  United States Court of Appeals
      for the Federal Circuit
              __________________________

       ARCELORMITTAL FRANCE AND
 ARCELORMITTAL ATLANTIQUE ET LORRAINE,
            Plaintiffs-Appellants,
                           v.
             AK STEEL CORPORATION,
                 Defendant-Appellee,
                          AND

         SEVERSTAL DEARBORN, INC. AND
            WHEELING-NISSHIN INC.,
               Defendants-Appellees.
              __________________________

                      2011-1638
              __________________________

    Appeal from the United States District Court for the
District of Delaware in case no. 10-CV-0050, Judge Sue L.
Robinson.
                __________________________

              Decided: November 30, 2012
              ___________________________

   CONSTANTINE L. TRELA, JR., Sidley Austin LLP, of
Chicago, Illinois, argued for plaintiffs-appellants. With
him on the brief were DAVID T. PRITIKIN and CONSTANTINE
KOUTSOUBAS. Of counsel on the brief were JEFFREY B.
ARCELOR MITTAL   v. AK STEEL CORP                        2


BOVE and CHAD S.C. STOVER, Connolly Bove Lodge &
Hutz LLP, of Wilmington, Delaware.

    CHRISTOPHER N. SIPES, Covington & Burling, LLP, of
Washington, DC, argued for all defendants-appellees.
With him on the brief were RODERICK R. MCKELVIE and
JEFFREY H. LERNER for AK Steel Corporation. Of counsel
on the brief were RICHARD W. HOFFMANN and DAVID J.
SIMONELLI, Reising Ethington, PC, of Troy, Michigan for
Severstal Dearborn, Inc, et al.
              __________________________

 Before DYK, CLEVENGER, and WALLACH, Circuit Judges.
Opinion for the court filed by Circuit Judge DYK. Opinion
   dissenting-in-part filed by Circuit Judge WALLACH.
DYK, Circuit Judge.
    ArcelorMittal France and ArcelorMittal Atlantique et
Lorraine (collectively “ArcelorMittal”) appeal from a final
judgment of the United States District Court for the
District of Delaware. The judgment is based on a jury
verdict finding that defendants AK Steel Corporation,
Severstal Dearborn, Inc., and Wheeling-Nisshin Inc. (“AK
Steel”) did not infringe ArcelorMittal’s U.S. Patent No.
6,296,805 (“the ’805 patent”) and that the asserted claims
were invalid as anticipated and obvious. ArcelorMittal
challenges both the district court’s claim construction and
the jury’s verdict.
    We uphold the district court’s claim construction in
part and reverse it in part. We also reverse the jury’s
verdict of anticipation. With respect to obviousness, a
new trial is required because the district court’s claim
construction error prevented the jury from properly
considering ArcelorMittal’s evidence of commercial suc-
3                          ARCELOR MITTAL   v. AK STEEL CORP


cess. We therefore affirm-in-part, reverse-in-part, vacate-
in-part, and remand for a new trial.
                       BACKGROUND
     The ’805 patent covers boron steel sheet with an alu-
minum-based coating applied after rolling the sheet to its
final thickness. The steel is used for “hot-stamping,” a
process which involves rapidly heating the steel, stamping
it into parts of the desired shape, and then rapidly cooling
them (“quenching”). The rapid heating and cooling alters
the crystalline structure of the steel, converting it to
austenite and then martensite. By altering the steel’s
microstructure in this manner, hot-stamping produces
particularly strong steel. Because hot-stamped steel is so
strong, parts created by hot-stamping can be thinner and
lighter than steel parts produced by other processes while
being just as strong. This is particularly desirable in the
manufacture of automobile parts because strong parts are
required for safety and light parts promote fuel efficiency.
     Although hot-stamping has clear benefits, its use has
historically been limited because of problems associated
with the process. The high temperatures required for hot-
stamping cause oxidation, resulting in the formation of
“scale” on the steel’s surface. Scale must be removed
before the steel can be painted or welded, but removing it
requires expensive and environmentally harmful “shot-
blasting” and “pickling” operations, in which the steel is
blasted with an abrasive material and immersed in a
chemical bath. Shot-blasting is also problematic because
it can damage thin parts, undermining the strength and
efficiency advantages of hot-stamping. Oxidation also
causes the loss of carbon from the steel’s surface (“decar-
burization”), which weakens the steel.
   The aluminum-based coating claimed in the ’805 pat-
ent prevents oxidation from occurring during hot-
ARCELOR MITTAL    v. AK STEEL CORP                      4


stamping. As a result, scale does not form and decarburi-
zation does not occur when the claimed steel is hot-
stamped. This makes hot-stamping less costly, reduces
its environmental impact, and allows its use in the pro-
duction of parts that are too delicate to survive shot-
blasting.
    The asserted claims of the ’805 patent are claim 1 and
dependent claims 2, 5, 7, and 16. Claim 1, the only as-
serted independent claim, reads:
    1. A hot-rolled coated steel sheet comprising a
    hot-rolled steel sheet coated with an aluminum or
    aluminum alloy coating, wherein the steel in the
    sheet comprises the following composition by
    weight:
        0.15%<carbon<0.5%
        0.5%<manganese<3%
        0.1%<silicon<0.5%
        0.01%chromium<1%
        titanium<0.2%
        aluminum<0.1%
        phosphorus<0.1%
        sulfur<0.05%
        0.0005%<boron<0.08%, the remainder be-
           ing iron and impurities inherent in
           processing, and the steel sheet has a
           very high mechanical resistance after
           thermal treatment and the aluminum
           or aluminum alloy coating provides a
           high resistance to corrosion of the steel
           sheet.
’805 patent col. 4 l. 64 to col. 5 l. 15.
5                          ARCELOR MITTAL   v. AK STEEL CORP


