FSW Tool Performance and Lifetime in High Strength Aluminium Alloys

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Back to Core Research Programme AMorph – 4D Printing for Field Morphing Structures Automation of Composite and Hybrid Joining Process Coaxial Wire Additive Manufacturing Processes and In-Line Monitoring Tools Development of Coded Excitation Technique for Non-Metallic Pipes Inspection Development of Digital Twin technology as a demonstrator for real-time integrity assessment of crack growth in tensile specimens Development of Friction Stir Welding (FSW) for Hydrogen Fuel Storage Tanks Development of Leak-Before-Break Hydrogen Storage Composite Pressure Vessels With Polymeric Liner Establishing Assessment Methods for Determining Safe Service Limits of High-Temperature Materials in Extreme Environments Fracture toughness in aggressive environments: effect of crack monitoring techniques on test results In-process detection and non-destructive testing of electron beam weld imperfections Internal Bore Coatings for Applications in Corrosion and Hydrogen Environment Joining of Additively Manufactured Materials Long term behaviour of polymeric liner materials/coatings in hydrogen service Techniques for High Temperature Ultrasonic Inspection of Arc Welding Ultimate Leverage Fund

Project Code: 0904-06

Research Need

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.

Objectives

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.