scholarly journals Dissimilar friction stir lap welding of AA 5754-H22/AA 6082-T6 aluminium alloys: Influence of material properties and tool geometry on weld strength

2015 ◽  
Vol 87 ◽  
pp. 721-731 ◽  
Author(s):  
M.I. Costa ◽  
D. Verdera ◽  
C. Leitão ◽  
D.M. Rodrigues
Keyword(s):  
Material Properties ◽  
Aluminium Alloys ◽  
Weld Strength ◽  
Tool Geometry ◽  
Friction Stir Lap Welding ◽  
Friction Stir ◽  
Lap Welding

Friction Stir Lap Welding of Thin AA6061-T6 and AISI304 Sheets at Different Values of Pin Penetrations

2018 ◽  
Author(s):  
Raju Prasad Mahto ◽  
Surjya K. Pal
Keyword(s):  
Intermetallic Compound ◽  
Joint Strength ◽  
Detrimental Effect ◽  
Steel Substrate ◽  
Weld Strength ◽  
Steel Matrix ◽  
Friction Stir Lap Welding ◽  
Depth Of Penetration ◽  
Friction Stir ◽  
Lap Welding

The present paper focuses on the influence of pin penetration on joint strength achieved in friction stir lap welding between AA6061-T6 and AISI304. Penetration of pin into the steel substrate, which is placed below the aluminium, has an influencing role in achieving a good weld. Beyond a certain depth of penetration of pin into the steel, non-uniform thicker intermetallic compound and the weld defects have been found. Defects were found to be located in the stir zone. Thus, an excessive penetrations of the pin into the steel matrix has been produced a detrimental effect to the weld strength. An optimum penetration of pin has been experimentally found out.

Laser-Assisted Friction Stir Lap Welding of Aluminum

2005 ◽  
Author(s):  
Nicholas Able ◽  
Frank Pfefferkorn
Keyword(s):  
Contact Resistance ◽  
Laser Power ◽  
Frictional Heat ◽  
Total Power ◽  
Bottom Plate ◽  
Tool Geometry ◽  
Transfer Model ◽  
Friction Stir Lap Welding ◽  
Friction Stir ◽  
Lap Welding

The objective of this research is to determine the effects of laser preheating on friction stir lap welding. Laser preheating of the top surface of the material during friction stir lap welding is used to reduce the welding forces and torque, thereby reducing the stiffness requirements on the clamping and FSW tool. Preheating also has the potential to enable higher welding speeds and reduced tool wear particularly when applied to welding of higher melting temperature alloys. A transient three-dimensional finite element heat transfer model of the workpieces was developed to predict the influence of preheating on the temperature distribution and heat flux within the workpieces. The model accounts for conduction in the workpieces, contact resistance between them, laser absorption, frictional heat generation under the FSW tool shoulder, and losses to the surroundings. Predicted temperatures at discrete locations were compared with thermocouple measurements and found to be in good agreement. The model showed that the energy deposited by the laser in the top plate does not penetrate into the bottom plate ahead of the tool due to the contact resistance between the plates. Hence, the thermal contact resistance, inherent to lap welds, controls the effectiveness of preheating. The effect of preheating on FSW of aluminum was investigated by varying the laser power and workpiece material while maintaining constant tool geometry and material. The results of the parametric study are presented and show that while forces and torques are reduced by preheating, not as much as in butt welding because of the contact resistance produced by the nature of the weld. It was also found that the total power consumed in the process, defined as the sum of tool power and absorbed laser power, can decrease with preheating.