    On January 22, 2010, ArcelorMittal brought an in-
fringement action against AK Steel in the United States
District Court for the District of Delaware, alleging that
AK Steel’s aluminum coated steel sheet products infringe
the asserted claims of the ’805 patent. The parties agreed
upon an expedited trial schedule in which AK Steel
agreed to limit itself to two invalidity defenses and to
arguing non-infringement based on the construction of
two claim terms.
     Pursuant to that schedule, on December 16, 2010, the
district court issued a claim construction decision inter-
preting the claim terms “a hot-rolled steel sheet coated
with an aluminum or aluminum alloy coating” and “the
steel sheet has a very high mechanical resistance after
thermal treatment.” ArcelorMittal Fr. v. AK Steel Corp.,
755 F. Supp. 2d 542, 545 (D. Del. 2010). The court first
construed the term “hot-rolled steel sheet.” Id. at 546–49.
The court noted that those of ordinary skill in the art
distinguished between “hot-rolled” and “cold-rolled” steel
sheet based on which process is used to reduce the sheet
to its final thickness. Id. at 547. Relying on evidence of
this industry convention, the court concluded that Arce-
lorMittal “did not claim a ‘sheet’” generally but rather
“specifically claimed a sheet made by hot-rolling.” Id. at
548. Consequently, the court assigned “hot-rolled steel
sheet” the meaning “a steel sheet that has been reduced
to its final thickness by hot-rolling.” Id. at 549. This
construction excluded steel that was first hot-rolled and
then cold-rolled to its final thickness.
    The court next examined the term “the steel sheet has
a very high mechanical resistance.” Id. The court noted
that there is no applicable industry standard defining
“very high” mechanical resistance. Id. at 550. The court
relied on the statements in the specification that “high”
and “substantial” mechanical resistance “may exceed 1500
ARCELOR MITTAL   v. AK STEEL CORP                           6


MPa.” Id. at 550–51. Accordingly, the court construed
“the steel sheet has a very high mechanical resistance” to
mean that “the flat-rolled steel has been subjected, after
rolling, to additional controlled heating and cooling and
has an ultimate tensile strength of 1500 MPa or greater.”
Id. at 550.
    None of AK Steel’s accused products literally in-
fringed the claims as construed, so the district court
prohibited ArcelorMittal from asserting literal infringe-
ment. Memorandum Order, ArcelorMittal Fr. v. AK Steel
Corp., No. 10-CV-00050 (D. Del. Jan. 4, 2011), ECF No.
205. The case proceeded to trial on the basis of the doc-
trine of equivalents, and the jury returned a verdict on
January 14, 2011, finding that AK Steel did not infringe
the ’805 patent and that the asserted claims were both
obvious and anticipated. ArcelorMittal then moved for
judgment as a matter of law on the invalidity issues and
for a new trial on infringement. The district court denied
those motions and entered final judgment for AK Steel on
August 25, 2011. ArcelorMittal Fr. v. AK Steel Corp., 811
F. Supp. 2d 960 (D. Del. 2011). ArcelorMittal timely
appealed.     We have jurisdiction under 28 U.S.C.
§ 1295(a)(1).
                        DISCUSSION
     This court “review[s] a district court’s denial of . . .
judgment as a matter of law without deference, and its
denial of a motion for [a] new trial for abuse of discretion.”
CytoLogix Corp. v. Ventana Med. Sys., Inc., 424 F.3d
1168, 1172 (Fed. Cir. 2005). We review de novo the
district court’s claim construction. Markman v. Westview
Instruments, 52 F.3d 967, 979 (Fed. Cir. 1995) (en banc),
aff’d 517 U.S. 370 (1996).
7                           ARCELOR MITTAL    v. AK STEEL CORP


                   I Claim Construction
                A. “Hot-rolled steel sheet”
     All claim construction issues concern claim 1, the only
asserted independent claim in the patent. ArcelorMittal
first argues that the district court erroneously construed
the term “hot-rolled steel sheet,” improperly excluding
from the scope of the claim steel sheet that has been cold-
rolled to its final thickness following initial hot-rolling.
AK Steel replies that the district court properly inter-
preted the term in accordance with its ordinary and
customary meaning in the art. We agree with ArcelorMit-
tal.
     By its use of the term “comprising,” claim 1 expressly
contemplates additional, unstated steps such as cold-
rolling. “The transition ‘comprising’ creates a presump-
tion . . . that the claim does not exclude additional, unre-
cited elements.” Crystal Semiconductor Corp. v. TriTech
Microelectronics Int’l, Inc., 246 F.3d 1336, 1348 (Fed. Cir.
2001). To rebut this presumption, AK Steel offers only
the conclusory assertion that “[t]he very definition of ‘hot-
rolled steel sheet’ is steel sheet that has been reduced to
its final thickness by hot-rolling.” Appellee’s Br. 36–37.
It is true that there is ample extrinsic evidence establish-
ing that the ordinary meaning of “hot-rolled steel sheet”
in the industry refers to steel sheet that has not been
cold-rolled. Expert witnesses for both ArcelorMittal and
AK Steel agreed that this definition was customary in the
industry. Furthermore, a leading steel-making treatise
classified steel sheet according to this industry usage.
    However, while AK Steel is correct that the ordinary
meaning of the term in the industry is clear, the specifica-
tion is not consistent with that meaning. In Phillips v.
AWH Corp., we emphasized that the specification is the
primary guide to claim interpretation, recognizing that
ARCELOR MITTAL   v. AK STEEL CORP                          8


