Similar Welds Research Articles

Effect of welding speeds on microstructure and mechanical properties of dissimilar friction stir welding of AA7075 and AA5083 alloy

Effect of welding speeds is studied in Friction stir welding (FSW) using cylindrical tool for the welding of Aluminum 7075 and 5083 alloys. Sound joint of similar and dissimilar FSW were obtained by use of 20 and 45 mm/min welding speed. The temperature distribution on entire weld zone influences the grain size of FSW. The grain size at different zones, affect the properties of FSW. This study, observed that the dissimilar joining of AA7075 and AA5083 exhibits better strength at the welding speed of 20 mm/min. Similar FSW achieved better strength at 45 mm/min welding speeds. Dissimilar welding required higher heat input as compare to similar welding.

Microstructural characterization and mechanical behavior of Cr25Ni35NbM alloy dissimilar weld joint for application in a hydrogen reformer furnace

The microstructural characterization and mechanical behavior of Cr25Ni35NbM/15CrMo and Cr25Ni35NbM/SUS321 dissimilar weld joints were studied in this paper. The microstructure, room temperature and high temperature (1173 K) tensile strength of dissimilar weld joints were analyzed through optical microscopy (OM), scanning electron microscopy (SEM) and electronic universal tensile testing machine. The microstructure of HAZ in 15CrMo steel of Cr25Ni35NbM/15CrMo dissimilar weld joint transformed from ferrite-pearlite into ferrite-martensite. A large volume fraction of α phase was found to have precipitated in the HAZ of SUS321 austenitic stainless steel for Cr25Ni35NbM/SUS321 dissimilar weld joint. At room temperature, the tensile strength and yield strength of these two type dissimilar weld joints is less than Cr25Ni35NbM alloy similar weld joint. The high temperature tensile strength of these two type dissimilar weld joints is less than Cr25Ni35NbM alloy similar weld joint. Both at room and high temperature, the fracture locations of two types dissimilar weld joints are the HAZ of the base metal 15CrMo and SUS321 stainless steel, respectively. It indicates that the weak part of the Cr25Ni35NbM alloy dissimilar weld joints is the low-performance base metals 15CrMo and SUS321 stainless steel.

Effect process parameters in TIG/MIG welding on the mechanical properties and corrosion behaviour of dissimilar welded DSS/HSLA steel

The metallurgical factors controlling dissimilar metal weld is more challenging and intricate than similar welding due to the necessity of obtaining required mechanical properties with desired microstructure for marine applications. The fundamental reason for this exploration work is to study the tensile behaviour and Tafel polarisation of dissimilar weld between duplex stainless steel (DSS) and HSLA steel, to establish a sound weld free from weld discontinuities for distinctive welding parameters common for two TIG and MIG welding systems. The dissimilar DSS and HSLA steel are welded with TIG and MIG welding process using a single-V groove test specimen; with angle of 70°, face root and root gap is kept at 1 mm. E309L-16 filler rod is used for TIG welding and E304l filler wire is used for MIG welding. The feller metals are selected based on the best matching suitable chemical compositions for welding dissimilar metals. The mechanical properties are evaluated by microhardness and tensile test. Potentiostat is used for plotting Tafel plot to indicate the corrosion behaviour of dissimilar weldments.

The Similar and Dissimilar TIG Welding of 316L and 321 Austenitic Stainless Steels

Being one the modern high quality industrial welding process especially for stainless steels and titanium alloys. TIG welding process has been has been researched for decades in order to define its parameters such as welding speed, current and arc length to improve the weld penetration. Hence it is a popular technique for joining thin materials - the thickness of the work piece is in general restricted to less than 6 mm- in manufacturing industries. In this study, AISI 321 and 316L stainless steel sheets of 4 mm of thickness were used as welding metals. Thus, AISI 321 welding metal couples, AISI 316L welding metal couples and AISI 321 and 316L welding metal couples were selected to ensure a combination of similar and dissimilar metals. The filler metal rod was made of 316L SS. The specimens were cut in dimensions of 150 x 30 x 4 mm as using an abrasive cutter, then the V weld butt joint configuration with single groove of 37.5o ± 2.5o groove angle by a lathe machine. The welding current was 200 A and TIG welding process was performed manually in single under argon shielding gas atmosphere. After TIG welding process, the separate metallographic preparations, then microscopic and macroscopic examinations of the specimens, also hardness measurements of specimens were made. The rest of them was shaped for tensile strength measurement using Instron Universal Testing Machine. The hardness of the specimens were observed being altered in the range of 145-151 HRV(average) and their tensile strength values in the scale of 345-400 MPa (average).

