The steel and automotive industries have been working together to keep future vehicles strong, resilient and safe even amid lightweighting efforts. Third-generation steel products provide engineers with an increasing array of choices that will help steel maintain its role as the dominant material used in the construction of light vehicles.
Special Report
Fastmarkets
June 2020
By Robert England
It’s all about collaboration
Collaboration between the steel industry and the automotive
industry is a fundamental driver of adoption of third-generation
advanced high-strength steels (AHSS) in the design and
production of light vehicles.
While some collaboration has been going on
behind the scenes, a big part of it is being
accomplished under the banner of the Auto/Steel
Partnership.
The partnership “is on the front lines of how thirdgeneration
steel can be used,” John Catterall,
vice president of the automotive program for
the American Iron and Steel Institute (AISI) and
the former executive director of the Auto/Steel
Partnership, said in an interview with Fastmarkets.
In March, Michael Davenport was appointed to
replace Catterall as head of the partnership.
“It’s unique in the materials industry – the amount
of collaboration with the end-user customer,”
Catterall said. “It’s a cradle-to-grave approach.
You produce the materials and then help the
customer implement those materials. That’s what
separates the steel industry from other materials
providers.”
The Auto/Steel Partnership was formed in 1987 as
a consortium of the AISI’s automotive program
and the United States’ Big Three automakers: Ford
Motor Co, FCA US LLC.
From its inception, the partnership has helped
automakers enhance vehicle safety, raise fuel
economy and improve design and manufacturing.
Its steel industry members include ArcelorMittal,
Nucor, AK Steel, Posco America, Algoma Steel,
Stelco and Ternium. Gestamp and Martinrea,
manufacturers of auto components and systems,
are also members.
The focus of the Auto/Steel Partnership shifted
several years ago, after the US Department of
Transportation’s National Highway Traffic Safety
Administration and the Environmental Protection
Agency jointly set a corporate average fuel
economy (Cafe) goal of 54.5 miles per gallon
(mpg) for 2025 model-year cars to improve fuel
efficiency and lower greenhouse gas emissions.
This year, those agencies finalized updated Café
covering model years 2021-26, under the
Safer Affordable Fuel Efficient (Safe) Rule.
“Under the Safe Rule, the projected overall
industry average required fuel economy in [model
years] 2021-2026 is 40.4 miles per gallon, compared
to the 46.7 mpg projected requirement in [model
year] 2025 under the 2012 standards,” the groups
wrote in a joint press release.
The higher fuel-economy standards posed a
challenge to steel’s role as the metal of choice
for automobiles, and the Auto/Steel Partnership
shifted its focus toward making lighter and more
ductile steel. Ductility is a measure of a material’s
ability to undergo significant plastic deformation
before it breaks.
“Auto came to steel and said: We like hardened
steels, but we need to form this at a room
temperature,” Abey Abraham, managing director
of automotive materials at DuckerFrontier, said in
an interview with Fastmarkets.
The steel industry then came back to the auto
industry and offered it a choice of third-generation
steel grades that are stronger, lighter and
“extremely formable,” Abraham added.
So far, in the battle for higher fuel efficiency, steel
has lost only marginal market share compared
with other materials. The metal is estimated to
account for 53% of average light vehicle weight
in 2020, down slightly from 54% in 2018 and from
55% in 2013, according to the 2018 North American
Automotive Steel Content Market Study by Ducker
Worldwide, now DuckerFrontier.
As steel has slipped, aluminium has gained ground,
rising from 9% of average lightweight vehicle
weight in 2013 to 12% in 2018. Aluminium has taken
market share from other materials – especially
iron content in blocks, knuckles and control arms,
according to the Ducker study.
As lightweight steel has replaced heavier steel,
however, automakers have been able to achieve
lower average curb weights. Average curb weight
stood at 3,790 lb in 2018, down from an average
3,821 lb for 2013 model-year vehicles, according to
the Ducker study.
