Exhibit 99.1 Metallus Announces Second-Quarter 2025 Results CANTON, Ohio: August 7, 2025 – Metallus (NYSE: MTUS), a leader in high-quality specialty metals, manufactured components and supply chain solutions, today reported second-quarter 2025 net sales of $304.6 million and net income of$3.7 million, or $0.09 per diluted share. On an adjusted basis (1) , the second- quarter 2025 net income was$8.4 million, or $0.20 per diluted share, and adjusted EBITDA was$26.5 million. This compares with the sequentia ...