HarbisonWalker International (HWI) is the largest supplier of refractory products and services in the United States and the largest producer in North America. The company manufactures and distributes high-temperature materials essential for heavy industries such as iron and steel, aluminum, glass, petrochemicals, cement, and power generation. Its operations are supported by 25 manufacturing sites and 20 distribution centers across North America, including Canada, Brazil, and Mexico.
Founded in 1865, HWI has a history spanning more than 160 years. The company is headquartered in Pittsburgh, Pennsylvania, and operates an Advanced Technology and Research Center in West Mifflin, Pennsylvania. Since 2023, HWI has been a member of the Calderys Group following a merger.
The company's work involves refractory materials and high-temperature material science, providing what it describes as one of the refractory industry's widest lines of solutions. HWI emphasizes a focus on safety, quality, customer satisfaction, and sustainability across its operations.






