and a rear cone on carrier shell subassembly welding equipment to form carrier shell subassembly, welding a front flange, a front connection tube, a middle connection tube, and the welded carrier shell subassembly on a front subassembly welding equipment to form a front subassembly, and welding flexible connection, a rear connection tube, a rear flange and the front subassembly on assembly welding equipment so as to form a catalytic converter assembly. The catalytic converter assembly welding method for the vehicle exhaust system has the advantages of greatly reducing cumulative welding residual stress caused by integrated welding and forming, avoiding deformation of complex welding on junctions of various part, improving product quality, eliminating quality problems caused by welding residual stress and a large of unqualified products owing to the welding deformation, and improving production efficiency.

The invention relates to a method for measuring sheet welding residual stress. The method comprises the steps of sticking two rows of symmetrically distributed resistance strain gages on a weldment at first and enabling the direction of a strain grid to be consistent with the direction of a weld joint, next, cutting the weldment into two parts with the same size in a direction perpendicular to the weld joint so that the residual stress is released, observing and recording the changes of readings of the two groups of strain gages to obtain two groups of strain values released in the direction of the weld joint, and performing numerical value averaging on the obtained two groups of strain values of the two cut surfaces of the weldment, carrying out polynomial fitting through EXCEL, and finally, obtaining an original residual stress distribution curve in the direction of the weld joint through conversion according to Hooke's law. The method has the beneficial effects of high measurement accuracy, multi-point measurement, high reliability, convenient operation and low equipment cost.

The invention relates to a preparation method for a hydraulic pressure composite thermometal oil pipe. A carbon steel outer pipe is subjected to abrasive blasting and derusting, and the cleaning of the inner surface of the carbon steel outer pipe and the outer surface of a stainless steel inner pipe is ensured; the inner pipe penetrates into the outer pipe, and hydraulic pressure composite is conducted through a hydraulic press after the penetration is completed; the carbon steel outer pipe is made to deform elastically and the stainless steel inner pipe is made to deform plastically in the composite process, so that the inner pipe and the outer pipe are made to combined closely. After the composite process, pipe end machining is conducted before welding, and eddy current inspection is conducted on the whole oil pipe after the pipe end machining is completed; if the oil pipe is qualified through the inspection, the two pipe ends are subjected to bead welding which is completed through an automatic welder, and the bonding strength of the pipe ends are ensured. Pipe end heat treatment is conducted for removing the residual stress of the welding after the welding is completed. After the stress is removed, coping of a screened pipe and turning of threads are conducted, and inspection is conducted after the turning of threads is completed. Coupling and path opening are conducted after the oil pipe is qualified. The whole inner surface of the product prepared through the preparation method is corrosion resistant, and the corrosion-resistance strength is high; the outer pipe ensures that the strength of the composite oil pipe is enough, so that the stainless steel composite oil pipe has the characteristics of anticorrosion and abrasion resistance. Besides, the cost is low and the service life is long.

The invention discloses a technological method for welding low-alloy high-strength steel, which comprises the following steps: a divided edge is formed, a welding area is polished and cleaned, and the strength of welding material is equivalent to that of steel to be welded; Ar+CO2 mixed gas protective welding is adopted, preheating is performed before welding, and the welding speed is 250-300mm/min; a 800MPa solid welding wire is adopted to perform multilayer multirun welding; the interlayer temperature is kept at 150 DEG C plus or minus 20 DEG C during the welding process, a preheating spray gun is used from time to time for temperature compensation, the welding line energy is 16-18KJ/cm, low temperature aging is performed to the whole after welding, and the temperature is 300-400 DEG C. The welding technological method prevents welding cracks from being generated, eliminates residual stress generated during welding large-sized structural members, and serves the purpose that the tensile strength of weld joins equals the tensile strength of parent metal.

The invention discloses a self-reset magnetic fluid damper. The self-reset magnetic fluid damper comprises an outer tube, an inner tube, outer tube inner casing tubes, inner tube outer casing tubes, damper pistons, a magnetorheological fluid, permanent magnets, a magnetism isolating ring, sealing end plates, a left side spring and a right side spring, wherein first bosses are inwards arranged on the inner wall of the middle of the outer tube, outer tube fixing baffles are inwards arranged at two ends of the outer tube and are round baffles provided with round holes formed in the middles, the outer tube inner casting tubes are fixedly arranged on the inner wall of the outer tube between the first bosses and the outer tube fixing baffles, and second bosses are arranged at the ends, close to the first bosses, of the outer tube inner casting tubes. A force is transferred in the inside through the inner tube, the outer tube and the casting tubes, assembly is simple, a welding range is greatly decreased, change of the metallographic structure and mechanical performance of a steel product caused by welding and residual welding stress are avoided, and the stress performance of the members is more stable. The self-reset magnetic fluid damper is convenient to use and has higher reliability.