“the specification is ‘the single best guide to the meaning
of a disputed term.’” 415 F.3d 1303, 1320–21 (Fed. Cir.
2005) (en banc) (quoting Vitronics Corp. v. Conceptronic,
Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)). Although
definitions based on dictionaries, treatises, industry
practice, and the like often are important aids in inter-
preting claims, they may not be “used to contradict claim
meaning that is unambiguous in light of the intrinsic
evidence.” Id. at 1324. Here, the specification makes
clear that the claim term “hot-rolled steel sheet” does not
preclude a cold-rolling step.
     References to an optional cold-rolling step abound in
the specification of the ’805 patent. ’805 patent col. 1 ll.
47–48, col. 2 ll. 30–31, 37–40, col. 3 ll. 7–9. AK Steel
argues that these references describe “distinct products”
and that the specification elsewhere uses the word “sheet”
where it means to refer to both steel that has been hot-
rolled to its final thickness and steel that was also cold-
rolled. Appellee’s Br. 29. The district court based its
claim construction on similar reasoning. See ArcelorMit-
tal, 755 F. Supp. 2d at 546–47. However, that is not a
coherent reading of the specification for at least two
reasons.
     First, the specification contemplates that “[t]he sheet
according to the invention . . . may be cold-rerolled again
depending on the final thickness desired.” ’805 patent col.
2 ll. 37–40. It also describes the invention’s purpose as
including the production of “cold-rolled steel sheet.” Id. at
col. 1 ll. 37–38. This directly contradicts the district
court’s claim construction, under which the sheet must be
reduced to its final thickness by hot-rolling. The claims
and specification should be read “‘in a manner that ren-
ders the patent internally consistent.’” Pfizer, Inc. v. Teva
Pharm. USA, Inc., 429 F.3d 1364, 1373 (Fed. Cir. 2005)
9                           ARCELOR MITTAL   v. AK STEEL CORP


(quoting Budde v. Harley-Davidson, Inc., 250 F.3d 1369,
1379–80 (Fed. Cir. 2001)).
     Second, the specification describes an embodiment
“having a thickness of approximately 1 mm.” ’805 patent
col. 4 ll. 8–9. That thickness, at least at the time of the
invention, could only have been achieved by cold-rolling.
Indeed, the specification states that “[a]ccording to the
invention” the sheet’s thickness may be as low as 0.25
mm, ’805 patent col. 3 ll. 44–46, a thickness that even AK
Steel concedes is achievable only by cold-rolling. To be
sure, patent protection does not extend to subject matter
disclosed but not claimed. Unique Concepts, Inc. v.
Brown, 939 F.2d 1558, 1562–63 (Fed. Cir. 1991). How-
ever, “[w]e normally do not interpret claim terms in a way
that excludes disclosed examples in the specification.”
Verizon Servs. Corp. v. Vonage Holdings Corp., 503 F.3d
1295, 1305 (Fed. Cir. 2007).
    Because the specification unambiguously contem-
plates cold-rolling, the district court erred by interpreting
the claim term “hot-rolled steel sheet” to exclude steel
sheet subsequently cold-rolled.1 The correct construction
of “hot-rolled steel sheet” is “a steel sheet that has been
hot-rolled during its production.”




    1    This conclusion is not contradicted by the prosecu-
tion history. Although ArcelorMittal amended claim 1 to
remove the explicit reference to optional cold-rolling, the
initial rejection of the claim was because it was ambigu-
ous whether the coating was optional, and the substitu-
tion of the “comprising” language made clear that optional
additional steps were still contemplated. Nothing in the
prosecution history amounted to a disclaimer of cold-
rolling.
ARCELOR MITTAL   v. AK STEEL CORP                        10


