scholarly journals Influence of tool rotational speed on the evolution of microstructure and mechanical properties of precipitation-hardened Aluminium 6061 butt joint during friction stir welding

Author(s):  
Biplab Ghosh ◽  
Hrishikesh Das ◽  
Asis Samanta ◽  
Jyotsna Dutta Majumdar ◽  
Manojit Ghosh

Abstract The present investigation intends to interpret the effect of tool rotational speed on the mechanical properties and microstructural evolution in Aluminium 6061-T6 alloy during friction stir welding. A higher value of tool rotation produces more hardness at the nugget zone, which is attributed to the higher intensity of reprecipitation at higher rpm, revealed by transmission electron microscopy. The nugget zone is revealed as a nearly precipitate-free region, while the thermo-mechanically affected zone contains coarse precipitates, deformed and dynamically recovered grains with a few recrystallized grains. Significant reduction in grain size in the stirred zone is also a key finding. The observations depict the dependence of microstructure, and thus mechanical behaviour on tool rotational speed. A specific combination of process parameters has been determined from experiments, which corresponds to the maximum joint efficiency.

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.


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):  
Laxmana Raju Salavaravu ◽  
Lingaraju Dumpala

Submerged friction stir welding (FSW) is used to improve the weld zones mechanical properties in the present study. This research aims to obtain the optimized process parameters used to fabricate the AA6063 Submerged FSW joint. In the Submerged FSW process, the most important influential factors are tool rotational speed, traverse speed, and pin profile in a seawater environment. The different workpieces are friction stir welded while submerged in seawater at different tool rotational speeds, traverse speeds, and tool pin profiles such as square pin, cylindrical taper pin, and threaded pin. The produced weldments were tested for the mechanical properties of higher tensile strength, microhardness, corrosion rate, and the microstructure of weldments was characterized by using a scanning electron microscope, transmission electron microscope, and X-ray diffractometer. The corrosion rate is investigated by using an electrochemical analyzer by potential dynamic polarization open-circuit technique. For this investigation, The Taguchi method with the L9 orthogonal array design of experimentation is adopted. The maximum UTS was acquired in the weld joint fabricated with 1250 r/min of tool rotational speed, 45 mm/min traverse speed, and a square tool pin. The stirred zone is tested for microhardness. High hardness is achieved with high tool rotational speed and low traverse speed with a square tool pin profile. The corrosion rate is also decreased with high tool rotational speed, low traverse speed, and a square tool pin profile.


2019 ◽  
Vol 969 ◽  
pp. 720-726
Author(s):  
Ajay Kumar Revelly ◽  
B. Rajkumar ◽  
V. Swapna

The main aim of the present topic is friction stir welding (FSW) of Aluminium HE-30, which shows that improved microstructures, strong weld and with less of defects. In the other hand, an attempt was made to correlate the welding parameters and mechanical properties. In the present investigation four rotational speeds of 1000 rpm, 1200 rpm, 1400 rpm and 1600 rpm with travelling speed of 30 mm/min. and tool geometry (straight cylindrical) was chosen. It was observed that the tool rotational speed is a sensitive parameter to decide the ultimate tensile strength and yield strength of the present material. Similarly, the hardness of Al plates is improved at the weld zone. Hence, it is suggested that to consider a parameter such as welding tool rotational speed, travelling speed and materials in selecting the welding methods of sound joints, because it influences the microstructure and mechanical properties in various applications. In the present study, non-destructive tests are also confirmed the defective nature of the weld zone of Al plates.


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