Experimental and computational analyses on fatigue fracture and microstructure in dissimilar metal weldments with circular sharp stress raiser

Fatigue strengths of dissimilar metal weldments with a circular sharp stress raiser, which were the inner peripheral side welded joints of flange pipes with tungsten inert gas (TIG) or metal inert gas (MIG) welding process, were defined through bending fatigue experiments. Fatigue strengths decreased according to stress concentration factors in some cases but not in samples with a different welding process, and stress intensity factors at the sharp weld notch were applied for analyses using the energy release rate method. The crack states corresponded to the fact that the fatigue cracks propagated at nearly right angles to the maximum stress direction, and it is possible to predict their propagation direction. The local fatigue resistance of the martensite-ferrite structure with the TIG welding was higher than that of the austenite-ferrite structure with the MIG welding which has a largely different penetration rate. In the samples which have similar weld metal microstructure, the nominal fatigue strength declines according to the increase in the stress concentration factor. The TIG samples and the MIG samples reach their fatigue failure in the same level of stress intensity factors, except for a MIG sample which has a large excess metal shape and a different fracture mode. The stress intensity factors can be used as the fatigue fracture threshold criterion in the weldments with a circular sharp stress raiser, where have the complex stress effects.

Review and Analysis of Mechanical Properties of Friction Stir Welds of High Strength Aluminium Alloys

There have been significant advancements of recent in the studies of friction stir welding of high strength Aluminium alloys. These studies cover developments in the welded joint properties of these alloys. This paper reviews some available literature on evolving mechanical properties of friction stir welding of high strength aluminium alloys especially those of 7075 aluminium alloy which happens to be the most versatile member of the high strength aluminium alloy group. This review is aimed at establishing a correlation between the tensile behavior, plate thickness and temper conditions of the 7075 alloy when joined by friction stir welding (FSW) in both similar and dissimilar joints with other metals. The average values of reported ultimate tensile strength, yield strength, and percentage elongation have been calculated and presented. Comparative analysis was made between the tensile properties at different temper designation and plate thickness. The analysis revealed that temper conditions significantly affect the mechanical properties of both the similar and the dissimilar joints and that similar welding at T6 and T651 temper conditions gave higher weld efficiencies than dissimilar welding with other groups in the aluminium series. However plate thickness have little or no influence on the ultimate tensile behaviour, yield strength and elongation of the welds. The review also indicates that there is a range of temperature between which post weld heat treatment (PWHT) could be performed in order to obtain maximum tensile property This paper is a significant approach to enhance high performance joining techniques and the reliability or otherwise of friction stir welding technology to join 7075 aluminium alloys under different heat treatment or temper conditions of the alloys for better industrial applications.

Evaluation of Mechanical Properties and Microstructure of AA3003, AA6082 and AA64430 Aluminum Under Friction Stir

Aluminum compounds are an remarkable alternative for decreasing the price, weight supplanting steels in severa applications and Friction Stir Welding procedure is a financially savvy and a green technique. Grinding blend welding is a strong nation joining method that uses a non-consumable turning welding equipment to create plastic disfigurement and frictional warm temperature at the location of the welding; along those lines, the material that is in the strong kingdom is motivated by using the use of the development of a joint. Grating blend welding is all around utilized for turning into a member of Al compounds for marine automobile, aviation and numerous wonderful uses of agency significance. This exam is to get the parameters which might be ideal for the substances under contemplations, to explore the Heated Affected sector (HAZ), Thermo – Mechanical Affected zone (TMAZ) and Nugget area (NZ) aside from to consider the imperfections going on during welding system by utilising numerous parameters picked, recognise the smaller scale auxiliary changes and mechanical houses of touch blend welding of disparate aluminum joints approximately thickness is 4 mm, the aluminum divergent joints (AA3003-AA64430), (AA3003-6082) and (AA64430-AA6082) had been finished under a similar welding parameters are 2000 rpm (rotational pace) and eleven mm/min (transverse tempo) on vertical processing device. wherein rectangular tool is carried out. The gadgets are made on a Lathe gadget. This take a look at builds up the welding time table and technique parameters for best welds AA3003-AA6082-AA64430 aluminum utilizing tool H13 chrome steel. After the elements are welded with the aid of the use of welding, wonderful trial of pragmatic nature are accomplished at the elements which may be welded which includes the stress, Fatigue check, Hardness check, microstructure study.

