Germany-based steelmaker thyssenkrupp Steel has announced the restart of trial operations at hot strip mill 4 in Duisburg following the completion of extensive repair and modernization work after a major fire last year.
The facility was forced to suspend operations after a deflagration in the furnace area on October 24, 2025, caused significant damage to the furnaces and parts of the roof structure.
According to thyssenkrupp Steel, repair work over the past several months included the replacement and refurbishment of damaged equipment as well as the implementation of additional technical improvements designed to enhance operational reliability and process stability.
Modernization efforts support long-term operational performance
Alongside repair activities, thyssenkrupp Steel used the shutdown period to carry out modernization measures intended to improve plant availability and support more stable production processes.
The associated continuous casting line, which supplies feedstock to the hot strip mill, had already resumed operations in mid-December 2025. The latest commissioning phase involves trial production and testing procedures before the facility returns to full operational capacity.
Hot strip mill 4 remains key asset for premium flat steel production
Hot strip mill 4 occupies a central position within thyssenkrupp Steel’s production network and broader modernization strategy. The facility manufactures a wide range of hot-rolled flat steel products serving both standard and high-value-added market segments.
Its production portfolio includes standard steel grades as well as high-strength and thin-gauge premium steels that require stringent dimensional tolerances, high surface quality and advanced mechanical properties. These products are supplied to several strategically important sectors, including automotive manufacturing, electric mobility, machinery and plant engineering, construction and energy.