scholarly journals Optimizing the Integrity of Linear Friction Welded Ti2AlNb Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 802
Author(s):  
Xi Chen ◽  
Zhao Zhang ◽  
Faqin Xie ◽  
Xiangqing Wu ◽  
Tiejun Ma ◽  
...  

The knowledge of process parameters–weld integrity-aging treatments–tensile property relationship is of great concern for linear friction welded (LFWed) Ti2AlNb-based alloy and requires a systematic characterization. Thus, the Ti2AlNb-based alloy was LFWed under various process parameters and then subjected to different aging treatments. Twelve welding conditions were used to evaluate the weld integrity, showing that impurities and cracks at weld interface can be eliminated under strong welding parameters and the feed rate has the greatest influence on the weld integrity among all process parameters. Relationships among aging temperatures, microstructure evolution, and mechanical properties were investigated. After aging treatment, acicular O phase has precipitated in B2 grains both in the weld zone and thermo-mechanical affected zone (TMAZ). The size of precipitated O phase increases along with the increase of temperature, and the α2 +·O mixtures have finally decomposed into the aggregated acicular O phase. The microhardness and tensile strength of the joints have been enhanced due to the precipitation hardening of O phase and refined grain strengthening after aging treatments.

2020 ◽  
Vol 117 (6) ◽  
pp. 618
Author(s):  
M. Bakkiyaraj ◽  
G. Saikrishnan ◽  
V. Balasubramanian

The present study aims to develop the numerical relationship to attain maximum tensile strength of the friction welded AISI410 MSS joints by using response surface methodology. The friction welding (FW) process parameters considered for optimization namely rotational speed, upset pressure, friction time, and upset time. The FW parameters of 31 sets have been used to manufacture the joints to attain the maximum strength. Moreover, the detail relates the optimization procedure with respect to welding conditions on AISI410 MSS joints and its optimized parameters were reported. The optimized results have been correlated with the weld interface of the specimen with reference to tensile properties, macro and microstructure features, hardness, and fracture morphology. Finally, the results concluded that the rotational speed as the most effectual process parameter on the joint properties of the FW AISI410 MSS joint.


2013 ◽  
Vol 765 ◽  
pp. 716-720 ◽  
Author(s):  
N. Kishore Babu ◽  
Patil Yogesh Bhikanrao ◽  
K. Sivaprasad

AA5083 alloy is welded with gas tungsten arc welding using optimized welding parameters. Al-Si-Sc master alloy filler with varying contents of scandium is used for welding. Welding was carried out with and without AC-pulsed current techniques. A narrow heat affected zone with more refined grain structure is observed in the case of the pulsed current technique. Furthermore, it is observed that the columnar solidification structure in the fusion zone was suppressed and fine equiaxed grains were formed in the weld zone with increasing scandium content, which is attributed to the grain refinement effect of scandium with the generation of increased nucleating sites during weld solidification. This effect is reflected in mechanical properties also. An increased hardness of about 10 % results with pulsed current technique compared to about 20 % with an addition of 0.75 % scandium. However, in the case of tensile properties pulsing resulted in about 8 % increase in tensile strength and addition of 0.75 % scandium resulted in about 40 % increase in tensile strength. Both the pulsed current technique and the addition of scandium were observed to be better in increasing not only strength but also elongation due to the refined grain structure in the weld fusion zone.


2015 ◽  
Vol 766-767 ◽  
pp. 701-704
Author(s):  
R. Ramesh ◽  
S. Suresh Kumar ◽  
R.V. Srinivasan

Aluminum alloys exhibit poor weldability by conventional fusion welding process. The heat treatable aluminum alloy AA2014 is extensively used in the aircraft industry because it has good ductility and high strength to weight ratio. In this paper the effects of welding parameters and tool profile on the mechanical properties of friction stir welded butt joints of dissimilar aluminum alloy sheets AA6082 and AA2014. The process parameters such as rotational speed, transverse speed and axial forces were considered. The effect of parameters on weld quality was analyzed. Hardness and tensile tests are carried out at room temperature to examine the mechanical properties of the welded joints. The joints produced with straight square tool pin profile have higher ultimate tensile strength, whereas the straight cylindrical tool pin profile results in lower tensile strength.


