The global automotive composites market is anticipated to reach nearly $15 billion in 2018, according to online statistics company Statista Inc. That certainly seems like a lot. However, composites only represent about 1 percent of all materials used in light vehicle production, according to consultancy Industrial Market Insight. Other materials vying for the attention of automakers include high-strength steel and aluminum.
At the Advanced Design & Manufacturing (ADM) conference in Cleveland earlier this year, speakers in the automotive track discussed material innovations that will contribute to lightweighting, including CFRP. The November/December issue of Composites Manufacturing magazine will include a full-length feature article on composites in the automotive market. So rather than highlight composites here, we opted to take a look at what those pitching competitive materials – in particular, high-strength steel (HSS) and aluminum – have to say.
Highlights of HSS
“When you think about lightweighting in automotive, steel isn’t always on the list,” said Jody Hall, vice president of the automotive market for the Steel Development Institute, in her presentation at ADM. “I’m here to talk to you about why it’s not only on the list, but it’s at the top of the list for many applications in automotive, especially for body structures.”
Hall provided attendees a quick history lesson on innovation in steel sheet materials, beginning with the launch of HSS in the 1980s. Today, there are more than 200 grades of steel, with innovations in the past decade focused on high-strength, highly formable materials. Twinning-induced plasticity (TWIP) steels have become popular in automotive because of their excellent mechanical properties, high energy absorption and high stiffness. However, admitted Hall, TWIP steels are heavily alloyed, a bit more expensive and difficult to join.
Hall indicated that the steel industry is currently working on the “gap area” in its third-generation materials. “Now that we have the third generation of advanced high-strength steel, we need to deliver more cost-effective steels than the TWIPs, but also provide great ductility along with high strength.”
The Steel Market Development Institute is part of a consortium called the Auto/Steel Partnership that has several initiatives to improve the quality of steel and stamped components. Much of the focus is on enabling manufacturing. “Automakers are very confident they know how to design with the material, but manufacturing is an issue,” said Hall. “They need to be able to stamp these parts and join them together to make a good structure.” Some of the consortium’s main projects focus on body stamping, tooling, simulation to optimize formability, reparability and chassis work. (You can learn more about the projects at www.a-sp.org.)
“Advanced high-strength steel is the fastest growing material on a vehicle,” said Hall. “We are actually replacing ourselves – mild steel and high-strength, low-alloy steel – with high-strength steel so we can reduce the mass of a vehicle.”
She called steel the “first choice” for automakers, but acknowledged that other materials are gaining ground. “Steel is the most cost-effective, and [automakers’] infrastructure is set up for steel, so they try to use it first to hit performance targets and mass reduction,” said Hall. “But if they can’t do it with steel, they’ll work with other materials.” Materials like CFRP.
A Look at Aluminum
Henry Bertolini, technical director at Pennex Aluminum Co., began his presentation at ADM by admitting one of the challenges for aluminum: “How do we improve our strength and not go up in cost?” he asked. That’s a concern shared by CFRP suppliers and one that hinders both aluminum and composites from gaining more market share in the automotive sector.
