scholarly journals Parametric Optimization of Butt Welded Polycarbonate using Response Surface Methodology

Author(s):  
Abid Imtiaz ◽  
Adnan Tariq ◽  
Ajaz Bashir Janjua ◽  
Fahad Sarfraz ◽  
Amar ul Hassan Khawaja

Friction Stir Welding (FSW) is a solid-state joining process for metals, non-metals and polymers. It is carried out with the help of a specially designed, non-consumable tool. The heat required, for creating a softened region at the faying surfaces, is generated by rotation of tool against the work piece material. Being a solid-state welding process, it offers several advantages like inducing minimum effect on the mechanical properties of base material, reduced shrinkage and distortion, no spatter or Ultra Violet (UV) radiations etc. However, developing a sound weld requires an appropriate combination of several process parameters e.g. the design of tool, its rotational and traversing speeds etc. To substantiate this aspect, an approach based on Response Surface Methodology (RSM) is presented during this paper that optimizes the combination of process parameters while investigating their effect on the mechanical properties of a friction stir welded butt joint configuration of Polycarbonate. To minimize the total number of combinations a Central Composite Rotatable Design (CCRD) is used with three factors and two levels. The results have shown that the butt joints fabricated at a traverse speed of 14 mm/min, rotational speed of 1700 RPM and with simple cylindrical conical tool geometry yielded the maximum ultimate tensile strength of 51.299 MPa.

Author(s):  
Akshansh Mishra ◽  
Adarsh Tiwari ◽  
Mayank Kumar Shukla ◽  
A. Razal Rose

A relatively new joining process, friction stir welding (FSW) produces no fumes; uses no filler material; and can join aluminium alloys, copper, magnesium, zinc, steels, and titanium. FSW sometimes produces a weld that is stronger than the base material. The tool geometry plays a critical role in material flow and governs the transverse rate at which FSW can be conducted. The tool serves three primary functions, i.e., (a) heating of the work piece, (b) movement of material to produce the joint, and (c) containment of the hot metal beneath the tool shoulder. Heating is created within the work piece by friction between both the rotating tool pin and shoulder and by severe plastic deformation of the work.


2016 ◽  
Vol 852 ◽  
pp. 317-323 ◽  
Author(s):  
S. Vignesh ◽  
P. Dinesh Babu ◽  
C. Balamurugan ◽  
S. Martin Vinoth

One of the most innovative solid state welding techniques used in the aerospace, automotive, defence, rail and marine industries is Friction Stir Welding (FSW) process, as it is used for joining aluminium, copper and magnesium alloys. The weld quality is decided by the FSW process parameters such as rotational speed, welding speed and pin profile. A regression model was developed relating the welding input parameters (tool rotational speed, welding speed and pin profile) and the output response parameters (tensile strength, hardness and toughness) based on the experiments carried out with the help of Response Surface Methodology. The obtained regression equations were used in determining the optimal welding process parameters. A new method, Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) based on evolutionary algorithm has been used in the optimisation. The optimum results gathered from the desirability approach through Response Surface Methodology (RSM) were compared with those obtained through the evolutionary algorithm. The results show that the proposed evolutionary method is much effective, faster than the desirability approach discussed in the work.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1157
Author(s):  
Danka Labus Zlatanovic ◽  
Sebastian Balos ◽  
Jean Pierre Bergmann ◽  
Stefan Rasche ◽  
Milan Pecanac ◽  
...  

Friction stir spot welding is an emerging spot-welding technology that offers opportunities for joining a wide range of materials with minimum energy consumption. To increase productivity, the present work addresses production challenges and aims to find solutions for the lap-welding of multiple ultrathin sheets with maximum productivity. Two convex tools with different edge radii were used to weld four ultrathin sheets of AA5754-H111 alloy each with 0.3 mm thickness. To understand the influence of tool geometries and process parameters, coefficient of friction (CoF), microstructure and mechanical properties obtained with the Vickers microhardness test and the small punch test were analysed. A scanning acoustic microscope was used to assess weld quality. It was found that the increase of tool radius from 15 to 22.5 mm reduced the dwell time by a factor of three. Samples welded with a specific tool were seen to have no delamination and improved mechanical properties due to longer stirring time. The rotational speed was found to be the most influential parameter in governing the weld shape, CoF, microstructure, microhardness and weld efficiency. Low rotational speeds caused a 14.4% and 12.8% improvement in joint efficiency compared to high rotational speeds for both tools used in this investigation.


Author(s):  
Thomas Robinson ◽  
Malcolm Williams ◽  
Harish Rao ◽  
Ryan P. Kinser ◽  
Paul Allison ◽  
...  

