DETAILED ACTION
Response to Amendment
The Amendment filed 02/09/2026 has been entered. Claims 1-3 and 5-10 remain pending in the application. Claims 6-10 have been withdrawn due to a restriction requirement. Claim 4 has been canceled. Claims 1-3 and 5 are presented for examination on the merits.
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 and 5 are rejected under 35 U.S.C. 103 as being unpatentable over US 2019/0071757 A1 of Murata (cited in prior Office action).
Regarding claims 1-3 and 5, Murata teaches a high-strength steel sheet (Title, Abstract, reads on the claimed steel sheet).
List 1
Element
Instant claims (wt%)
Murata (mass%)
Murata Ex. 12, steel d (mass%)
C
0.25-0.75
0.15-0.35
0.33
Si
≤ 4.0
Si+Al: 0.5 to 2.5
1.08
Mn
0.9-5.0
1.0-4.0
1.98
Al
≤ 5.0
Si+Al: 0.5 to 2.5
0.03
P
≤ 0.15
≤ 0.05 (excluding 0)
0.007
S
≤ 0.03
≤ 0.01 (excluding 0)
0.002
N
≤ 0.03
-
-
Total of Si and Al
1.0-6.0
0.5 to 2.5
1.11
Comprising (claim 2):
(1) one or more of
Ti: 0-0.5
Nb: 0-0.5
V: 0-0.5
(2) one or more of
Cr: 0-3.0
Mo: 0-3.0
(3) one or more of
Cu: 0-4.5
Ni: 0-4.5
(4) B: 0-0.005
(5) one or more of
Ca: 0-0.05
REM: 0-0.05 (excluding Y)
Mg: 0-0.05
(6) one or more of
W: 0-0.5
Zr: 0-0.5
(7) one or more of
Sb: 0-0.5
Sn: 0-0.5
(8) one or more of
Y: 0-0.2
Hf: 0-0.2
(9) Co: 0-1.5
(a) at least one of:
Cu, Ni, Mo, Cr, B: more than 0 and 1.0% or less in total
(b) at least one of V, Nb, Ti, Zr, and Hf: more than 0 and 0.2% or less in total
(c) at least one of Ca, Mg, and REM: more than 0 and 0.01% or less in total
-
Fe and unavoidable impurities
Balance
Balance (“inevitable impurities”)
Balance (“inevitable impurities”)
Tempered martensite
30-70 vol%
Tempered martensite + bainite: ≥ 30 area%
Tempered martensite + bainite: 51 area%
Bainite
10-45 vol%
Tempered martensite + bainite: ≥ 30 area%
Tempered martensite + bainite: 51 area%
Retained austenite
10-40 vol%
≥ 10 vol%
20.5 vol%
Ferrite
3-20 vol%
5-50 area%
14 area%
Unavoidable structure
“an”
Martensite-austenite component (MA)
Martensite-austenite composite (MA): 35 area%
BT∙E
≥ 22,000 MPa%
≥ 22,000 MPa%
Upper limit: ~35,000MPa%
26,773 MPa%
BT∙H
7*106 MPa2%1/2
2.7×106 MPa2%1/2 to 1.3×107 MPa2%1/2
7.3×106 MPa2%1/2 (calculated from TS of 1206 MPa and λ of 25%)
Regarding the chemical composition of claims 1-2, the elements including the limitation “or less” or a value of “0” are considered optional, such as P, S, N, Si and Al of claim 1 and all the elements listed in claim 2.
