Advanced Microstructural Engineering for Novel Ultra High Strength Wire EngD

A major emphasis of UK Government policy, and funding streams, in 2018, is centred around CO2 savings through 'light-weighting' of products. The UK Government 'lightweighting' initiative is being reflected throughout many developed economies, with a resulting escalation of legislation proving to be a major driver of materials innovation. This project addresses the problem of 'light-weighting' through research aimed at developing products with a higher strength-to-weight ratio.

There is a continuous drive from the automotive, construction and offshore industries to increase the strength of steel wires, as improvements in the strength-to-weight ratio will yield cost efficiencies in fuel economy (each 100kg of mass reduction can save 8g/km of CO2), construction weight savings, and enable deeper oilfields to be exploited. To date, the highest tensile strength reported in a pearlitic cold drawn wire is ~6 GPa, but this is still a long way off being commercially available. Traditionally, fully pearlitic (0.8wt%C) Vanadium or Chromium microalloyed steels are utilised for the production of ultra-high strength wires, as the lamellar structure is ideal for cold drawing. However, such microstructures have limitations and it is becoming ever more difficult to push the strength levels beyond what is now commercially viable, owing to the detrimental effects on wire ductility. Therefore, this project aims to assess the potential of alternative microstructures to pearlite in order to produce ultra-high tensile strength wire, whilst still retaining adequate levels of ductility, in a cost effective manner.

British Steel and other producers have carried out work in this area in the past, with limited success, as the market is dominated by pearlitic wires. Therefore, the project will first examine the current state-of-the-art in microstructural evolution during cold drawing of a variety of targeted microstructures, which should include:-

(i) Pearlite
(ii) Dual Phase steels
(iii) Quench and Partitioned steels
(iv) Carbide-Free Nano-Bainitic steels

Microstructural modelling should be employed in order to determine the optimum microstructure (and chemistry) of the rod feedstock and so predict the behaviour and evolution of properties during cold drawing to high levels of drawing strain. Experimental wire drawing trials will then be carried out.

Successful completion of the project will result in a better understanding of the microstructural requirements of rod feedstock necessary to produce ultra-high strength wire with adequate ductility, and possibly lead to the commercialisation of 6 GPa wires and a viable alternative to pearlitic steels.

The successful candidate for this project will be expected to gain experience and expertise from attending suitable international conferences, and visits to collaborating researchers. We would envisage that the work encompassed within this project would offer the exciting opportunity of publication or development of intellectual property.

The research engineer will be located in the Rotherham/Sheffield area throughout the project, residing with the British Steel Research & Development team, where the industrial supervisor will be on hand on a daily basis. Whilst on-site, the research engineer will constitute part of the BSR&D Rods team, and will attend the required briefings, including those on safety and business performance. There will be considerable interaction with other business functions, including production, engineering, commercial and marketing at our main Scunthorpe site. There may also be opportunities to visit other parts of the business during the course of the project, as well as possible interaction with the technical departments of our customers.