Overall curb weight averages, however, have not
come down as much as one would expect from
the weight reductions in individual models. That
is because consumers have increasingly favored
light trucks, pickups, sports utility vehicles (SUVs)
and crossovers, which are heavier than passenger
cars, according to Abraham. Consumers have also
increased their preference for electric vehicles
(EVs), which are comparatively heavier than
combustion engine vehicles.
“If you look at nearly all vehicles on a model-tomodel
perspective, each subsequent generation
of vehicle proves the OEM [original equipment
manufacturer] engineers are hard at work
in making the vehicle lighter and safer – and
achieving weight savings. However, when you have
a greater mix of bigger and ‘heavier’ vehicles, it
will make it look like weight savings are not being
achieved, which is not the case in my opinion,”
Abraham said.
As average curb weights and steel’s share of vehicle
weights have declined, that has translated into a
corresponding drop in demand for sheet steel – to
1,480 lb per vehicle on average in 2018 from 1,615 lb
in 2013, according to the Ducker study.
“Steel has essentially been replacing itself,”
Catterall said. “Basically, they are lightweighting
the steel content of automobiles.”
Indeed, some third-generation steels are replacing
earlier high-strength steel and high-strength low
alloy (HSLA) products, according to the Ducker
can augment the performance of hardened steel
and advanced high-strength steels.
Lightweighting
New third-generation steel grades can meet key
requirements for lightweighting automobiles, but
also provide higher strength where it is required
and higher formability where it is needed.
“The [front] beam has to hold the crash,” Abraham
said, and thus needs to be stronger even though it
is lighter.
“But the structure behind that beam has to be able
to deform in a controlled fashion” to absorb the
impact of the crash and protect the passengers, he
continued. “This can be done with lower-strength
steels.”
The number of choices in steel grades and
characteristics is “one advantage the steel
company has above other materials companies,”
Catterall said. “There are more than 200 steel
grades to design car bodies. It gives engineers the
flexibility to pick the right material for the right
application and put it in place.”
Steel companies are confident about the role
third-generation steels can play in ensuring that
steel remains a leading materials provider for
automakers.
“Once the solutions mature in the right
applications and meet the OEMs’ expectations,
there is an opportunity for third-generation steels
to grow and displace other materials,” according
to Bala Krishnan, ArcelorMittal’s director of
automotive product applications.
Intrusion prevention applications – those that
buffer and contain crashes – offer considerable
promise because of their corrosion protection,
according to Krishnan.
Further, Krishnan said that martensitic grades with
a tensile strength of 1,700 megapascals (MPa)
and higher “could start to reverse the trend of
aluminium use in bumper applications.” In addition,
new grades of steel could “potentially stop
aluminium in its tracks for the battery enclosure
applications.
What are third-generation steels?
Efforts to advance steel technology started out with a focus on strengthening steel.
FIRST GENERATION
In this phase, material
engineers added alloying
elements and strengthening
mechanisms to mild steels
to develop high-strength,
low-alloy (HSLA) steel,
according to the American
Iron and Steel Institute
(AISI).
These steels had greater
strength, but that
improvement sacrificed their
elongation or stretchability.
This was followed by the
development of dual-phase
(DP), transformation induced
plasticity (TRIP)
and martensitic steels
that further increased
strength but also decreased
elongation.
SECOND GENERATION
Material engineers achieved
both higher strength and
higher elongation in the
second generation, which
was accomplished by
adding significant levels of
alloying elements to develop
twinning-induced plasticity
(TWIP) and austenitic
stainless steels.
The adoption of these steels
was limited, however, by their
high cost and challenges in
joining these products to
other steel grades
THIRD GENERATION
Here, material engineers developed
steel grades with improved tensile
strength and ductility, a measure
of a material’s ability to undergo
significant plastic deformation
before it breaks or ruptures, this also
improves formability.
These grades make steel structures
lighter by enabling thickness
reduction, but this also requires
improved geometries to stabilize the
thinner sections.
Third-generation steel grades are
being used successfully to improve
the structural safety components
of automobiles while lowering their
weight, including in front and rear
rails and the elements that make up
the safety cage (the A pillar, roof rail,
B pillar, sill and hinge pillar).