Murata teaches a steel with a chemical composition ([0009]-[0013], [0047]-[0067], claims 1-4), microstructure ([0011], [0023]-[0034], [0046] claim 1), and BT∙E values ([0074], a product of TS and total elongation EL, TS×EL is required to be 22000 MPa % or more, with an upper limit of 35000 MPa %; the product of Murata reads on the claimed BT∙E value expressed by Relational Expression 3 of the instant invention) overlapping with the claimed steel, as shown in List 1. While Murata does not explicitly disclose a BT∙H value expressed by Relational Expression 4, Murata teaches a tensile strength of 780 MPa or more and an upper limit of around 1300 MPa ([0070]-[0071]) and a hole expansion ratio λ of 20% or more with an upper limit of around 60% ([0075]-[0076]) and therefore one can perform the calculation using the tensile strength and hole expansion ratios of Murata to obtain the BT∙H values, as shown in List 1. The BT∙H values were obtained by using the lower and upper limits of the ranges of Murata, as well as the values of the inventive example, as follows (using the lower limit as an example):
780
M
P
a
2
×
20
%
1
/
2
=
2.7
×
10
6
M
P
a
2
%
1
/
2
Murata further teaches an inventive example (Example 12, which uses Steel d as shown in Table 2-1) with a chemical composition (Steel d, Table 1), microstructure (Example 12, Table 3), BT∙E value (Example 12, Table 4 from TS × EL value), and BT∙H value (Example 12, Table 4, calculated using TS and λ values) lying inside 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.
Murata therefore reads on the limitations a steel sheet comprising: by wt%, C: 0.25 to 0.75%, Si: 4.0% or less, Mn: 0.9 to 5.0%, Al: 5.0% or less, P: 0.15% or less, S: 0.03% or less, N: 0.03% or less, and a balance of Fe and unavoidable impurities; and as microstructures, tempered martensite, bainite,10 to 40 vol % of retained austenite, 3 to 20 vol % of ferrite, and an unavoidable structure of claim 1, further comprising: the following (1) to (9), by wt% of claim 2, wherein a total content of Si and Al is 1.0 to 6.0 wt% of claim 3, wherein a balance BT∙E is 22,000 (MPa%) or more of claim 5, and a balance BT∙H is 7*106 MPa2%1/2 of claim 5.
Regarding the tempered martensite and bainite of claim 1, Murata only teaches a sum of tempered martensite and bainite and does not explicitly disclose the specific values or ranges of tempered martensite and bainite individually. Murata teaches the total of tempered martensite and bainite is set to 30 area% or more and has an upper limit of about 85 area% ([0028]).
However, Murata does not explicitly disclose 30 to 70 vol % of tempered martensite and 10 to 45 vol % of bainite of claim 1, the limitations regarding Relational Expressions 1 and 2 of claim 1, and the limitations regarding bendability BR expressed by Relational Expression 5 of claim 5.
Regarding the tempered martensite and bainite of claim 1, the instant specification recites when the fraction of the tempered martensite is less than a certain level, it is difficult to secure the balance (TSXEl) of tensile strength and elongation of 22,000 MPa% or more or the balance (TS2XHER1/2) of tensile strength and hole expansion rate of 7*106 (MPa2%1/2) or more ([0175]). Since the total tempered martensite and bainite of Murata is within the claimed ranges of tempered martensite and bainite and has overlapping values of TSxEI and TS2XHER1/2, one of ordinary skill in the art would reasonably expect the individual contents of tempered martensite and bainite to overlap with the claimed steel. Additionally, or alternatively, the instant specification recites the secondary cooling stop temperature should be between 100°C and 300°C to obtain the bainite and tempered martensite of the instant invention ([0218]) and that when the tertiary maintaining time is less than 50 seconds, the tempered martensite is excessively formed ([0220]).
To meet the claimed [Si + Al]F and [Si + Al]γ content of Relational Expression 1 of claim 1, instant specifications recite the cold-rolled steel sheet is primarily heated to a temperature within a range of Ac or higher and less than Ac3 and maintained for 50 seconds or more ([0208]), a primary cooling stop temperature of 600-850°C ([0212]), a secondary cooling rate of 2°C/s or more and secondary maintaining temperature of 300-500°C ([0214]), a tertiary cooling with an average cooling rate of 2°C/s or more and a secondary cooling stop temperature of at least 100°C ([0218]), and a tertiary maintaining temperature of at least 350°C and tertiary maintaining time of at least 50 seconds ([0220]).
