- Move marks Nippon Steel’s first full replacement of a hot-rolling line in 42 years
- Investment to boost ultra-high-tensile automotive steel production capacity
Nippon Steel has completed a new hot-rolled steel sheet line at its Nagoya Works after investing around JPY 300 billion ($1.8 billion), with commercial production set to start this month. The investment is aimed at improving the productivity and quality competitiveness of high-end flat steel products, including ultra-high-tensile steel for automobiles. It is the first full replacement of a hot-rolling line by Nippon Steel in 42 years.
Nippon Steel held an opening ceremony for the new hot-rolling line on 6 August at Nagoya Works in Tokai, Aichi Prefecture. Commercial production is scheduled to start during August, with production volumes from the existing line to be gradually transferred to the new facility. The company plans to consolidate production at the new line during fiscal 2026.
The new hot-rolling line has an annual production capacity of around 6 million tonnes (mnt), about 20% higher than the existing line’s 5 mnt. Investment increased to around JPY 300 billion from the originally planned JPY 270 billion ($1.69 billion), mainly due to higher material and labour costs since the investment decision was made in 2022.
Focus on ultra-high-tensile automotive steel
The core focus of the investment is to strengthen Nippon Steel’s production system for high-end automotive steel, particularly ultra-high-tensile steel. Automakers are facing growing requirements for lighter and stronger vehicle bodies as environmental regulations and crash-safety standards become more stringent, while the adoption of electric vehicles is also increasing.
Ultra-high-tensile steel requires precise control of the microstructure during rolling and cooling to maintain high strength while securing formability. Nippon Steel classifies steel with a tensile strength of 1.0 GPa or more as ultra-high-tensile steel.
The new line is equipped with a rolling mill capable of handling one of the world’s highest levels of rolling loads. Its rolling and temperature control capabilities have been significantly improved compared with the existing equipment, allowing more precise control of the steel’s microstructure. Nippon Steel expects this to support stable mass production of high-end steel products while reducing production costs.
The company also plans to improve the production efficiency of ultra-high-tensile steel, whose productivity had been constrained by equipment limitations on the existing hot-rolling line. The new line will also be used to develop next-generation products with further improvements in strength and formability.
Nippon Steel said in its official announcement that the new hot-rolling line is a core facility for fundamentally strengthening its production system for high-end flat steel products, including ultra-high-tensile steel.
Tadashi Imai, president and chief operating officer of Nippon Steel, said at the opening ceremony that the company would actively use the new line to develop new products with higher strength and improved formability. The company plans to develop Nagoya Works as a “mother plant” for automotive steel, using it as a base for technology deployment across domestic and overseas production sites to strengthen its global competitiveness.
Existing line to be idled
Once production is fully transferred to the new line, the existing hot-rolling line, which has operated for 63 years since 1963, will be idled. Nippon Steel has officially said it plans to idle the existing hot-rolling line during fiscal 2026.
Nippon Steel currently operates five hot-rolling lines in Japan and is reorganising the roles of its production sites to strengthen its flat steel business. Automotive steel production will be centred in three sites: Nagoya Works, the Kimitsu district of East Nippon Works, and the Yawata district of Kyushu Works.
With the start-up of the new line, Nagoya Works will see both its production capacity and high-end steel production capabilities increase. Its role within Nippon Steel’s automotive steel business is therefore expected to become more important.
The full replacement of a hot-rolling line is Nippon Steel’s first since the Hirohata Works, now the Hirohata district of Setouchi Works, in 1984, marking a gap of 42 years between major hot-rolling line replacements.
Note: This article has been published as part of a content exchange agreement between SteelDaily and BigMint.
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