Xie, Yuxuan et al.

Patent Trials and Appeals Board

Mar 31, 2020

13030170 - (D) (P.T.A.B. Mar. 31, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/030,170 02/18/2011 Yuxuan Xie 213532.00232 2131
21324 7590 03/31/2020
HAHN LOESER & PARKS, LLP
200 Public Square, Suite 2800
Cleveland, OH 44114
EXAMINER
WALCK, BRIAN D
ART UNIT PAPER NUMBER
1736
NOTIFICATION DATE DELIVERY MODE
03/31/2020 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
patents@hahnlaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte YUXUAN XIE,
CHEN ZHU, JULIE M. CAIRNEY,
SIMON P. RINGER, CHRISTOPHER R. KILLMORE,
FRANK BARBARO, and JAMES WILLIAMS
__________

Appeal 2019-004035
Application 13/030,170
Technology Center 1700
____________

Before MICHAEL P. COLAIANNI, GEORGE C. BEST, and
DEBRA L. DENNETT, Administrative Patent Judges.

COLAIANNI, Administrative Patent Judge.

DECISION ON APPEAL

Appellant appeals under 35 U.S.C. § 134(a) the final rejection of
claims 15–19 and 21–30.1 Claims 1–14, the other claims pending in this
application, stand withdrawn from consideration by the Examiner. Claim 20
is canceled. We have jurisdiction over the appeal. 35 U.S.C. § 6(b).
We AFFIRM.

