scholarly journals Backing plate effect on temperature controlled FSW process

2018 ◽  
Vol 224 ◽  
pp. 01084 ◽  
Author(s):  
Igor Zybin ◽  
Konstantin Trukhanov ◽  
Andrey Tsarkov ◽  
Sergey Kheylo

Friction stir welding (FSW) has become an important application in modern industries. Friction stir welding is a widely used solid state joining process for soft materials such as aluminum alloys as it avoids/minimizes common problems of fusion welding processes, i.e. distortion, porosity, solidification and liquation cracking etc. Improper selection of parameters such as welding speed, rotational speed, forge force, back plate material etc. affects the weld quality. Thermal boundary condition at the bottom of the work pieces to be joined is important in determining the result of weld quality and its properties, for a given alloy type, tool geometry and selected process parameters (welding speed, rotational speed etc), These thermal boundary conditions are governed by the back plate material used. By using backing plates made out of materials with widely varying thermal diffusivity this work seeks to elucidate the effects of the root side thermal boundary condition on weld process variables and resulting joint properties. Welds were made in 5-mm-thick AMг5 (AA 5056) using siliceous coating, stainless steel, mild steel, and aluminum as backing plate (BP) material. Effects of backing plate material on the tensile strength and elongation were obtained for a particular case.

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1236
Author(s):  
Ni ◽  
Mao ◽  
Qin ◽  
Xiao ◽  
Fu

Thermal cycles and deformations during high-speed micro friction stir welding (μFSW) under different welding conditions were studied by experimental methods. The results show that the peak temperature and elevated-temperature exposure time (t150) increased with the increasing of rotational speed and decreased with the increasing of welding speed. Increasing rotational speed or welding speed led to an increase in both heating and cooling rates. The joint fabricated by the pinless tool experienced a lower peak temperature, a shorter elevated-temperature exposure time, and a larger temperature gradient than that by the pin tool. The welded sheet presented an anti-saddle deformation character, with convex bending in a longitudinal direction and concave angular bending in a transverse direction. In comparison to the pin tool, the longitudinal maximum bending deformation, Zmax, of the joint fabricated by the pinless tool was reduced by 12.35%, and the transverse angular deformation, α, was reduced by 6.67%. In comparison to the steel backing plate, the Zmax of the joint produced using a copper backing plate was reduced by 40.66%, but the α was increased by 53.27%.


Author(s):  
Shubham Verma ◽  
Joy Prakash Misra ◽  
Meenu Gupta

The present study deals with the application of sequential procedure (i.e. steepest ascent) to obtain the optimum values of process parameters for conducting friction stir welding (FSW) experiments. A vertical milling machine is modified by fabricating fixture and tool ( H13 material) for performing FSW operation to join AA7039 plates. The steepest ascent technique is employed to design the experiments at different rotational speed, welding speed, and tilt angle. The ultimate tensile strength is considered as a performance characteristic for deciding the optimal levels. The mechanical and metallurgical characteristics of the joints are studied by executing tensile and microhardness tests. It is concluded from the graphical analysis of the steepest ascent technique that the optimal maximum and minimum values are 1812–1325 r/min for rotational speed, 43–26 mm/min for welding speed, and 2°–1.3° for tilt angle, respectively. Besides, optical microscope and scanning electron microscope are utilized for microstructural and fractographic analyses for a better understanding of the process.


2011 ◽  
Vol 295-297 ◽  
pp. 1929-1932
Author(s):  
Yi Min Tu ◽  
Ran Feng Qiu ◽  
Hong Xin Shi ◽  
Xin Zhang ◽  
Ke Ke Zhang

In order to obtain better understanding of the friction stir weldability of the magnesium alloy and provide some foundational information for improving mechanical properties of retardant magnesium alloy joints. A retardant magnesium alloy was weld using the method of friction stir welding. The influence of welding parameters on the strength of the joint was investigated. The maximum strength of 230 MPa was obtained from the joint welded at the tool rotational speed of 1000 r/min and welding speed of 750 mm/min.


2017 ◽  
Vol 867 ◽  
pp. 97-104 ◽  
Author(s):  
T. Ganapathy ◽  
K. Lenin ◽  
K. Pannerselvam

This paper deals with the effective application of friction stir welding similar to butt joining technique.AL6063 T-6 alloys prepared in 125x 100 x 7mm thickness plate and FSW tool setup were H13 of diameter 25mm rotary tool with straight cylindrical pin profile. The maximum strength was considered for selection of combined process parameter. The process parameters were optimized using Taguchi method. The Rotational speed, welding speed, and axial speed are the main process parameter which taken into our consideration. The optimum process parameters are determined with reference to tensile strength of the joint. From the experiments, it was found the effects of welding parameter are the axial force is highest substantial parameter to determining the tensile strength of the joint. The paper which revealed the optimal values of process parameter are to acquire a maximum tensile strength of friction stir welded AL6063-T6 plates is 101.6Mpa with the combination level of rotational speed, welding speed and axial force are found to be 1100 RPM, 60 mm/min and 12.5 KN. validation test was carried out and results were nearer to the optimized results confirmed by the optimum results.


