TWI has considerable knowledge and experience of the development of tools and procedures to support the application of FSW technology for a wide range of industrial applications. Many organisations work with TWI to gain information on the current state of the art with respect to FSW tool designs, tool material selection, and suitable welding procedures for particular applications, predominantly in aluminium alloys. The areas of FSW tool design and FSW procedure development for Al have generally been well explored and well documented, both by TWI, and by others throughout the world. Effective solutions exist for these requirements for most applications, however this is not true in the area of tool material selection, where less work has been conducted and/or reported.
It is noted that for many FSW applications (particularly those involving thin sheet 5xxx/6xxx series aluminium alloys) relatively standard tool steels have been found to perform perfectly well as tools and no further work is warranted. However, in higher strength, and thicker section, aluminium alloys, and in some castings, standard tool steel materials (and even the higher performance Ni-Co alloys are sometimes used) are not always sufficient. FSW operations in these more demanding cases are commonly limited by the performance of the tools being used, and the operating conditions and failure mechanisms of these are not always fully understood. Potential exists to develop improved FSW tool materials for high strength aluminium alloys by improving understanding of the tool probe performance and the tool failure mechanisms in these applications.
This project will aim to address this research need by developing a new generation of improved FSW tools for high strength aluminium alloys. The information generated will also have great relevance for FSW in general, and will support the development improved tool lifetimes and improved FSW productivity in many current applications.
Review the current state of the art with respect to FSW tool materials selection, and to identify a range of candidate FSW tool materials for high strength aluminium alloys.
Produce sample FSW tools in a range of high performance alloys, and to assess the performance of these materials in representative FSW trials.
Evaluate the potential for further tool performance enhancement via surface treatment and/or surface coating technologies.
Relevant Industry Sectors
Aerospace, Power, Construction and Engineering, Road Transport, Electronics and Sensors
Technical and Economic Benefits
Improved understanding of FSW tool performance, and tool failure mechanisms in high strength aluminium alloys, leading to improved tool materials for these applications.
A new generation of FSW tools, capable of improved tool lifetime and improved process productivity for many current applications and process users.
Development of coatings and surface improvement procedures for further enhancement of FSW tool performance, particularly for challenging applications.