          B. “Very high mechanical resistance”
     ArcelorMittal also disputes the district court’s inter-
pretation of the claim term “very high mechanical resis-
tance.” The district court interpreted that term to mean
“the flat-rolled steel has been subjected, after rolling, to
additional controlled heating and cooling and has an
ultimate tensile strength of 1500 MPa or greater.” Arce-
lorMittal, 755 F. Supp. 2d at 549–50. We agree with the
district court. We begin with the specification, which
states that a “high” or “substantial” mechanical resistance
“may exceed 1500 MPa.” ’805 patent col. 2 ll. 51–54, col. 3
ll. 52–54. The specification does not define “very high”
mechanical resistance, but it implies that the 1500 MPa
level is necessary for “high” mechanical resistance. If
1500 MPa is high mechanical resistance, then very high
resistance must be at least 1500 MPa. ArcelorMittal
argues that “very high” mechanical resistance can include
a resistance as low as 1000 MPa, pointing to language in
the specification stating that the invention “makes it
possible to obtain a mechanical resistance in excess of
1000 MPa.” Id. at col. 1 ll. 40–42. However, the specifica-
tion does not refer to 1000 MPa as “high” much less “very
high.” Id. Thus, the specification supports the district
court’s construction.
    Turning to the extrinsic evidence, the district court
observed that the term “very high mechanical resistance”
is not a term of art in the steelmaking industry and does
not have any ordinary meaning. ArcelorMittal, 755 F.
Supp. 2d at 550. ArcelorMittal points to various docu-
ments suggesting that steel with mechanical resistance as
low as 700 MPa may be considered “ultra high” strength
steel, but the record does not establish that these refer-
ences concern boron steel comparable to that described in
the patent. On the other hand, one of the inventors of the
’805 patent coauthored an article on heat-treated boron
11                          ARCELOR MITTAL   v. AK STEEL CORP


steel before the patent was filed. This article is prior art.
The article describes steel with “high mechanical charac-
teristics (UTS > 1500 MPa and YS > 1100 MPa)” after
heat treatment. X. Bano & JP. Laurent, Heat Treated
Boron Steels in the Automotive Industry, in XXXV 39th
MWSP Conf. Proc. ISS 673, 673, 677 (1998) (“Bano”).
Prior art can “help to demonstrate how a disputed term is
used by those skilled in the art.” Vitronics Corp., 90 F.3d
at 1584. Thus, while testimony regarding an inventor’s
subjective understanding of patent terminology is irrele-
vant to claim construction, Howmedica Osteonics Corp. v.
Wright Med. Tech., Inc., 540 F.3d 1337, 1346–47 (Fed. Cir.
2008), when an inventor’s understanding of a claim term
is expressed in the prior art, it can be evidence of how
those skilled in the art would have understood that term
at the time of the invention. Markman, 52 F.3d at 991
(“[E]vidence, in the form of prior art documentary evi-
dence or expert testimony, can show what the claims
would mean to those skilled in the art”); Howmedica, 540
F.3d at 1347 & n.5. By defining “high” mechanical resis-
tance as greater than 1500 MPa, the prior art here sug-
gests that “very high” mechanical resistance would be
understood to be at least that high.
    Accordingly, both the intrinsic evidence and extrinsic
evidence support the district court’s conclusion that “a
very high mechanical resistance” means a mechanical
resistance of 1500 MPa or greater. Therefore, we affirm
the district court’s construction of “the steel sheet has a
very high mechanical resistance.”
    At oral argument, AK Steel’s counsel conceded that at
least some accused products have a mechanical resistance
of 1500 MPa or greater. However, as a result of the
district court’s incorrect claim construction of “hot-rolled
steel sheet,” the jury was instructed at trial to consider
direct infringement only under the doctrine of equiva-
ARCELOR MITTAL   v. AK STEEL CORP                        12


lents. Final Jury Instructions, ArcelorMittal Fr. v. AK
Steel Corp., No. 10-CV-00050, at 22 (D. Del. Jan. 14,
2011), ECF No. 212. Thus, there has been no determina-
tion below regarding which accused products would or
would not literally infringe under the correct claim con-
struction. That infringement issue will need to be ad-
dressed in the first instance on remand, either by the
court on summary judgment or by a jury in a new trial.
Because the jury found no infringement under the doc-
trine of equivalents, and ArcelorMittal has not challenged
that aspect of the verdict, any infringement analysis
found to be necessary on remand should be limited to
literal infringement.
                      II Anticipation
    ArcelorMittal argues that the evidence cannot support
the jury’s anticipation verdict. “Anticipation is a question
of fact, reviewed for substantial evidence when tried to a
jury.” Finisar Corp. v. DirecTV Grp., Inc., 523 F.3d 1323,
1334 (Fed. Cir. 2008). The jury’s finding of anticipation
was based on Bano. The Bano article was written and
presented by inventor Jean-Pierre Laurent and his col-
league Xavier Bano during the development of the pre-
coated steel claimed in the ’805 patent, and the parties
agree that it discusses hot-stamping boron steel. AK
Steel argued, and the jury found, that the article disclosed
the entire invention. ArcelorMittal challenges that find-
ing on the grounds that Bano disclosed neither coating
the steel sheet before thermal treatment nor coating the
steel sheet with aluminum or an aluminum alloy. We
conclude that there is not substantial evidence that Bano
disclosed coating with aluminum or aluminum alloy.
    A claim is anticipated only where “each and every
limitation is found either expressly or inherently in a
single prior art reference.” Celeritas Techs., Ltd. v. Rock-
13                         ARCELOR MITTAL   v. AK STEEL CORP