Abstract In recent years, additive manufacturing (AM) has gained prominence in rapid prototyping and production of structural components with complex geometries. Magnesium alloys, whose strength-to-weight ratio is superior compared to steel and aluminum alloys, have shown potential in lightweighting applications. However, commercial beam-based AM technologies have limited success with magnesium alloys due to vaporization and hot cracking. Therefore, as an alternative approach, we propose the use of a near net-shape solid-state additive manufacturing process, Additive Friction Stir Deposition (AFSD), to fabricate magnesium alloys in bulk. In this study, a parametric investigation was performed to quantify the effect of process parameters on AFSD build quality including volumetric defects and surface quality in magnesium alloy AZ31B. In order to understand the effect of the AFSD process on structural integrity in the magnesium alloy AZ31B, in-depth microstructure and mechanical property characterization was conducted on a bulk AFSD build fabricated with a set of acceptable process parameters. Results of the microstructure analysis of the as-deposited AFSD build revealed bulk microstructure similar to wrought magnesium alloy AZ31 plate. Additionally, similar hardness measurements were found in AFSD build compared to control wrought specimens. While tensile test results of the as-deposited AFSD build exhibited a 20 percent drop in yield strength, nearly identical ultimate strength was observed compared to the wrought control. The experimental results of this study illustrate the potential of using the AFSD process to additively manufacture Mg alloys for load bearing structural components with achieving wrought-like microstructure and mechanical properties.


Author(s):  
Rajat Gupta ◽  
Kamal Kumar ◽  
Neeraj Sharma

This chapter presents the friction stir welding (FSW) of aluminum alloy AA-5083-O using vertical milling machine. In present FSW experimentation, effects of different process parameter namely tool rotation speed, welding speed, tool geometry, and tool shoulder diameter have been determined on welding quality of two pieces of AA-5083-O using response surface methodology (RSM). The optimal sets of process parameters have been determined for weld quality characteristics namely tensile strength (UTS) and percentage elongation (%EL). In present experimentations, a specially designed tool made of high carbon steel with different shoulder diameters (15mm, 17.5mm, and 20 mm) having constant pin length (6 mm) were used for FSW of two pieces of aluminum alloy. The ANOVA and pooled ANOVA were used to study the effect of FSW parameters on UTS and %EL. Multi response optimization has been carried out using desirability function in conjunction with RSM to obtain the optimal setting of process parameters for higher UTS and lower %EL.


2013 ◽  
Vol 58 (2) ◽  
pp. 595-599 ◽  
Author(s):  
P. Lacki ◽  
Z. Kucharczyk ◽  
R.E. Śliwa ◽  
T. Gałaczyński

Friction stir welding (FSW) is one of the youngest methods of metal welding. Metals and its alloys are joined in a solid state at temperature lower than melting points of the joined materials. The method is constantly developed and friction stir spot welding (FSSW) is one of its varieties. In the friction stir spot welding process a specially designed tool is brought into rotation and plunged, straight down, in the joined materials. Heat is generated as a result of friction between the tool and materials, and plastic deformation of the joined materials. Softening (plastic zone) of the joined materials occurs. Simultaneously the materials are stirred. After removal of the tool, cooling down the stirred materials create a solid state joint. Numerical simulation of the process was carried out with the ADINA System based on the finite element method (FEM). The problem was considered as an axisymmetric one. A thermal and plastic material model was assumed for Al 6061-T6. Frictional heat was generated on the contact surfaces between the tool and the joined elements. The model of Coulomb friction, in which the friction coefficient depends on the temperature, was used. An influence of the tool geometry on heat generation in the welded materials was analysed. The calculations were carried out for different radiuses of the tool stem and for different angles of the abutment. Temperature distributions in the welded materials as a function of the process duration assuming a constant value of rotational tool speed and the speed of tool plunge were determined. Additionally, the effect of the stem radius and its height on the maximum temperature was analysed. The influence of tool geometry parameters on the temperature field and the temperature gradient in the welded materials was shown. It is important regarding the final result of FSSW.


2013 ◽  
Vol 753-755 ◽  
pp. 431-434 ◽  
Author(s):  
Pierpaolo Carlone ◽  
Gaetano S. Palazzo

In recent years friction stir welding process has received a great deal of attention from the transport industry. During the process, heat generation and material stirring induce significant microstructural alteration in the base material, affecting the properties of the welded assembly. In this paper the influence of process parameters, namely rotating speed and welding speed, on mechanical properties of AA2024-T3 friction stir butt welds is experimentally investigated. An increase of the yield stress has been found decreasing the heat input, while an opposite variation was measured for the elongation.


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