Development of New Vehicle Safety Structures by Using Third-Generation Steels

• Published in: SAE International journal of materials and manufacturing 2022-01, Vol.15 (2), p.155-174, Article 05-15-02-0011
• Main Authors: Erzincanlioğlu, Samet, Aydiner, Tamer, Aras, Firat, Çelik, Hafize, Billur, Eren, Karabulut, Semih, Gümüs, Iskender Onder
• Format: Article
• Language: English
• Subjects: Advanced high-strength steel (AHSS); Automobile industry; Automotive parts; Carbon dioxide emissions; Cold working; Crashworthiness; Dual phase steels; Formability; High strength steels; Industrial development; Iron and steel industry; Iron compounds; R&D; Research & development; Steel; Steel industry; Strength to weight ratio; TBF (TRIP-aided bainitic ferrite); Third-generation steels; Transportation equipment industry; TRIP steels; Vehicle safety; Weight reduction
• ISSN: 1946-3979; 1946-3987; 1946-3987
• DOI: 10.4271/05-15-02-0011

Research and development efforts in the automotive industry have been long focused on crashworthy, durable vehicles with the lowest mass possible as higher mass requires more energy and, thus, causes more CO2 emissions. One way of approaching these objectives is to reduce the total vehicle weight by using higher strength-to-weight ratio materials, such as Advanced High-Strength Steels (AHSS). Typically, as the steel gets stronger, its formability is reduced. The steel industry has been long developing (so-called) third-generation (Gen3) AHSS for the automotive industry. These grades offer higher formability compared to first-generation (Gen1) and cost less compared to the second-generation (Gen2) AHSS. Transformation Induced Plasticity (TRIP)-aided Bainitic Ferrite (TBF) and Quenching and Partitioning (Q&P) steel families are considered to be the Gen3 AHSS. These grades can be cold-formed to more complex shapes, compared with the Gen1 Dual Phase (DP) and TRIP steels at equivalent strength levels. In this article, new single-piece A- and B-pillar reinforcements were designed using a Gen3 AHSS, TBF980. Spot-welding operations were eliminated due to part consolidation with the more formable steel. These parts will be the first structural automotive parts which were manufactured with cold-forming technology using TBF steels with a sstrength level close to 1 GPa or even more. Weight and cost reductions were realized by the new design while improving the crash performance.