scholarly journals Influence of Tool Material, Tool Geometry, Process Parameters, Stacking Sequence, and Heat Sink on Producing Sound Al/Cu Lap Joints through Friction Stir Welding

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 875 ◽  
Author(s):  
Wei ◽  
Latif ◽  
Hussain ◽  
Heidarshenas ◽  
Altaf
Keyword(s):  
Friction Stir Welding ◽  
Welding Speed ◽  
Heat Sink ◽  
Tool Material ◽  
Lap Joints ◽  
Tool Geometry ◽  
Welding Parameters ◽  
Stacking Sequence ◽  
Friction Stir ◽  
Lap Shear

The present study was focused on establishing guidelines for successful friction stir welding of Al alloys and Cu lap joints. Detailed investigations in respect to tool geometry, tool material, work-piece material, welding parameters, stacking sequence, and heat sink were carried out. The soundness of welded joints was tested through microscopic analysis and the lap shear test. The results revealed that the tungsten carbide (WC) tool with square-pin produced sound joints in terms of minimized defects and high strength. Further, the use of heat sink proved as an important pre-requisite when the stacking sequence was inversed (i.e., Cu-Al), and this stacking configuration in comparison with the Al-Cu stacking yielded weaker joints. The influence of the tool welding speed (F, mm/min) was found to depend upon the tool material. A range of tool welding speed (23.5–37.5 mm/min) worked well for the WC tool. However, only two values of welding speed (30 mm/min and 37 mm/min) were observed to be conducive when the tool material was HSCo (high-speed cobalt)-steel. Finally, it was concluded to employ the WC tool with square-pin, a welding speed of 30 mm/min, the rotational speed (S, rpm) of 1500 mm/min, and Al-Cu stacking sequence to successfully process the Al/Cu lap joints.

scholarly journals Friction Stir Welding of AZ31B-H24 Magnesium Alloy in Lap Configuration

2021 ◽  
Author(s):  
Bhukya Srinivasa Naik
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Sheet Thickness ◽  
Lap Joints ◽  
Welding Parameters ◽  
Friction Stir ◽  
Rotational Rate ◽  
Secondary Cracks

Friction stir welding (FSW) being an enabling solid-state joining technology can be suitably applied for the assembly of lightweight magnesium alloys. In this study, AZ31B-H24 Mg alloy sheets with a thickness of 2 mm were friction stir welded in lap configuration using two tool rotational rates of 1000 and 1500 rpm and two welding speeds of 10 and 20 mm/s. The joint quality was characterized in terms of the residual stresses, welding defects, microstructure, and texture. The mechanical properties including hardness, room and elevated temperature tensile and fatigue properties were also evaluated and correlated to the structure and defects. It was observed that the hardness decreased from the base metal (BM) to the stir zone (SZ) across the heat-affected zone (HAZ) and thermomechanically-affected zone (TMAZ). The lowest value of hardness appeared in the SZ. With increasing tool rotational rate or decreasing welding speed, the average hardness in the SZ decreased owing to increasing grain sizes, and a Hall-Petch-type relationship was established. The shear tensile behavior of the lap joints was evaluated at low (-40°C), room (25°C), and elevated (180°C) temperatures. The failure load was highest in the lower heat input condition that was obtained at a tool rotational rate of 1000 rpm and a welding speed of 20 mm/s at all the test temperatures, due to a smaller hooking height, larger effective sheet thickness, and lower tensile residual stress, as compared with other two welding conditions that were obtained at a higher tool rotational rate or lower welding speed. The lap joints usually fractured on the advancing side of the top sheet near the interface between the TMAZ and the SZ. Elevated temperature testing of the weld assembled at a tool rotational rate of 1000 rpm and a welding speed of 20 mm/s led to the failure along the sheet interface in a shear fracture mode due to the high integrity of the joint that exhibited large plastic deformation and increased total energy absorption. Fatigue fracture of the lap welds always occurred at the interface between the SZ and TMAZ on the advancing side where a larger hooking defect was present (in comparison with the retreating side). The welding parameters had a significant influence on the hook height and the subsequent fatigue life. A relatively “cold” weld, conducted at a rotational rate of 1000 rpm and welding speed of 20 mm/s, gave rise to almost complete elimination of the hooking defect, thus considerably (over two orders of magnitude) improving the fatigue life. Fatigue crack propagation was basically characterized by the formation of fatigue striations concomitantly with secondary cracks.

