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Showing papers on "Butt welding published in 2011"


Journal ArticleDOI
TL;DR: In this article, a single-mode continuous-wave fiber laser was used in butt welding of Ti-6Al-4V to Inconel 718, and the results showed that the formation of intermetallic brittle phases and welding defects could be effectively restricted at welding conditions produced by the combination of higher laser power, higher welding speed and shifting the laser beam from the interface to the Inconels 718 alloy side.
Abstract: Challenges in dissimilar materials welding are the differences of physical and chemical properties between welding materials and the formation of intermetallic brittle phases resulting in the degradation of mechanical properties of welds. However, dissimilar materials welding is increasingly demanded from the industry as it can effectively reduce material costs and improve the design. In aerospace applications, Ti-6Al-4V titanium alloy and Inconel 718 nickel alloy have been widely used because of their superior corrosion resistance and mechanical properties. In this study, a single-mode continuous-wave fibre laser was used in butt welding of Ti-6Al-4V to Inconel 718. Investigations including metallurgical and mechanical examinations were carried out by means of varying processing parameters, such as laser power, welding speed and the laser beam offset position from the interface of the metals. Simple analytical modelling analysis was undertaken to explain the phenomena that occurred in this process. Results showed that the formation of intermetallic brittle phases and welding defects could be effectively restricted at welding conditions produced by the combination of higher laser power, higher welding speed and shifting the laser beam from the interface to the Inconel 718 alloy side. The amount of heat input and position of laser beam to improve the Ti-6Al-4V/Inconel 718 weld quality are suggested.

184 citations


Journal ArticleDOI
TL;DR: In this paper, the relationship between primary friction stir welding process parameters and varied types of weld-defect discovered in aluminum 2219-T6 friction stir butt-welds of thick plates was investigated.

138 citations


Journal ArticleDOI
TL;DR: In this article, the tensile strength and bead profiles of laser welded butt joints made of AISI 904 L super austenitic stainless steel are investigated using the Taguchi approach.
Abstract: This paper presents a study carried out on 3.5 kW cooled slab laser welding of 904 L super austenitic stainless steel. The joints have butts welded with different shielding gases, namely argon, helium and nitrogen, at a constant flow rate. Super austenitic stainless steel (SASS) normally contains high amount of Mo, Cr, Ni, N and Mn. The mechanical properties are controlled to obtain good welded joints. The quality of the joint is evaluated by studying the features of weld bead geometry, such as bead width (BW) and depth of penetration (DOP). In this paper, the tensile strength and bead profiles (BW and DOP) of laser welded butt joints made of AISI 904 L SASS are investigated. The Taguchi approach is used as a statistical design of experiment (DOE) technique for optimizing the selected welding parameters. Grey relational analysis and the desirability approach are applied to optimize the input parameters by considering multiple output variables simultaneously. Confirmation experiments have also been conducted for both of the analyses to validate the optimized parameters.

63 citations


Journal ArticleDOI
TL;DR: In this article, a load-controlled friction stir welding (FSW) machine with a Si 3 N 4 -based tool at various welding speeds was used to obtain full-penetrated and defect-free butt welded joints.
Abstract: In this study, the friction stir butt welding of 2-mm-thick high nitrogen-containing stainless steel (HNS; Ni-free austenitic stainless steel containing 1 mass% nitrogen) plates was performed using a load-controlled friction stir welding (FSW) machine with a Si 3 N 4 -based tool at various welding speeds, i.e., 50 mm/min, 100 mm/min, 200 mm/min and 300 mm/min, and a constant tool rotating speed of 400 rpm. To determine the optimum welding conditions to create reliable HNS FSW joints, the effect of the heat input on the mechanical properties of the HNS FSW joints was studied. The mechanical properties were evaluated by the Vickers hardness test and the tensile strength test. Full-penetrated and defect-free butt welded joints were successfully produced, under all the applied welding conditions. The stir zones consisted of very fine grained structures and showed an increase in the Vickers hardness. These joints also showed a higher tensile strength and yield strength than the base metal. In particular, the FSW welds obtained at a welding speed of 100 mm/min, which showed the best mechanical properties, had a relatively higher Vickers hardness, which indicates a good relationship between the welding parameter (heat input) and the hardness profile due to the microstructure refinements. It was estimated that these welding conditions were optimal, and under these conditions both grain growth and α-phase formation were prevented.

