Statistical Investigations on Friction Stir Welded Aluminum Tailored Blanks for a Robust Process Window

2005 ◽  
pp. 599-606 ◽  
Author(s):  
Arthur Giera ◽  
Marion Merklein ◽  
Manfred Geiger
Keyword(s):  
Process Window ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Robust Process

Cascaded Control of Power Input and Welding Temperature During Sealing of Spent Nuclear Fuel Canisters

2010 ◽  
Author(s):  
Lars Cederqvist ◽  
Olof Garpinger ◽  
Tore Ha¨gglund ◽  
Anders Robertsson
Keyword(s):  
Spent Nuclear Fuel ◽  
Power Input ◽  
Process Window ◽  
Welding Temperature ◽  
Loop Control ◽  
Friction Stir ◽  
Thermal Boundary Conditions ◽  
Welding Procedure ◽  
Robust Process ◽  
Weld Cycle

The friction stir welding procedure to seal copper canisters requires variable power input throughout the 45 minute long weld cycle to keep the welding temperature within the process window. This is due to variable thermal boundary conditions throughout the weld cycle which, together with fast disturbances in the spindle torque, requires control of both the power input and the welding temperature to achieve a stable and robust process. By using a cascaded loop that determines the power input requirement, the regulator will not be dependent on repeatability in the necessary power input between weld cycles. As a result, a more accurate and reliable closed-loop control of the welding temperature is acquired.

Investigations on the Mechanical Properties and Formability of Friction Stir Welded Tailored Blanks

2007 ◽  
Vol 344 ◽  
pp. 143-150 ◽  
Author(s):  
Gianluca Buffa ◽  
Livan Fratini ◽  
Marion Merklein ◽  
Detlev Staud
Keyword(s):  
Mechanical Properties ◽  
Stress Condition ◽  
Research Effort ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Sheet Stamping ◽  
Wide Range

Tight competition characterizing automotive industries in the last decades has determined a strong research effort aimed to improve utilized processes and materials in sheet stamping. As far as the latter are regarded light weight alloys, high strength steels and tailored blanks have been increasingly utilized with the aim to reduce parts weight and fuel consumptions. In the paper the mechanical properties and formability of tailored welded blanks made of a precipitation hardenable aluminum alloy but with different sheet thicknesses, have been investigated: both laser welding and friction stir welding have been developed to obtain the tailored blanks. For both welding operations a wide range of the thickness ratios has been considered. The formability of the obtained blanks has been characterized through tensile tests and cup deep drawing tests, in order to show the formability in dependency of the stress condition; what is more mechanical and metallurgical investigations have been made on the welded joints.

An Experimental Study on Voids in Mixed Alloy Assemblies

2006 ◽  
Author(s):  
Felix Bruno ◽  
Purushothaman Damodaran ◽  
Krishnaswami Srihari ◽  
Guhan Subbarayan
Keyword(s):  
Solder Joint ◽  
Manufacturing Industry ◽  
Research Effort ◽  
Lead Free ◽  
Process Window ◽  
Electronics Manufacturing ◽  
Solder Joint Reliability ◽  
Process Step ◽  
Joint Reliability ◽  
Robust Process

The electronics manufacturing industry is gradually migrating towards to a lead-free environment. During this transition, there will be a period where lead-free materials will need to coexist with those containing lead on the same assembly. The use of tin-lead solder with lead-free parts and lead-free solder with components containing lead can hardly be avoided. If it can be shown that lead-free Ball Grid Arrays (BGAs) can be successfully assembled with tin-lead solder while concurrently obtaining more than adequate solder joint reliability, then the Original Equipment Manufacturers (OEMs) will accept lead-free components regardless of the attachment process or material used. Consequently, the Electronics Manufacturing Service (EMS) providers need not carry both the leaded and the unleaded version of a component. Solder voids are the holes and recesses that occur in the joints. Some say the presence of voids is expected to affect the mechanical properties of a joint and reduce strength, ductility, creep, and fatigue life. Some believe that it may slow down crack propagation by forcing a re-initiation of the crack. Consequently, it has the ability to stop a crack. The primary objective of this research effort is to develop a robust process for mixed alloy assemblies such that the occurrence of voids is minimized. Since there is no recipe currently available for mixed alloy assemblies, this research will study and 'optimize' each assembly process step. The difference between the melting points of lead-free (217°C) and tin-lead (183°C) solder alloys is the most important constraint in a mixed alloy assembly. The effect of voids on solder joint reliability in tin-lead assembly is well documented. However, its effect on lead-free and mixed alloy assemblies has not received due attention. The secondary objective of this endeavor is to determine the percentage of voids observed in mixed alloy assemblies and compare the results to both tin-lead and lead-free assemblies. The effect of surface finish, solder volume, reflow profile parameters, and component pitch on the formation of voids is studied across different assemblies. A designed experiments approach is followed to develop a robust process window for mixed alloy assemblies. Reliability studies are also conducted to understand the effect of voids on solder joint failures when subjected to accelerated testing conditions.