To meet the claimed T(γ) and V(γ) content of Relational Expression 1 of claim 1, instant specifications recite a secondary maintaining temperature of 300-500°C and a secondary maintaining time of less than 5 seconds ([0214]), an average cooling rate of the tertiary cooling is 2°C/s or more and a secondary cooling stop temperature of 100-300°C ([0218]), and a tertiary maintaining temperature of 350-550°C and a tertiary maintaining time of at least 50 seconds ([0220]).
Regarding the bendability (R/t) of claim 5, instant specifications recite that the total Si and Al content ([0167]), ratio of fraction of tempered retained austenite of the steel sheet to the retained austenite fraction ([0171]), an austenite range of 10 to 40 vol% ([0173]), tempered martensite ([0175]), TS×EL of 22000 MPa % or more ([0175]), TS2 x HER1/2 values greater than 7 x 106 MPa2 %1/2 ([0175]), and bainite ([0176]) are important to achieve the claimed bendability (R/t). Regarding processing steps, instant specifications recite that, to achieve claimed bendability (R/t), the secondary maintaining temperature should be 300-500°C and should be maintained for at least 5 seconds ([0214]), the tertiary cooling is 2°C/s or more ([0218]), and tertiary heating should be 350-550°C and maintained for at least 50 seconds ([0220]).
Regarding its processing, Murata teaches:
heating to a temperature T1 of (Ac1×0.8+Ac3×0.2) or higher and lower than Ac3 ([0085]) holding the temperature for 1-1800 seconds ([0086]) at an average heating rate HR1 of 1-20°C/s ([0088], corresponds to the primary heating and primary maintaining steps of the instant application),
cooling to a rapid cooling start temperature T2 of 650°C or higher ([0090]) at an average cooling rate CR1 of 0.1-10°C/s ([0039], corresponds to the primary cooling and primary cooling stop temperature steps of the instant application) to a cooling stop temperature T3a of 300-500°C at an average cooling rate CR2 of 30°C/s or more ([0090], corresponds to the secondary cooling step of the instant application),
gradual cooling after rapid cooling in to a temperature T3b in the temperature range 300-500°C at an average cooling rate of 0-10°C/s for 10-300 seconds after rapid cooling ([0094], corresponds to the secondary cooling and secondary maintaining steps of the instant application),
cooling after gradual heating to cooling stop temperature T4 of 100-300°C at an average cooling rate CR3 of 10°C/s or more ([0101]) with a retaining time at cooling stop temperature T4 of 1-600 seconds ([0104], corresponds to the tertiary cooling and secondary cooling stop temperature of the instant application),
reheating to temperature T5 of 300-500°C ([105]) with a retaining time at T5 of 50 seconds or more ([0108]) and an average heating rate HR2 that is not especially limited ([0108], corresponds to the secondary heating and tertiary maintaining steps of the instant application),
cooling after reheating may be performed to room temperature at an average cooling rate CR4 of 2-20°C/s ([0109], corresponds to the quaternary cooling step of the instant application).
Since the steel sheet of Murata has a chemical composition, including Si and Al total content, microstructure, BT∙E, BT∙H, and processing overlapping with the instant invention, one of ordinary skill in the art would reasonably expect the steel of Murata to necessarily possess the claimed contents of tempered martensite and bainite, [Si + Al]F and [Si + Al]γ content, T(γ) and V(γ) content, and bendability of the instant invention despite not explicitly disclosing those properties.
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 alloy 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 (see microstructure analysis 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).
Therefore, the steel sheet of Murata reads on all the limitations of claims 1-3 and 5.
Response to Arguments
Applicant's arguments filed 02/09/2026 have been fully considered but they are not persuasive.