2020 ◽  
Vol 14 (1) ◽  
pp. 6259-6271
Author(s):  
Srinivasa Rao Pedapati ◽  
Dhanish Paramaguru ◽  
Mokhtar Awang ◽  
Hamed Mohebbi ◽  
Sharma V Korada

Underwater Friction Stir Welding (UFSW) is a solid-state joining technique which uses a non-consumable tool to weld metals. The objective of this investigation is to evaluate the mechanical properties of the AA5052 Aluminium alloy joints prepared by UFSW. The effect of different type of welding tools and welding parameters on the weld joint properties are studied. Square, tapered cylindrical and taper threaded cylindrical type of welding tools have been used to produce the joints with the tool rotational speed varying from 500 rpm to 2000 rpm while the welding speed varying from 50 mm/min to 150 mm/min. Tensile strength, micro-hardness distribution, fracture features, micro-and macrostructure of the fabricated weld joints have been evaluated. The effect of welding process parameters that influences the mechanical properties and fracture characterization of the joints are explained in detail. A maximum Ultimate Tensile Strength (UTS) value of 222.07 MPa is attained with a gauge elongation of 14.78%. Microstructural evaluation revealed that most of the fracture are found on the thermal mechanically affected zone (TMAZ)adjacent to the weld nugget zone (WNZ) due to bigger grain sizes. It is found that most of the joints exhibit ductile characteristics in failure. Fractography analysis has been used to find the behavior of weld joints in failure.


2019 ◽  
Vol 7 (1) ◽  
pp. 17-23
Author(s):  
Azzam Sabah Albunduqee ◽  
Hussein R Al-Bugharbee

Friction Stir Welding is one of the technologies of joining solid states, which still attracts the researchers’ interest.  In welded joints the mechanical properties are affected by a number of mechanical properties of the joined materials and by the process parameters as well. In the present study, the effect of a number of friction stir welding parameters on the tensile strength of the welded joint have been investigated using the Taguchi method and the analysis of variance (ANOVA). The study considers different levels of friction stir welding variables; namely, different rotational speeds of (2000, 1600, 1250 rpm), different welding speeds (12.5, 16, 20 mm / min), and different welding tilt angles (0, 1, 2 degrees).  The optimum process parameters and their contribution rate were selected based on the Taguchi method for test design and by using the Minitab 16 program. In this study, the best results (i.e, higher tensile strength) were obtained at a rotational velocity of 1600 rpm, linear velocity of 16 mm / min, and welding angle, 1o. The highest tensile strength was obtained under these conditions.                                                                                       


Mildsteel is the largely material for industrial and commercial applications. Gas Metal Arc Welding (GMAW) and Gas Tungstan Arc Welding (GTAW) process is the largely used metal joining process for thin gauge milsteel and stainless. This research focus on the on the effect of process welding parameters for acquring greater mechanical properties of weld plates. the Taguchi parametric optimization methodology and regression analysis is identified and used for Acquring the greater welding effectiveness and efficiency. The shielding gas, weld volrage& current is choosen as a process parameters for this research to Acquring the greater welding effectiveness and efficiency. At end of process, the mechanical properties like ultimate tensile strength, toughness and hardness of the weldment. After completion of the experimental work, the S/N ratio and mean S/N ratio were evaluated and the optimum values of each parameters was evaluated through the Taguchi method. Subsequently the significant co-efficient for each input factor of the mechanical properties was evaluated of by using the analysis of variance and prediction on the mechanical properties is evaluated by using regression analysis. In this research, 15 mm IS2062 Mild Steel is welded by GMAW with the shielding gas mixtures of pure(100%) CO2 , Ar+20% CO2, and Ar+10% O2. The tensile strength optimum value was provided by the shielding gas mixture Ar+20% CO2 and also it gives the optimum value for toughness. The superior hardness value is obtained by Pure(100%) CO2 with respect to other shielding gas mixtures. The evaluated values tells that the welding current & shielding gas and have impressive effect on the IS2062 weldment mechanical properties.