These complex shapes need to be
formed accurately to maintain the
quality of the vehicle and
resist high vehicle loading forces.
Most importantly, they have to
absorb impact energy in a crash while
protecting passengers, AISI has stated
The above definitions are based on descriptions written by Michael Davenport, published on October 5, 2017,
in the Stamping Journal titled “Third-generation advanced high-strength steel emerges.” That, in return,
relied on a U.S. Steel Corp presentation by Murali Tumuluru at the 4th Lightweight Vehicle Manufacturing
Summit 2017 in Detroit.
AISI confirmed that the information holds true today.
Utilization gains
The utilization of third-generation AHSS in automobiles and
light trucks has come a long way.
The total weight for all high-strength steels in light
vehicles averaged 209 lb in 2012, with 45 lb of that
representing third-generation and ultra-high-strength
steels (UHSS), Ducker Worldwide, now DuckerFrontier,
said in its North American Automotive Steel Content
Market Study released in June 2018.
By 2018, the total weight for all high-strength steels
had risen by 57.4% to 329 lb. The use of thirdgeneration
and UHSS rose at a similar rate of 57.8%
to 71 lb. That represented a nearly 22% share of
advanced steels, just as it did in 2012.
The Ducker study projected that by 2020, the use of
advanced steels would rise by a further 31% to 431
lb on average in auto and light truck models, with
third-generation/UHSS more than doubling to 170 lb
versus 2018. That would represent a 39.4% share of
total advanced steels used in light vehicles.
Further, by model year 2025, the Ducker study
forecast that advanced steels would represent 570
lb on average in light vehicles, up by another 32.3%
from projected 2020 levels. Third-generation UHSS
was expected to rise 47.1% to 250 lb in the same
comparison, representing a 43.9% share.
“The utilization of advanced grades of steels remain
on track” to make the utilization gains forecast for
2020 and 2025, Abey Abraham, managing director
of automotive and materials at DuckerFrontier, said
in an interview with Fastmarkets. He oversaw the
research conducted by Ducker in 2018.
Mills are ramping up
A number of steel mills have been adding galvanized
production lines to meet an anticipated rise in demand for
third-generation AHSS from the auto industry.
Nucor Corp
Nucor is one of these steelmakers. “We have
completed several [capital expenditure] projects
that will allow us to produce [third-generation]
grades efficiently, as desired by our automotive
customers,” Katherine Miller, director of public
affairs and corporate communications at the
Charlotte, North Carolina-based steelmaker, told
Fastmarkets in an interview.
One key capex investment is Nucor’s $230-million
specialty cold mill complex in Hickman, Arkansas,
which is slated to start in mid-2021. The complex
will have the capacity to produce 500,000 tons per
year of third-generation steels and grades with
yield strengths up to 1,400 megapascals (MPa),
Miller said.
Nucor is already producing products classified as
ultra high-strength steel (UHSS), which have tensile
strengths above 980 MPa. These include presshardened,
dual-phase 980 and several martensitic
steel products, she added.
“When [original equipment manufacturers] become
comfortable with the safety and durability of
the third-generation AHSS grades coming into
the market, implementation should be steady as
automakers work to meet [corporate average fuel
economy] standards,” Miller said.
Nucor expects the automotive industry to face a
learning curve in terms of utilizing third-generation
AHSS grades, she said.
“These grades behave very differently than
conventional dual-phase or press-hardened steels
currently in use, so the design changes would be
significant,” Miller said.
Nucor chief financial officer, treasurer and executive
vice president James Frias noted during an earnings
call on Tuesday April 28 that the company “is taking
advantage of the current marketplace disruption to
run development orders for automotive advanced
high-strength steels” at the specialty cold mill
complex in Hickman.
Nucor is “using the downturn to do more prototypes
with customers in the advanced high-strength steel
arena,” Philip Gibbs, analyst at KeyBanc Capital
Markets, said in an interview with Fastmarkets.
