CO2-NiCE: Carbon neutral steel in a circular economy

The steel industry is facing a necessary transition towards climate neutrality, where increased use of recycled steel is a key factor. A key challenge is to manage variations in alloying elements without compromising the quality of the material. This project, led by Luleå University of Technology, aims to develop knowledge and methods to optimize scrap management and manufacturing processes. The goal is to enable a more resource-efficient and sustainable steel production within a circular economy.

• Read more on the project website

The project focuses on evaluating the effect of scrap sorting on steel properties, developing rapid methods for material validation, and designing robust manufacturing processes that can handle greater variation in material quality. The sustainability aspect is ensured through life cycle analysis to minimize negative environmental impacts.

The project is funded by the Just Transition Fund, with a total budget of SEK 15.5 million. The project is carried out in close collaboration with industry, ensuring a close link to applied research and practical implementation.

The work is organized in three parts: project management and collaboration, resource-efficient steel value chains, and implementation of carbon-neutral materials. It includes research, industrial collaboration and regular external evaluations.

Expected results include new methods for material validation, improved recycling processes and knowledge dissemination through publications and conferences. The project supports industry's transition to fossil-free steel, especially in the automotive sector, and contributes to the UN Sustainable Development Goals on sustainable industry, resource efficiency and skills development.

The project runs from February 2025 to January 2028 and is expected to provide crucial insights for a more sustainable and circular steel production.

Project organization and work packages

Work Package 1: Management and coordination

The work within Work Package 1 will consist of a project management function with
project manager and coordinator. Within this work package, the activities will be managed, reported to the Swedish Agency for Economic and Regional Growth, and be followed up for goal fulfillment. The project's dissemination of results and contact with industrial stakeholders will also be handled within this package.

Within the work package, courses and workshops are organized for knowledge transfer and dialogue with parties outside the project organization. As the project will contribute to
excellence for the green transition, it is of utmost importance that knowledge is disseminated and disseminated also outside traditional channels

1.1 Management and coordination activities

This activity includes reporting, coordination, steering group meetings and financial follow-up. Organization of workshops with external stakeholders as well as project dissemination of results and contact with industrial stakeholders. Courses and workshops for knowledge transfer and dialogue with parties outside the project organization are also included.

Work package 2: Resource efficient and resilient steel value chains

The objective is to improve the circularity and resource efficiency of steel by improving
management of steel resources in terms of recycling and sustainability.

With the transition to a fossil-free society, steel and other metals and minerals will
minerals will play a crucial role. Today, the focus is on replacing fossil carbon in
iron production from ore, but even if we succeed in producing fossil-free steel, we need to
increase resource efficiency in the recycling of steel. Steel already has a high recycling rate today, but unfortunately much of the recycling involves a form of downcycling, where the recycled steel is of lower quality than the original. This is due to the large variation in composition of the incoming steel resources. Another issue is the accumulation of alloying elements, especially those that are more noble and less volatile than iron, as these are more difficult to remove. This work package aims to improve the efficiency of steel recycling, avoid depreciation in the recycling cycle and create a comprehensive understanding of the impact of different measures on the value chain.

2.1 Efficient management of resources (scrap)

The objective is to maintain and improve the value of secondary steel (scrap) through optimized sorting and characterization. Scrap used in recycling is divided into two or three main categories. The first category, generated by the industry itself, is Home and Prompt scrap. Scrap in this category is relatively easy to recycle because its composition is well known, it is only handled by companies and can be kept within the same specialized value chain. The second category is Obsolete scrap, scrap consisting of used products, which is more challenging to recycle. This scrap is collected from various sources, such as the construction and automotive industries, and generally enters the recycling system without specific material data and has been used in a variety of applications.

The different applications contribute with different contaminants (tramp elements), such as organics (e.g. oil, grease, plastics), as well as metals such as zinc and copper. In this activity we will try to map the recycling practices of industry. This includes both the internal scrap of steel producing companies and their internal practices, as well as the collection and management of obsolete scrap, i.e. scrap collected after the product's lifetime. This can be steel from the construction industry, the automotive industry and others. Furthermore, different possible sorting and characterization methods will also be evaluated. The optimization of the recycling process, i.e. through optimized sorting and improved characterization, will be based on this mapping.

2.2 Accumulation of alloying elements

The aim is to understand how accumulated alloying elements affect the properties of steel, with particular focus on accumulation after several recycling cycles. This is an area that is currently relatively unexplored. Accumulated substances can have unexpected and undesirable effects on the. This activity aims to develop strategies to avoid negative effects of accumulated alloying elements. Examples of such strategies include steel refining and/or tailor-made thermomechanical treatments that can be adapted and optimized according to the actual composition of the steel.

The first step will be to identify the alloying elements that pose the greatest risk of causing
significant quality degradation. For each alloying element or group of alloying elements
a recommended strategy will be developed. The results of this activity willbe fed back to Activity 2.1 and can thus also form a basis for future recycling procedures. Similarly, the mapping carried out in Activity 2.1 will contribute to the prioritization of which alloying elements are first considered in this activity. Furthermore, a close collaboration is seen with Work Package 3 where the impact of these alloying elements are quantified and addressed.