1 We use the word “Appellant” to refer to “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies Nucor Corp. as the real party in interest
(Appeal Br. 3).
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STATEMENT OF THE CASE
Appellant’s invention is directed to a method for making a high
strength thin cast strip by a twin roll caster (Spec. ¶ 1; Fig. 2). The
Specification describes that twin roll casting has enabled the development of
a Nb-microalloyed steel thin cast strip (id. at ¶ 7). According to the
Specification, the Nb-microalloyed steel’s properties can be improved by
nitriding (id.).
Claim 15 is illustrative (emphasis added):
15. A method of preparing nitrided thin cast steel strip
comprising the steps of:
assembling internally a cooled roll caster having laterally
positioned casting rolls forming a nip between them, and
forming a casting pool of molten steel supported on the casting
rolls above the nip and confined adjacent the ends of the casting
rolls by side dams,
counter rotating the casting rolls to solidify metal shells
on the casting rolls as the casting rolls move through the casting
pool, and
forming from the metal shells downwardly through the
nip between the casting rolls a steel strip, and
cooling the steel strip at a rate of at least 10 °C per
second, coiling the cast strip and nitriding the steel strip to
provide a composition comprising by weight, less than 0.25%
carbon, between 0.20 and 2.0% manganese, between 0.05 and
0.50% silicon, less than 0.01 % aluminum, between 0.01 % and
0.20% niobium, and between 0.01 and 0.075% nitrogen, and
having a majority of the microstructure comprised of bainite
and acicular ferrite, having more than 70% niobium in solid
solution prior to nitriding, and having yield strength between
about 600 MPa and 723.4 MPa, tensile strength between about
650 MPa and 802.4 MPa, and having a total elongation of
between about 10% and 16.5%.
Appeal Br. 31 (Claims App.).
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The Examiner maintains the following rejection:
1. Claims 15–19 and 21–30 are rejected under 35 U.S.C. § 103(a)
as unpatentable over Williams et al. (US 2008/0219879 A1; published
Sept. 11, 2008, “Williams”), in view of C.H. Knerr et al., Gas
Nitriding, ASM Handbook: Vol. 4, Heat Treating, ASM International
(1991) 387–409 (“Knerr”) (Final Act. 3–7).
Appellant offers separate arguments in support of independent claim
15 and dependent claims 16–19 (Appeal Br. 8–24). Appellant argues claims
21 and 22 as a group; claims 23–26 as a group; and claims 27–30 as a group
(id. at 24–26). Each of these claims and claims groups will be discussed
separately.
FINDINGS OF FACT & ANALYSIS
After review of the respective positions provided by Appellant and the
Examiner, we affirm the Examiner’s prior art rejection under 35 U.S.C.
§ 103(a) for the reasons presented by the Examiner and add the following for
emphasis.
A. Rejection of claims 15–19 and 21–30 as unpatentable over the
combination of Williams and Knerr.
1. Claim 15
With respect to claim 15, the Examiner’s findings and conclusions
regarding Williams and Knerr are located on pages 3–5 of the Final Office
Action.
The Examiner finds that Williams’ method of preparing a thin cast
steel strip would have rendered obvious each step of the method recited in
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independent claim 15, except that Williams does not disclose two recited
features (Final Act. 3–5).
Regarding Williams’ first missing feature, the Examiner finds that
Williams’ method does not disclose nitriding the steel strip to produce a
composition with between 0.01 and 0.075% nitrogen (id. at 4).
The Examiner finds that Knerr discloses “[p]rincipal reasons for
nitriding” steel, including a list of several properties that are conferred to
steel that has been nitrided (id. (citing Knerr 387)).
The Examiner determined that it would have been obvious for one of
ordinary skill in the art at the time of the invention to nitride Williams’ steel
strip as suggested by Knerr (Final Act. 4). According to the Examiner, one
of ordinary skill in the art would have been motivated to implement Knerr’s
nitriding step in preparing Williams’ steel strip “to obtain high surface
hardness, increase wear resistance and antigalling properties, improve
fatigue life [and] corrosion resistance, and to obtain a surface that is resistant
to the softening effect of heat at . . . the nitriding temperature” (id. (citing
Knerr 387)).
With respect to Williams’ second missing feature, the Examiner finds
that Williams does not explicitly disclose each of the claimed ranges for the
steel strips’ properties (id. at 5). The Examiner, however, finds that
Williams’ thin cast steel strip has a
yield strength of at least 650 MPa (overlapping the instantly
claimed range of between about 600 MPa and 723.4 MPa) and
tensile strength of at least 700 MPa (overlapping the instantly
claimed range of between about 650 MPa and 802.4 MPa) and
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having a total elongation of at least 10% (overlapping the
instantly claimed range of at least 10%).
Id. at 4. The Examiner determines that it would have been obvious to one of
ordinary skill in the art at the time the invention was made to select any
portion of the disclosed ranges, including the ranges recited in claim 15, as
“Williams discloses the same utility throughout the disclosed ranges” (id. at
5).
Appellant argues that one of ordinary skill in the art would not have
combined Knerr’s nitriding step with Williams’ method of preparing a thin
cast steel strip less than 3 mm in thickness (Appeal Br. 10). Specifically,
Appellant argues that Knerr does not teach or suggest nitriding steel less
than 6 mm in thickness (id.).
We are not persuaded by this argument because it is directed to
limitations not recited in independent claim 15, which is silent regarding any