Applicant argues that the claimed microstructure cannot be determined by several specific processing steps disclosed in the instant application and that the claimed microstructure of the final product is determined by the entire processing steps disclosed in the instant application, as well-known in the art (remarks, page 8, emphasis in original text). Applicant further argues that Examiner must prove that Murata teaches "30 to 70 vol% of tempered martensite," and "10 to 45 vol% of bainite," respectively, not the total amount of "tempered martensite and bainite: 30 area % or more" and further argues that each of the claimed "30 to 70 vol% of tempered martensite" and "10 to 45 vol% of bainite is of great importance in obtaining, e.g., the desired mechanical properties of a final product (remarks, page 14, emphasis in original text).
In response, Murata explicitly teaches a broader disclosure of a steel sheet with an overlapping microstructure and an inventive example within the claimed ranges, as explained in the 35 U.S.C. 103 rejection in this Office action and shown in List 1 above. The steel sheet of Murata teaches a sum of tempered martensite of 30-85 area% ([0028]). The sum of the instant invention is at least 40 vol% given the claimed lower limit of 30 vol% tempered martensite and 10 vol% bainite, and therefore the microstructure taught by Murata is overlapping with the microstructure of the instant invention. By Applicant’s own admission, the individual ranges of tempered martensite and bainite are “of great importance in obtaining the desired mechanical properties of a final product”. Given the overlapping chemical composition, microstructure, BT∙E value, BT∙H value, and processing steps, one of ordinary skill in the art would reasonably expect the individual contents of tempered martensite and bainite to be present in the steel sheet of Murata despite not being explicitly disclosed, as described in the 103 rejections in this Office action.
Further regarding the claimed microstructure, the instant specification recites that fractions of bainite and tempered martensite are difficult to distinguish among them and were calculated using an expansion curve after evaluation of dilation ([0252], emphasis added). By Applicant’s own admission, the bainite and tempered martensite are difficult to distinguish from each other and therefore reporting their sum, as Murata does, is an easier alternative than calculating their individual contents by an indirect measurement such as dilation, as is done in the instant invention. However, the microstructure of Murata’s steel is not changed by its measurements and one of ordinary skill in the art would reasonably expect the tempered martensite and bainite of Murata to read on the 30 to 70 vol % of tempered martensite and 10 to 45 vol % of bainite of claim 1 since the steel sheet of Murata and the instant invention have overlapping chemical compositions, microstructures, properties, and processing steps.
Applicant argues that the local chemical composition of individual phases like ferrite and retained austenite varies significantly based on the manufacturing process (remarks, page 9). Applicant further argues that that the Examiner must provide evidence that each and every the processing steps in the instant application and Fujiwara are identical or substantially identical to each other, including the order of those processing steps (remarks, page 10, emphasis in original text). Applicant argues that the processing steps of Murata are not identical or substantially identical to those of the instant application (remarks, page 12, emphasis in original text).
In response, regarding the arguments about Fujiwara, it is unclear what Applicant is arguing by “each and every the processing steps in the instant application and Fujiwara are identical”. The Examiner also notes that the 35 U.S.C. 103 rejection is based solely on the teachings of Murata and no prior art by “Fujiwara” is used in this or any prior Office action. Therefore, the arguments are not persuasive because the arguments are unclear and Fujiwara is not relevant to the instant case.
Regarding the arguments of the processing steps of Murata, the steel sheet of Murata has a chemical composition, including Si and Al total content, microstructure, BT∙E, and BT∙H overlapping with the claimed invention. "Products of identical chemical composition can not have mutually exclusive properties." See MPEP 2112.01(II). In this case, absent any clear and convincing evidence and/or arguments to the contrary, one of ordinary skill in the art would expect the steel sheet of Murata to possess the claimed properties. A prima facie case of obviousness has been properly established herein. As the Patent Office does not possess the laboratory facilities to test any differences in the claimed invention versus that of the reference, the burden shifts to applicant to demonstrate otherwise.
