DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 05/22/2026 has been entered.
Response to Amendment
The Amendment filed 05/22/2026 has been entered. Claim 1 remains pending in the application and is presented for examination on the merits. Claim 2 has been canceled.
Claim Interpretation
Claim 1 recites the limitation “a ferritic stainless steel consisting of”. The transitional phrase "consisting of" excludes any element, step, or ingredient not specified in the claim. In this case, the composition of the claimed steel is interpreted as a closed composition that may only include the claimed C, N, Si, Cr, Ti, Fe, and inevitable impurities.
Regarding the claimed formulas of claim 1, the instant claim is drawn to a ferritic stainless steel and is therefore a product claim. The formulas used in the instant invention are interpreted as a description of the claimed steel’s composition. The claimed formulas do not serve to patentably distinguish the claimed steel from a steel of the prior art with overlapping chemical compositions despite disclosing the compositions in a different manner.
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.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over US 4986857 A of Hewitt.
Regarding claim 1, Hewitt teaches corrosion resistant steels from which martensite microstructures are generally absent (Title). Hewitt teaches typical corrosion resistant steels include 3CR12, 4003, and 409 and further teaches a ferrite factor used to improve properties of the instant invention and ferritic stainless steels (col. 1, lines 43-65; col. 2, lines 50-61; corrosion resistant steels of Hewitt read on claimed ferritic stainless steel; one of ordinary skill in the art further understands 3CR12, 4003 and 409 are ferritic stainless steels).
Instant claim (wt%)
Hewitt (mass%)
C
0.0005 - 0.02
0.25 max
N
0.005 - 0.02
0.1 max
Si
0.7 - 1.0
2.0 max
Cr
16.0 - 17.0
10-18
Ti
0.05 - 0.3
0-1.0
Optional:
Mn, Ni, Mo, V, Zr, Nb, Cu, Al, P
Fe and inevitable impurities
Balance
Balance (“and unavoidable impurities”)
Formula (1)
21-25
10-32
Tensile strength
≥ 470 MPa
Typically 520 MPa
Elongation
≥ 27%
Typically 25%
Formula (2)
More than 20
Undetermined to 26
(undetermined is due to a zero value for C and N being in the denominator)
Pitting potential
≥ 150 mV
-
Hewitt teaches a steel with a chemical composition (col. 2, lines 35-49; claims 2 and 24; one of ordinary skill in the art understands wt% and mass% are used interchangeably in the steel arts), microstructure (col. 1, lines 46-61; col. 3, lines 50-61; “absence of martensite microstructures” in Abstract), and tensile strength (col. 2, lines 5-12) overlapping with the claimed steel, 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.
Since Hewitt teaches Mn, Ni, Mo, V, Zr, Nb, Cu, Al, and P include a value of 0% (col. 2, lines 35-49), these elements are considered optional elements and the broader disclosure of Hewitt includes steels which do not include these optional elements.
Hewitt therefore reads on the limitation a ferritic stainless steel consisting of, in percent by weight, wt%: 0.0005 to 0.02% of C, 0.005 to 0.02% of N, 0.7 to 1.0% of Si, 16.0 to 17.0% of Cr, 0.05 to 0.3% of Ti, and the balance being Fe and inevitable impurities of claim 1 and wherein: a tensile strength is 470 MPa or more of claim 1.
While Hewitt does not explicitly disclose Formulae (1) and (2), performing the calculations using the compositions of Hewitt results in values overlapping with the claimed ranges 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.
Hewitt therefore reads on the limitation a value of Formula (1) below satisfies 21 to 25 of claim 1 and a value of Formula (2) below satisfies more than 20 of claim 1.
Regarding the elongation of claim 1, Hewitt teaches a typical elongation of 25% as an inventive example (col. 2, lines 5-12), but does not explicitly disclose an elongation range that encompasses all the composition ranges taught by Hewitt. A prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). See MPEP 2144.05 I. Furthermore, one of ordinary skill in the art would reasonably expect the steel of Hewitt to possess the elongation of the claimed steel sheet given the chemical compositions, microstructure, and tensile strength overlapping with the claimed invention.