58 citations


Patent
04 May 2011
TL;DR: Wang et al. as discussed by the authors proposed a welding track detection and control method based on laser ranging, including the following steps: A. track detection is carried out; B. track extraction and extraction are carried out, C. track control is carried on; D. the relative position relation between a welding gun and a welding seam is adjusted at last by performing mechanism actions.
Abstract: The invention relates to a welding track detection and control method of plate butt weld based on laser ranging, including the following steps: A. track detection is carried out; B. track identification and extraction are carried out; C. track control is carried out; D. the relative position relation between a welding gun and a welding seam is adjusted at last by performing mechanism actions. In the invention, the information of welding seam profile is obtained by transverse scanning of a laser sensor, and welding seam is rebuilt after effective wave filtering treatment to realize three-dimensional detection of the welding seam; simultaneously, the welding track curve is obtained by fit while detecting welding seam by using dynamic B spline fit algorithm, and the track control is carried out in combination with constant speed B spline track interpolation algorithm, thereby fundamentally solving the problem of track detection and control in automatic welding of plate butt weld. By usingthe method in the invention, the field test welding has welding profile identification precision of 0.15mm and welding track identification precision of 0.2mm, and the welding speed is more than fourtimes of common manual welding.

54 citations


Patent
08 Feb 2011
TL;DR: In this paper, a data structure for weld programs associates configuration data for a welding system with a plurality of weld programs and weld sequence data, allowing the welding system to be configured for a particular part, operator, or stage in a welding process.
Abstract: A data structure for weld programs associates configuration data for a welding system with a plurality of weld programs and weld sequence data. The data structure allows the welding system to be configured for a particular part, operator, or stage in a welding process, and to be easily reconfigured when the part, operator, or stage changes, providing improved efficiency and flexibility in operation.

53 citations


Journal ArticleDOI
TL;DR: In this article, the microsegregation/macrosegregation of Hastelloy C-276 weld joint in pulsed laser welding was investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electron probe microanalyzer (EMPA).
Abstract: The microsegregation/macrosegregation of Hastelloy C-276 weld joint in pulsed laser welding was investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electron probe microanalyzer (EMPA) The results indicated that during pulsed laser welding, the microsegregation was weakened compared with other welding process, and then the Brody-Flemings (BF) model with revised k was proposed to evaluate the element microsegregation in solid-solution strengthened Ni-based alloys Also, no phenomenal macrosegregation was observed in the weld joint compared with the base metal

45 citations


Journal ArticleDOI
TL;DR: In this paper, a fiber laser was used to join Ti-6Al-4V alloy to AZ31B Mg alloy with the same thickness of 2 mm, and a filler wire was employed to avoid weld underfill resulting from Mg vaporization.
Abstract: A fibre laser was used to join Ti–6Al–4V alloy to AZ31B Mg alloy with the same thickness of 2 mm, and a filler wire was used to avoid weld underfill resulting from Mg vaporisation. The acceptable joints were only obtained when the laser beam was offset from the edge of the weld seam at 0·2 mm to the AZ31B side of the joint. Cross-weld tensile testing found joint strengths of up to 200·3 MPa, which is 85·1% of the AZ31B tensile strength. All the joints were fractured at the Ti/fusion zone interfacial layer. When the laser offset increased from 0·2 to 0·3 mm or laser power reduced to 1·2 kW, the joining mode of the interfacial layer changed from a semimetallurgical joining with high strength to a mechanical joining with poor strength. Moreover, the fracture surface of acceptable joints was characterised by scraggly remaining weld metal, while that of poor joints was almost only characterised by smooth Ti surface.