“Nucor [has] made a massive investment to get
up the auto curve,” he said. “This is what they do
at Nucor when they commission new assets. They
take losses for a little bit and then come out of
the qualifying and trial period, and then bill their
book.”
Nucor also “delivered production at our dualconfiguration
reversing mill [in Hickman during the
first quarter of 2020] that was more than double
the average output of the three quarters that had
operated last year,” Frias added.
U.S. Steel Corp
U.S. Steel is another steelmaker that has been at
the forefront of developing third-generation steel
products. Its martensitic-grade “Mart-Ten1500,”
with an ultimate tensile strength of more than
1,500 MPa, was utilized on the 2019 Chevrolet
Silverado. It also won the 2018 Altair Enlighten
Award from the Center for Automotive Research
and Altair Engineering.
Pro-Tec Coating, a Leipsic, Ohio-based joint venture
of U.S. Steel and Kobe Steel, completed a 500,000-
ton UHSS, continuous hot-dipped galvanizing
(HDG) line last summer. The $400-million line is
designed to produce steel with tensile strengths of
780 MPa and higher.
“It’s up and running, but I’m not sure at what
capacity,” Gibbs said of the Pro-Tec line.
Metal Strategies chief executive officer Christopher
Plummer has previously estimated that the HDG
line should increase Pro-Tec’s total AHSS production
capacity to 1.5 million tons per year.
Neither Pittsburgh-based U.S. Steel nor Japan’s
Kobe Steel have made any public announcements
about the new HDG line since it was completed
last year.
Big River Steel LLC
Big River Steel has hired Austria’s Andritz AG to build
a galvanizing line at its Osceola, Arkansas, facility to
produce third-generation AHSS, CEO David Stickler
told Fastmarkets.
“We are calling it the next-generation galvanizing
line,” he said, declining to specify the cost of the
project.
Construction of the galvanizing line “won’t get
started until this fall or early next year,” Stickler
added.
Lighter, stronger and safer
Automakers are engaged in a careful and thorough review
of how they might go about incorporating third-generation
AHSS into various parts and components of automobiles, steel
industry leaders said.
how the new third-generation grades can best be
used for stamping, welding and joining while also
improving passenger safety, Nucor Corp director
of public affairs and corporate communications
Katherine Miller said.
“The safety of those parts is crucial, so the [original
equipment manufacturers] are making sure no
problems are encountered when switching to these
new grades. Progress has been slow for this reason,”
Miller told Fastmarkets in an interview.
Big River Steel chief executive officer David Stickler
believes that lighter third-generation steels not only
can be stronger but also safer than rigid structures
when used in the crumple zone between the car’s
engine and passenger cabin.
“A long time ago the steel in the crumple zone was
very rigid,” he said. With the advent of higher and
higher fuel-economy standards, “that didn’t work,
especially as cars got smaller and the crumple zone
itself became smaller.”
To demonstrate the safety of its new steels, Big
River Steel turned to the Center for Collision Safety
and Analysis at George Mason University to test the
performance of a range of third-generation steel
grades.
“We have been working with them on the possibility
different steel grades and with different structures,”
Cing-Dao (Steve) Kan, professor of mechanical
engineering at George Mason University and
director of the Center for Collision Safety and
Analysis.
Kan is finding that there are plenty of steel grades
to test, with a single vehicle having “10, 20, 30, even
40 different grades of steel.”
Third-generation steels have a material property
known as ductility, the ability to undergo significant
plastic deformation before breaking or rupturing.
“The challenge is that once it pushes a threshold,
they just crack,” Kan said.
Engineers can do a predictive analysis on a given
steel material and determine how it can perform
based on accumulated knowledge gained from
engineers working with steel for more than a
century, he said, noting that in comparison
it is more difficult to do the same analysis for
composites and aluminium.
Not all of the testing occurs on paper. The center
also conducts crash tests of vehicles at its Federal
Outdoor Impact Laboratory and can crash test
automobiles to determine how the materials and
structures hold up in addition to how the crash
affects test dummies seated inside the vehicles.
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