The welds created for this investigation also represent an evolution of friction stir welding by starting with a milling machine; a very basic piece of engineering workshop equipment.
Friction stir welds were then recreated and cone tested which reveals the different levels of deformation occurring across the entire weld section and the unaffected parent material.
The Friction Stir Welding (FSW) is a latest process of Advanced Welding Technology and was invented in 1991 by The Welding Institute (TWI) at Cambridge, in United Kingdom. In 1995, Friction Stir Welding has been used in production applications by introducing welding of extrusions to form paneling for marine applications in Europe and USA. Since then, the process has been commercialized in many other applications including rail car, automotive, aerospace, heavy truck, medical applications, etc. In this book a detailed emphasis is given about historical developments, types of welding processes, working principles of friction stir welding, design feature of FSW tools, processing on aluminium alloys and application in various industries. Author has also tried to place the opinions of researchers as to what they say about the latest techniques of Friction Stir Welding.
It delivers proven weld quality, excellent mechanical properties, virtually no porosity and the opportunity for reduced wall thickness in many applications.
About Powerstir friction stir welding
Patented by TWI (The Welding Institute), friction stir welding is a unique and innovative means of jointing metals.
Used primarily for jointing aluminium, magnesium, copper, titanium, steel, lead and zinc, the Powerstir friction stir welding process provides a clean, highly aesthetic alternative to traditional welding.
The friction stir welds have been created using novel tools which are oversized for the material thickness used; this creates a wider weld region of fine equiaxed grains which are suitable for SPF.
The aim of the work reported in this thesis is to develop friction stir welding for superplastic titanium alloys. A number of studies have shown that friction stir welding is capable of retaining the fine-grained superplastic microstructure of the base metal and so there has been much commercial interest in combining it with superplastic forming processes.
Within this programme friction stir welding was performed with a variety of process parameters and in both the conventional and stationary shoulder configuration. This meant that a number of welds were created with various rates of heat input. The elevated temperature and intense plastic deformation associated with the friction stir welding process substantially alters the base metal microstructure. As a result the influence of the process parameters on the microstructure, texture and residual stress development has been identified within this investigation. Tool wear and deformation also remains a hindrance in the commercialisation of friction stir welding titanium alloys. Wear and deformation of the tool not only changes its shape, but it can have further implications on the structural integrity of the weld. Thus the influence of the process parameters on wear and deformation of the tool have also been identified.
With our considerable expertise in friction stir welding, we are providing automotive OEMs with highly viable manufacturing solutions for battery housings, solutions which involve no surface finishing and remove the risk of heat damage to delicate components.”
Working with magnesium alloys
As manufacturers of the world-acclaimed Powerstir range of friction stir welders, PTG Heavy Industries is an acknowledged leader in this innovative means of jointing metals.
Working with magnesium alloys of 3mm – 5mm in thickness, and to tolerances of typically 50 microns, the company is currently assisting automotive OEMs in the production of vehicle battery trays, associated electronics boxes and coolant units, by using its 2D friction stir welding techniques.
Using industry standard CNC systems, fitted with PTG Powerstir friction stir welding software, data-logging and multi-axis interpolation, 2D welding can be carried out on accurate tool paths, together with force control to create consistent welded seams.
Superior high-strength joints
“Our work to-date, involving the production of automotive battery enclosures using friction stir welding techniques, is exciting and is providing novel opportunities for vehicle design engineers to achieve both light weight and structural rigidity in electronics units that benefit from superior high-strength welded joints,” adds Peter Jowett.
Proven weld quality
Since their launch, Powerstir machines have attracted considerable interest from organisations seeking an innovative way of creating superior high-strength welded joints.
The PTG range includes heavy duty lathes, deep hole drilling machines, friction stir welding machines, ultra precision grinding machines for rotor, thread and gear operations; rotor milling machines and special purpose machine tools for the manufacture of precision components.