scholarly journals Friction Stir Welding of AZ31B-H24 Magnesium Alloy in Lap Configuration

2021 ◽  
Author(s):  
Bhukya Srinivasa Naik
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Sheet Thickness ◽  
Lap Joints ◽  
Welding Parameters ◽  
Friction Stir ◽  
Rotational Rate ◽  
Secondary Cracks

Friction stir welding (FSW) being an enabling solid-state joining technology can be suitably applied for the assembly of lightweight magnesium alloys. In this study, AZ31B-H24 Mg alloy sheets with a thickness of 2 mm were friction stir welded in lap configuration using two tool rotational rates of 1000 and 1500 rpm and two welding speeds of 10 and 20 mm/s. The joint quality was characterized in terms of the residual stresses, welding defects, microstructure, and texture. The mechanical properties including hardness, room and elevated temperature tensile and fatigue properties were also evaluated and correlated to the structure and defects. It was observed that the hardness decreased from the base metal (BM) to the stir zone (SZ) across the heat-affected zone (HAZ) and thermomechanically-affected zone (TMAZ). The lowest value of hardness appeared in the SZ. With increasing tool rotational rate or decreasing welding speed, the average hardness in the SZ decreased owing to increasing grain sizes, and a Hall-Petch-type relationship was established. The shear tensile behavior of the lap joints was evaluated at low (-40°C), room (25°C), and elevated (180°C) temperatures. The failure load was highest in the lower heat input condition that was obtained at a tool rotational rate of 1000 rpm and a welding speed of 20 mm/s at all the test temperatures, due to a smaller hooking height, larger effective sheet thickness, and lower tensile residual stress, as compared with other two welding conditions that were obtained at a higher tool rotational rate or lower welding speed. The lap joints usually fractured on the advancing side of the top sheet near the interface between the TMAZ and the SZ. Elevated temperature testing of the weld assembled at a tool rotational rate of 1000 rpm and a welding speed of 20 mm/s led to the failure along the sheet interface in a shear fracture mode due to the high integrity of the joint that exhibited large plastic deformation and increased total energy absorption. Fatigue fracture of the lap welds always occurred at the interface between the SZ and TMAZ on the advancing side where a larger hooking defect was present (in comparison with the retreating side). The welding parameters had a significant influence on the hook height and the subsequent fatigue life. A relatively “cold” weld, conducted at a rotational rate of 1000 rpm and welding speed of 20 mm/s, gave rise to almost complete elimination of the hooking defect, thus considerably (over two orders of magnitude) improving the fatigue life. Fatigue crack propagation was basically characterized by the formation of fatigue striations concomitantly with secondary cracks.

scholarly journals Thermo-mechanical analysis of linear welding stage in friction stir welding - influence of welding parameters

2021 ◽  
pp. 186-186
Author(s):  
Darko Veljic ◽  
Marko Rakin ◽  
Aleksandar Sedmak ◽  
Nenad Radovic ◽  
Bojan Medjo ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Heat Generation ◽  
Welding Speed ◽  
Reaction Force ◽  
Material Model ◽  
Element Model ◽  
Welding Parameters ◽  
Al Alloy ◽  
Friction Stir ◽  
Fsw Parameters

The influence of friction stir welding (FSW) parameters on thermo-mechanical behaviour of the material during welding is analysed. An aluminium alloy is considered (Al 2024 T351), and different rotating speed and welding speed are applied. Finite element model consists of the plate (Al alloy), backing plate and welding tool, and it is formed and solved in software package Simulia Abaqus. The influence of the welding conditions on material behaviour is taken into account by application of the Johnson-Cook material model. The rotation of the tool affects the results: if increased, it contributes to an increase of friction-generated heat intensity. The other component of the generated heat, the plastic deformation of the material, is negligibly changed. When the welding speed is increased, the intensity of friction-generated heat decreases, while the heat generation due to plastic deforming increases. Combined, these two effects cause small change of the total heat generation. For the same welded joint length, the plate welded by lower speed will be heated more intensively. The changes of the heat generation influence both the temperature field and reaction force, which are also considered.