2014 ◽  
Author(s):  
Xun Liu ◽  
Shuhuai Lan ◽  
Jun Ni

Friction stir welding (FSW) of dissimilar Al 6061 and TRIP 780/800 steel has been performed under different process parameters, including tool rotational speed, welding speed as well as the relative position of the tool axis to the abutting edge. Temperature and mechanical welding force was recorded during the process. Welding speed has an insignificant effect on either the maximum temperature or welding force. However, it can directly change the length of high temperature duration, which will accordingly influence temperature distribution in the weld and the microstructure. Higher rotational speed can effectively elevate weld temperature through greater amount of heat input. Metallurgical observations on weld cross sections perpendicular to the joint line was performed using both optical and scanning electron microscope. Microstructure evolution was analyzed and related to the force and temperature measurement results during the FSW process.


10.30544/221 ◽  
2017 ◽  
Vol 23 (2) ◽  
pp. 119-130 ◽  
Author(s):  
Nagabhushan Kumar Kadigithala ◽  
Vanitha C

Friction stir welding (FSW) is an efficient technique which can be used particularly for magnesium and aluminum alloys that are difficult to fusion weld. In this work AZ91D Mg alloy plates 3mm thick were friction stir welded at different process variables such as rotational speed and welding speed. The range of rotational speeds varied from 1025 to 1525 rpm, and the welding speed varied from 25 to 75 mm/min. Good quality welds were obtained under 1025 rpm of rotational speed with the welding speeds range from 25 to 75 mm/min. The microstructure of the AZ91D alloy consists of primary α-phase, eutectic α-phase and eutectic β (Mg17Al12) phase in the received condition (gravity die cast). The original dendrite grain structure completely disappeared and was transformed to fine equiaxed grains in stir zone (SZ). It was observed that there was a slight increase in hardness in SZ, because of fine recrystallized grain structure. The transverse tensile test results of weld specimens indicated constant strength irrespective of traveling speed. Fractrographic analysis of the friction stir welded specimens showed the brittle failure.


2021 ◽  
Author(s):  
CHENYU ZHAO ◽  
Xun Liu

Abstract A pressure-dependent friction boundary condition is developed based on wear theory for modeling self-reacting friction stir welding using computational fluid dynamics approach. The importance of shear layer in weld formation is emphasized. Effects of welding speed on the weld cross section geometry can be robustly captured with this newly developed boundary condition. Computational results showed at higher welding speed, the distance between the TMAZ boundary and the pin periphery at the advancing side is reduced, which corresponds to the experimental observations. This tendency could serve as a numerical criterion to predict void defect formation.


Author(s):  
C Ganesan ◽  
K Manonmani

Friction stir welding is a high potential technology for joining similar and dissimilar aluminum materials, utilized extensively in aerospace and automotive industrial applications to eradicate the problems like hot cracking, porosity, element loss, etc. due to the fusion welding process. This Research addresses the joining of two dissimilar materials of AA 5754 – H32 and AA 8090T6511 – Al-Li and their mechanical properties analysis with the effects of friction stir welding process parameters like tool rotational speed, welding speed and axial load on weld nugget zone formation quality. The significant roles of different tool pin profiles are also emphasized. A mathematical modeling equation was formed by using regression analysis to optimize the process parameter and found the best tool pin profile for defect-free weld nugget zone and higher tensile and hardness properties. This research also portrays the contribution of various pin profiles and each process parameter on the ultimate tensile strength by response surface methodology. The results indicate that the defect-free weld joints are observed with 1800 r/min of rotational speed, welding speed of 15 mm min−1 and 8.5 kN of axial load with hexagonal pin profile.


Author(s):  
Anganan K ◽  
Narendran RJ ◽  
Naveen Prabhu N ◽  
Rahul Varma R ◽  
Sivasubramaniyam R

Friction stir welding (FSW) is an innovative solid state joining technique and has been employed in industries for joining aluminum, magnesium, zinc and copper alloys. The FSW process parameters such as tool, rotational speed, welding speed, axial force, etc play major role in deciding the weld quality. A mathematical modeling was developed based on experiments to predict the tensile strength of dissimilar FSW aluminum alloys. The maximum tensile strength of 210 MPa can be obtained at the tool rotational speed of 1100 rpm, welding speed of 35mm/min and an axial load of 7 kN is the Optimum welding parameters.


2018 ◽  
Vol 14 (1) ◽  
pp. 19-28
Author(s):  
Kharia Salman Hassan

The influence of pre- shot peening and welding parameters on mechanical and metallurgical properties of dissimilar and similar aluminum alloys AA2024-T3 and AA6061-T6 joints using friction stir welding have been studied. In this work, numbers of plates were equipped from sheet alloys in dimensions (150*50*6) mm then some of them were exposed to shot peening process before friction stir welding using steel ball having diameter 1.25 mm for period of 15 minutes. FSW joints were manufactured from plates at three welding speeds (28, 40, 56 mm/min) and welding speed 40mm/min was chosen at a rotating speed of 1400 rpm for welding the dissimilar pre- shot plates. Tow joints were made at rotational speed of 1000 rpm and welding speed of 40m/min from shot and without shot peening plats. Welding temperature was measured in three zones using thermocouple. Micro hardness (HV) and tensile tests were performed to evaluate the mechanical characteristic of the joints. The results show a decay in mechanical qualities when the welding speed was increased and the best result was at (28) mm/min and the opposite result was obtained when rotational speed increased and pre-shot contributed in improving of this decay at 88% of welding speed (40) mm/min and 98%  at the rotational speed of 1000 rpm.      


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