required thickness. We, furthermore, agree with the Examiner that there is
no teaching that nitriding is limited to case hardening a surface of a thicker
steel (Ans. 6). Rather, Kerr explicitly states that “at suitable temperature[,]
all steels are capable of forming iron nitrides in the presence of nascent
nitrogen” (Knerr 387) (emphasis added).
Appellant argues that Knerr recognizes the trade-off between
increased hardness and increased brittleness and that “[t]hese potential
drawbacks are only amplified in a thin steel strip of less than 3 mm as taught
by Williams” (Appeal Br. 10). In particular, Appellant argues that Knerr
teaches away from nitriding Williams’ coiled strip because Knerr’s nitrided
steel requires additional stabilizing treatment or stress relieving steps, which
require grinding and machining the strip (id. at 15–17). Appellant argues
that Knerr recognizes nitriding’s effects on aluminum-containing steels, such
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as the tradeoff of low ductility (id. at 18; see also id. at 19 (arguing that the
Examiner ignores “the drawbacks of Knerr’s[,] e.g.[,] nitriding
ductility/hardness tradeoffs; distortion and dimensional changes;
stabilizing/stress relieving; etc.”)).
Appellant’s arguments are not persuasive because Knerr explicitly
discloses that “[f]or many parts, this lengthy [stress relieving] procedure
may not be required” (Knerr 394). With respect to stabilizing treatments and
low ductility as evidence that Knerr teaches away, we agree that a person of
ordinary skill in the art would have understood and weighed this tradeoff in
benefits. Winner Int’l Royalty Corp. v. Wang, 202 F.3d 1340, 1349 n.8
(Fed. Cir. 2000) (“The fact that the motivating benefit comes at the expense
of another benefit, . . . should not nullify its use as a basis to modify the
disclosure of one reference with the teachings of another. Instead, the
benefits, both lost and gained, should be weighed against one another.”).
Therefore, we do not find that Kerr’s disclosure teaches away; it does not
indicate that “the line of development flowing from the reference’s
disclosure is unlikely to be productive of the result sought by the applicant.”
In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994). As set forth above, the
Examiner finds that Knerr discloses several beneficial properties that are
conferred to steel post-nitriding (Final Act. 4).
Appellant argues that the combination of Williams and Knerr would
not have rendered the instantly claimed nitrogen content obvious (Appeal
Br. 10, 20; see also Reply Br. 11–14). In particular, Appellant argues that
because “Knerr does not recite how much nitrogen should be added to a steel
such as disclosed in Williams,” there is no recognition that nitrogen content
is recognized as a result-effective variable (Appeal Br. 20).
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As the Examiner finds, however, because
Knerr recognizes that the case depth (and thus nitrogen content
. . .) of the steel may be controlled by conditions of nitriding[,]
such as duration of nitriding time[,] and that the case depth
affects the resultant hardness profile of the steel[,] . . . [i]t
would require little more than routine experimentation by one
of ordinary skill in the art to determine the optimal or workable
ranges of case depth (and thus nitrogen content) to achieve a
desired hardness profile for a given application of [Williams’]
steel . . . in view of Knerr.
Final Act. 5 (citing Knerr 390–91; Fig. 5). Appellant, moreover, does not
allege any criticality with respect to the claimed nitrogen content between
0.01 and 0.075% (see Ans. 7).
Therefore, the preponderance of the evidence favors the Examiner’s
finding and conclusion that, in the absence of unexpected results, it would
have required routine experimentation to determine the optimum value of a
result effective variable, such as the claimed nitrogen content between 0.01
and 0.075%.
Appellant argues that Williams’ steel, modified in view of Knerr,
would not have possessed the instantly claimed properties because nitriding
the steel of Williams would have changed the properties of Williams’ steel
(Appeal Br. 11). Appellant argues that there is no teaching in either Knerr
or Williams to select and then nitride Williams’ specific steel composition
(id. at 20).
We are not persuaded by these arguments as Appellant has not
presented evidence other than attorney argument. As set forth above, the
Examiner has provided a well-reasoned analysis of how and why the
ordinarily skilled artisan would have reasonably expected that Williams’
modified thin cast steel strip made by a similar process would possess the
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yield and tensile strength and total elongation properties recited in the claim.
On this record, Appellant has not met the burden of showing that the
Examiner’s proposed thin cast steel strip does not possess the claimed
strengths and elongation properties. In re Best, 562 F.2d 1252, 1255 (CCPA
1977) (explaining that “[w]here . . . the claimed and prior art products are
identical or substantially identical, or are produced by identical or
substantially identical processes, the PTO can require an applicant to prove
that the prior art products do not necessarily or inherently possess the
characteristics of his claimed product.”). We, furthermore, agree with the
Examiner that one of ordinary skill in the art at the time of the invention
would have gleaned from Knerr that appropriate nitriding conditions may be
selected to maintain desirable strengths and elongation properties in
Williams’ steel (see Ans. 7, 9–10).2
Accordingly, Appellant’s arguments do not persuasively address the
Examiner’s reasoning, which supports the findings and conclusions in the
stated rejection. Therefore, Appellant’s arguments are insufficient to
convince us of reversible error in the Examiner’s rejection.

