DETAILED ACTION
Response to Amendment
The Amendment filed 10/20/2025 has been entered. Claims 1, 3-6, and 10-14 remain pending in the application. Claims 2, 7-9, and 15-23 have been canceled. Claims 1, 3-5, and 11-14 are currently amended. No new claims have been added. Applicant's amendments to the drawings have overcome the objections previously set forth in the Non-Final Rejection mailed 07/18/2025. Applicant's amendments to the abstract and specification have overcome the objections previously set forth in the Non-Final Rejection mailed 07/18/2025. Applicant's amendments to the claims have overcome the 112(b) rejections previously set forth in the Non-Final Rejection mailed 07/18/2025.
Information Disclosure Statement
One (1) information disclosure statement (IDS) was submitted on 08/05/2025. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the IDS is being considered by the examiner.
Examiner’s Note
The Examiner notes that the limitation “a maximum grain size of grains observed is 343 μm or more” of claim 1 is inconsistent with the instant disclosure. The instant specification recites “the maximum grain size of grains observed is preferably 500 μm or more, and the maximum grain size is more preferably 1000 μm or more” ([0057]), both values of which are higher than the claimed 343 μm. Table 3 of the instant specification recites Test No. 3 as an inventive example with a maximum grain size of 343 μm, which provides support for the claimed 343 μm but is inconsistent with the maximum grain size of grains observed recited in [0057] of the instant specification.
Claim Interpretation
Regarding the steps (a)-(c) for determining a magnetized region of claim 1, the claimed property is the magnetized area fraction and this property will be interpreted as inherent to the steel sheet based on the claimed composition and microstructure since a property will remain the same regardless of how it is measured.
Claim Rejections - 35 USC § 112
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 3-6, and 10-14 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites the limitation "a maximum grain size of grains observed is 343 μm or more" in line 26. This limitation renders the claim indefinite since it is unclear whether the claimed grain size is conditional given the term “observed”, or if the claimed grain size only applies to the grains that are observed, and therefore the limitation would be further indefinite since it is unclear which grains must be observed to meet the claimed grain size. A steel sheet will necessarily have a maximum grain size whether it is observed or not. However, as currently written, the claim reads as if the claimed grain size is not required if the grains are not observed.
Claims 3-6 and 10-14 depend on claim 1, do not resolve the aforementioned issues, and are thereby also indefinite.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 3-6, and 10-14 are rejected under 35 U.S.C. 103 as being unpatentable over JP H062044 A of Minamino (as cited in IDS mailed 01/03/2025 with reference to its English machine translation) in view of US 5601664 A of Kosa (as cited in prior Office action and in IDS mailed 05/17/2023).
Regarding claims 1, 3-6, and 10-14, Minamino teaches a ferritic stainless steel (Overview) and provides a steel sheet which is rich in cast piece toughness and excellent in intergranular corrosion resistance ([0003], ferritic stainless steel and steel sheet read on the claimed ferritic stainless steel sheet).
List 1
Instant claims (mass%)
Minamino (weight%)
Minamino Ex. 3 (mass%)
C
≤ 0.015
≤ 0.03
0.008
Si
≤ 3.0
≤ 0.60 (claim 3)
≤ 1.0
0.10
Mn
≤ 1.0
≤ 1.0
0.16
S
≤ 0.0040
≤ 0.03
0.002
P
≤ 0.08
≤ 0.04
0.024
Al
≤ 0.80
0.05-1.0 (“one or ≥ 2 kinds among”)
0.024
N
≤ 0.030
≤ 0.03
0.0084
Cr
15.0-25.0
10.0-35.0
17.05
Mo
0.5-3.0
0.1-5.0 (“one or ≥ 2 kinds among”)
1.11
Ti
0-0.5