The invention provides a method and device for laser peening correction size precision online control for a welded metal plate. A laser machine emits a laser beam, the laser beam is transmitted to a workpiece welding area through a light path system, a water limiting layer covers the welding area, and a limiting layer is formed. Under the action of laser pulse, impulse waves are formed on the welding surface, residual compressive stress is generated in the welded metal plate, and the residual compressive stress is eliminated. Efficiency of laser penning is high, a deep residual compressive stress layer can be generated, size correcting efficiency is high, the size correcting makes the surface and a certain depth range of a peening area of a welded piece to be subjected to plastic deformation, the straightening purpose is achieved, and meanwhile, fatigue strength of a welded joint is improved. According to the method and device for the laser peening correction size precision online control for the welded metal plate, precise size correcting can be conducted on the welded piece, working efficiency is high, controllability is good, and the range of application is wide.

The invention relates to a method for analog calculation of a welding value by taking temperature as a control variable, which comprises the following steps: 1) arranging welding temperature field distribution into a function of time and space: T(x, y, z,t)=f(x)f(y)f(z)f(t); 2) taking the obtained temperature distribution function T(x, y, z, t)=f(x)f(y)f(z)f(t) as a thermology boundary condition to add into a mechanics analysis model of a welding structure in a subprogram form; and 3) calculating the welding residual stress and the residual deformation of the model. The method converts the control variable in the welding simulation from heat to temperature, adds the proper temperature distribution in a sectional mode onto the mechanical analysis model for the analysis of stress and deformation, and can reduce the mechanical value analyzing time within 10 percent of the time used by a moving heat source method. The method can be widely used for welding welded structures with long welding lines, multiple welding lines and multiple passes, and has very important function on promotion and reference in projects.

The present invention discloses an extra-thick sheet submerged-arc welding technique. The technique comprises the following technological parameters and steps: 1) connector preparation: X-type beveled edges are adopted by extra-thick sheets; 2) preheating: first heating a back side of an extra-thick sheet and then a front side of the extra-thick sheet, a preheating temperature being 150 DEG C to 160 DEG C, and a heating rate being not higher than 105 DEG/h; 3) backing welding: after preheating, using flux-cored wire gas shield welding for backing welding for two paths to form two layers, and using submerged-arc welding to fill at least two paths to form one layer, maintaining interlayer temperature to be not higher than 230 DEG C; 4) turning over after an inter-welding deformation is not larger than 6-8 mm; 5) backside welding: after carbon gouging and back chipping, backing welding according to the step 3) after the extra-thick sheet reaches a preheating requirement according to the preheating method described in the step 2); 6) stress relief treatment; and 7) carrying out post heating treatment at 200 DEG C/2h after the welding, then slowly cooling the extra-thick sheet to be at the room temperature. With adoption of the technique provided by the present invention, rooting welding deformation is reduced, welding residual stress for subsequently filling a cover face is also reduced, and thus turn-over times in welding of the extra-thick sheet are reduced.

The invention discloses a butt joint method for super-thick steel plates. The butt joint method for the super-thick steel plates comprises the steps of: machining grooves at butt joint parts of the steel plates, wherein the grooves are U-shaped grooves with symmetrical two surfaces, the angle of each groove is 8-10 degrees, and the radius of the arc at the root of each groove is 9-11mm; pre-heating before welding, wherein the preheating temperature is 40-60 DEG C, and locating welded joints after preheating; alternatively welding the welded joints on two sides by turning over for many times, backstep welding the layers of welding joints; keeping temperature in a welding process to be not more than 200 DEG C; keeping warm after welding, and cooling slowly. Since the U-shaped grooves are employed, the sectional area of the welded joints are greatly reduced, thermal input is reduced, control on welding deformation is facilitated, welding residual stress is reduced by backstep welding, two sides of the welded joint of the steel plate are subjected to uniform force by turning over for many times in welding, deformation in the welding process is corrected, the super-thick steel plate is rapid in heat dissipation after welding, quality of the welded joint is ensured by the method of keeping warm after welding, and stress deformation can be reduced by slowly cooling.

A method for eliminating the welding residual stress by utilizing high-pressure water jet belongs to technical field of welding. The high-pressure water jet (3) sprayed by a nozzle (1) moves on a weld (4), the axial dynamic pressure of the water jet (3) is adjusted to be 220-700MPa; the distance between the water outlet of the nozzle (1) and the weld (4) is kept to be 5-10mm, the water jet (3) moves back and forth for 4 to 8 times along the weld track and perpendicular to the workpiece surface, and the stress eliminating effect is reinforced. The method for eliminating the welding residual stress is easy to operate, and quickly eliminates the residual stress on the welding part after welding. The stress on the weld in a narrow space can be eliminated, such as dead angle part and repair welding part, and can ensure that the whole weld stress eliminating effect is good, stable and average.