Furthermore, Applicant is reminded that the instant claims are drawn to a product, and not to a manufacturing process. Consequently, the features upon which applicant relies (i.e., processing steps) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). While it is well known in the steel arts that the processing method influences the resulting properties of the steel, one of ordinary skill in the art also understands that there are various processing paths that may arrive at the same properties.
Furthermore, MPEP § 2112.01 merely requires the burden of proof either based on identical structure or compositions OR (emphasis added) produced by identical or substantially identical process. In the instant case, Examiner provided specific and explicit evidence of the steel sheet of Murata having overlapping chemical composition and microstructure. Hence, burden is shifted to Applicant to provide rebuttal evidence that the closest prior art of Murata having overlapping chemical composition and microstructure would not result in the claimed properties. Since Applicant fails to meet such burden, the 35 U.S.C. 103 rejections are therefore maintained absent evidence of the contrary.
Additionally, Applicant's arguments fail to comply with 37 CFR 1.111(b) because they amount to a general allegation that the claims define a patentable invention without specifically pointing out how the language of the claims patentably distinguishes them from the references. In this case, Applicant does not specifically point out which processing steps are different to those of the prior art and why those differences would result in a patentably distinct product than the one of the prior art.
In the instant case, since the steel sheet of Murata has a chemical composition, including Si and Al total content, microstructure, BT∙E, BT∙H, and processing overlapping with the instant invention, one of ordinary skill in the art would reasonably expect the steel of Murata to necessarily possess the claimed contents of tempered martensite and bainite, [Si + Al]F and [Si + Al]γ content, T(γ) and V(γ) content, and bendability of the instant invention despite not explicitly disclosing those properties, as explained in the 35 U.S.C. 103 rejections in this Office action.
Applicant lists several Appeal Board decisions and argues that the court issued a decision "identical or substantially identical processing steps" and Applicant therefore respectfully submits that the above claimed features cannot be inherent in Murata (remarks, page 10).
In response, it is noted that the cited PTAB decisions do not involve the instant case nor any parent case to this application. Further, as MPEP § 2115 recites, “[c]laim analysis is highly fact-dependent” and the instant fact situation appears distinct from Application No. 15/250,022, 16/315,767, and 16/471,226. As explained above, MPEP § 2112.01 merely requires the burden of proof either based on identical structure or compositions OR (emphasis added) produced by identical or substantially identical process. In the instant case, Examiner provided specific and explicit evidence of the steel sheet of Murata having overlapping chemical composition and microstructure. Since Murata teaches a steel sheet with identical structure and composition, a prima facie case of obviousness has been properly established herein. Additionally, Examiner provided a mapping of how the processing steps of Murata overlap with the instant invention in pages 7-8 of the Non-Final Rejection mailed 11/25/2025. Thus, Murata not only teaches identical structure or compositions, but is also produced by identical or substantially identical process. As the Patent Office does not possess the laboratory facilities to test any differences in the claimed invention versus that of the reference, the burden shifts to applicant to demonstrate otherwise.
Applicant argues the same or overlapped mechanical properties such as like BT.E and BT.H cannot be an evidence that the claimed microstructural features are inherent in the prior art, as well known in the art, and mechanical properties can be achieved through various independent metallurgical routes (remarks, page 13).
In response, as discussed above, Murata explicitly teaches a broader disclosure of a steel sheet with an overlapping chemical composition, microstructure, and mechanical properties, and an inventive example within the claimed ranges, as explained in the 35 U.S.C. 103 rejection in this Office action and shown in List 1 above. Absent any clear and convincing evidence and/or arguments to the contrary, one of ordinary skill in the art would expect the steel sheet of Murata to possess the claimed properties. A prima facie case of obviousness has been properly established herein. As the Patent Office does not possess the laboratory facilities to test any differences in the claimed invention versus that of the reference, the burden shifts to applicant to demonstrate otherwise.
Conclusion
THIS ACTION IS MADE FINAL. 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 mailing 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
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