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) (emphasis added). "When the PTO shows a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not." In re Spada, 911 F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). Therefore, the prima facie case can be rebutted by evidence showing that the prior art products do not necessarily possess the characteristics of the claimed product. In re Best, 562 F.2d at 1255, 195 USPQ at 433. See also Titanium Metals Corp. v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985). In this case, the steel of Hewitt is considered identical or substantially identical in structure or composition since Hewitt teaches a steel with a chemical composition, microstructure, tensile strength, values of Formula (1) and values of Formula (2) overlapping with the claimed steel.
Hewitt therefore reads on the limitation an elongation is 27% or more of claim 1.
However, Hewitt does not explicitly teach a pitting potential is 150 mV or more of claim 1.
While Hewitt does not explicitly state a pitting potential of their products, one of ordinary skill in the art would reasonably expect the steel of Hewitt to possess the claimed pitting potential of the claimed invention given overlapping chemical composition and microstructure (the steels of Hewitt and the instant invention are ferritic stainless steels), as it is well known in the metallurgical arts that the properties of a steel are dependent on its structure and composition.
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), and b) the claimed and prior art products are identical or substantially identical in structure (both are ferritic stainless steels). 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).
In this case, the steel of Hewitt and the instant invention have overlapping microstructures (both are ferritic stainless steels) and chemical compositions, as well as overlapping tensile strength and values for Formula (1) and Formula (2), and thus are considered to be identical or substantially identical in structure and composition. Therefore, one of ordinary skill in the art would reasonably expect the steel of Hewitt to necessarily possess the claimed pitting potential, despite Hamada not explicitly measuring or disclosing these properties.
Hewitt therefore reads on the limitation of a pitting potential is 150 mV or more of claim 1.
Hewitt therefore reads on all limitations of claim 1.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over US 4986857 A of Hewitt in view of “Application Key Technologies of Ferritic Stainless Steel for Traffic Sign Substrate Plate” of Guo.
Regarding claim 1, Hewitt teaches corrosion resistant steels from which martensite microstructures are generally absent (Title). Hewitt teaches typical corrosion resistant steels include 3CR12, 4003, and 409 and further teaches a ferrite factor used to improve properties of the instant invention and ferritic stainless steels (col. 1, lines 43-65; col. 2, lines 50-61; corrosion resistant steels of Hewitt read on claimed ferritic stainless steel; one of ordinary skill in the art further understands 3CR12, 4003 and 409 are ferritic stainless steels).
Instant claim (wt%)
Hewitt (mass%)
C
0.0005 - 0.02
0.25 max
N
0.005 - 0.02
0.1 max
Si
0.7 - 1.0
2.0 max
Cr
16.0 - 17.0
10-18
Ti
0.05 - 0.3
0-1.0
Optional:
Mn, Ni, Mo, V, Zr, Nb, Cu, Al, P
Fe and inevitable impurities
Balance
Balance (“and unavoidable impurities”)
Formula (1)
21-25
10-32
Tensile strength
≥ 470 MPa
Typically 520 MPa
Elongation
≥ 27%
Typically 25%
Formula (2)
More than 20
Undetermined to 26
(undetermined is due to a zero value for C and N being in the denominator)
Pitting potential
≥ 150 mV
-
Hewitt teaches a steel with a chemical composition (col. 2, lines 35-49; claims 2 and 24; one of ordinary skill in the art understands wt% and mass% are used interchangeably in the steel arts), microstructure (col. 1, lines 46-61; col. 3, lines 50-61; “absence of martensite microstructures” in Abstract), and tensile strength (col. 2, lines 5-12) overlapping with the claimed steel, 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.
Since Hewitt teaches Mn, Ni, Mo, V, Zr, Nb, Cu, Al, and P include a value of 0% (col. 2, lines 35-49), these elements are considered optional elements and the broader disclosure of Hewitt includes steels which do not include these optional elements.
The Examiner notes that, while Hewitt teaches overlapping contents for C and N, the 0.25 max carbon content and 0.1 max nitrogen content ranges of the steel of Hewitt are broader than the 0.0005 - 0.02 wt% C and 0.005 - 0.02 wt% N of the claimed invention.