A diffusion connection method of carbide ceramic relates to a carbide ceramic welding method. The diffusion connection method aims at solving the problem that when a metal middle layer is used for connecting the carbide ceramic and composite ceramic, a residual metal middle layer is formed in a welded joint, and the structure of the welded joint is inhomogenous. The diffusion connection method comprises the steps of: 1, carrying out surface cleaning; 2, electroplating a Ni metal layer; and 3, welding, thus completing the diffusion connection of the carbide ceramic. The diffusion connection method has the advantages that 1, the welded joint without the residual middle layer and with the homogeneous structure is formed, the welding residual stress caused by the residual middle layer in a common diffusion welding joint is relieved, the room-temperature mechanical property of the welded joint is increased, and the high-temperature mechanical property and oxidation resistance of the welded joint are also increased; and 2, the diffusion connection method is simple and practicable without needing complex working procedures and equipments. The diffusion connection method of the carbide ceramic, provided by the invention, is mainly used for diffusion welding of the carbide ceramic.

The invention discloses a water-cooling argon-arc welding method for welding austenitic stainless steel, which is characterized in that: after finishing backing welding at the welding seam of a workpiece, the back of the welding seam is cooled with cold water when filling and cover-welding is carrying out for the welding seem. The invention solves the problems that high welding stress and poor corrosion resistance exist in the prior austenitic stainless steel welding and ensures that the welding seam of the austenitic stainless steel has fine metal crystal grains, uniform structure and small residual welding stress. The invention can not only obtain ideal welding joints but also improve the productive efficiency of welding.

The invention discloses a method for eliminating welding residual stress. The method comprises the steps that an X-ray diffraction (XRD) test is conducted on a welding part for surface welding residual stress testing, and welding residual stress surface layer data is obtained; a welding simulation model of the welding part is established, simulation data of the welding residual stress is calculated, and then the distribution law of the welding residual stress of the welding part is finally obtained; numerical simulation calculation of the vibration impact process is conducted by simulating the impact frequency and the impact amplitude on the basis of the distribution law of the welding residual stress, and then vibration impact parameters for eliminating the welding residual stress are obtained; the welding part is clamped in a drivable positioning workbench, the positions of an impact head and a welding part welding joint on the positioning workbench are adjusted, and impact treatment is conducted in the mode that the axis of the impact head arranged on the workbench is perpendicular to the weld joint surface of the welding part according to the impact frequency and impact amplitude which are obtained before. The method has the advantages of being precise, low in energy consumption, good in eliminating effect, high in efficiency and the like.

The present invention discloses a welding residual stress measurement method based on the ABAQUS. The method comprises: according to the geometry of the test piece, establishing a 3D geometric model of the welded test piece; performing global mesh generation on the model; loading material data and thermal boundary conditions to simulate the welding process; and finally solving the temperature field and the stress field. The numerical simulation results of the method disclosed by the present invention have high accuracy and can be used as an effective tool for welding process design and parameter optimization.

The invention discloses an accumulated fatigue damage self-diagnosis system for a railway steel truss bridge node. When a train boards a bridge, a stress response time-history signal of a middle cross section of a truss rod piece which is connected with the tested node when the train goes by is automatically acquired through a strain sensor; a bending moment and shaft force time-history conversion module converts the stress response time-history signal into a bending moment and shaft force time-history signal; a dynamic stress analysis module takes a node welding residual stress field which is determined according to a construction process of a node welding line as an initial stress field, and superposes a node train traveling dynamic stress field which is determined by the bending momentand shaft force time-history signal to obtain the position of a most dangerous point and the strain state of the bridge node welding line; and finally, a fatigue accumulation analysis module determines the fatigue damage accumulation degree of the most dangerous point when the train goes by according to the position of the most dangerous point and the strain state and the strain fatigue critical surface method, and then a man-machine interaction interface informs a user of the fatigue damage accumulation degree. Therefore, the system can automatically inform the user of fatigue information ofthe welding line of the railway steel truss bridge node in time so as to repair the railway steel truss bridge in time and guarantee the safety of the railway steel truss bridge.

The invention discloses a method for lowering a weld seam cracking risk in the heat treatment process after welding of a large inserting plate of an extra-high pressure container, and relates to the technical field of pressure container welding. The method includes the following steps of increasing the width of a weld seam cover; grinding the weld seam cover; determining a heating region, and arranging heating sheets and heat preservation cotton; and carrying out post-welding heat treatment by adopting a six-section three-times symmetric heating mode. The method has the beneficial effects thatby increasing the width of the weld seam cover and combining a mechanical grinding method, the weld seam cover and a base material are made to in smooth transition, stress concentration and tensile welding residual stress at weld seams and weld toes of the large inserting plate of the extra-high pressure container are remarkably lowered, the six-section three-times symmetric heating mode is adopted for post-welding heat treatment, large discordant deformation in the post-welding heat treatment process is avoided, deformation coordination on two sides of the weld seams is improved, and the weld seam cracking risk is effectively lowered.