well Int’l Corp., 150 F.3d 1354, 1361 (Fed. Cir. 1998).
Anticipation must be proven by clear and convincing
evidence. Microsoft Corp. v. i4i Ltd. P’ship, 131 S. Ct.
2238 (2011). Bano does not expressly disclose either pre-
coating or particular coating compositions. However, it
does state that “it is advisable to protect heat treated
finished parts with coatings” and that “[i]t is possible to
coat this new heat treated boron steel after degreasing as
with conventional steels.” Bano at 676.
     As discussed in the next section, these statements
could have supported a jury finding that Bano disclosed
pre-coating. However, the jury’s apparent conclusion that
Bano disclosed coating with aluminum or aluminum alloy
is more problematic. In denying JMOL, the district court
relied on In re Petering, 301 F.2d 676 (C.C.P.A. 1962), to
hold that “aluminum was a member of a very small class
of metals suitable for use in coating boron steel,” and
therefore inherent in Bano. ArcelorMittal, 811 F. Supp.
2d at 967–68. Petering establishes that when a prior art
reference discloses a “definite and limited class” of suit-
able members within a general formula, it may be read to
disclose each member of that class. Petering, 301 F.2d at
681. Yet Bano does not even explicitly refer to coating
with metals; indeed, the only specific coating it references
is “phosphatization . . . followed by cataphoresis.” Bano at
676. That process refers to coating with paint, not metal,
and it is not clear how paint and metal coatings would
both fit into any general formula comparable to that
found in the prior art in Petering. Moreover, even if paint
and metal were part of the same general formula, the
record does not support a finding that there is a “definite
and limited class” of coatings for steel sheet. There is
insufficient evidence that the varieties of paints and
metal alloys are sufficiently narrow that one of ordinary
skill in the art would “at once envisage each member of
ARCELOR MITTAL   v. AK STEEL CORP                        14


this limited class.” Petering, 301 F.2d at 681 (emphasis
added).
    Without an explicit disclosure of aluminum coating or
substantial evidence that aluminum belonged to a suffi-
ciently definite and limited class of possible coatings, the
jury verdict of anticipation based on Bano cannot stand.
We therefore reverse the district court’s denial of JMOL
as to anticipation.
                      III Obviousness
    ArcelorMittal also urges us to overturn the jury’s ob-
viousness verdict, arguing both that the jury’s verdict was
not supported by substantial evidence and that the jury
was foreclosed from consideration of the secondary factor
of commercial success by the district court’s incorrect
claim construction. “We review [the] jury’s conclusions on
obviousness, a question of law, without deference, and the
underlying findings of fact . . . for substantial evidence.”
Cordis Corp. v. Boston Scientific Corp., 561 F.3d 1319,
1332 (Fed. Cir. 2009) (alterations in original) (internal
quotations omitted).
                   A. Prima Facie Case
    ArcelorMittal concedes that “each element of the in-
vention” was known in the prior art. Appellant’s Br. 3.
The jury found the asserted claims of the ’805 patent
obvious in view of Bano in combination with French
Patent No. 1,297,906 (“French ’906 patent”). The French
’906 patent describes coating steel with aluminum to
protect against oxidation during hot forging (the missing
element in the anticipation finding). We agree that Bano
15                         ARCELOR MITTAL   v. AK STEEL CORP


together with the French ’906 patent supported a jury
finding of a prima facie case of obviousness.2
    The aluminum-based coating described in the ’805
patent is applied to the steel sheet prior to hot-stamping
in order to prevent oxidation. Regarding that pre-coating
requirement, AK Steel argues that Bano in discussing
coating distinguishes between “heat treated finished
parts” and “boron steel,” and that the reference to coating
the latter inherently discloses coating before hot-
stamping. Appellee’s Br. 44–45. Further, AK Steel
argues that the reference to coating after degreasing
makes clear that the coating is applied before hot-
stamping. ArcelorMittal counters that the “degreasing”
language could refer to the removal of oil applied after
hot-stamping and that the article’s discussion of decar-
burization problems is inconsistent with pre-coating.3
What a prior art reference discloses is a factual question.
Tegal Corp. v. Tokyo Electron Am., Inc., 257 F.3d 1331,
1345–46 (Fed. Cir. 2001). We think the resolution of this
factual dispute was up to the jury, and that the jury could


     2  Because the correct claim construction broadens
the scope of the claims, it does not undermine the prima
facie case of obviousness found by the jury.
    3   The Bano reference contains graphs that show de-
carburization which would not occur if the steel was
coated in accordance with claim 1 of the ’805 patent.
However, there is no evidence that other coatings not
covered in claim 1 would have prevented decarburization.
Moreover, Bano only states that “[i]t is possible to coat
this new heat treated boron steel.” Bano at 676. This
language suggests that coating is only an optional step,
and there is no reason to assume that the steel would
have necessarily been coated for the purposes of measur-
ing decarburization during thermal treatment. Thus, the
graph is of limited use in evaluating whether or not Bano
disclosed pre-coating.
ARCELOR MITTAL   v. AK STEEL CORP                        16


properly conclude that Bano teaches applying the coating
before thermal treatment.
    As for coating with aluminum, the French ’906 patent
disclosed coating steel with aluminum during hot forging4
to protect against the same oxidation and decarburization
problems that the ’805 patent was intended to address.
AK Steel thus urges that the invention described in the
’805 patent is no more than the application of known
solutions to equivalent problems in an analogous context.
The thrust of ArcelorMittal’s objection to this reasoning is
that the hot forging described in the French ’906 patent is
so different from hot-stamping that there would be no
motivation to combine. ArcelorMittal points to several
differences between the hot forging process described in
the French ’906 patent and hot-stamping and cites evi-
dence that those skilled in the art did not think that an
aluminum coating would survive hot-stamping. Arcelor-
Mittal’s implication appears to be that hot-stamping and
hot forging are not analogous art. For its part, AK Steel
points to the similarity of the problems confronted by the
two patents and evidence that aluminum coatings were
known to survive thermal treatment and quenching.
Whether a particular technology is analogous art is a
question of fact. Wyers v. Master Lock Co., 616 F.3d 1231,
1237–38 (Fed. Cir. 2010). As with the evidence about
whether a skilled artisan would read Bano to disclose pre-
coating, we think this factual dispute was for the jury to
resolve. We also conclude that substantial evidence
supports the jury’s determination that there was a suffi-
cient motivation to combine. AK Steel provided signifi-
cant expert testimony that a person of ordinary skill in
the art would have had the knowledge to combine the