Constant Heat Input Friction Stir Welding of Variable Thickness AZ31 Sheets Through In-Process Tool Rotation Control

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Gianluca Buffa ◽  
Davide Campanella ◽  
Archimede Forcellese ◽  
Livan Fratini ◽  
Michela Simoncini ◽  
...  
Keyword(s):  
Variable Thickness ◽  
Heat Input ◽  
Weld Line ◽  
Sheet Thickness ◽  
Strain Curve ◽  
Thickness Change ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Joint Properties ◽  
Tool Rotation

Tailored blanks characterized by variable thickness were friction stir welded (FSWed) with the aim to obtain constant joint properties along the weld seam, regardless of the thickness change. To pursue this goal, the heat input was kept constant by in-process control of tool rotation. A dedicated numerical model of the process was used to determine the tool rotation values as a function of the sheet thickness. The mechanical properties and the microstructure of the FSWed joints, produced with varying process parameters, were studied. It was found that the proposed approach can produce joints with uniform properties along the weld line in terms of stress–strain curve shape, joint strength, elongation at failure, and microstructure.

Incremental Forming of Friction Stir Welded Taylored Sheets

2006 ◽  
Author(s):  
G. Ambrogio ◽  
L. Fratini ◽  
F. Micari
Keyword(s):  
Metal Forming ◽  
Cost Reduction ◽  
Large Scale ◽  
Incremental Forming ◽  
Research Work ◽  
Sheet Thickness ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Metal Stamping ◽  
Light Components

In the last decade sheet metal forming market has undergone substantial mutations since the development of more efficient strategies in terms of flexibility and cost reduction is strictly due. Such requirements are not consistent with traditional metal stamping processes which are characterized by complex equipment, capital and tooling costs; thus the industrial application of such processes is economically convenient just for large scale productions. For this reason most of the research work developed in the last years has been focused on the development of new sheet forming processes able to achieve the above discussed goals. Contemporary, with particular reference to the automotive industries the requirement of light components and the engineering of the outer skin parts of the vehicles have determined the growing utilization of tailored blanks characterized by either different material or different sheet thickness. In the paper SPIF processes of FS welded aluminium blanks are investigated in order to analyse the product properties in terms of strength and formability. A proper experimental investigation has been carried out and interesting guidelines have been highlighted in the next paragraphs.

Development of Friction Stir Welded Tailored Blanks of 6000 Series Aluminum Alloy

2005 ◽  
Author(s):  
Masaki Kumagai ◽  
Tadashi Minoda ◽  
Koji Tanaka ◽  
Mineo Asano
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Series Aluminum Alloy

Friction Stir Blind Riveting for Joining Dissimilar Cast Mg AM60 and Al Alloy Sheets

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Junying Min ◽  
Jingjing Li ◽  
Blair E. Carlson ◽  
Yongqiang Li ◽  
James F. Quinn ◽  
...  
Keyword(s):  
Loading Condition ◽  
Tensile Load ◽  
Strengthening Mechanism ◽  
Frictional Heat ◽  
Process Window ◽  
Al Alloy ◽  
Forming Process ◽  
Friction Stir ◽  
Lap Shear ◽  
Riveting Process

A new one-sided joining method, friction stirring blind riveting (FSBR) was successfully implemented to form lap-shear joints for dissimilar metals from pairs of 3.05 mm thick cast Mg AM60, rolled 1.5 mm thick Al AA6022, and extruded 3.15 mm thick Al AA6082 specimens. The concept of this process is riveting the two workpieces with reduced force under frictional heat and fastening the workpieces through blind riveting once the rivet is fully inserted. In this research, the process was experimentally analyzed and optimized for four joint combinations. It was demonstrated that switching the positions of Mg and Al alloy specimens has a significant effect on the process window and maximum tensile load of the joints. Three quality issues of the FSBR joints were observed and discussed. During tensile testing, the sheet closer to the rivet tail work-hardens due to tail forming process but has worse loading condition than the sheet closer to the rivet head. For AA6xxx sheets, precipitate hardening due to frictional heat is another strengthening mechanism in FSBR compared to the conventional riveting process, which leads to higher tensile loads in FSBR joints.

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