Task 9: Product Development, Late Stage Definition and Integration

SUSTAIN Task 9 - Product Development, Late Stage Definition and Integration

Prof. Mark Rainforth, Prof. Eric Palmiere, Dr Martin Strangwood, Dr Peng Gong, Sam Morgan

Efficiency in steel production requires relatively minimal changes in the upstream procedures with product differentiation occurring during the latter stages of processing.

The austenite transformation to various transformation products is probably the single most important factor in determining the final properties of most steels. The role of local segregation is also critical in the transformation and subsequent heat treatment.

The ability to exert greater control over the transformation gives the ability to have greater control of the transformation product and subsequent final properties of the steel.

This applies across all steel types, whether long products, strip or sections.

Progress

The control of retained or reverted austenite, which is present in many high-strength steels, remains a key processing issue.

The stability of the austenite, and therefore the likelihood of it transforming during forming, or in service, is controlled by many factors including composition, shape and size.

Small variations in the amount of austenite in the structure can have dramatic effects on the mechanical properties.

For example, in a Super 13% Cr steel, small changes in heat treatment temperature (as small as 5°C) can lead to changes in austenite content of ~10% which can lead to changes in yield strength of up to 300MPa.

In order to give better control of the heat treatment the fundamental reasons controlling the stability of the austenite need to be understood. This project has used alloy design and detailed microstructural analysis to answer this issue.

Key findings to date

A systematic range of compositions was produced, within the specified composition for Super 13% Cr steels, but with systematic changes in the Ni, Mn and Mo contents. This has shown just how small differences in these alloy additions can have a major effect on the amount of reverted austenite and the temperature at which the austenite content peaks.

A detailed analysis of the austenite has shown how the elements strongly partition between the reverted austenite and the tempered martensite. The carbon content in reverted austenite is a linear function of the tempering temperature for the first temper but does not change on the second temper. Ni strongly partitions to the austenite, while Mn also partitions, but to a lesser extent. Additional Ni increases the growth rate of reverted austenite as well as increasing the total quantity, before the reverted austenite becomes too large and transforms on cooling. An increase in Mn also increases the amount of reverted austenite, although to a lesser extent than Ni, but displaces the peak in austenite content to a higher temperature.

The effect of these additions on the shape of the austenite is under investigation. The change in composition also has a marked effect on the tensile properties, but not in a predictable manner.

Understanding this will be key to solving the problem of the extreme sensitivity of tensile properties to the heat treatment conditions.

Industrial applications

The research has led to recommendations for adjustments to the steel composition and the heat treatment schedules at Liberty Steel. This will allow the amount and stability of the reverted austenite to be better controlled which will deliver a more consistent product. The changes are straightforward to implement and therefore there are no barriers.

What’s next for this task?

The task is coming to an end. The next step is to work with Liberty Steel to look at whether the recommendations from the research can be implemented.

Further reading
  1. Kwok, T. W. J., Gong, P., Xu, X., Nutter, J., Rainforth, W. M., & Dye, D. (2022). Microstructure Evolution and Tensile Behaviour of a Cold Rolled 8 Wt Pct Mn Medium Manganese Steel. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 53(2), 597–609. https://doi.org/10.1007/s11661-021-06534-9
  2. Gong, P., Turk, A., Nutter, J., Yu, F., Wynne, B., Rivera-Diaz-del-Castillo, P., & Mark Rainforth, W. (2022). Hydrogen embrittlement mechanisms in advanced high strength steel. Acta Materialia, 223. https://doi.org/10.1016/j.actamat.2021.117488
  3. Jones, B. L., Jolfaei, M. A., Hobson, S., Rainforth, W. M., & Davis, C. L. (2022). Magnetic characterisation of strain ageing in near eutectoid drawn pearlitic wire using an electromagnetic (EM) sensor. Engineering Failure Analysis, 131. https://doi.org/10.1016/j.engfailanal.2021.105909
  4. Gong, P., Wynne, B. P., Knowles, A. J., Turk, A., Ma, L., Galindo-Nava, E. I., & Rainforth, W. M. (2020). Effect of ageing on the microstructural evolution in a new design of maraging steels with carbon. Acta Materialia, 196, 101–121. https://doi.org/10.1016/j.actamat.2020.06.029

About the author

Latest articles

Featured article
  • Women with Metal

    Women with Metal

    It’s been 7 weeks since the first Women with Metal event and the 2nd edition of this sell out conference has already been booked top take place on 29 October 2024. Kirsty is increasing the size and scale of the event and has booked a hall at the ICC Birmingham for year 2 with the…

    Read article →

  • Organized Crime Drives Metal Theft Epidemic: UK Economy Loses Half a Billion Annually.

    Organized Crime Drives Metal Theft Epidemic: UK Economy Loses Half a Billion Annually.

