Showing papers on "Butt welding published in 2007"

Welding job sequencer

Abstract: A semi-automatic welding work cell, including a welding job sequencer that automatically selects a welding schedule for use by an operator in the semi-automatic welding work cell. The automatic selection may be by way of elapsed time, a detection of welding operations, a detection of the amount of welding wire supplied for the welding operation, or a detection of the amount of energy supplied for the welding operation.

Stress corrosion cracking behavior of Nd:YAG laser butt welded AZ31 Mg sheet

Abstract: In this study, the stress corrosion cracking (SCC) behavior of samples fabricated from AZ31 Mg alloy by laser butt welding was investigated in slow strain rate tensile (SSRT) and constant load tests. The results show that the laser butt welded AZ31 Mg samples are highly susceptible to SCC. The failure of the samples occurred in the fusion boundary when tested in corrosion environment in contrast to failures in the fusion zone (FZ)/base region observed for tests in air. It is suggested that weakening of the fusion boundary is due to the localized corrosion attack along the region.

The effect of thermal properties and weld efficiency on residual stresses in welding

Abstract: Purpose: A parametric model is adopted and the technique of element “birth and death” is used to estimate the effect of thermal properties and weld efficiency on residual stresses in butt weld joints. Design/methodology/approach: Residual stresses and distortions on butt welded joints are numerically evaluated by means of finite element method. The FE analysis allows to highlight and evaluate the stress field and its gradient around the fusion zone of welded joints, higher than any other located in the surrounding area. Findings: The main conclusion is the significant effect of varying the value of the conductivity on residual stresses. Practical implications: Several experimental destructive and non destructive techniques for directly measuring residual stress have been developed. However, the application of these methods in practice is usually limited by either cost or accuracy. Numerical simulation based on finite element techniques, therefore, offers a comprehensive solution for the prediction of residual stress and strain as well as welding distortion in complex welded structures.

The influence of thermal properties and preheating on residual stresses in welding

Abstract: A 2D finite element model has been carried out to analyse temperature distribution in butt weld joints. Temperature fields have been investigated by varying both thermal properties and an initial preheating treatment. Successive thermo-mechanical analyses were performed to evaluate resulting residual stresses. Temperature distribution and residual stresses were determined in a single-pass butt joint welded by Gas Metal Arc Welding (GMAW) process. A finite element parametric model was carried out and the technique of 'element birth and death' was adopted to simulate the process of filler metal addition. By means of finite element analysis high stresses were evaluated, with particular regard to Fusion Zone (FZ) and Heat-Affected Zone (HAZ). The influence of thermal properties and preheating on residual stresses in welding was also investigated. In the last few years, various experimental destructive and non-destructive methods were developed to evaluate residual stresses. However it is impossible to obtain a full residual stress distribution in welded structures by means of experimental methods. This disadvantage can be solved by means of computational analysis, which allows to determine the whole stress and strain fields in complex structures. This paper demonstrates that the technique of 'element birth and death' is suitable to simulate welding processes. Moreover, the study of welded joints should take into consideration the effect of material thermal properties and preheating treatment. [Received 18 November 2005, Accepted 20 January 2007]

In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

Abstract: A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 µm spot diameter. It was revealed that a 45 µm narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 µm gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam.

Orbital carrier comprising at least two components in the form of segments of a circle able to be connected together; device for butt-welding pipes to form a pipeline comprising such an orbital carrier

Abstract: The invention relates to an orbital carrier (2) for a device for butt-welding pipes (C, C) to form a pipeline, said device comprising at least one welding carriage (1) supporting at least one welding head (6) which has at least one welding torch, said orbital carrier (2) surrounding the pipes (C, C) to be welded and being designed to enable positioning and movement in the plane of the joint between the pipes (C, C) of said welding carriage or carriages (1), and said orbital carrier (2) also being movable translationally along the pipeline as it grows. The invention consists in the fact that said orbital carrier (2) consists of at least two components (20) in the form of segments of a circle able to be connected together to form the orbital carrier (2) around the pipes (C, C) during a welding phase and also to allow said orbital carrier (2) to be opened, at least at the top, to allow it to pass an obstruction on the outside of the pipe (C, C). Application: the welding of pipes (C, C).

Method for laser butt-welding copper or aluminum and carbon steel

Abstract: The invention is concerned with the laser butt-joint welding method for copper or aluminum in heterogeneity metal joint technology field. It is: designs the joint between the copper or aluminum and the carbon-steel plate to be slanting end face joint mode without slope, adjusts the focus of the laser beam to the bottom of the welding working piece surface, biases the laser beam to one side of the carbon-steel plate with better absorptivity, in order that another side of the copper or aluminum is heated and melted.