Effect of Mechanical Properties and Corrosion Behaviour of Martensitic Stainless Steel 410 1.6mm Butt Welded by Plasma Arc Welding

Plasma Arc Welding (PAW) is one of the important arc welding processes used in electronics, medical, automotive and aerospace industries due its high accuracy and ability of welding any hard materials which is more tolerant to joint misalignment than Laser Beam Welding (LBW) at a lower cost. Thickness of 1.6mm plates were used to obtain full penetration and a strong joint with a very narrow Heat Affected Zone. The present study deals with the effect of mechanical and corrosion resistance properties of butt welded 1.6 mm thick martensitic stainless steel-similar (SS410 and SS410) joints made by plasma arc welding technique. Similar butt Welded joints were analyzed by using mechanical (Bend test, Erichsen cup test, Tensile test) characterization methods. Their corresponding corrosion resistance properties were also investigated by potentiodynamic polarization corrosion testing technique. The tensile strength was found to be 341 MPa for similar SS410 weld. During tensile test the failure occurred on the base metal on both similar joints Keywords: SS304; SS410; PAW; Butt weld; Erichsen Cup Test; Microstructure.

Investigation on interface morphology and joint configuration of dissimilar sheet thickness FSSW of marine grade Al alloy

Aim of this study is to investigate the interface morphology and joint configuration of dissimilar thickness aluminium alloy 5052-H32 sheets during friction stir spot welding. The investigation begins with the optimization of two important process parameters, viz. tool rpm and dwell time, from welding of similar thickness sheets. Further, different combinations of sheet thicknesses were welded using the optimized parameters. Effect of altering sheet thickness on the mechanical and structural properties were compared with welds of similar sheet thickness. For similar thickness welds, maximum failure load of 4020 N was noted at minimum tool rotational speed of 450 rpm and maximum dwell time of 8 s. The obtained weld zones revealed the presence of hook which was found to vary in its pattern and location for different combinations of sheet thicknesses. Minimum hardness of 63 HV was obtained in the periphery of the thermo-mechanically affected zone and heat-affected zone. In addition, welds with thinner top sheets showed higher load-bearing capacity and wider bonded area as compared to thicker and equal thickness top sheet welds. The maximum failure load of 7160 N was obtained for 1.5 and 2.5-mm-thick top and bottom sheets, respectively. Moreover, three fracture modes were observed in tensile/shear tests, namely interfacial, circumferential and nugget pullout fracture mode. Samples which failed in circumferential and nugget pullout fracture mode showed better joint strength.

Effect of weld angle on the creep rupture life of ferritic/austenitic dissimilar weld interfaces under remote mode I fracture

Dissimilar metal welded structures (DMWs) used extensively in conventional and nuclear power plants can suffer from in-service failures at the dissimilar interface with a much reduced life compared to similar metal weld counterparts at the same operating stress and temperature. This paper evaluates the effect of weld angle on the interface creep failure mode of two-dimensional DMW plates consisting of a ferritic steel P91 and an Inconel 82 filler metal within a finite element (FE) framework. A physical cavity growth damage zone model is developed to describe the damage accumulation at the interface, which naturally takes into account the local mode mixity. The material parameters are calibrated against standard 90° weld creep rupture data and used to predict the rupture life of DMWs with a range of axial loads and reduced weld angles (75°, 60°, 45° and 30°). The predicted results match reasonably well with the limited interface failure data for a 45° weld angle. This work also provides additional evidence and insights regarding the improvement of interface creep rupture life of DMWs in power plant pipelines, in particular: (1) Compared with a 45° weld angle, a 60° weld angle is more detrimental to the creep life and should be avoided in actual components – on the contrary, damage tolerance can be promoted by designing and adopting weld angles smaller than 45°, which can have lives exceeding that of standard 90° welded components; (2) A weld interface with alternating weld angles/paths is expected to enable a greater fraction of the creep rupture life to be taken up with crack propagation compared with a flat weld interface, which also increases the probability of damage detection; (3) A fully constrained boundary condition is beneficial to the creep rupture life compared with a free boundary condition; (4) For weld angles less than 90°, the diversion of the crack into the HAZ is less likely compared with a 90° weld angle. Type IV failure mode through the FGHAZ is also less likely to occur.