    A newly released report by the All-Party Parliamentary Group on Metal, Stone, and Heritage reveals that metal theft orchestrated by organized crime groups is costing the UK economy a staggering half a billion pounds each year. The comprehensive study, titled “Tackling Metal Theft,” exposes a rising trend in metal-related crimes since 2019, amounting to a…

    Read article →

  • Van Leeuwen: The Energy Project

    Van Leeuwen: The Energy Project

    In December 2021 Jill Clements told me about the Energy Project that had been signed off by Van Leeuwen UK. Jill was animated when talking about the news, and excitedly explained the potential that this opened up to her and the team. “I am very excited about it. I am really happy that finally we…

    Read article →

  • Drywall Steel Sections Secures £9.5 Million WMCA Investment

    Drywall Steel Sections Secures £9.5 Million WMCA Investment

    £13 million was all it took for a family run manufacturing business to make a monumental transformation in the historic heart of the steel industry! Drywall Steel Sections Ltd are on the move after securing loan funding of £9.5 million from the West Midlands Combined Authority (WMCA). Their Cradley Heath site was no longer fit…

    Read article →

  • The NASS Golf day & Summer Gathering 2023

    The NASS Golf day & Summer Gathering 2023

    On the 29th of June, Matt Tipper, Stewart Andrews and I had a swing of the clubs at Priory Breadsall in Derby. A week later, on the 6th of July, I attended the Summer Gathering in central Birmingham. Two entirely different events, seven days apart, both hosted by The National Association of Steel Service Centres…

    Read article →

  • The Stainless Steel Industry Meets at the BSSA Annual Conference & Dinner

    The Stainless Steel Industry Meets at the BSSA Annual Conference & Dinner

    The British Stainless Steel Association (BSSA) met at The Grand Hotel in Birmingham in May 2023 for their annual conference and dinner. Having attended the last four BSSA annual conferences and this year’s Food and Beverage Industry event (link to article), it was great to catch up with familiar faces from the industry and new…

    Read article →

  • Q2 Review: Analysing The Recruitment Landscape

    Q2 Review: Analysing The Recruitment Landscape

    Large corporate companies are facing challenges attracting new talent and retaining skilled staff especially when their salary structures, work flexibility and staff benefits are outdated compared to smaller, more agile SMEs. Smaller companies can have the advantage of being able to offer more flexibility and quicker decision-making, meaning they’re a more appealing option for certain…

    Read article →

  • How to use LinkedIn for YOUR Metal Business.

    How to use LinkedIn for YOUR Metal Business.

    The below presentation was given at the National Association of Steel Service Centres (NASS) 2023 Summer Gathering. In 12 days I’ll have been using LinkedIn for 12 years! On the day I joined I thought: “Wow! This business Facebook thingy is incredible! Everyone I want to do business with is right here, this will be…

    Read article →

  • Leading the Charge: Steel Dynamics in the Nuclear Industry

    Leading the Charge: Steel Dynamics in the Nuclear Industry

    Prime Minister Rishi Sunak recently unveiled the Great British Nuclear initiative, marking a significant milestone in the UK’s pursuit of a sustainable energy future. With nuclear power playing a crucialrole in achieving net-zero emissions and reducing greenhouse gases, this announcement signals a remarkable leap forward in the nation’s commitment to clean and reliable energy sources.…

    Read article →

  • Steel Dynamics Group Ltd. Acquires Ferrari Stainless & Alloys.

    Steel Dynamics Group Ltd. Acquires Ferrari Stainless & Alloys.

    Steel Dynamics Group Ltd. Acquires Ferrari Stainless & Alloys Ltd. Launching P&P Non Ferrous: A Gateway to Enhanced Customer Services and Expansion Down South In a strategic move to bolster its position in the industry, Steel Dynamics Group Ltd. proudly announces the successful acquisition of Ferrari Stainless & Alloys Ltd. in Wimborne. This transformative development…

    Read article →

  • Sustainability is key to modern manufacturing

    Sustainability is key to modern manufacturing

    During my time supplying specialist metals into the manufacturing sector, I have noticed several things regarding the supply chain local to me in South Yorkshire. 1 Large Manufacturing companies often have difficult onboarding processes.  This makes it difficult for smaller SMES or new market entrants to be able to supply them. 2 Manufacturing companies are…

    Read article →

  • Lasers: The Tesla of Tooling

    Lasers: The Tesla of Tooling

    Welcome back, I’m LaserEd, and I work with lasers. I’ll be laser-educating for The Metal Magazine and I hope it results in more metal parts being lasered! First of all, I haven’t had an accident after writing my last article about Laser Safety. I have been busy researching. Although it is time consuming, I love…

    Read article →

  • Implementing QMS Certifications for Small Businesses and Start-Up Companies

    Implementing QMS Certifications for Small Businesses and Start-Up Companies

    Welcome to the fourth and final instalment of this short series on Quality Management System certification for small businesses and start-up companies. In this 4 part series I have been explaining exactly what third-party certification involves, and how you can level up your business through this process. The standard we are focussing on is ISO9001:2015, as…

    Read article →

Get notified when we publish new articles!

Want to feature in the next edition?