Method for Welding a Workpiece

Abstract: The invention describes a method of welding a workpiece (16) having a consumable welding wire (13) which is moved essentially in the direction of the workpiece (16) during a welding process by means of a wire feed unit (11), wherein a process for removing slag (42) at the end of the welding wire (13) is started and carried out. To provide a welding process which is not impaired by slag (42) possibly adhering to that end of the welding wire (13) which is to make contact and ensure reliable striking of the arc (15), provision is made for the welding current (I) to be reduced to a minimum at the start of the slag-removal process, and for the welding wire (13), during the slag-removal process, to be moved cyclically with a rapid recurring forward/backward movement by a predetermined displacement length in the direction of the workpiece (16) and by a smaller displacement distance away from the workpiece (16) again until a short circuit between the welding wire (13) and the workpiece (16) is detected by short-circuit monitoring, whereupon the slag-removal process is ended.

Computational methods and experimental validation of welding distortion models

Abstract: Multiply-stiffened, thin plate, welded fabrications are used in a wide variety of transport fields, however the resulting out-of-plane distortion associated with welding exacts a severe design penalty. Depending on the information required, the size of the structure under investigation and the computer power at hand, three computational strategies may be considered to predict welding distortion. If prediction of the localized residual stresses from welding is of major importance, then a full transient, uncoupled thermo-elastoplastic analysis is preferred. This method is not readily applicable to predict welding distortions in industrial-scale welded structures. More computationally efficient models are required and two other models are suggested in the current study. A series of experimental tests of a realistic nature were performed to validate the proposed computational strategies. Computational and experimental study of butt and fillet welding of small and industrial size fabrications is considered.

Iron wire connecting butt welder

Abstract: The utility model discloses an iron wire connection butt welding machine, belonging to the automatic welding equipment field. The utility model is arranged with a machine frame, the machine frame is arranged from left to right with a controlling panel, an alignment mechanism, a material leading mechanism, a welding mechanism, an autoswitch mechanism, an examining switch and a deburring mechanism, the right side of the machine frame is also equipped with a back feed mechanism and the back feed mechanism has the same structure and principle with the front feed mechanism, the machine frame is also equipped with a controlling circuit connected with the controlling panel and is used in controlling various mechanism revolutions; the iron wire welded by the utility model the butt welding machine, the iron wire intensity can be 80% of the new iron wire intensity, and the intensity request of griping the cotton can be satisfied. The utility model has the advantages of high automaticity and high production efficiency, thereby suitable for the iron wire welding filed.

Welding polymeric panels to metal surfaces

Abstract: A joining portion of a polymeric component, such as a vehicle door panel, may be welded (for example, a spot weld) to a metal component, such as a mating vehicle panel, using a molded-in-place metallic welding insert. The welding insert is shaped to provide welding surfaces at both surfaces of the joining portion of the plastic component and to conduct a welding current between the surfaces. When the workpieces are assembled for welding, opposing spot welding electrodes bear against the outer surfaces of the metal part and the metal insert in the plastic part. A spot welding operation produces a weld nugget between the facing surface of the metal part and the metal insert anchored in the plastic part. Continuous seam welds or a series of stitch seam welds may be made using suitably shaped welding inserts.

The effect of welding fixtures on welding distortions

Abstract: Purpose: of this paper is to examine the effect of welding fixture used to prevent the distortions during cooling process utilizing a robot controlled gas metal arc welding method on cooling rate and distortions of welded structures Design/methodology/approach: Using a specially designed welding fixture for a welded steel structure, six different types of AISI 1020 steel specimens are tested in three different welding speeds and two different cooling conditions either at fixture or without using fixture Findings: designed fixture is reduced amount of distortions The preheating effect of previous weld on the next weld has increased distortions on the other side of part Increase in distortions is directly proportional to the increase in welding speed which affects the weld heat input Research limitations/implications: the study can be repeated on more complex structures and fixtures Practical implications: the study has shown that the fixture design has an important effect on cooling rate of the welded parts

Efficient Weld Seam Detection for Robotic Welding from a Single Image

Abstract: The weld seam recognition is a key technology in robotic welding. This paper presents an efficient algorithm of weld seam detection for butt joint welding from a single image. The basic idea of our approach is to find a pair of weld seam edges in the local area first. Then, starting from the two endpoints of each edge, search for the remnant edge by iterative edge detection and edge linking. This method is insensitive to the variance of the background image and can apply to most type of weld seams in butt joint welding. Experimental results on several type of weld seam images are shown