6(C+N) to 1.0
0 to 1.0
(implied since C and N include 0)
0.21
Nb
0-0.5
-
-
Ni
0-0.5
0.05-0.50 (claims 4, 10; “one or more elements selected from”)
0.3-5.0 (“containing if necessary”)
0.12
Cu
0- less than 0.1
0.01- less than 0.1 (claims 4, 10; “one or more elements selected from”)
0.2-1.0 (“one or ≥ 2 kinds among”)
0.01
Zr
0-1.0
0.01-1.0 (claims 4, 10; “one or more elements selected from”)
-
-
V
0-1.0
0.01-1.0 (claims 4, 10; “one or more elements selected from”)
0.1-1.0 (“one or ≥ 2 kinds among”)
0.054
REM
0-0.05
0.005-0.05 (claims 4, 10; “one or more elements selected from”)
-
-
B
0-0.01
0.0002-0.01 (claims 4, 10; “one or more elements selected from”)
0.0003-0.003 (“further containing”)
Tr
Fe and impurities
Balance
Balance (“with inevitable impurities”)
Balance (“with inevitable impurities”)
Formula (i)
Ti + Nb
0.10-0.50
0-1.0
0.21
Formula (ii)
PREN = Cr +3.3Mo + 16N
≥ 20.0 (claims 5 and 11-14)
10.3-52.0
20.8
Minamino teaches a ferritic stainless steel with a chemical composition within the claimed ranges (Ex. 3, Table 1) and overlapping with the claimed ranges (claims 1-4, [0004], [0006]-[0012]), as shown in List 1. While Minamino does not explicitly disclose the values for formulas (i) and (ii), one can calculate the values using the composition ranges of Minamino, which results in values within the claimed ranges (Ex. 3, Table 1) and overlapping with the claimed ranges (claims 1-4, [0004], [0006]-[0012]), as shown in List 1. In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). See MPEP § 2144.05 I.
Minamino therefore reads on the limitations wherein a chemical composition consists of, in mass%:C: 0.015% or less, Si: 3.0% or less, Mn: 1 .0% or less, S: 0.0040% or less, P: 0.08% or less, Al: 0.80% or less, N: 0.030% or less, Cr: 15.0 to 25.0%, Mo: 0.5 to 3.0%, Ti: 0 to 0.50%, Nb: 0 to 0.50%, Ni: 0 to 0.50%, Cu: 0% or more to less than 0.1%, Zr: 0 to 1.0%, V: 0 to 1.0%, REM: 0 to 0.05%, and B: 0 to 0.01%, with the balance: Fe and impurities, and satisfies Formula (i) shown below: 0.10 ≤ Ti+Nb ≤ 0.50 of claim 1, wherein the chemical composition contains, in mass%, Si: 0.60% or less of claim 3, wherein the chemical composition contains one or more elements selected from, in mass%: Ni: 0.05 to 0.50%, Cu: 0.01% or more to less than 0.1%,Zr: 0.01 to 1.0%, V: 0.01 to 1.0%, REM: 0.005 to 0.05%, and B: 0.0002 to 0.01% of claims 4 and 10, and wherein a pitting resistance equivalent number PREN that is calculated by Formula (ii) shown below is 20.0 or more of claims 5, 11, 12, 13, and 14.
However, Minamino does not explicitly disclose a maximum grain size of grains observed is 343 μm or more of claim 1, the ferritic stainless steel sheet comprises a magnetized area fraction of 60% or more of claim 1, and in a rolling direction crystal orientation, F1 that is given by Formula (iii) shown below and is a ratio between a total area S<001> of grains having orientations parallel to a <001> direction and a total area S<111> of grains having orientations parallel to a <111> direction is 5.0 or more of claims 5, 11, 12, 13, and 14, and wherein a maximum grain size of grains observed is 500 μm or more of claim 6.
The instant specifications recite the content of Si is preferably reduced to increase the magnetized area fraction described later to 70% or more ([0031]). The instant specifications recite a cold rolling step with rolls having diameters of 100 mm or less are preferably used and a reduction rate is preferably set to 75% or more to obtain a magnetized area fraction and F1 values ([0062]-[0063]). The instant specifications further recite an adjustment annealing with an annealing temperature to within the range of more than 750°C to 1350°C or less and set the annealing time to within the range of 1 to 24 hours to obtain a magnetized area fraction, F1 value and a maximum grain size of 500 μm or more ([0065]-[0068]).