Weld bead temperature and residual stresses evaluations in multipass dissimilar INCONEL625 and SS316L by GTAW using IR thermography and x-ray diffraction techniques

Thick plates of SS to Inconel are used in nuclear reactors to withstand high temperatures and pressures. This study is to evaluate the GTAW joining of SS316L to Inconel625 to evaluate the weldability; the temperature distribution in the longitudinal and transverse directions, resulting in distortions and the induced residual stresses. To obtain real-time temperature images Infrared thermography measurements were made. Similar welding joints of SS to SS and Inconel to Inconel were used as a reference for comparison with the dissimilar welding parts in this evaluation. Compatible Filler rods were selected: SS316 filler rod was used for welding of SS316L samples and ERNiCrMo-3 was used when a part is IN625. This study reports the temperature distribution for a SS to Inconel weld process and the resulting distortion and residual stresses were within the acceptable limits.

Investigation on keyhole mode fiber laser welding of SS 316 in a self-protected atmosphere

This work focuses on examining the influence of welding parameters under different welding atmospheres and evaluation of keyhole profile during fiber laser welding operation. The experiments are carried out in two different welding atmospheres, namely self-protected atmosphere of Ar gas and open atmospheric conditions. The effect of these two atmospheric conditions on weld profile formation and dimensions, and microstructural evolution for SS 316 plates are examined. In addition, the keyhole profile is evaluated by using a semi-analytical mathematical model, a point-by-point energy balance determination at the keyhole wall, which is mapped with experimentally measured weld macrographs for similar welding conditions. It has been determined that the weld quality is profound in the case of a self-protected atmosphere with respect to aspect ratio, weld defects, and microstructural characterization. Moreover, better weld bead profile and cleaner weld seam on the upper surface is determined in samples welded in a self-protected atmosphere.

Residual Stresses in Similar and Dissimilar Friction Stir Welds of AA5083 and AA6061

Similar and dissimilar friction stir welds of AA5083 and AA6061 were produced modifying the location of the materials in the joint (advancing or retreating side) and travel speed (73 and 206 mm/min). Longitudinal and transverse residual stresses were evaluated by X-ray diffraction technique on the mid-length of each welded sample, in the transverse direction to the weld on a 42 mm distance. Unstrained lattice spacing (d0) and full width at half maximum (FWHM) were also measured. A peak of tension stress at the edge of stirred zone was detected, describing an “M” like profile, which were more asymmetrical for dissimilar joints. Variations in d0 and FWHM were also observed through the welded joint, which were related to microestructural changes.

On the stability, microstructure, and mechanical property of powder metallurgy Al–SiC nanocomposites during similar and dissimilar laser welding

Aluminum matrix nanocomposites consolidated by powder metallurgy (P/M) have significant potential for practical applications in the aerospace and automotive industries considering their admirable strength to weight ratio and good corrosion resistance. Due to dimensional restrictions in traditional P/M manufacturing routes, similar and dissimilar joining would be essential to design complex structures, however, the stability of Al-matrix nanocomposites during joining process is a crucial issue. In this research, the stability of an Al-6 vol% (50 nm, ex-situ) SiC-2 vol% (15 nm, in situ) Al2O3 hybrid P/M nanocomposite was evaluated during laser joining in comparison to similar and dissimilar joints with commercially pure aluminum (AA1050 alloy). The processing parameters were optimized with a constant focus spot size of 200 μm, laser power of 4 kW, and travel speed of 8 m/min to achieve full-penetration joints. According to the experimental results, the similar P/M nanocomposite exhibited unstable behavior during laser welding due to the formation of porosity associated with clustering and void expansion near SiC nanoparticles. Hence, the fusion zone in both joint designs consisting of similar and dissimilar containing nanocomposite material became heterogeneous due to the presence of clusters and shrinkage micro-voids. The mechanical properties of weldments deteriorated considerably, with large fluctuations in the hardness profiles as well as low joining efficiency (<30%) and brittle fracture. Defects present in dissimilar welds were mainly located at the nanocomposite side.