Welding equipment and method thereof

Abstract: PROBLEM TO BE SOLVED: To simply and easily realize highly efficient welding work and then to realize high-quality butt welding. SOLUTION: The welding equipment comprises: mounting a butt arranged straight pipe 13 and elbow pipe 24 on a pipe cradle 15 and a joint pipe cradle 16; inserting a pipe centering-holding device 40 into the straight pipe 13; moving a travel unit 44 of the pipe centering-holding device 40 in the pipe and adjusting the position; driving a hydraulic mechanism 436 of its head section 43 to adjust a clamp claw 435 to elongate and contrast and to bring the clap claw into press contact with the inside of the pipes thereby centering and holding the pipes, tack welding the pipes in this state at a plurality of the points of the mutual grooves; mounting a preheater 30 to the outside near the butt portion of the elbow pipe 14 and heating the preheater 30; then thermally controlling the temperature fluctuation of the hydraulic mechanism 436 of the head section 43 of the pipe centering-holding device 40; and rotating the straight pipe 13 and the elbow 14 and performing groove downward welding to whole periphery of the butt portion of the pipe by a welding torch. COPYRIGHT: (C)2008,JPO&INPIT

Apparatus and method for tapered core drum package payoff

Abstract: Arrangements and methods for welding wire payoff sources. A tapered core and base plate, optionally along with a wire guide insert, are configured with a payout drum package and a cover containing a welding wire stack such that the welding wire may be payed off smoothly from the wire stack during an arc welding operation, without the welding wire flipping or tangling.

Motor-operated valve and solenoid valve

Abstract: PROBLEM TO BE SOLVED: To reduce material cost of a rotor case, and to reduce cost by high productivity, by providing required pressure resistant breaking strength by compensating for reduction in allowable stress by welding heat influence, without causing reduction in excitation force efficiency by an increase in the case thickness. SOLUTION: The rotor case 33 is formed of a deep drawing process product of deeply drawing a raw material having the thickness corresponding to the thickness of a welding edge part, by thickening the thickness ts' of a butt welding part to a valve housing 11 of the rotor case 33 more than the thickness ts of a coil installing part. COPYRIGHT: (C)2007,JPO&INPIT

Verification of validity and generality of dominant factors in high accurate prediction of welding distortion

Abstract: When out-of-plane distortion was measured objecting to butt welding, if tack welding was easily performed, the position of a neutral axis was variously changed by the linear misalignment. Out-of-plane distortion was generated in the unexpected direction because the neutral axis changed. From such as bitter experience, a test specimen to measure out-of-plane distortion was proposed so as to solve this problem. Using the proposed specimen, out-of-plane distortion was measured for butt welding.In the high accurate prediction of welding distortion, the dominant factors, which were satisfying the yield condition (especially at high temperature above 700 degree Celsius) and regarding the weld metal as welds, had been specified in fillet welding previously. So as to verify the validity of the dominant factors, the experiment and thermal elastic plastic analysis by FEM were carried out using newly developed specimen for butt welding. The validity of the dominant factors in the high accurate prediction of welding distortion objecting to fillet welding was verified by the results of butt welding and its generality was confirmed. It was confirmed that residual stress was also highly predicted because welding distortion was highly predicted.

Effect of Size of Butt Weld Repairs on Weld Overlay Residual Stresses

Abstract: Weld overlays have been used to provide repair and mitigation to stress corrosion cracking (SCC) susceptible butt welds in nuclear power plant piping. Among the several advantages associated with weld overlays are the beneficial compressive residual stresses that are developed in the inner portion of the component after application of the overlay. These compressive stresses can provide significant mitigation against SCC in these welds. To determine the residual stresses resulting from the weld overlay process in analytical modeling, a weld repair during original fabrication of the butt weld is typically assumed before application of the weld overlay. If the fabrication records are available, the details of the weld repair can be simulated in the analysis. However, in most cases, the weld records are not easily accessible and in instances where they are available, the quality and completeness of the information are questionable. As such, various conservative assumptions are made on the extent of the weld repair to be simulated in the analytical modeling. In this paper, the residual stress results of an axisymmetric finite element simulation of a bimetallic weld subjected to an inside surface weld repair followed by a weld overlay repair are presented. Three through-wall weld repair sizes (25%, 50% and 75% of the wall thickness without the overlay) assumed to be full 360° around the circumference were considered in the study. The results indicate that for all three weld repair cases, the inside of the configuration is very tensile after the weld repair indicating that regardless of the size of the weld repair, SCC is a possibility. The post weld repair stress distribution of the 50% and the 75% repair cases are similar indicating that an assumed 50% repair is fairly representative of repairs that can be assumed for analysis purposes. The application of the overlay resulted in favorable compressive stresses on the inside portion of the configuration for all the three weld repair cases indicating that regardless of the size of the initial weld repair, the application of the weld overlay provides mitigation against SCC.Copyright © 2007 by ASME

Welding process and geosynthetic products thereof

Abstract: An ultrasonic welding method which requires no external pressure during the welding step is disclosed. A plurality of multi-layer strips can be welded such that the weld area is not thinner than the rest of the strip and has good UV protection. The method comprises: stacking a plurality of strips; providing external pressure; removing the external pressure, positioning the ultrasonic welding apparatus so that it places no external pressure on the stack; welding at least two strips; and removing the welding apparatus.