2.3 Life cycle assessment of the steel value chain

The activity aims at promoting and utilizing a holistic perspective of the whole steel value chain steel value chain, taking into account both industry and society at large. This activity mainly consists of a life cycle analysis, focusing on a comparative (comparative) analysis comparing different scenarios with each other. The scenarios will be be based on the results of the other activities of the project. The aim of the life cycle assessment is to avoid rebound effects and problem shifting, and to provide recommendations that improve the project's technical activities and promote the effective future implementation of the project
results.

Work package 3: Implementation of carbon neutral steel materials

In order to accelerate the implementation of carbon neutral steels, there are challenges
with end-user acceptance of new materials and requirements for more robust
manufacturing processes for materials with greater dispersion in constituent properties due to increased scrap content. This is particularly true of the automotive industry, where lead times of several years new steel is on the market until it is in the end user's production. The automotive industry is also considered to be the most important user, at least initially, of the new steels produced in northern Sweden, which makes this challenge even more relevant to solve.

The work package addresses this challenge by developing methods for rapid
material characterization relevant to the spread seen in properties due to increased
scrap content. Furthermore, it will be studied how different manufacturing processes such as forming and stamping can be robustly designed to accept a larger span in constituent alloying elements with a negligible reduction in final properties. A special focus will be directed in one of the activities on the surface properties of the steel material such as surface finish and oxide layer. Furthermore, as different surface coatings will be investigated as their interaction with different alloying elements in the steel is not investigated but also that coatings in themselves affect recyclability.

The research in Work Package 3 will both provide the steel industry with new methods to
validate the quality of steel to end users but also provide end users with processes to
to accept materials with a greater variability.

3.1 Validation of material properties

The increasing scrap content as an effect of fossil-free steel production leads to a change and greater variability in steel properties due to a greater variety of alloying elements used. For example, formability, weldability and mechanical properties such as fracture toughness and fatigue strength can change.

At present, the steel industry needs to carry out a large amount of testing according to different standards for each steel grade to ensure these properties before end users such as the automotive industry purchase the steel for their production. This leads to lead times of sevral years for new materials to reach the market and will delay the use of the new steels. Therefore, this activity aims to develop new effective test methods to ensure that the properties of the new steels meet end-user requirements.

Effective test methods such as fracture mechanics, hardness tests and various forms of
tensile tests, will be investigated together with what can be seen via microstructural
investigations. The aim is to quantify both the material properties but also the variation in
these properties. In addition to the design of new test methods, an important issue will be how many tests need to be performed and how large a volume of material needs to be
to be examined to obtain representative values of the mechanical properties and their
dispersion. The activity will lead to a basis for developing a new standard for
validation of material properties.

3.2 Process requirements and final properties

Today's manufacturing processes are optimized towards the best possible final properties.
Examples that will be dealt with in this work package are hot and cold forming and
cutting and punching of sheet metal, which are common manufacturing processes in the automotive industry. The hallenge when these processes are highly optimized is that they are sensitive to disturbances and a clear deterioration of the final properties can be seen if, for example, there is a variability in properties of the incoming material. This is exactly the case with the new steels with a higher scrap content where a greater variability in alloying elements and hence a greater variability in e.g. yield strength and ductility will be seen.

For thermomechanical processes such as press hardening, this variability is particularly
worrisome. Different alloying elements in combination control hardenability and a local
variation in alloying elements can therefore lead to localized areas of response in the component.

In this activity, the manufacturing processes mentioned above will be optimized for robustness, in other words, a variation in input material properties leads to small
variations in the output quality of finished components. Examples of parameters to study
are the impact of the cutting tool design on the quality of the cutting edge, which further controls the strength of the component in fatigue and crash. Also, the process requirements for dispersion in properties, and hence alloying elements, should be defined to provide suitable specifications for the steel producing industry.

3.3 Surface quality and coating

The surface quality of the steel product after undergoing various manufacturing processes and whether any coatings are used has a major impact on the final properties of the product. For example, oxide layers, defects such as cracks and indentations, and surface finish will negatively affect fatigue properties as well as the visual properties, affecting the usability of the steel material in certain applications. With the shift to more scrap-based steelmaking, the tolerance ranges of different alloying elements will vary more, which will also affect the surface quality of the steel due to changes in the oxide composition but also mechanical properties that have an impact on the behavior of the steel during forming and processing.

This also applies to the possibilities of coating the steel with different surface layers where issues such as adhesion and suitable composition need to be investigated. On the one hand, the content of the coatings will play a major role in the final properties of the product, but also in the recycling of the products. The work in this activity will focus on mapping mechanical properties, chemical composition and the interaction between these on, for example, oxide layers formed when the steel is processed or surface coatings added by a separate process and how these interact with tools in different manufacturing processes.

By creating an increased knowledge of this, and its link to surface defects, process windows can be optimized for different manufacturing processes with the goal of minimizing the impact of any variations on incoming steel material. A long-term goal is to be able to contribute with the data and information needed to create an increased robustness for manufacturing processes with regard to variations in incoming materials regarding composition and previous process history.