   4    Hot forging does not involve the rapid heating and
cooling of hot-stamping and does not change the steel’s
microstructure.
17                         ARCELOR MITTAL   v. AK STEEL CORP


aluminum coating disclosed by the French 906 patent
with the pre-coating that the jury found Bano disclosed
and would have expected to succeed. In short, the jury
properly concluded that AK Steel had established a prima
facie case of obviousness.5 The district court properly
denied ArcelorMittal’s JMOL motion of non-obviousness.
              B. Secondary Considerations
    The final issue is whether the district court’s errone-
ous claim construction of “hot-rolled steel sheet” requires
a new trial on obviousness. ArcelorMittal argues that a
new trial is necessary because under the district court’s
claim construction the jury could not consider the com-
mercial success6 of their cold-rolled commercial product.
Although ArcelorMittal’s commercial success evidence
was before the jury, the district court instructed the jury
only to consider “[c]ommercial success or lack of commer-
cial success of products covered by the asserted claims.”
Final Jury Instructions, ArcelorMittal Fr. v. AK Steel
Corp., No. 10-CV-00050, at 37 (D. Del. Jan. 14, 2011)
(emphasis added). The jury was also instructed that only
steel sheet hot-rolled to its final thickness was covered by
the asserted claims. Id. at 20. Thus, the jury was pro-
scribed from considering the commercial success of Arce-
lorMittal’s cold-rolled steel sheet.
    A district court’s incorrect claim construction may re-
quire a new trial, Ecolab Inc. v. Paraclipse, Inc., 285 F.3d
1362, 1374–76 (Fed. Cir. 2002), but only where the party
     5   We conclude that AcelorMittal’s assertion that
claim 7 would not have been obvious even if claim 1 would
have been obvious was waived. Claim 7 must stand or
fall with claim 1.
     6   ArcelorMittal makes passing reference to other
secondary considerations such as copying and unexpected
results, but ArcelorMittal has not briefed those issues
sufficiently to preserve them.
ARCELOR MITTAL   v. AK STEEL CORP                         18


seeking a new trial shows that they were prejudiced by
the error. Verizon Servs. Corp. v. Vonage Holdings Corp.,
503 F.3d 1295, 1307 (Fed. Cir. 2007).
    AK Steel argues that it is not necessary to consider
the commercial success of the cold-rolled product because
of the well-established principle that claims which read
on obvious subject matter are unpatentable even if they
also read on nonobvious subject matter. Muniauction,
Inc. v. Thomson Corp., 532 F.3d 1318, 1328 n.4 (Fed. Cir.
2008) (noting the “long-established rule that ‘[c]laims
which are broad enough to read on obvious subject matter
are unpatentable even though they also read on nonobvi-
ous subject matter.’” (quoting In re Lintner, 458 F.2d
1013, 1015 (C.C.P.A. 1972))). AK Steel urges that even if
the claims included both hot-rolled steel (which was not
cold-rolled) and cold-rolled steel, the jury’s verdict that
the hot-rolled steel embodiment was obvious rendered the
whole claim obvious whether or not the cold-rolled em-
bodiment is nonobvious in view of its commercial success.
However, this is not a situation in which the claims
themselves describe distinct alternative embodiments of
the invention, and where the obviousness of one embodi-
ment would invalidate the entire claim. Rather, it is a
situation in which the claim is limited to steel that is hot-
rolled, but contains “comprising” language permitting the
performance of an additional (cold-rolling) step. In such
circumstances our cases make clear that the commercial
success of the embodiment with additional unclaimed
features is to be considered when evaluating the obvious-
ness of the claim, provided that embodiment’s success has
a sufficient nexus to the claimed and novel features of the
invention. In re Kao, 639 F.3d 1057, 1068 (Fed. Cir.
2011); In re Glatt Air Techniques, Inc., 630 F.3d 1026,
1030 (Fed. Cir. 2011); Applied Materials, Inc. v. Advanced
Semiconductor Materials Am., Inc., 98 F.3d 1563, 1570
19                         ARCELOR MITTAL   v. AK STEEL CORP