2014 ◽  
Vol 622-623 ◽  
pp. 540-547 ◽  
Author(s):  
Massimo Callegari ◽  
Archimede Forcellese ◽  
Matteo Palpacelli ◽  
Michela Simoncini

Robotic friction stir welding experiments were performed on AA5754 aluminium alloy sheets, 2.5 mm in thickness, in two different temper states (H111 and O-annealed). A six axes robot with a hybrid structure, characterised by an arm with parallel kinematics and a roll-pitch-roll wrist with serial kinematics, was used. The effect of the process parameters on the macro-and micro-mechanical properties and microstructure of joints was widely analysed. It was shown that, under the same process condition, the mechanical properties of the joints are strongly influenced by the initial temper state of the alloy. In particular, as AA5754-H111 is welded, the ultimate tensile strength is not significantly affected by the process parameters whilst the ultimate elongation significantly depends on the welding speed. In AA5754-O, both ultimate values of tensile strength and elongation are affected by the welding speed whilst a negligible effect of the rotational speed can be observed. Irrespective of the welding parameters, the H111 temper state leads to mechanical properties higher than those given by the O-annealed state. An investigation has been also carried out in order to evaluate the micro-hardness profiles and microstructure of the FSWed joints in order to understand the mechanisms operating during robotic friction stir welding.


10.30544/245 ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 269-284
Author(s):  
Jyoti Menghani ◽  
Kunal Dwivedi

The present investigation has two main objectives; first is optimization of welding process parameters of submerged arc welding (SAW) using Taguchi philosophy and second is to improve the mechanical properties such as strength and microhardness of weld joint by alloying with varying amounts of molybdenum. For optimization of welding process, parameters Taguchi philosophy have been applied on a mild steel plate (AISI C- 1020) of 10 mm thickness with 60o groove angle with arc voltage and welding speed as variables and bead width as output variables. A mathematical relationship between bead width, arc voltage and welding speed has also been found using multiple regression analysis for the present base metal plate geometry. After optimizing welding parameters, molybdenum has been added individually to the welding area in varying percentages. The properties of alloyed and unalloyed weld metal bead are compared. The mechanical characterization of weld has been done in terms of microhardness, tensile strength, whereas microstructural characterization has been performed using optical microscopy, XRD and EDS. The presence of molybdenum resulted in bainite structure in weld bead having a refined grain structure, enhancement in tensile strength and microhardness. The XRD results showed the formation of molybdenum carbides justifying the increase in microhardness value.


2018 ◽  
Vol 877 ◽  
pp. 157-162 ◽  
Author(s):  
Muralimohan Cheepu ◽  
V. Muthupandi ◽  
Woo Seong Che

Friction welding of stainless steel to titanium with aluminum insert metal was investigated to improve the mechanical properties of the joints. Two different methods were used to insert the aluminum as a barrier between to substrates. The process parameters were found to be different for these two methods to obtain the sound welds. The friction welds between stainless steel and titanium with aluminum insert prevented the formation of brittle intermetallic compounds in the weld interface. A new intermetallic compounds such as AlTi and Al3Ti were formed between titanium and aluminum insert metal interface which are more ductile than the FeTi and CrTi intermetallic compounds. The joints characterized that the aluminum insert metal improved the metallurgical reaction at the weld interfaces thus indicates the results of decrease in microhardness of the intermetallic compounds which have major influence on the strength of the joints. The tensile strength of the aluminum insert welds was higher than the direct joints between the stainless steel and titanium. Higher tensile properties were attained at higher upset pressure condition due to the effect of higher force upon the welded materials and the remnant narrower thickness of insert metal.


2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.


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