The history of OTK dates back to our start as a welded steel pipe factory founded in 1957 in Mitejima, Osaka. We have consistently expanded the scale of our business with the establishment of the Shiga Plant in 1970 and the Tokushima Plant in 1991. Not bound by the status quo of the industry, our superior and revolutionary products have been highly praised from many fields. OTK large diameter steel pipes are used in a wide variety of fields including oil refining plants and symbolic landmark structures in major cities