As described above, Minamino teaches a Si content within and overlapping with the claimed range as shown in List 1. Minamino teaches using a cold rolling roll with a diameter of 50 mm ([0017], overlaps with the rolls having a diameter of 100 mm or less of the instant invention). Minamino teaches cold rolling from a 3 mm slab to a 0.5 mm thickness ([0017]), which results in a reduction rate of 83.3% by calculating the difference between the initial and final thickness and dividing by the initial thickness of 3 mm (calculated reduction rate overlaps with the reduction rate of 75% or more of the instant invention). Minamino teaches a finish annealing at 880°C ([0013]) and an example with a final annealing of retention at 950°C for 30 seconds ([0017], finish annealing and final annealing overlap with the cold-rolled sheet annealing of the instant invention).
However, Minamino does not explicitly disclose an adjustment annealing step.
Kosa teaches a ferritic stainless steel (Abstract), with a chemical composition similar to the composition of Minamino and is similarly concerned with a ferritic stainless steel and its magnetic properties. Kosa teaches the hot-worked alloy is heat treated by annealing at a temperature of 800-1100°C for at least about 1-4 hours and preferably at 1000°C to obtain a fine grain size (column 4, lines 35-48, the annealing temperatures and times overlap with those of the instant invention). Kosa teaches a combination of heat treatments may be used to optimize magnetic properties (col. 4, lines 59-61). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to add the annealing step of Kosa to the steel sheet of Minamino to obtain a fine grain size and optimize magnetic properties.
Since modified Minamino teaches a chemical composition, microstructure (both are ferritic stainless steels), and processing conditions overlapping with the claimed invention, one of ordinary skill in the art would reasonably expect the steel of modified Minamino to possess the claimed properties of a magnetized area fraction, F1 value, and maximum grain size. Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP § 2112.01 I. “Products of identical chemical composition can not have mutually exclusive properties.” A chemical composition and its properties are inseparable. Therefore, if the prior art teaches the identical chemical structure, the properties applicant discloses and/or claims are necessarily present. In re Spada, 911 F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). See MPEP § 2112.01 II. Therefore, it is expected that the steel of the prior art possesses the properties as claimed in the instant claims since a) the claimed and prior art products are identical or substantially identical in composition (see compositional analysis above), b) the claimed and prior art products are identical or substantially identical in structure (both are ferritic stainless steel sheets as described above), and c) the claimed and prior art products are produced by identical or substantially identical processes (see processing analysis above). Since the Office does not have a laboratory to test the reference alloy, it is applicant’s burden to show that the reference alloy does not possess the properties as claimed in the instant claims. See In re Best, 195 USPQ 430, 433 (CCPA 1977); In re Marosi, 218 USPQ 289, 292-293 (Fed. Cir. 1983); In re Fitzgerald et al., 205 USPQ 594 (CCPA 1980).
Modified Minamino therefore reads on the limitations a maximum grain size of grains observed is 343 μm or more of claim 1, the ferritic stainless steel sheet comprises a magnetized area fraction of 60% or more of claim 1, and in a rolling direction crystal orientation, F1 that is given by Formula (iii) shown below and is a ratio between a total area S<001> of grains having orientations parallel to a <001> direction and a total area S<111> of grains having orientations parallel to a <111> direction is 5.0 or more of claims 5, 11, 12, 13, and 14, and wherein a maximum grain size of grains observed is 500 μm or more of claim 6.
Response to Arguments
Applicant’s arguments, see pages 11-15, filed 10/20/2025, with respect to the rejections of claims 1, 3-6, and 10-14 under 35 U.S.C. 103 have been fully considered and are persuasive. Since the claimed chemical composition of prior claim 2 was amended from “comprising” to “consists of” in currently amended claim 1, the chemical composition now excludes any element not specified in the claimed, and therefore may not include Sn. See MPEP 2111.03. Therefore, the rejection has been withdrawn. However, upon further consideration, a new grounds of rejection is made over JP H062044 A of Minamino (as cited in IDS mailed 01/03/2025 with reference to its English machine translation) in view of US 5601664 A of Kosa (as cited in prior Office action and in IDS mailed 05/17/2023).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MAYELA ALDAZ whose telephone number is (571)270-0309. The examiner can normally be reached Monday -Thursday: 10 am - 7 pm and alternate Friday: 10 am - 6 pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Keith Hendricks can be reached at (571) 272-1401. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/M.A./Examiner, Art Unit 1733
/REBECCA JANSSEN/Primary Examiner, Art Unit 1733