Mechanical Property of Friction Stir Welded Retardant Magnesium Alloy Joint

2011 ◽  
Vol 295-297 ◽  
pp. 1929-1932
Author(s):  
Yi Min Tu ◽  
Ran Feng Qiu ◽  
Hong Xin Shi ◽  
Xin Zhang ◽  
Ke Ke Zhang
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Welding Speed ◽  
Rotational Speed ◽  
Maximum Strength ◽  
Welding Parameters ◽  
Tool Rotational Speed ◽  
Friction Stir

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.

scholarly journals Influence of Tool Geometry and Process Parameters on Torque, Temperature, and Quality of Friction Stir Welds in Dissimilar Al Alloys

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6020
Author(s):  
Neves Manuel ◽  
Daniel Beltrão ◽  
Ivan Galvão ◽  
Rui M. Leal ◽  
José D. Costa ◽  
...  
Keyword(s):  
Welding Speed ◽  
Tool Material ◽  
Al Alloys ◽  
Stir Zone ◽  
Tool Geometry ◽  
Friction Stir ◽  
Dissimilar Welds ◽  
Simple Geometry ◽  
Higher Temperature

In the current investigation, the influence of the tool geometry, the position of the materials in the joint, the welding speed on the temperature and torque developed, and on the quality of the welds in dissimilar and tri-dissimilar T joints were analysed. The aluminium alloys used were AA2017-T4, AA6082-T6, and AA5083-H111 and the friction stir welds were performed with identical shoulder tools, but with either a pin with simple geometry or a pin with progressive geometry. Progressive pin tools proved to be a viable alternative in the production of dissimilar and tri-dissimilar welds, as they provide a larger tool/material friction area and a larger volume of dragged material, which promotes an increase in the heat generated and a good mixing of the materials in the stir zone, although they require a higher torque. Placing a stronger material on the advancing side also results in a higher temperature in the stir zone but requires higher torque too. The combination of these factors showed that tools with a progressive pin provide sound dissimilar and tri-dissimilar welds, unlike single-pin tools. The increase in the welding speed causes the formation of defects in the stir zone, even in tri-dissimilar welds carried out with a tool with a progressive pin, which impairs the fatigue strength of the welds.

Effects of welding speeds on the microstructural and mechanical properties of AZ91D Mg alloy by friction stir welding

2020 ◽  
Vol 11 (6) ◽  
pp. 769-782 ◽  
Author(s):  
Nagabhushan Kumar Kadigithala ◽  
Vanitha C
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Welding Speed ◽  
Base Material ◽  
Welding Parameters ◽  
Content Type ◽  
Friction Stir ◽  
Az91d Magnesium Alloy ◽  
Transverse Tensile

PurposeThe main purpose of the present work is to evaluate, the microstructural and mechanical properties of friction stir welded plates of AZ91D magnesium alloy with 3 mm thickness, and to determine the optimum range of welding conditions.Design/methodology/approachMicrostructure and fractographic studies were carried out using scanning electron microscopy (SEM). Vickers micro hardness test was performed to evaluate the hardness profile in the region of the weld area. The phases in the material were confirmed by X-Ray diffraction (XRD) analysis. Transverse tensile tests were conducted using universal testing machine (UTM) to examine the joint strength of the weldments at different parameters.FindingsMetallographic studies revealed that each zone shown different lineaments depending on the mechanical and thermal conditions. Significant improvement in the hardness was observed between the base material and weldments. Transverse tensile test results of weldments had shown almost similar strength that of base material regardless of welding speed. Fractographic examination indicated that the welded specimens failed due to brittle mode fracture. Through these studies it was confirmed that friction stir welding (FSW) can be used for the welding of AZ91D magnesium alloy.Research limitations/implicationsIn the present study, the welding speed varied from 25 mm/min to 75 mm/min, tilt angle varied from 1.5° to 2.5° and constant rotational speed of 500 rpm.Practical implicationsMagnesium and aluminum based alloys which are having high strength and low density, used in automotive and aerospace applications can be successfully joined using FSW technique. The fusion welding defects can be eliminated by adopting this technique.Originality/valueLimited work had been carried out on the FSW of magnesium based alloys over aluminum based alloys. Furthermore, this paper analyses the influence of welding parameters over the microstructural and mechanical properties.

