Yükselen Çelik AS is a supplier of tool, alloy, carbon and structural steels used in machinery, mold, automotive, defense, and manufacturing industries. Its brands include DSS, POLDI, TOOLGO, TTA, SHIPEX, SMART STEEL, and DSS. The company was founded by Yüksel Göktürk and Ferhan Göktürk on March 20, 1989 and is headquartered in Esenyurt, Turkey.