System and method for butt-welding of steel plate

Abstract: The present invention discloses a butt welding system and a butt welding method of steel plate by which the quality of a product can be ensured. Butting portions of blank members (1, 2) to be joined together are butted and a predetermined butting load is applied to the butting portion. Under that state, the blank members (1, 2) are moved relatively in the direction of the welding line thus matching the butting portions. Consequently, protrusions and recesses formed on each butting portion of each blank member (1, 2) are flattened, and linear precision at each butting portion of each blank member (1, 2) is enhanced as compared with a case where the butting portions are not matched. Since the gap is reduced extremely at the butting portion, welding is facilitated at the butting portion. Good welding beads are thereby obtained at the butting portion and the quality of a product is ensured.

Shearing butt welding machine

Abstract: The utility model relates to a shearing butt welding machine which is characterized by comprising plain rollers, a pinching and centering device, a stroke stopping block, a bottom base, a shearing device, a welding device, a fixing bolt and a waste collecting frame. The plain rollers are arranged on a front beam and a rear beam of the bottom base. A front sliding base and a rear sliding base are arranged on the front beam and the rear beam of the bottom base behind the plain rollers. The pinching and centering device, the shearing device and the welding device which slide along the sliding bases are arranged on the front sliding base and the rear sliding base. The pinching and centering device and the plain rollers fixed on the bottom base through the fixing bolt are arranged at ends of the front beam and the rear beam behind the sliding welding device. The stroke stopping block is arranged on a lateral side of the bottom base behind the sliding pinching and centering device. The shearing butt welding machine is reasonable in design and compact in structure, ensures shearing and welding quality of strip steel, obviously improves work efficiency, has a feeding function between processes, can intensively recover shearing waste, and has the advantages of being small in occupied space, mitigating work intensity, reducing cost, and being safe to operate and convenient.

Copper-aluminum pipe butt welding technique

Abstract: The invention relates to a method for butting and welding copper and aluminum, in particular to a method for butting and welding copper and aluminum thin tubes. The invention is characterized in that one stainless steel tube with same inner diameter of the outer diameters of copper and aluminum tubes is sheathed on the outer ends of copper tube and aluminum tube, to weld stainless steel and copper, stainless steel and aluminum. The invention has large welding area, reliable quality, high firmness, non leakage, hand-operation or the like.

Method of and device for butt welding without weld filler materials thin metal sheets using clamping pressing devices, at least one pressing element being suitable for applying two or more distinct pressure levels

Abstract: The invention relates to a device for the linear butt welding of thin metal sheets without weld filler materials comprising movable welding head, a carrier table (1), a clamping device (3) having at least two pressing elements (4, 5) which operate independently of one another and at least one of the pressing elements (4, 5) being suitable for applying two or more distinct pressure levels. Additional horizontal pressing elements (11) are further provided in order to press the metal sheets to be welded against one other while being deformed, until full-area contact of the metal-sheet edges butting against one another is achieved. The invention further relates to a welding method using such device.

Butt welding device of pipes

Abstract: An equipment for butt welding of steel pipes is provided to improve weldability by performing butt welding of the steel pipes using a TIG(tungsten inert gas) welding machine, thereby welding steel pipe joints more accurately. In a steel pipe welding equipment comprising a circular body, a welding traveling part, and a welding robot(220), an equipment for butt welding of steel pipes is characterized in that the welding robot comprises: a traveling drive part moved along a traveling rail to connect the welding robot to the circular body; a verticality and horizontality adjusting part(240) supported to the traveling drive part to adjust positions of the welding robot in horizontal and vertical directions; a hanger base(250) that is connected to the verticality and horizontality adjusting part and supports a TIG welding torch(222), a welding wire(223) and a contact type sensor(225); a sensor mounting and adjusting part(260) connected to one side of the hanger base to support the contact type sensor; a torch mounting and adjusting part(270) connected to the other side of the hanger base to support the welding torch; and a distance maintenance mechanism(280) installed between the hanger base and the torch mounting and adjusting part to carry out a welding operation while a predetermined distance is always maintained between the end of the welding torch and outer surfaces of the steel pipes.

Electrogas arc welding method

Abstract: PROBLEM TO BE SOLVED: To provide an electrogas arc welding method that reduces heat input per welding unit length below a conventional level and that makes stable welding speed possible above a conventional level. SOLUTION: In a one-electrode electrogas arc welding method, two steel plates with a thickness of ≥45 mm and ≤75 mm are placed opposite to each other and welded with a single welding wire by single pass vertical position butt welding. The method is characterized in that the welding wire diameter is 3 . COPYRIGHT: (C)2008,JPO&INPIT