TWISTER: Titanium Wire for Inovative Spring Technologies and Emissions Reduction

The contribution from the University of Sheffield to the "Titanium Wire for Inovative Spring Technologies and Emissions
Reduction (TWISTER)" project will be on the development and validation of optimum tooling and process parameters for
the continuous extrusion machine and the designing of optimum wiredrawing and heat treatment schedules for subsequent
wire production that will feed into Performance Springs and the springmaking process routes. The UOS will also support
the developed in the downstream spring design and manufacture through metallography and finite element modelling. This
will be undertaken by Dr Jackson and a Postdoctoral Research Associate. Thus the aim of the project in its broadest sense
is: Development of a novel extrusion and cold drawing process route for the production of titanium wire for subsequent
valve and suspension spring manufacturing for the automotive sector. This will be achieved by the following four work
packages.
Work Package 1: CONTINUOUS ROTARY EXTRUSION (CRE) TOOL LIFE ASSESSMENT (UOS and Meltech): This
includes design of tooling through finite element modelling (and know how) and then in collaboration with Meltech
determining tooling wear rates during continuous extrusion for different titanium particulate morphologies and chemistries
for production rates in the order of 5 metres per minute. From such work, process maps of wire production rates for
different particulate and chemistries; including machined swarf, commercial titanium powder and emergent novel low cost
alloy powder will be created.
Work Package 2: WIRE-DRAWING OPTIMISATION (UOS): This work package will use DEFORM finite element modelling
software to determine of the optimum cold drawing schedule and die design for downstream spring feedstock. It is
envisaged that the continuous extruded material will need minimal cold drawing compared to conventionally produced wire,
but this work package will acceletrate the optimisation of the die design and pass schedule, including any intermediate
annealing stages. Cold drawing schedules will be deisgned for each particulate feedstock.
Work Package 3: SPRING DESIGN & MANUFACTURE (Performance Springs and UOS): This will include the design and
manufacture of valve and suspension springs for Bentley and K-Tech Suspensions respectively. UOS will support
Performance Springs by using DEFORM and outputs from work packages 1 and 2 to model the CNC coiling operation.
UOS will also conduct metallography and testing of spring product supporting Performance Springs primary development.
Work Package 4: MECHANICAL TESTING & VALIDATION (Performance Springs, Bentley, K-Tech and UOS): This work
package will focus on the mechanical testing (both static and dynamic testing) of both wire and spring product generated
throughout the programme. Optimum spring designs will be tested in suspension arrangements and engine tests in
collaboration with the end users Bentley and K-Tech.

This project has much potential impact for a number of sectors and industries such as automotive, aerospace, marine, rail,
steelmaking, rapid metals manufacturing industry and biomedical sectors.
A successful project will enable the automotive industry to exploit low cost titanium springs in applications such as valve
springs where mechanical property requirements, such as fatigue are demanding. Slightly less demanding mechanical
properties will also be exploited in the suspension spring market for both motorbikes and cars, but also it wil provide
opportunities for titanium precision springs in the marine and rail transport sectors. Furthermore large springs for landing
gears in the aerospace industry and where there is a strong UK presence will also benefit from such technology as
corrosion of steel springs is a major problem. The technology will also impact on applications such as wire feedstock for
the biomedical applications, such as orthodontics, where mechanical property requirements are slightly less demanding
than the precision spring markets. Lesser demanding wire applications include laser additive feedstock material for rapid
metals manufacturing technology and titanium cored wire for controlled steel additive purposes in the steelmaking industry.
The greater competitiveness and improved efficiencies generated by this project will help maintain the UK's leading role in
the manufacturing of high performance components for a large range of transport and metals sectors. This will lead to
enhanced employment opportuinities and reduction in greenhouse gases.