45 citations


Journal ArticleDOI
TL;DR: In this paper, a finite element modeling procedure for predicting fatigue crack growth rate in butt welds subject to mode I loading condition was presented, where the residual stress effect on the growth rate was modeled by calculating the stress intensity factor due to the residual stresses field based on the superposition rule of the linear elastic fracture mechanics.

39 citations


Book ChapterDOI
01 Jan 2011
TL;DR: A method to automatically locate the weld seam between two objects in butt welding applications is introduced using images captured from a low cost web-cam and is able to plan a robot path along the identified seam.
Abstract: To make robotic welding systems more flexible, vision sensors are introduced as they provide large amount of information about the welding components. In this paper a method is introduced to automatically locate the weld seam between two objects in butt welding applications. The proposed method provides flexibility for robotic welding by having the ability to locate the weld seam on arbitrarily positioned work pieces. This method is also cost effective as it is developed using images captured from a low cost web-cam. Furthermore, the proposed method is able to plan a robot path along the identified seam. Simulation and experimental results show that the method can be used successfully in detecting and locating seams on variously shaped work pieces and robot paths can be successfully generated to follow the weld seams.

39 citations


Journal ArticleDOI
TL;DR: In this paper, a thermal elastic-plastic analysis using finite element techniques was performed to evaluate the residual stresses and welding distortion on the AZ31B magnesium alloy and 304L steel butt joint in laser-TIG hybrid welding.

Journal ArticleDOI
TL;DR: In this article, the influence of process parameters on formation of weld surface, cross-section morphology and strength were studied, and the results showed that, Titanium and Aluminum dissimilar alloy is difficult to be butt joined by FSW, and some defects such as cracks and grooves are easy to occur.
Abstract: Titanium alloy TC1 and Aluminum alloy LF6 were butt jointed and lap jointed by friction stir welding (FSW), and the influence of process parameters on formation of weld surface, cross-section morphology and strength were studied. The results show that, Titanium and Aluminum dissimilar alloy is difficult to be butt joined by FSW, and some defects such as cracks and grooves are easy to occur. When the tool rotation rate is 950 r/min and the welding speed is 118 mm/min, the tensile strength of the butt joint is 131MPa which is the highest FSW is suitable for lap joining of TC1 Titanium alloy and LF6 Aluminum alloy dissimilar materials, an excellent surface appearance is easy to obtain, but the shear strength of the lap welding joint is not high. At the welding speed of 60 mm/min and the tool rotation rate of 1500 r/min, the lap joint has the largest shear strength of 48 MPa. At the welding speed of 150 mm/min and the tool rotation rate of 1500 r/min, crack like a groove occurs on the interface and the shear strength is zero.

Journal ArticleDOI
TL;DR: In this paper, the effect of welding power and upset pressure on microstructure, tensile strength and fatigue life of the joint were investigated using scanning electron microscopy (SEM).

Journal ArticleDOI
TL;DR: In this article, the dissimilar butt welded joint of reduced-activation ferritic/martensitic steel (RAF/M) F82H and austenite stainless steel (AISI304 (SUS304)) were studied by friction stir welding.
Abstract: The dissimilar butt welded joint of reduced-activation ferritic/martensitic steel (RAF/M) F82H and austenite stainless steel (AISI304 (SUS304)) were studied by friction stir welding. The effect of the position of the steels and tool plunging was considered in order to prohibit the mixing of the F82H and SUS304. When the dissimilar butt welding was performed such that the F82H plate was on the advancing side and the tool was plunged on the F82H side, defect-free joints could be successfully fabricated. Optical microscopy and EDX analysis were used to characterize the dissimilar joint microstructures and the interface. It was confirmed that the dissimilar joint formed no mixed structure and inter-metallic compounds.

Patent
13 Apr 2011
TL;DR: In this article, a downward and butt welding process for super-thick high-strength steel plates for ships is proposed, aiming at downward and tail welding of EH36Z 100mm-thicken high strength steel plates.
Abstract: The invention in particular relates to a welding process for super thick high strength steel plates for ships and provides a downward and butt welding process aiming at downward and butt welding of EH36Z 100mm-thick high strength steel plates for a ship structure. By putting forward effective specifications for welding grooves, weld preheating, welding temperature, welding sequence, welding variables and cold treatment after welding, the welding process of the high strength steel for super thick plates can be smoothly implemented; and by using the welding process, the labor efficiency is improved, the raw materials is saved, the production cost is reduced, the ship building period is shortened, large scale practical application of the steel to the engineering is successfully implemented for the first time and the gap in the technical specifications in welding of the EH36Z 100mm-thick high strength steel for thick plates for the ship structure at home is filled in.

