United States Court of Appeals
for the Federal Circuit
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ARCELORMITTAL ATLANTIQUE ET LORRAINE,
ARCELORMITTAL,
Plaintiffs-Appellants
v.
AK STEEL CORPORATION,
Defendant-Appellee
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2017-1637
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Appeal from the United States District Court for the
District of Delaware in No. 1:13-cv-00685-SLR, Judge Sue
L. Robinson.
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Decided: November 5, 2018
SEALED OPINION ISSUED: November 5, 2018
PUBLIC OPINION ISSUED: November 14, 2018 *
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CONSTANTINE L. TRELA, JR., Sidley Austin LLP, Chi-
cago, IL, argued for plaintiffs-appellants. Also represent-
ed by HUGH ABRAMS, Shook Hardy & Bacon, LLP,
* This opinion was originally filed under seal and has
been unsealed in full.
Chicago, IL; JEFFREY B. BOVE, Ratner Prestia, Wilming-
ton, DE.
CHRISTOPHER NEIL SIPES, Covington & Burling LLP,
Washington, DC, argued for defendant-appellee. Also
represented by JEFFREY HOWARD LERNER.
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Before REYNA, WALLACH, and HUGHES, Circuit Judges.
REYNA, Circuit Judge.
Appellants appeal from a grant of summary judgment
of non-infringement. The U.S. District Court for the
District of Delaware granted summary judgment as a
matter of law after concluding Appellants’ infringement
action was collaterally estopped. Because evidence indi-
cates a material difference in the accused products in this
action, collateral estoppel does not apply and the entry of
summary judgment was error. We vacate and remand.
BACKGROUND
Plaintiff-Appellants ArcelorMittal Atlantique et Lor-
raine and ArcelorMittal and Plaintiff-Appellants’ prede-
cessor in interest, ArcelorMittal France (collectively
“ArcelorMittal”) own U.S. Patent No. 6,296,805 (the “’805
patent”) and two reissues of the ’805 patent, U.S. Patent
Nos. RE44,153 (the “RE153 patent”) and RE44,940 (the
“RE940 patent”). This appeal primarily involves the
RE940 patent.
1. Hot-Stamped Boron Sheets
The asserted RE940 patent, issued June 10, 2014, re-
lates to boron steel sheets with an aluminum-based
coating that, when hot-stamped, become highly mechani-
cally resistant. Mechanical resistance, or ultimate tensile
strength (“UTS”), is measured in megapascals (“MPa”).
ARCELORMITTAL ATLANTIQUE v. AK STEEL CORPORATION 3
Hot-stamping is a thermal treatment process where
steel blanks are rapidly heated, inserted into a stamping
machine that contains special dies, stamped into a partic-
ular shape, and then rapidly cooled, or quenched. See
ArcelorMittal Fr. v. AK Steel Corp., 700 F.3d 1314, 1317–
18 (Fed. Cir. 2012) (“ArcelorMittal I”). The hot-stamping
process alters the crystalline microstructure of the steel,
and thereby its UTS, by transforming at least a portion of
the steel’s microstructure to a form known as martensite.
Id. Steel with a martensitic microstructure is capable of
having a high UTS. See id. The hot-stamping process
gives the steel significantly higher UTS than its pre-
stamped state. Id. Thus, two steel sheets of the same
composition can have significantly different UTSs depend-
ing on whether and how they have been thermally treat-
ed. The high UTS of the hot-stamped steel is desirable for
use in the production of auto parts.
Independent claim 17 of the RE940 patent is repre-
sentative of the asserted product-by-process claims and
recites:
17. A hot-rolled coated steel sheet comprising
a hot-rolled steel sheet coated with an alu-
minum or aluminum alloy coating, wherein
said coated steel sheet is in the form of a de-
livery coil and the steel in the sheet compris-
es the following composition by weight:
0.15%