(Fed. Cir. 1996) (“[A] patentee need not show that all
possible embodiments within the claims were successfully
commercialized in order to rely on the success in the
marketplace of the embodiment that was commercial-
ized.”)
    Thus, in Kao, we required consideration of a patent
applicant’s commercially successful controlled release
painkiller even though the success was not proven across
the full range of claimed dissolution rates. 639 F.3d at
1069. However, we emphasized that the required consid-
eration of commercial success includes a threshold deter-
mination of whether the commercial success has the
necessary nexus with the claimed invention. Id. at 1068–
69; see also Wyers, 616 F.3d at 1246. The same rules
apply here. The commercial success of ArcelorMittal’s
cold-rolled embodiment must be considered to the extent
that its success results from the claimed combination of
elements that constitutes the invention, rather than from
cold-rolling, which was not claimed and already known in
the prior art, or from other unclaimed features. In other
words, whether there is a nexus here depends upon a
comparison between cold-rolled steel produced by the
patented process and cold-rolled steel produced by alter-
native processes to see if the former achieved material
commercial success over and above the latter. Absent a
demonstrated nexus, ArcelorMittal’s commercial success
evidence is not significant. See Ormco Corp. v. Align
Tech., Inc., 463 F.3d 1299, 1312 (Fed. Cir. 2006) (“[I]f the
feature that creates the commercial success was known in
the prior art, the success is not pertinent.”).
    The remaining issue is whether a new trial on obvi-
ousness is required to address the issue of commercial
success. We think this is not a case in which the prima
facie case so strong that, as a matter of law, it would
overcome ArcelorMittal’s commercial success evidence.
ARCELOR MITTAL   v. AK STEEL CORP                        20


See, e.g., Wyers, 616 F.3d at 1245. Therefore, we conclude
that the district court’s claim construction prejudiced
ArcelorMittal with respect to obviousness. Accordingly,
we vacate the jury’s obviousness verdict and remand for a
new trial addressing only the commercial success aspect
of obviousness and infringement under the correct claim
construction.
                       IV Conclusion
     On remand, the district court must address whether,
under the correct claim construction, the asserted claims
of the ’805 patent are obvious in light of any evidence of
commercial success of hot-rolled steel that is also cold-
rolled and that has the required nexus with ArcelorMit-
tal’s claims. Additionally, as discussed above, the district
court must address the issue of literal infringement under
the correct claim construction. In remanding for a limited
new trial addressing only infringement under the correct
claim construction and whether ArcelorMittal has perti-
nent commercial success evidence sufficient to overcome
the prima facie case of obviousness, we do not foreclose
the district court from entertaining a motion for summary
judgment on these issues that might obviate the need for
a further trial.
    AFFIRMED-IN-PART, REVERSED-IN-PART,
        VACATED-IN-PART, REMANDED
                           COSTS
   Costs to neither party.
  United States Court of Appeals
      for the Federal Circuit
              __________________________

       ARCELORMITTAL FRANCE AND
 ARCELORMITTAL ATLANTIQUE ET LORRAINE,
            Plaintiffs-Appellants,
                           v.
             AK STEEL CORPORATION,
                 Defendant-Appellee,
                          AND

         SEVERSTAL DEARBORN, INC. AND
            WHEELING-NISSHIN INC.,
               Defendants-Appellees.
              __________________________

                      2011-1638
              __________________________

    Appeal from the United States District Court for the
District of Delaware in case no. 10-CV-0050, Judge Sue L.
Robinson.
                __________________________

WALLACH, Circuit Judge, dissenting-in-part.
    I do not agree that “very high mechanical resistance”
means a mechanical resistance of 1500 MPa or greater.
Rather, because I conclude that intrinsic evidence sup-
ports a reading of this term to mean a mechanical resis-
tance in excess of 1000 MPa, I respectfully dissent.
ARCELOR MITTAL   v. AK STEEL CORP                           2


    The disputed term “very high mechanical resistance”
is not defined expressly in the specification. “Mechanical
resistance” and “resistance,” however, are discussed in
multiple passages.      Their references throughout the
specification are instructive, and they necessarily conflict
with the majority’s construction for the following reasons.
     The majority’s focus on “very high,” “high,” and “sub-
stantial” is unwarranted because these terms, and other
similar laudatory terms, are used interchangeably in the
’805 patent. See Bid for Position, LLC v. AOL, LLC, 601
F.3d 1311, 1317-18 (Fed. Cir. 2010) (holding “bid” and
“value of the bid” to have the same meaning because the
claim language and specification used the terms inter-
changeably). For example, the patent is entitled, “Coated
Hot- and Cold-Rolled Steel Sheet Comprising a Very High
Resistance After Thermal Treatment.” ’805 patent col. 1
ll. 1-4 (emphasis added). The “subject of the invention” is
then described as a steel composition that ensures a “very
high mechanical resistance after thermal treatment” and
a “high resistance to corrosion.” Id. col. 1 ll. 47, 61-63
(emphases added). Also, the “purpose of the invention” is
purported as producing a coated steel sheet with a me-
chanical resistance in excess of 1000 MPa after thermal
treatment, which is described as “substantial resistance to
shocks, fatigue, abrasion and wear” and a “good resis-
tance to corrosion.” Id. col. 1 ll. 37-43 (emphases added).
In another instance, the patent states that the “descrip-
tion which follows will make the invention clearly under-
stood . . . .” and recites a steel sheet that exhibits “a high
mechanical resistance after thermal treatment and a high
resistance to corrosion . . . .” Id. col. 2 ll. 34-35, 43-44
(emphasis added).
    Other passages in the specification further exemplify
the interchangeability of these terms. For instance, the
patent reads in one paragraph that “[t]he thermal treat-
3                             ARCELOR MITTAL   v. AK STEEL CORP