BookDOI
28 Sep 2011
TL;DR: In this paper, special solution methods are presented for the prediction of distortion in stiffened plate fabrications, caused by butt welds and fillet welds, which involve strategic reduction of the many complex features embodied in full multi-physics welding simulation.
Abstract: Special solution methods are presented for the prediction of distortion in stiffened plate fabrications, caused by butt welds and fillet welds. These methods involve strategic reduction of the many complex features embodied in full multi-physics welding simulation. In particular, an analytical method is used to replace the thermo-elastic-plastic stage of a typical full computational analysis. The aim is to provide a robust solution strategy that enables clear understanding of the effects of different welding and fabrication procedures. The approach is underpinned by full-scale practical trials, and two case studies relating to typical fabrication questions are included.

Journal ArticleDOI
12 Sep 2011
TL;DR: In this paper, the authors used regression analysis, a back-propagation neural network (BPNN), and a genetic algorithm-tuned neural network(GANN) to model the weld-bead parameters, namely bead width and its depth of penetration, and weld strength in terms of yield strength and ultimate tensile strength.
Abstract: Butt welding of austenitic stainless steel 304 plates was carried out using an electron beam. Experiments were conducted for various combinations of input process parameters determined according to central composite design. Three input parameters, namely accelerating voltage, beam current, and welding speed were considered during the experiments. The weld-bead parameters, namely bead width and its depth of penetration, and weld strength in terms of yield strength and ultimate tensile strength, were measured as the responses of the process. Input–output modelling of this process was carried out in the forwards direction using regression analysis, a back-propagation neural network (BPNN), and a genetic algorithm-tuned neural network (GANN). Reverse mapping of this process was also attempted using the BPNN and GANN-based approaches, although the same could not be done from the obtained regression equations. The GANN was found to outperform the other two approaches in forward mapping. In reverse mapping also,...

Journal ArticleDOI
TL;DR: In this article, a 0.2 mm-thick TiNi shape memory alloy sheet (SMA) was carried out using impulse laser, and tensile strength, fracture morphology, microstructure and phase change behaviour of welded joint were studied.

Journal ArticleDOI
TL;DR: In this paper, a magnetic-impelled arc butt welding (MIAB) module was developed to weld alloy steel tubes of boilers with specially made MIAB welding equipment.

Journal ArticleDOI
TL;DR: In this paper, both an experiment and a finite element (FE) method were utilized to investigate residual stress distribution in high strength SM570-TMCP (thermo-mechanical controlled process) steel weldment, which was constructed using a multi-pass butt welding process.
Abstract: During fusion welding process, complex thermal stresses are inevitably generated. The presence of residual stresses can be detrimental to the integrity and the service behavior of the welded part. In this study, both an experiment and a finite element (FE) method were utilized to investigate residual stress distribution in high strength SM570-TMCP (thermo-mechanical controlled process) steel weldment, which was constructed using a multi-pass butt welding process. Firstly, experiments which included a tensile test at elevated temperatures, an observation of the microstructures and a residual stress measurement were carried out to examine characteristics of residual stresses in the weldment. Secondly, a three-dimensional thermo-mechanical FE model was developed to simulate the temperature field and the residual stress field incorporating the experimental results. The thermo-mechanical model used as well as the experimental procedure is described in detail, and the results obtained from the FE model are compared with the experimental measurements and discussed.