scholarly journals Combined Response Surface Method and Modified Differential Evolution for Parameter Optimization of Friction Stir Welding

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1080
Author(s):  
Thanatkij Srichok ◽  
Rapeepan Pitakaso ◽  
Kanchana Sethanan ◽  
Worapot Sirirak ◽  
Parama Kwangmuang
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Ultimate Tensile Strength ◽  
Differential Evolution ◽  
Welding Speed ◽  
Tool Material ◽  
Optimal Parameters ◽  
Friction Stir ◽  
Surface Method ◽  
Tool Pin

In this study, we constructed a new algorithm to determine the optimal parameters for friction stir welding including rotational speed, welding speed, axial force, tool pin profile, and tool material. The objective of welding is to maximize the ultimate tensile strength of the welded aluminum. The proposed method combines the response surface method and the modified differential evolution algorithm (RSM-MDE). RSM-MDE is a method that involves both experimental and simulation procedures. It is composed of four steps: (1) finding the number of parameters and their levels that affect the efficiency of the friction stir welding, (2) using RSM to formulate the regression model, (3) using the MDE algorithm to find the optimal parameter of the regression model obtained from (2), and (4) verifying the results obtained from step (3). The optimal parameters generated by the RSM-MDE method were a rotation speed of 1417.68 rpm, a welding speed of 60.21 mm/min, an axial force of 8.44 kN, a hexagon-tapered tool pin profile, and the SKD 11 tool material. The ultimate tensile strength obtained from this set of parameters was 294.84 MPa, which was better than that of the RSM by 1.48%.

scholarly journals Effect of Tool Geometry and Welding Parameters on Friction Stir Welded Lap Joint Formation with AA2099-T83 and AA2060-T8E30 Aluminium Alloys

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 872 ◽  
Author(s):  
Egoitz Aldanondo ◽  
Javier Vivas ◽  
Pedro Álvarez ◽  
Iñaki Hurtado
Keyword(s):  
Aluminium Alloys ◽  
Defect Formation ◽  
Lap Joints ◽  
Tool Geometry ◽  
Welding Parameters ◽  
Lap Joint ◽  
Friction Stir ◽  
Reaction Forces ◽  
Cold Lap ◽  
Probe Geometry

In this paper the effect of tool geometry and welding parameters on friction stir welded lap joints with AA2099-T83 and AA2060-T8E30 aluminium alloys has been investigated through the study of the material flow and weld formation along with the reaction forces during friction stir welding (FSW) for various sets of welding parameters and two FSW tools with different geometrical features. The results showed that welding parameters and tool probe geometry strongly affect the characteristics of the typical defect features (hook and cold lap defects) of the friction stir welded lap joints. From the relationship established between the welding parameters, tool probe geometry and the hook and cold lap defect formation, some guidelines are concluded with the objective of guaranteeing appropriate FSW lap joint properties.

Experimental Analysis on Mechanical Properties of Friction Stir Welding in Dissimilar Aluminum Alloys

2020 ◽  
pp. 64-68
Author(s):  
Anganan K ◽  
Narendran RJ ◽  
Naveen Prabhu N ◽  
Rahul Varma R ◽  
Sivasubramaniyam R
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Welding Speed ◽  
Rotational Speed ◽  
Copper Alloys ◽  
Welding Parameters ◽  
Tool Rotational Speed ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys

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.

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