ment applied . . . makes it possible to obtain high me-
chanical characteristics which may exceed 1500 MPa” and
in the very next paragraph, describes a “substantial
resistance to abrasion, wear, fatigue, shock, as well as a
good resistance to corrosion . . . .” Id. col. 2 ll. 49-52, 59-60
(emphases added). Likewise, the claimed steel sheet is
disclosed as having a “substantial resistance to corrosion
in the delivery state, during shaping and thermal treat-
ments as well as during usage of the finished casting,”
and after thermal treatment, is described as having “a
substantial mechanical resistance, which may exceed
1500 MPa . . . .” Id. col. 3 ll. 49-53 (emphases added).
Finally, the specification explains that modulation of
certain elements in the composition of the steel including
“carbon makes it possible to achieve high mechanical
characteristics . . . .” Id. col. 4 ll. 20-21 (emphasis added).
     The patentee’s use of “very high,” “high,” and “sub-
stantial” shows that these terms are used interchangea-
bly. It does not appear the patentee made technical
distinctions as to varying resistance levels with the use of
these terms. On the contrary, the patentee used these
terms interchangeably and in a laudatory fashion without
any limiting purposes. See Minton v. Nat’l Ass’n of Sec.
Dealers, Inc., 336 F.3d 1373, 1381 (Fed. Cir. 2003) (declin-
ing to construe “traded efficiently,” in part, because
“efficiently” on its face does not inform the mechanics of
how the trade is executed and concluding that it is a
laudatory term characterizing the result of the executing
step); see also Allen Eng’g Corp. v. Bartell Indus., Inc., 299
F.3d 1336, 1346-47 (Fed. Cir. 2002) (declining to hold that
the “fast steering” language in the preamble was limiting
because it was laudatory, merely setting forth the in-
tended purpose of the claimed combination). As such, the
interchangeable use of these laudatory terms does not
shed light on the disputed claim’s proper scope.
ARCELOR MITTAL   v. AK STEEL CORP                           4


    I would instead focus on the touted increase in me-
chanical resistance the ’805 patent purports to achieve
over prior art—namely, the obtention of mechanical
resistance “in excess of 1000 MPa.” Id. col. 1 ll. 41-42. In
particular, “very high,” “high,” and “substantial” were
used to promote the invention’s improved levels of resis-
tance without the “detriment of shaping properties”—a
problem in the prior art. Id. col. 1 ll. 10-11. The majority’s
construction of requiring a mechanical resistance of “at
least 1500 MPa” unduly contracts the wide breadth of the
invention the patentee discloses. Without clear language
providing otherwise, 1500 MPa cannot be set as the floor
of a range of mechanical resistance levels recited in the
patent, principally because “excess of 1000 MPa” is stated
as within the range of resistance levels that satisfy the
purpose of the invention. See Apple Comp., Inc. v. Articu-
late Sys., Inc., 234 F.3d 14, 25 (Fed. Cir. 2000) (“[T]he
claim must be interpreted in light of the teachings of the
written description and purpose of the invention described
therein.”). Additionally, other values of resistance levels,
including 1500 MPa, are recited in permissive form, and
therefore, are less than instructive in determining the
scope of “very high mechanical resistance.” ’805 patent
col. 2 ll. 51-53 (“may exceed 1500 MPa for mechanical
resistance . . . .”) (emphasis added); id. col. 4 ll. 52-61
(Table 2 illustrating ranges with examples of “maximal
resistance of the steel sheet according to the invention
after thermal treatment,” ranging from 1665 to 1695
MPa).
     The majority nevertheless takes a different approach.
It implies that the use of the terms, “high” or “substan-
tial,” correspond only to a mechanical resistance that
“may exceed 1500 MPa.” Based on this reading, the
majority determines that “if 1500 MPa is high mechanical
5                          ARCELOR MITTAL   v. AK STEEL CORP


resistance, then very high resistance must be at least
1500 MPa.” Majority Op. 10.
     As discussed above, however, the specification shows
that “high,” “substantial,” and other similar terms are
used to describe varying levels of mechanical resistance.
Specifically, in addition to references to “may exceed 1500
MPa” as “high” or “substantial” resistance, the patent
recites “excess of 1000 MPa” as “substantial” resistance.
Compare ’805 patent col. 3 ll. 52-53 (“[A] substantial
mechanical resistance, which may exceed 1500 MPa . . .
.”) (emphasis added), with id. col. 1 ll. 40-43 (“[M]akes it
possible to obtain a mechanical resistance in excess of
1000 MPa, a substantial resistance to shocks, fatigue,
abrasion and wear . . . .”) (emphasis added). The specifi-
cation thus describes both 1500 MPa and 1000 MPa as
“substantial.”
    “High” or “substantial” interchangeably describe in
similar context the mechanical resistance level of 1500
MPa, giving “high” and “substantial” similar meaning.
Hence, “high” or “substantial” likewise may describe
interchangeably the mechanical resistance level of “excess
of 1000 MPa.” Applying the majority’s logic, if 1000 MPa
characterizes both “substantial” and “high” mechanical
resistance, then “very high” resistance must be in excess
of 1000 MPa. Accordingly, “very high mechanical resis-
tance” should be construed as a mechanical resistance in
excess of 1000 MPa. I find the specification sufficiently
instructive, and therefore, no need to turn to extrinsic
evidence.