Patent
20 Apr 2011
TL;DR: The plain butt welding process has the advantages of enabling the process of welding a super-thin high strength steel plate to be implemented smoothly, improving the operating efficiency, saving the raw materials, reducing the production cost, and filling a domestic technical blank on the welding of a high strength thick hull structural steel (CCSE69040mm).
Abstract: The invention relates to a process for welding a high-strength hull structure steel, in particular to a plain butt welding process for a high strength hull structural steel plate (CCSE69040mm) The butt welding process is characterized in that effective specifications for bevel for welding, weld preheating, welding temperature, welding sequence, welding variables and after-welding cold treatment are provided The plain butt welding process has the advantages of enabling the process of welding a super-thin high strength steel plate to be implemented smoothly, improving the operating efficiency, saving the raw materials, reducing the production cost, reducing the shipbuilding period, and filling a domestic technical blank on the welding of a high strength thick hull structural steel (CCSE69040mm)

Journal Article
TL;DR: In this paper, the authors present the results on the mechanical properties of aluminum alloy 7020 and its friction stir welded (FSW) joints and show that the joints welded by FSW of 7020 alloy have higher strength properties then joints of alloys: 5083 and 5059.
Abstract: The article presents the research results on the mechanical properties of aluminum alloy 7020 and its friction stir welded (FSW) joints. For comparison alloy 5083 – the most currently used in shipbuilding alloy was chosen as well as 5059 - the new high-strength alloy. Besides the native material alloys there were investigated their joints welded by FSW - the same method as alloy 7020. Welding parameters used for the connection of the sheets made of 7020, 5083 and 5059 alloys were presented. Metallographic analysis showed the correct construction of structural bonded joints. Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods i.e. MIG or TIG. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standards PNEN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of + 20oC. The 7020 alloy has higher strength properties then alloys: 5083 and 5059. The yield stress is higher by 14.8% compared to 5083 alloy, and by 11.7% compared to the alloy 5059. Plastic properties of an alloy 7020 are the lowest, but with reserves meet the requirements of classification societies. The joints welded by FSW of 7020 alloy have higher strength properties then joints of alloys: 5083 and 5059. The yield stress achieves the highest value for alloy 7020 and is 24.2% higher than for 5083 alloy and 11.5% for the 5059 alloy. Despite the strength properties also plastic properties are best for 7020 alloy joints.

Journal ArticleDOI
TL;DR: In this paper, the fatigue life of a welded joint was calculated based on numerical integration of simple Paris' law and a reliable solution of the stress intensity factor (SIF), where the initial crack length (ai) was assumed to be equal to 0.1mm in case of weld toe.
Abstract: The fatigue life of welded joint was calculated based on numerical integration of simple Paris’ law and a reliable solution of the stress intensity factor (SIF). The initial crack length (ai) was assumed to be equal to 0.1 mm in case of weld toe. This length was satisfactory for different butt joints geometries. The comparisons with the available data from standards and literature were demonstrated. It was shown numerically that the machining of weld reinforcements will increase the fatigue life. The increase of plate thickness decreases the fatigue strength (FAT) and the number of cycles to failure when using the proportional scaling of crack length. The validation processes of the current calculations have been shown. Therefore, it can be concluded that it will prevent the unnecessary waste of time consumed to carry out the experiments.

Journal ArticleDOI
TL;DR: In this paper, a study concerned laser welding replacing the traditional bolted connection of the ring gear and differential case in the power train of the automobile, and the results of welding with Ni-base filler metal satisfied the torsional stiffness and durability, but compared to the bolted connection method, noise and hardness problems occurred.
Abstract: This study concerned laser welding replacing the traditional bolted connection of the ring gear and differential case in the power train of the automobile. Laser welding is necessary to reduce weight and manufacturing cost, since the bolted connection method requires additional parts and space. In the differential gear, however, it is difficult to control the welding processes because cast iron and carburized steel contain high carbon content. To solve these welding problems, laser welding using Ni-base filler metal was used in this work. The results of welding with Ni-base filler metal satisfied the torsional stiffness and durability, but compared to the bolted connection method, noise and hardness problems occurred. Therefore, to solve these problems, penetration depth was decrease from 5mm to 4mm and the carburized layer of the ring gear was cut with 1mm. As well, numerical method was used to evaluate welding deformation, torsional stiffness and fatigue.

