Automotive Engineering - June 2021 - 23

LIGHTWEIGHTING | COLD-STAMP STEEL FEATURE
AMD metallurgy expands materials choice
Dr. Gregory Vartanov.
Dr. Gregory Vartanov is chief engineer at
Advanced Materials Development Corp., a privately-owned
Toronto, Canada-based company
that develops high-strength steels and alloys for
the automotive, aerospace and defense industries.
He holds an M.S. and Ph.D. in materials engineering
and metallurgy. Dr. Vartanov has been
granted five U.S. patents in high-strength steel
alloys and he has authored numerous engineering
articles in the U.S. He spoke recently with SAE
editor Lindsay Brooke.
AMD Corp. may be new to some SAE readers. Your focus to date has been
in aerospace.
Yes. Our company has been in the auto industry about two years. We're now
working on ColdStamp-Steel sheet for automotive.
What are ColdStamp's primary advantages?
Our material offers a very competitive balance of strength, ductility, weldability
and cost-effectiveness compared with other steel alloys such as Docol,
MartiNSite, and Kobelco, and with aluminum alloys. ColdStamp-Steel gives
vehicle makers another choice in high-strength materials. Currently, it's being
evaluated at one North American company for possible implementation.
EV battery enclosures are an increasingly competitive area for materials, as
well as EV structures overall. Aluminum is targeting that business aggressively.
High-strength aluminum alloys become weaker as the service temperature
rises. They melt at about 1,260 degrees [F] and it have lost half of their
strength or more by the time they reach 600 degrees. For example, the
ultimate tensile strength of 6061-T6 is about 45 KSI at room temperature,
but is only about 4.6 KSI at 600°F. Even at only 400°F its strength is only 19
KSI. Our steel increases the safety of EV battery structures due to its better
thermal performance.
Cold-stamped steel also enables use of thinner wall material for the same
amount of strength, correct?
Yes. For example, a 1-mm-thick sheet of ColdStamp-Steel has the equivalent
strength of a 2.8-mm-thick sheet of 7075-T6 or 5-mm plate of 6061-T6. The
cost of the high-strength aluminum alloys is 100% higher than the cost of
ColdStamp-Steel.
For more information, see http://amdoncorp.com/.
ColdStamp-Steel can be coated in several ways. It can be galvanized
by electroplate or hot-dip processes, which supply durability at longterm
continuous exposures with the maximum temperature of up to
392°F (200°C). Continuous exposure to temperatures above this can
cause the outer free zinc layer to peel from the underlying zinc-iron
alloy layer. Galvanized ColdStamp-Steel (compositions SC1 and SC2)
possesses the mechanical properties as shown in Table 3 with some
corrections on the added galvanic layers; corrosion resistance of the
galvanized ColdStamp-Steel competes with the corrosion resistance of
high-strength AL alloys. Cost of production per pound of 6000-series
and 7000-series AL alloy sheet is more than 100% higher than the cost
per pound of the galvanized SC1 or SC2 sheets.
After quenching and high tempering at 1,000-1,050°F, SC1 and
SC2 possess tensile strength of more than 175 ksi (1,200 MPa) and
AUTOMOTIVE ENGINEERING
Room temperature engineering tensile stress diagrams of SC1
and SC2 after heat treatments.
elongation of 9-10%; quenched and high-tempered
SC1 and SC2 can be galvannealed without reduction
of their mechanical properties. Cost of the galvannealed
ColdStamp-Steel is slightly higher than the
cost of the hot-dip galvanized alloy.
ColdStamp Steel, coated by electroplating or hotdip
processes, offers definitive benefits for use in
battery-enclosure applications. The aluminized, galvannealed
and galvanized ColdStamp-Steel can prevent
failure of battery enclosures at temperatures of
up to 1,400°F (760°C) and withstand fire up to
2,200°F (1205°C), allowing for more time for EV passengers
to evacuate in the event of an emergency.
Durability of battery enclosures made from the aluminum
alloys cannot compete with the durability of
enclosures of the same weight made from coated
ColdStamp-Steel at ambient and elevated temperatures.
And the cost of of aluminized ColdStamp-Steel
sheet currently is half that of 6000- and 7000-series
AL sheet.
June 2021 23
http://www.amdoncorp.com/
Automotive Engineering - June 2021

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