Science Needs Integrity and Vision

China's abundant research resources, and its growing influence in the sci-tech sphere, may be important factors that attract foreign scientists to pursue their dreams in this country. For Professor Suck Joo Na, these attributes are indeed significant but there was something quieter, perhaps even unexpected, that drew him in: a shared love for traditional Chinese culture.

"My wife and I are highly interested in old Chinese history, and Xi'an was an ideal place for us to live in China over some years," he told Science and Technology Daily. Na is an ardent reader of Romance of the Three Kingdoms, one of the Four Great Classical Novels of Chinese literature.

Seduced by welding technology

Born in South Korea in the 1950s, Na grew up at a time when the country was shifting from an agricultural country to an industrial powerhouse. As a high school student, he was drawn naturally to mathematics and physics, which offered clarity in a changing world. Engineering, then seen as the engine of national progress, became the calling for his career.

This path led him to the Korea Advanced Institute of Science and Technology (KAIST) in the 1970s, where his country was investing in heavy industries. It was there that Na first encountered the field that would define his career: welding engineering. His academic journey took him to Germany thanks to a Humboldt scholarship, where he dived into welding technologies before expanding into laser materials processing, a natural evolution, given the physical similarities between welding and laser-based materials processing techniques.

Na is perhaps best known for linking the intricate dynamics of weld pool behavior during arc and laser welding, with the complex phenomena occurring inside the electric arc and deep keyholes created by high-power lasers. These insights have enabled engineers to simulate welding processes with unprecedented accuracy, paving the way for higher-quality welds and more efficient manufacturing systems.

His research also connects metallurgical and mechanical analyses with computational fluid dynamics (CFD) simulations, creating a bridge between theory and application. This multidisciplinary approach has proven especially valuable in the emerging field of additive manufacturing (AM), particularly in selective laser melting and laser metal deposition. According to Na, the challenges faced in simulating laser welding closely mirror those in AM, making his decades of experience in welding simulation a crucial foundation for future innovation.

"The welding simulation experience provides a solid foundation for simulation of laser and arc-based AM processes," he explained. "These will be needed in the near future to simulate the AM technologies in an efficient way."

Building bridges across borders

Na's career has always been marked by collaboration. In a field like welding technology, where different countries bring unique strengths to the table, international cooperation is not just beneficial but also essential. He has long advocated for stronger ties between South Korea and China, two nations that share a common drive to push technological boundaries in automotive and heavy industries.

Over four decades at KAIST and later at Xi'an Jiaotong University (XJTU), Na and his team have systematically developed capabilities in multiscale modeling across various welding technologies. These models are now instrumental in designing welding procedures for advanced steel structures, offering economic and environmental benefits. "Global collaboration allows us to complement each other effectively," he said.

At XJTU, Na found a vibrant ecosystem that is eager to embrace new ideas and open to international exchange. He played a pivotal role in transforming the university's laser welding laboratory into a world-class facility, complete with cutting-edge facilities and a dynamic team of researchers. More importantly, he helped secure the funding necessary to keep this platform thriving.

"XJTU has a strong background in welding and laser processing," he said. "And they've been very supportive in establishing a new research direction here."

Cultivating minds, not just models

Beyond the lab, Na sees himself as an educator first. He believes in nurturing students who can think independently, solve problems creatively, and communicate their findings.

"I encourage my students to develop their ideas from problem setting to conclusion," he explained. "They discuss, compare and refine their approaches throughout this process."

It is a philosophy that has borne fruit. Many of his former students have gone on to achieve notable success in academia and industry alike. For young researchers, Na emphasizes three key qualities: the will to tackle difficult problems head-on, deep expertise across disciplines like materials science and mechanical engineering, and access to a supportive institutional environment that encourages experimentation and discussion.

Despite the accolades from his colleagues and students, Na remains grounded. He continues to look forward, driven by a simple yet profound belief that science can make the world better when pursued with integrity and vision.

LEI Yanjun and HAO Liu at XJTU also contributed to this article.

Source: Science and Technology Daily