Guo teaches ferritic stainless steels (Title). Guo and Hewitt are considered analogous art since they are similarly concerned with ferritic stainless steels with similar compositions and are considered in the same field of endeavor.
Guo teaches it is useful that the carbon content of the ferritic stainless steel is less than 0.005% and the nitrogen content less than 0.015% to improve corrosion resistance and durability (page 230, “Corrosion Resistance” section).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the carbon and nitrogen content of Hewitt with the ranges of Guo, such as within claimed ranges, to improve corrosion resistance and durability of the ferritic stainless steel, as taught by Guo.
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.
Hewitt therefore reads on the limitation a ferritic stainless steel consisting of, in percent by weight, wt%: 0.0005 to 0.02% of C, 0.005 to 0.02% of N, 0.7 to 1.0% of Si, 16.0 to 17.0% of Cr, 0.05 to 0.3% of Ti, and the balance being Fe and inevitable impurities of claim 1 and wherein: a tensile strength is 470 MPa or more of claim 1.
While Hewitt does not explicitly disclose Formulae (1) and (2), performing the calculations using the compositions of Hewitt results in values overlapping with the claimed ranges 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.
Modified Hewitt therefore reads on the limitation a value of Formula (1) below satisfies 21 to 25 of claim 1 and a value of Formula (2) below satisfies more than 20 of claim 1.
Regarding the elongation of claim 1, Hewitt teaches a typical elongation of 25% as an inventive example (col. 2, lines 5-12), but does not explicitly disclose an elongation range that encompasses all the composition ranges taught by Hewitt. A prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). See MPEP 2144.05 I. Furthermore, one of ordinary skill in the art would reasonably expect the steel of Hewitt to possess the elongation of the claimed steel sheet given the chemical compositions, microstructure, and tensile strength overlapping with the claimed invention.
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) (emphasis added). "When the PTO shows a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not." In re Spada, 911 F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). Therefore, the prima facie case can be rebutted by evidence showing that the prior art products do not necessarily possess the characteristics of the claimed product. In re Best, 562 F.2d at 1255, 195 USPQ at 433. See also Titanium Metals Corp. v. Banner, 778 F.2d 775, 227 USPQ 773 (Fed. Cir. 1985). In this case, the steel of Hewitt is considered identical or substantially identical in structure or composition since Hewitt teaches a steel with a chemical composition, microstructure, tensile strength, values of Formula (1) and values of Formula (2) overlapping with the claimed steel.
Modified Hewitt therefore reads on the limitation an elongation is 27% or more of claim 1.
However, modified Hewitt does not explicitly teach a pitting potential is 150 mV or more of claim 1.
While Hewitt does not explicitly state a pitting potential of their products, one of ordinary skill in the art would reasonably expect the steel of Hewitt to possess the claimed pitting potential of the claimed invention given overlapping chemical composition and microstructure (the steels of Hewitt and the instant invention are ferritic stainless steels), as it is well known in the metallurgical arts that the properties of a steel are dependent on its structure and composition.
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), and b) the claimed and prior art products are identical or substantially identical in structure (both are ferritic stainless steels). 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).
In this case, the steel of Hewitt and the instant invention have overlapping microstructures (both are ferritic stainless steels) and chemical compositions, as well as overlapping tensile strength and values for Formula (1) and Formula (2), and thus are considered to be identical or substantially identical in structure and composition. Therefore, one of ordinary skill in the art would reasonably expect the steel of Hewitt to necessarily possess the claimed pitting potential, despite Hamada not explicitly measuring or disclosing these properties.
Hewitt therefore reads on the limitation of a pitting potential is 150 mV or more of claim 1.
Modified Hewitt therefore reads on all limitations of claim 1.
Response to Arguments
Due to claim amendments filed 05/22/2026, the 35 U.S.C. 103 rejection of claim 1 over JP 2020/164955 A of Hamada has been withdrawn. Amended claim 1 now recites a closed composition and therefore the composition of Hamada including Mn does not read on amended claim 1.
Applicant’s arguments with respect to claim 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
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/M.A./Examiner, Art Unit 1733
/REBECCA JANSSEN/Primary Examiner, Art Unit 1733
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