Friction Stir Lap Welding of Aluminium Alloys

2014 ◽  
Vol 611-612 ◽  
pp. 1421-1428
Author(s):  
Carlo Bruni ◽  
Giovanni Quercetti ◽  
Massimiliano Pieralisi
Keyword(s):  
Friction Stir Welding ◽  
Aluminium Alloys ◽  
Tensile Shear ◽  
Friction Stir Lap Welding ◽  
Friction Stir ◽  
Tool Geometries ◽  
Lap Welding ◽  
Welding Properties ◽  
Transverse Area ◽  
Tool Rotation

The friction stir welding of lap sheets can be performed considering different variables in terms of process parameters, tool configuration, welding typology and so on. The proposed investigation deals with the friction stir welding of blanks, with the same thickness, performed under lap configuration with the sheets welded, in one-side and in both sides as well, with different tool geometries and tool rotation-wise. The double side allows to extend the weld through the whole thickness leading to better mechanical welding properties at the blank to blank interface. The weld morphology has been investigated through microstructure observations performed on the transverse area, with respect to the welding velocity, of each joint. The tensile shear strength of the joint in one-side weld is generally lower than that detected in two side weld.

scholarly journals Microstructural and Process Parameters of aluminium alloys Using FSW

2021 ◽  
Vol 23 (12) ◽  
pp. 491-510
Author(s):  
Nuzhat Nazir ◽  
◽  
Manish Kumar Gupta ◽  
Keyword(s):  
Process Parameters ◽  
Aluminium Alloys ◽  
Optimal Combination ◽  
Grain Structure ◽  
Weld Strength ◽  
Tool Geometry ◽  
Relevant Parameter ◽  
Influence Of Process Parameters ◽  
Friction Stir ◽  
Fine Grain

Friction stir welding (FSW) has become a popular method for connecting low weight metals. Material joining occurs in the solid state in FSW. Inserting a rotating tool travelling over the faying surfaces of the material to be bonded is used to complete the procedure. It produces practically defect-free welds with little distortion and a fine grain structure. However, the welding mechanism and process parametric combination for welds with consistent and dependable outcomes are not well understood. The thesis details the experimental efforts made to suggest an optimal combination of parameters with simple tool geometry for FSW at greater linear speeds. The materials for research were two precipitation hardenable aluminium alloys: 6mm thick 2219-T87 and 5083H321. The influence of process parameters on weld microstructural changes and defect development was also examined. The optimal combination of process parameters for the FSW of aluminium alloys was proposed, and the most relevant parameter for weld strength and quality was discovered.

scholarly journals Influence of the Aluminium Alloy Type on Defects Formation in Friction Stir Lap Welding of Thin Sheets

2018 ◽  
Vol 23 (1) ◽  
pp. 32-42 ◽  
Author(s):  
M. I. Costa ◽  
C. Leitao ◽  
D. M. Rodrigues
Keyword(s):  
Aluminium Alloys ◽  
Fatigue Behaviour ◽  
Welding Parameters ◽  
Thin Sheets ◽  
Friction Stir Lap Welding ◽  
Friction Stir ◽  
Alloy Type ◽  
Heat Treated ◽  
Lap Welding ◽  
Applied Stresses

Abstract The weldability in Friction Stir Lap Welding (FSLW) of heat and non-heat treatable aluminium alloys, the AA6082-T6 and the AA5754-H22 aluminium alloys, respectively, are compared. For both alloys, welds were produced in very thin sheets, using the same welding parameters and procedures, and strong differences in welds morphology were found. The strength of the welds was evaluated by performing tensile-shear tests under monotonic and cyclic loading conditions. As-welded and heat-treated samples of the AA6082- T6 were tested. It was found that the heat-treatable alloy is more sensitive to defects formation, in lap welding, than the non-heat-treatable alloy. The presence of defects has a strong influence on the monotonic and fatigue behaviour of the welds. In spite of this, for very high-applied stresses, the heat-treatable alloy welds perform better in fatigue than the non-heat-treatable alloy welds.

scholarly journals Influence of Tool Geometry and Process Parameters on the Properties of Friction Stir Spot Welded Multiple (AA 5754 H111) Aluminium Sheets

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1157
Author(s):  
Danka Labus Zlatanovic ◽  
Sebastian Balos ◽  
Jean Pierre Bergmann ◽  
Stefan Rasche ◽  
Milan Pecanac ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Spot Welding ◽  
Minimum Energy ◽  
Tool Geometry ◽  
Friction Stir ◽  
Minimum Energy Consumption ◽  
Punch Test ◽  
Wide Range ◽  
Lap Welding

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.

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