Journal ArticleDOI
TL;DR: In this paper, a finite element method (FEM) was used to estimate residual stress distributions generated by butt welding and surface machining, and a crack growth analysis based on the stress intensity factor (SIF) calculation was performed using the calculated residual stresses distributions.

Patent
06 Sep 2011
TL;DR: In this article, a method to determine welding conditions includes relational expressions or tables about various parameters for setting welding conditions, such as welding current, welding voltage, wire feed speed, welding speed, and a leg length.
Abstract: A method to determine welding conditions includes relational expressions or tables about various parameters for setting welding conditions. The method can determine and display the recommended values for the welding conditions which are suitable for the information about the object to be welded and the information about the welding method set by the operator. The welding conditions include a welding current, a welding voltage, a wire feed speed, a welding speed, and a leg length. Furthermore, if the operator changes the recommended value for a welding condition to a new value, the method can determine new recommended values for the other welding conditions compatible with the new value and display the new recommended values.

Journal Article
TL;DR: In this article, a characterization of laser beam geometry is preliminary necessary, in order to correlate bead features and effective specific energy provided in welding aluminum alloy 2024 using Yb:YAG disk laser.
Abstract: In many industrial applications, in order to obtain good results in laser welding processes, it may not be sufficient to use a focused beam on the upper surface, so a defocused beam is required instead. This study aims to investigate which advantages a defocused beam may offer in welding aluminum alloy 2024 using Yb:YAG disk laser. A characterization of laser beam geometry is preliminary necessary, in order to correlate bead features and effective specific energy provided. Porosity content decrease and enhanced penetration depth have been obtained with defocused beam; welding behavior has been related to magnesium loss via EDS analysis. Considering the shape of the cross sections of the bead in butt welding, the relation between key-hole instability and porosity formation has also been discussed. For the alloy in exam, the welding range to perform structurally sound and defect-free welds is found to be tight.

Journal ArticleDOI
TL;DR: In this article, a fatigue assessment for multi-pass welds based on the simulation of a welding process, a post-weld heat treatment (PWHT) and a cyclic fatigue loading is presented.

Journal ArticleDOI
TL;DR: In this paper, a full contour map of longitudinal residual stresses on a weld cross section was determined in this way, revealing detailed information on the residual stress distribution in the inside of a friction stir weld, especially in the nugget zone.
Abstract: Residual stresses parallel to the welding direction on a cross-section of a 3 mm thick friction stir butt-welded aluminum alloy AA6082-T6 plate were determined using the contour method. A full contour map of longitudinal residual stresses on a weld cross section was determined in this way, revealing detailed information on the residual stress distribution in the inside of a friction stir weld, especially in the nugget zone. The typical M-shape, usually described for the residual stress distribution in friction stir welds, was found. The maximum residual stresses are below the yield strength of the material in the shoulder region and, outside of the welding region, low tensile and compressive residual stresses are responsible for the necessary stress equilibrium on the plane of interest. A comparison was made with the established incremental hole drilling technique on an equivalent plate for validation and good agreement of both techniques was obtained. The distribution, as well as the magnitude of the residual stresses measured by both techniques, is very similar, thus validating both the experimental and numerical procedures used for the contour method application, presented and discussed in the present paper.

Book ChapterDOI
01 Jan 2011
TL;DR: In this article, a user self-define path layout model is developed to realize teach offline programming for multi-pass weaving welding, where users can set the welding parameters of every pass, the number of layers and passes, and welding sequence according to the real welding technology.
Abstract: Multi-pass weaving welding is usually used in thick plates. Automatic path layout of multi-pass weaving welding is a key technology to realize robot automatic welding for thick plates. In this study, a user self-define path layout model is developed to realize teach offline programming for multi-pass weaving welding. Users can set the welding parameters of every pass, the number of layers and passes, and welding sequence according to the real welding technology. The developed system can produce the position, pose of welding torch and oscillation displacement of total passes automatically. The multi-pass welding shape is well and meets the actual production requirement through robot multi-pass weaving welding experiments for single V-groove thick plates.