Closed-Form Structural Stress Solutions for Spot Welds in Square Plates under Central Bending Conditions

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;A new closed-form structural stress solution for a spot weld in a square thin plate under central bending conditions is derived based on the thin plate theory. The spot weld is treated as a rigid inclusion and the plate is treated as a thin plate. The boundary conditions follow those of the published solution for a rigid inclusion in a square plate under counter bending conditions. The new closed-form solution indicates that structural stress solution near the rigid inclusion on the surface of the plate along the symmetry plane is larger than those for a rigid inclusion in an infinite plate and a finite circular plate with pinned and clamped outer boundaries under central bending conditions. When the radius distance becomes large and approaches to the outer boundary, the new analytical stress solution approaches to the reference stress whereas the other analytical solutions do not. The Mode II stress intensity factor solutions based on the new structural stress solution for a rigid inclusion in a square plate under central bending conditions are improved by up to 3% for similar spot welds in lap-shear specimens of equal thickness when compared with those obtained from the corresponding finite element analyses.&lt;/div&gt;&lt;/div&gt;

High-Velocity Impact Welding Process: A Review

High-velocity impact welding is a kind of solid-state welding process that is one of the solutions for the joining of dissimilar materials that avoids intermetallics. Five main methods have been developed to date. These are gas gun welding (GGW), explosive welding (EXW), magnetic pulse welding (MPW), vaporizing foil actuator welding (VFAW), and laser impact welding (LIW). They all share a similar welding mechanism, but they also have different energy sources and different applications. This review mainly focuses on research related to the experimental setups of various welding methods, jet phenomenon, welding interface characteristics, and welding parameters. The introduction states the importance of high-velocity impact welding in the joining of dissimilar materials. The review of experimental setups provides the current situation and limitations of various welding processes. Jet phenomenon, welding interface characteristics, and welding parameters are all related to the welding mechanism. The conclusion and future work are summarized.

Experimental Investigation and Process Optimization of DSS/DSS Similar Metal Weld Joint

Abstract This study aims to investigate and optimize the process parameter of similar metal weld joint between Duplex Stainless Steel and Duplex Stainless Steel. Plates of 2 mm thickness of DSS conforming to grade 2205 were butt welded using Gas Tungsten Arc welding, with Argon as shielding gas. Electrode to specification E 309LT-1 was used as filler metal. Test specimens were evaluated for tensile test and the values were observed as ultimate tensile strength 659 Mpa, yield strength 596 Mpa and the breaking load 23.74 KN. Objective of this work is to investigate mechanical properties and to optimize the process parameters to obtain higher tensile values by using Taguchi method. Voltage, Current and filler feed rate were chosen as a control factors in view of the impact on the input variables. Ultimate tensile strength was chosen as response variable to calculate the signal-to-noise ratio. Analysis of variance (Anova) method was adapted to identify the percentage contribution for all the factors and high important factor which is contributing for the optimum result.

Spatial distribution of residual stress in similar and dissimilar laser welding

Spatial distribution of residual stress in similar and dissimilar laser welding

Effect of tool rotational speed and feed rate on similar and dissimilar Friction Stir welded joints of Al 5082 and Al 6061

Abstract Friction Stir Welding (FSW) technique has a wide range of application in ship building, aerospace, automobile and other manufacturing industries. The process proves predominance for welding non-heat treatable and powder metallurgy components of aluminum alloys, to which the fusion welding cannot be applied. In this research work similar and dissimilar Aluminum metal alloys of Al 5082 and Al 6061 were joined using FSW process to study the mechanical properties of weld joints. HSS tool with Taper pin of square cross section is used to weld the joints. The process parameters tool rpm and feed rate are selected to develop best set of welding parameters for selected material combinations. The quality of the joints are analyzed by mechanical testing using tensile test and hardness test. The mechanical properties of similar and dissimilar welds of Al 5082 and Al 6061 were observed at two different tool rpm and feed rates.

Effect of Nitrogen Addition to Shielding Gas on Cooling Rates and in the Microstructure of Thin Sheets of Duplex Stainless Steel Welded by Pulsed Gas Tungsten Arc Welding Process

The effect of the nitrogen content in the shielding gas and its effect on temperature distributions at the welded zone of thin sheets of duplex stainless steel have been evaluated. The duplex stainless steels have many features due to unique microstructural combination of austenite and ferrite grains. The phase balance can be easily shifted depending on the welding parameters. Two sheets were welded using pure argon and pure argon plus 2% of nitrogen as shielding gas. The thermal profile had shown that N2-supplemented shielding gas lead to higher peaks of temperature using similar welding parameters. Microstructural examination showed that the austenite phase in the weld increased with the presence of nitrogen in the shielding gas. The added nitrogen promoted primary austenite formation and slightly increases the microhardness at the solidified zone. Microhardness mapping and metallographic imaging presented information about microstructures, confirming the formation of secondary phases during thermal cycle in the temperature range 850 °C and 950 °C. Control of ferrite amounts in the welds is essential mainly to improve mechanical properties and corrosion resistance of welding zones.