The door ring is a key structural part in the vehicle body-in-white that encircles each set of side doors. It plays a critical role in protecting the passengers and battery during a crash. ArcelorMittal Tailored Blanks Americas’ (AMTB) tailored blanks method for making door rings allows for material optimization, weight reduction, cost efficiency and manufacturing simplicity while reducing the carbon dioxide equivalent footprint of the car, according to Gagan Tandon, chief product officer.
In 2024, AMTB produced over 4 million door rings for six automotive brands in North America,
Based on projects in the pipeline, AMTB expects that by 2030 annual production for North America has the potential to grow to over 10 million door rings applied to over 19 brands.
The success of this technology will also reaffirm steel’s role as the dominant material used to make cars, the chief product officer said.
“Original equipment manufacturers [OEMs] no longer say to us, ‘Prove to me why we should apply it’ to new car door ring designs. Now more of them are saying, ‘Prove to me why we shouldn’t apply it,'” Tandon told Fastmarkets on a recent tour of the company’s facility in Detroit.
“Many of the OEMs are kind of risk averse. They want to implement technologies that have been proven up and established. And it took a long time for us collectively to work with the first Honda [Acura MDX] and get the first door ring [adopted in a new model design in 2014],” Ram Iyer, manager, automotive portfolio, at ArcelorMittal USA Research in Bloomfield Hills, Michigan, said.
“Since then, it’s got to a point in which there is industry acceptance. So yes, when you look today, it is perceived as an established solution in the automotive industry, You don’t have to really go and validate or relitigate the concept,” Iyer said.
In 2018, AMTB opened its $83 million refurbished state-of-the-art industrial facility in northern Detroit.
The press-hardened aluminium-coated steel for the facility is blanked into specific parts for designated car models at one of several local blanking companies in the area and shipped to the AMTB facility for ablation and welding.
From the AMTB plant, the welded blanks are sent to a hot stamper to be stamped into a structural part the OEM will incorporate into a new vehicle on its assembly line.
Efficiency gains
Parts consolidation is “a main benefit” provided by the new method for making door rings, according to Tandon.
“Press hardened steel is a material that gives you that unique ability to consolidate many parts into one large part,” he said.
“That’s possible because of the hot stamp process, when you heat the blanks to over 900 degrees [Celsius], you have formability similar to mild steel. And then after hot stamping, you have the highest strength possible, anywhere from 500-2,000 megapascals in the body structure,” Tandon said. “This gives you that anti-intrusion element for crash safety. All of that comes together in the hot stamped tailored blank.”
The process also reduces the scale of assembly operations, increases the light weighting of the auto body and reduces the carbon footprint of the automaking process.
“This happens because we reduce the amount of material consumption [and] because we are able to weld different thicknesses and different grades,” Tandon said.
“So, we can basically tailor the material as needed… so that it leads to crash worthiness improvement in the design,” the product manager said.
Laser welded blanks were initially developed in 1976 by Walter Duley, who founded Powerlaswers Limited, which was acquired by Dofasco in 2001 and ArcelorMittal acquired Dofasco in 2006, rebranding it as ArcelorMittal Tailored Blanks in 2010.
The automotive pioneers
AMTB works directly with automakers years in advance to collaborate on the design of any model that incorporates tailored welded blanks into its vehicle architecture.
ArcelorMittal Global research and development (R&D) pioneered the process in 2008 as an R&D concept and AMTB launched it with the 2014 Acura MDX.
The use of advanced high strength hot stamped steel grades with tailored blanks reduces the weight of the car by 4 kilograms and lowers carbon dioxide equivalent emissions by 37 million kgs over the life of the vehicle, according to AMTB.
So far, automakers who have adopted tailored blanks technology have seen weight reductions up to 18 kg with corresponding reductions in carbon emissions, with early adopters including the 2016 Chrysler Pacifica from Stellantis, the 2019 Acura RDX and the 2019 RAM 1500 truck from Stellantis.
Wider adoption
“It took us until 2018 to make our 1 millionth part and have it on three car models. Today we have it on 18 car models. So, between 2018 and 2025 we have gone from 1 million to 18.5 million [total door rings manufactured],” Tandon said.
AMTB has worked with Honda on the 2021 Acura MDX, with Stellantis on the 2021 Jeep Grand Cherokee and the 2021 Jeep Wagoneer and Grand Wagoneer.
The company also collaborated with Honda on the 2022 Honda Pilot and the 2025 Honda Passport.
AMTB has helped other undisclosed OEMs incorporate welded blanks into new vehicle designs, including a 2020 and 2021 electric vehicle (EV), a 2022 EV, plus a 2023 EV truck.
AMTB also provides other welded blanks for structural rails, door pillars, door inners and cowl sides.
“We have 30 additional designs that are in active development, out of which 18 are already confirmed,” Tandon said.
“The adoption has been tremendous in the last three years alone. We went from three main customers until now we have six customers using it. And by the time we get to 2030, we’ll have 19 different brands and different customers,” Tandon said.
Design centers
AMTB works with automakers’ design centers all across the globe to incorporate tailored blanks into new car designs, according to Tandon. .
“It’s not where the cars are manufactured, but where they are designed. For German automakers [selling in North America] we go work with the German design centers. For Japan we have to work with the Japanese design centers. For the US, we have to work with the US design centers,” he said.
AMTB also worked with Honda Acura in 2018 to introduce an adaptation of the RDX SUV model in China, the chief product officer said.
“China has had an incredible upswing” in adopting AMTB’s technology, Tandon said.
“They’re already at 11.5 million door rings produced. So they started much later than us [and] they are now close to catching up to us — and the number of designs and programs are just incredible,” Tandon said.
AMTB expects continued rapid adoption of its technology in North America with every North American automaker adopting it by 2035.
“Moving forward, we expect it to be the standard design,” Tandon said.
“We are seeing that change in a number of OEMs that have been resistant in the past to applying it,” but who are now working with AMTB to incorporate tailored blanks door ring designs into future models, the chief product officer said.
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