History
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Steel that embodies tradition, present, and future.
For over 150 years, we have been shaping the industrial history of Unterwellenborn.
From its beginnings in 1872 to today’s modern structural steel production, the history of Stahlwerk Thüringen is characterized by progress, stability, and continuous development.
1900
With the dawn of the new century, the Unterwellenborn steelworks underwent a significant expansion: two modern blast furnaces and a newly constructed Thomas steel plant complemented the existing facility.
The new technologies were specifically designed for the ore quality of the nearby Kamsdorf region, enabling more efficient, higher-performance production.
from 1920
In the years following World War I, the steelworks was modernized and expanded. Four new blast furnaces were constructed for this purpose. In addition, the Thomas steel plant was rebuilt. A rolling mill with a blooming mill was also added.
It supplies the primary material for a duo and a trio line. At that time, the steel plant produced small and medium-sized universal beams, angles, U-profiles, plates, rails and railway superstructure material.
1946
Despite severe destruction during World War II, the Unterwellenborn steelworks resumed production on February 6, 1946 – a powerful symbol of reconstruction.
The focus is on blast furnace II, which is the only one remaining at the site. In the middle of what was then the Soviet occupation zone, it became a symbol of the new beginning and the resilience of steel production in Thuringia.
1985
The basic structure of the steel plant remained largely intact in the GDR, but the pressure to increase productivity grew. In order to keep profile steel production internationally competitive, the construction of a modern rolling mill was decided at the end of the 1970s.
On June 28, 1985, the Combined Section Mill (KFS) commenced operations – a groundbreaking investment that formed the basis for the plant's continued existence after the reunification.
1992
With the takeover by the Luxembourg company ARBED, a new era began at the Unterwellenborn site: On July 1, 1992, Stahlwerk Thüringen GmbH (SWT) began its operations. Comprehensive modernization began – old blast furnaces, the converter steel plant and the blooming mill were shut down.
This created space for the construction of a new, forward-looking electric steel plant with a modern continuous casting plant.
1995
On November 11, 1995, a new chapter in the history of Stahlwerk Thüringen was opened: the newly constructed electric steel plant officially commenced continuous operation.
After three years of extensive planning, construction, and investment, steel was smelted again in Unterwellenborn for the first time – a significant milestone that definitively sealed the successful restart of the traditional location.
2001
In 2001, three major European steel groups merged:
ARBED from Luxembourg, ACERALIA from Spain, and USINOR from France.
This merger created the new major corporation Arcelor – an international steel giant that also shaped the development of Stahlwerk Thüringen in the following years.
2012
In February 2012, Stahlwerk Thüringen became part of the Brazilian Companhia Siderúrgica Nacional (CSN) – one of the largest steel groups in South America.
With the change to the internationally operating group of companies, the plant opens up to new markets, strategic perspectives and long-term development opportunities in global competition.
2023
In 2023, MAZET GmbH will become a 100% subsidiary of Stahlwerk Thüringen GmbH.
The traditional company will remain unchanged in its structure and will continue to provide high-quality mechanical engineering services for its customers – reliably, proven and with the usual quality.
2025
On January 8, 2025, the 25 millionth ton of profile steel will be produced in the rolling mill since the founding of Stahlwerk Thüringen GmbH. If you consider this amount with all the steel beams placed end to end, it corresponds to more than 20 times around the earth.
