Nissan Motor Co., Ltd. will build more models using a new type of super high formability (SHF) steel that combines high tensile strength with a previously unachievable degree of formability, resulting in lighter vehicles that can help lower emissions while protecting occupants. (Earlier post.)
Nissan is the world’s first carmaker to use the SHF steel, with a tensile strength of 980 megapascals (MPa), which was jointly developed by Nissan and Nippon Steel & Sumitomo Metal Corp.
The steel’s combination of stamping formability and strength makes it possible to form parts with complex shapes that are thinner and lighter than those made of conventional high tensile strength steel, while maintaining the ability to absorb energy in a collision.
The INFINITI QX50 premium midsize SUV, which went on sale in the US in March, is the first vehicle with front and rear side members made from 980-megapascal ultrahigh tensile strength steel, along with other body frame parts.
UNIPRES Corporation is producing the difficult-to-form car body structural parts using the SHF 980 MPa steel for the QX50. The SHF 980 MPa steel is applied to front side members, rear side members, and other under-body structural parts that are difficult to form.
Although the SHF 980MPa steel has elongation property close to that of conventional 590MPa steel, its application to the under-body structural parts having complex shapes was a challenge in terms of formation, UNIPRES said.
UNIPRES solved this problem by developing a unique press forming technology that enabled application for those parts that could not be formed with conventional 980MPa steel.
Nissan plans to expand the use of the material, which enhances fuel efficiency as well as driving performance by lowering vehicle weight, to other models.
Nissan launched a sustainability plan this month that calls for lowering CO2 emissions from its new vehicles by 40% by fiscal year 2022, compared with fiscal year 2000.
The company is aggressively developing technologies to expand the use of ultrahigh tensile strength steel, aiming for it to make up 25% of the company’s vehicle parts by weight. The material makes up 27% of the new QX50.
The 980-megapascal steel developed with Nippon Steel & Sumitomo Metal can be cold-pressed, making it suitable for mass production. This will help contain increases in vehicle cost.