2 Appellant cites the Board’s decision in Appeal No. 2017-006822, pages 5–
6, to support the argument that the Examiner has not established a prima
facie case of obviousness as Williams’ compositional ranges for nitrogen do
not overlap the claimed range (Appeal Br. 13). However, Appellant’s
reliance on Appeal No. 2017-006822 is unavailing as the sole reference
relied upon by the Examiner in that case did not teach or suggest each and
every limitation in the appealed claim. As set forth above and in the
Answer, the Examiner relies on Knerr’s disclosure for teaching or
suggesting the instantly claimed nitrogen content between 0.01 and 0.075%
in Williams’ modified thin steel strip (see, e.g., Final Act. 4–5).
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Thus, based on a preponderance of evidence in this record, we sustain
this rejection as to claim 15.
2. Claim 16–19
With regard to claims 16–19, the Examiner’s findings and conclusions
regarding Williams and Knerr are located on page 6 of the Final Office
Action. Representative claim 16 is set forth below:
16. The method of preparing nitrided thin cast steel strip as
claimed in claim 15 where the steel strip as coiled has fine
oxide particles of silicon and iron distributed through the steel
microstructure having an average particle size less than 50
nanometers.
Appeal Br. 32 (Claims App.).
The Examiner finds that “Williams discloses the steel strip as coiled
may have fine oxide particles of silicon and iron distributed through the steel
microstructure having an average particle size less than 50 nanometers”
(Final Act. 6 (citing Williams claim 116)).
Appellant argues that “Knerr requires stabilizing
treatment . . . and . . . stress relieving” of the steel prior to the nitriding step,
but “[t]his simply cannot occur in the coiled steel of Williams” (Appeal Br.
22 (citing Knerr 394)).
For the reasons set forth above and in the Answer, Appellant has not
identified reversible error in the Examiner’s findings that Knerr’s stabilizing
treatment and stress relieving steps are not mandatory (see Ans. 10). Rather,
these steps are tradeoffs to be weighed by one of ordinary skill in the art in
light of the benefits conferred by nitriding (see Winner Int’l Royalty Corp.,
202 F.3d at 1349 n.8).
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Claims 17–19 depend on claim 16. Although Appellant offers
separate arguments in support of dependent claims 17–19 (Appeal Br. 21–
24), we find that each of these arguments are substantially similar to
Appellant’s unpersuasive arguments in support of claim 16. Thus, based on
a preponderance of evidence in this record, we sustain this rejection as to
claims 16–19.
3. Claims 21 and 22
With regard to claims 21 and 22, the Examiner’s findings and
conclusions regarding Williams and Knerr are located on page 6 of the Final
Office Action. Claims 21 and 22 are set forth below:
21. The method of preparing [a] nitrided thin cast steel strip
as claimed in claim 15 where the total elongation is between
12.5 ± 0.5% and 14.2 ± 2.3%.
22. The method of preparing a nitrided thin cast steel strip as
claimed in claim 16 where the total elongation is between 12.5
± 0.5% and 14.2 ± 2.3%.
Appeal Br. 33 (Claims App.).
The Examiner finds that “Williams discloses the strip has a total
elongation of at least 6% or 10% . . . overlapping the instantly claimed
ranges” (Final Act. 6 (citing Williams Abstract)).
Appellant argues that Knerr teaches away from nitriding aluminum-
containing steel when good ductility or elongation is required (Appeal Br.
24). Appellant argues that the Examiner has not met the “burden of
establishing [that] a nitrided version of the steel strip of Williams possesses
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the presently claimed elongation properties” recited in claims 21 and 22
(id.).
For the reasons set forth above and in the Answer, Appellant has not
identified reversible error in the Examiner’s findings that low ductility or
