Cracking the code: Senior design students deliver for steel industry

Determining the Need

Nucor Steel, a leading American manufacturer of steel products, is a vendor for countless critical industries. They provide the materials responsible for building sturdy and reliable construction equipment, irrigation and grain storage solutions for the agriculture industry, onshore and offshore applications for oil and gas, and much more.

“The thing that I was missing was an optical analysis tool that could come back to me with numbers that allow me to evaluate a much larger sample set in ways other than good or bad.”

Drew Kofahl, Nucor Steel

Drew Kofahl, a 1997 metallurgical engineering graduate of The Grainger College of Engineering at the University of Illinois Urbana-Champaign, has nearly three decades of experience in the steel industry. He works as a technical services supervisor for Nucor, and a key role in his job is the examination of steel samples to determine the level of microsegregation — the uneven distribution of alloying elements at a material’s microstructural level when the steel solidifies, affecting its quality — occurring in a given product. It's through this process where he noticed a problem that needed to be solved.

"In our manufacturing facility, I use optical microscopy and take digital pictures. The thing that I was missing was an optical analysis tool that could come back to me with numbers that allow me to evaluate a much larger sample set in ways other than good or bad," Kofahl said. "I can look at something, but I can't make small numerical distinctions."

Finding accurate, numerical determinations for the severity of microsegregation can be a complex, time-consuming and potentially expensive task. Kofahl needed something to address all three of those challenges and brought a concept to a professional connection: Assistant Professor Jean-Charles Stinville of the Department of Materials Science and Engineering.

Stinville, a former mentee of Kofahl, would be receiving a grant from the Association for Iron and Steel Technology called the Kent D. Peaslee Faculty Award. The three-year award is focused on promoting the steel industry and funding steel-based research projects. Stinville suggested the two men become partners in the pursuit of an optical analysis solution, using a fraction of the Peaslee funding as a baseline, and Kofahl quickly agreed.

Carrying Out the Work

Soon after the partnership formed between Stinville and Kofahl, the project caught the interest of students taking part in the Illinois materials department's senior design program. As a requirement for graduation, groups of students must find a materials-based solution to a real-world problem. Topics can involve the help of a corporate sponsor from an array of options.

Kofahl's group would involve five total students. They developed interest in the project due to a fascination with the company and a hands-on opportunity to work with steel. But the project would need time to get off the ground, as senior design initiatives involve a fall semester of classroom learning before the hands-on process can begin in the spring. Initial steps would involve building a knowledge base for the project, including subject matter research, details about resources and safety practices in metallurgical laboratory environments and project budgeting. 

Through these initial steps and until project completion, Kofahl would meet with the students twice each month, and their excitement for the work immediately made an impression.

"At first they were all joining virtually, but after a while they met together and would call me, which I thought was a really neat thing," Kofahl said. "Seeing them form a team, because that's so important in the industry, and to see students learn cohesiveness throughout the project was very rewarding."

“Seeing them form a team, because that's so important in the industry, and to see students learn cohesiveness throughout the project was very rewarding.”

Drew Kofahl, Nucor Steel

In December of 2024, Kofahl delivered the group its first steel samples, which included the same types of steel Nucor uses in its day-to-day operations. The group would begin pushing their project from theory to hands-on development in January of 2025, as soon as preparations of their laboratory space were completed. What followed was an impressively compressed timeline — the team would build functional code in just one semester of hands-on work.

As the students built their program, they utilized the assistance of Assistant Professor Marie Charpagne, an expert in metallurgy research, to best understand how optical analysis tools function. Progress accelerated through the spring semester. In mid-February, during one of his regular work trips through the area, Kofahl spent several hours in the lab working directly with students, demonstrating his techniques for sample preparation and microscope use.

"I was able to share 28 years of experience firsthand. It was so much fun to be back at my alma mater doing that," Kofahl said.

Within several months, the resulting code was ready. While not overly complex, it was elegant in its simplicity — a one-page program that solved an important industry problem. Kofahl noted one student was able to spearhead writing the program as it matched their unique skill set, while the rest of the group made their contributions through preparation, photography and completing the final analysis package. 

Delivery would prove to be a success. In May of 2025, Kofahl said the students met with him in a video call and walked him through their full technique. He could see the results in the software, which could identify and interpret materials phases (or bands) present in steel samples, measure the distance between them and finally provide a quantitative "degree of microsegregation" rating.

"I can take 100 samples and I can begin to perform some actual analysis," Kofahl said. "I can take samples from different product sizes (and) different locations in the steel bar. The tool that they (built) allowed us to capture all of this, and it was captured in a spreadsheet that I can perform some statistical analysis on."

This transformation — from subjective "good, bad, or ugly" visual assessments to quantitative statistical analysis — represented a fundamental shift in how Nucor could approach product development and quality investigation.

Kofahl was proud to attend the group's presentation in person at the end of the spring 2025 semester. The session, in which senior design students displayed thorough details about their project on poster boards in the hallways of the Materials Science and Engineering Building, gave him a chance to talk with them in person about the final product they had achieved.

Real-World Impact

Implementation started at Nucor just months after poster presentation day. The company asked the senior design team members to teach a summer intern how to use the microsegregation tool. In a remarkable display of continued commitment, the leader of code development made himself available after graduation to train the intern virtually in an hour-long session. This post-graduation support demonstrated not just the students' ownership of their work, but the practical usability of the tool they'd created.

"As soon as she learned the technique and was able to share it with me and a couple of other colleagues, we were able to use it for characterization," Kofahl said

Kofahl knew immediately that the resulting code would have practical uses for Nucor. The students had delivered something that was not only simpler to use than commercial solutions, but also cheaper. Any comparable alternative would have cost as much as Nucor's entire donation to participate in the senior design program. While Nucor wouldn't necessarily use optical analysis in everyday production, the student solution would be efficient in assisting with product development and customer service.

"If we're working on an application we want to develop or if we have a report from a customer of less-than-ideal mechanical properties, we can take this tool and apply it to that product," Kofahl said. "There was a recent project where we couldn't use the tool exactly because of sample orientation, but we were able to use its principles in solving an issue that a customer was facing with our product."

The success of this initial collaboration has proven both sustainable and repeatable. Kofahl and Stinville are partnering on a second senior design project for spring 2026, this time focused on computational modeling to optimize rolling processes. The goal is to reduce the risk and expense of production trials, which can cost $10,000 to $50,000 each, by developing better predictive tools before committing to manufacturing changes. For Kofahl, the experience represents a unique intersection of professional value and personal fulfillment.

"The opportunity to work with an enthusiastic group of students required only a modest input of my time, yet I gained access to the university's laboratory resources and faculty expertise," Kofahl said. "I find that of great value, and it's also personally rewarding for me as an alumnus."

Illinois Grainger Engineering Affiliations

Marie Charpagne is an Illinois Grainger Engineering assistant professor of Materials Science and Engineering and is affiliated with the Department of Mechanical Science and Engineering and the Department of Aerospace Engineering, the Materials Research Laboratory and the Beckman Institute. 

Jean-Charles Stinville is an Illinois Grainger Engineering assistant professor of materials science and engineering in the Department of Materials Science and Engineering. He is affiliated with the Materials Research Laboratory.