2024/06/13

Nippon Steel Co., Ltd.

Nippon Steel Co., Ltd. (hereafter, Nippon Steel) received the 2023 (54th) Japan Welding Association Award “Featured Welding Invention Award” for a patent relating to tailored blanks for aluminum-plated hot-stamped steel sheets. This award is given to inventors of “patented inventions recognized as worthy of attention” that have contributed to the development of domestic industries and the improvement of people's lives in the welding field.
Nippon Steel has a next-generation steel vehicle concept “nSAFE^Ⓡ-A new concept “nSAFE” that further deepens the weight reduction technology of “AutoConcept”^Ⓡ-AutoConcept ECO³(Eco Cubic) (hereafter, NSAC ECO³)” is proposed. The technology invented this time is NSAC ECO³Weight reduction, CO, which are the main proposals of₂It is one of the core technologies for realizing “integration of parts using iron,” which realizes emission reduction, cost reduction, and labor saving.

An overview of the patented inventions that have been awarded is as follows.
1. Award details
(1) Award name: Japan Welding Association Award “Welding Featured Invention Award”
(2) Title of invention: Method for manufacturing steel plates and tailored blanks, and method for manufacturing steel pipes (Patent No. 7056738)
(3) Patent outline: Patent relating to tailored blanks for aluminum-plated hot-stamped steel sheets
2. Background of the invention
The application of tailored blank (hereinafter, TWB) technology (*1) and hot stamped steel sheets (*2) to automobile parts is effective in reducing the weight of automobile bodies, improving collision safety performance, and reducing greenhouse gas emissions during the life cycle, and aluminum-plated hot stamp (hereinafter, AL-HS) steel sheets, which have the effect of suppressing scale generation at high temperatures, are widely used as hot-stamped steel sheets.
However, when AL-HS steel sheets are laser welded for TWB conversion, a large amount of aluminum derived from plating is mixed into the welded metal, and there is an issue where joint strength decreases after hot stamping, making it difficult to apply AL-HS steel sheets bonded with TWB technology to automobile parts. Meanwhile, the technology for laser welding AL-HS steel sheets with TWB was an essential technology for realizing “integration of parts using iron.”
(*1) A processing technology in which steel plates with different plate thicknesses and tensile strengths are joined by laser welding to form a single steel plate (blank material), and then pressed. By using steel plates using TWB technology, it is possible to improve component performance, reduce weight, and reduce costs by optimizing strength and plate thickness.
(*2) A technology for manufacturing extremely high-strength automobile parts by heating a special steel plate with adjusted components to an austenitic temperature in a heating furnace, molding with a water-cooled mold, and simultaneously hardening.
3. Outline of the Invention
In response to the problem that joint strength decreases after hot stamping, Nippon Steel invented and developed TWB manufacturing technology for AL-HS steel sheets with high joint strength and excellent corrosion resistance in laser-welded parts. Specifically, with welding pretreatment technology that removes aluminum plating adjacent to the weld bead, which has an adverse effect on joint strength, it is possible to stably secure the strength characteristics of the joint while improving the corrosion resistance of the welded metal by melting a small amount of aluminum plating on the tip of the steel plate into the welded metal.
4. Achievements of the invention
Nippon Steel commercialized the present invention in the Kyushu Steel Works Yawata area, and in collaboration with customers, they mass-produced lightweight B-pillars, which are automobile skeleton parts using TWB AL-HS steel plates. The TWB B-pillar, which uses lightweight and high-strength AL-HS steel sheets, has improved safety by protecting occupants during collisions and is highly effective in reducing greenhouse gas emissions due to weight reduction, and is the result of a meaningful invention that greatly contributes to the development of Japanese industry and the improvement of people's lives.
In the future, we believe it can also contribute to “integration of parts made of iron” such as door rings and rear modules.
Nippon Steel always pursues the world's best technology and manufacturing capabilities, and will continue to contribute to social development through activities (“specific measures against climate change”) that are in line with the “Sustainable Development Goals” (SDGs) adopted by the United Nations.
(Reference) CO in society₂Nippon Steel's brand “NSCarbolex” is a general term for high-performance products and solution technologies that contribute to reducing emissions Please refer to the following URL for “Solution”.
https://www.nipponsteel.com/product/nscarbolex/solution/

Return to the list of press releases