Knife steel has come a long way in the last few decades, and today's metallurgy in the field is marked by advances in material technology, manufacturing techniques, and precision customisation. At the heart of these developments is the work of companies like Alleima, a pioneering force in the evolution of knife steel.
In Sweden, iron production can be traced back millennia, with Högbo Bruk as one important site for iron production dating back to the 17 century, the area now home to Alleima. As Jonas Nilsson, technical business developer at Alleima, explains, "In 1862, Högbo Stål & Jernwerks AB was founded, which became the foundation for Alleima. In the early years, we produced steel for knife applications like bayonet steel for export and expanded into the consumer segment with the development of razor blade steel."
Since the 19th century, Alleima's innovation has been integral to advancements in knife steel. One major breakthrough was the introduction of the Bessemer process, which allowed for a more efficient steel production. "We were basically the first in the world succeeding with that technique," Nilsson highlights. By the 1970s, the company had developed a full portfolio of stainless steel grades, specifically for edge applications, which became the standard for knives across multiple industries.
The success of any blade lies in the precise balance of its microstructure and metallurgical properties. As Nilsson describes, razor blade and surgical microtome producers have high expectations, requiring "a very homogeneous and clean microstructure with small non-metallic inclusions, enabling extremely keen edges, high hardness, and good toughness." Advances in this area have not only improved the sharpness of blades but have also enhanced their corrosion resistance.
In 2009, Alleima's launch of the 14C28N steel grade marked a significant leap in the handheld knife segment. "The demand was to match the hardness and stability of razor blade steel while improving corrosion resistance," Nilsson explains. More recently, in 2017, the introduction of 10C28Mo2, with an ultra-fine carbide distribution, brought further improvements in toughness, edge durability and corrosion resistance. Both grades being the result of exciting development work in close collaboration with customers.
Today, Alleima's knife steel portfolio is renowned for its ability to meet diverse application requirements, from everyday carry knives to military-grade tools and professional chef's knives. "When choosing the steel for a knife, it's important to bear in mind the application for which the knife will be used," Nilsson advises, emphasising that different challenges require specific grades and treatments.