poor elongation are tradeoffs to be weighed by one of ordinary skill in the
art in light of the benefits conferred by nitriding (see Winner Int’l Royalty
Corp., 202 F.3d at 1349 n.8; see Ans. 11). We, furthermore, agree with the
Examiner that one of ordinary skill in the art at the time of the invention
would have gleaned from Knerr that appropriate nitriding conditions may be
selected to maintain desirable strengths and elongation properties in
Williams’ steel (see Ans. 7, 9–10; see also Best, 562 F.2d at 1255).
Thus, based on a preponderance of evidence in this record, we sustain
this rejection as to claims 21 and 22.
4. Claims 23–26
With regard to claims 23–26, the Examiner’s findings and conclusions
regarding Williams and Knerr are located on page 6 of the Final Office
Action. Representative claim 23 is set forth below:
23. The method of preparing a nitrided thin cast steel strip as
claimed in claim 15 where the steel product is a thin cast steel
strip of less than 3 millimeters in thickness.
Appeal Br. 33 (Claims App.).
Appellant argues that Knerr’s Figure 9 illustrates that undesirable
growth of the wall section of a hollow cylinder increases at an exponential
rate below 5 mm (Reply Br. 9 (citing Knerr 395; Fig. 9)). According to
Appellant, one of ordinary skill in the art would not have looked to Knerr’s
wall section of a hollow cylinder and found any motivation to nitride
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Williams’ thin cast steel strip of 3 mm or less (Reply Br. 10; see also Appeal
Br. 25–26).
Appellant’s arguments are not persuasive because the exponential
growth that Appellant refers to ranges from about 100 µm to about 240 µm
(Knerr Fig. 9). This change in diameter amounts to an approximate
additional 0.1–0.24 mm in thickness. We are not persuaded that such a
relatively minor increase to Williams’ 3 mm strip teaches away from the
Examiner’s proposed combination (see Gurley, 27 F.3d at 553). As the
Examiner finds, “Williams discloses the strip may have a thickness of 1.1
mm . . . lying within the instantly claimed ranges” (Final Act. 6 (citing
Williams Table 1)).
Thus, based on a preponderance of evidence in this record, we sustain
this rejection as to claims 23–26.
5. Claims 27–30
With regard to claims 27–30, the Examiner’s findings and conclusions
regarding Williams and Knerr are located on pages 6–7 of the Final Office
Action. Representative claim 30 is set forth below:
30. The method of preparing a nitrided thin cast steel strip as
claimed in claim 15 where the steel product is nitrided for 1
hour.
Appeal Br. 34 (Claims App.).
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The Examiner supports the rejection of these claims by finding that
“Knerr recognizes that nitriding is a result effective variable which
influences the case depth of the steel” (Final Act. 6).
Appellant argues that “Knerr does not teach nitriding for any time less
than 8 hours” and, thus, the Examiner’s “basis for optimization . . . is
misapplied” (Appeal Br. 26 (citing Knerr Table 2)).
Appellant’s arguments are not persuasive. For the reasons set forth
above and in the Answer, the Examiner reasonably concluded that “[i]t
would require little more than routine experimentation by one of ordinary
skill in the art to determine the optimal or workable ranges of nitriding time
to achieve a desired case depth for [Williams’] steel . . . in view of Knerr.”
(Final Act. 6–7 (citing Knerr 390 (explicitly disclosing that “[c]ase depth
and case hardness . . . vary . . . with the duration . . . of nitriding.”); Figs. 5,
7, 17, 31)).
Thus, based on a preponderance of evidence in this record, we sustain
this rejection as to claims 27–30.
CONCLUSION
In summary:
Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
15–19, 21–
30
103(a) Williams, Knerr 15–19, 21–30
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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).
AFFIRMED