DETAILED ACTION
Response to Amendment
The Amendment filed 07/17/2025 has been entered. Claims 1-8 remain pending in the application. Claims 4-6 have been withdrawn. No claims have been canceled. No new claims have been added. Claims 1-2 and 8 are currently amended. Applicant's amendments to the specification and drawings have overcome the objections previously set forth in the Non-Final Rejection mailed 04/17/2025. Applicant's amendments to the claims have overcome the objections previously set forth in the Non-Final Rejection mailed 04/17/2025.
Applicant's arguments and amendments to the claims have overcome the 112(b) rejections previously set forth in the Non-Final Rejection mailed 04/17/2025. The examiner agrees that the average block size of martensite and bainite, axial ratio of martensite and bainite, and steel microstructure are separate properties and not “narrower ranges” of the microstructure (Applicant’s remarks, page 14) and therefore an average block size and average axial ratio of martensite and bainite can be calculated even if the microstructure contains no bainite.
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 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over JP 2016/050343 A of Yokoyama (as cited in IDS mailed 07/21/2022 with reference to machine translation), in view of “The effect of carbon content on the c/a ratio of as-quenched martensite in Fe-C alloys” of Lu.
Regarding claims 1 and 8, Yokoyama teaches an ultra-high strength cold rolled steel sheet having excellent hydrogen embrittlement resistance (Abstract, ultra-high strength cold rolled steel sheet reads on the claimed steel sheet).
List 1
Element
Instant claims (mass%)
Yokoyama (mass%)
C
0.14 - 0.60
0.15-0.3
Si
More than 0 - 3.00
0.001-2.0
Al
More than 0 - 3.00
0.001-1.0
Mn
≤ 5.00
2.10-4.0
P
≤ 0.03
0.05
S
≤ 0.005
0.01
N
≤ 0.015
0.01
B
0 - 0.005
0.0001-0.01
Ni
0 - 5
0.001-1.0 (one or more of Cr, Ni, Cu)
Cu
0 - 5
0.001-1.0 (one or more of Cr, Ni, Cu)
Cr
0 - 5
0.001-1.0 (one or more of Cr, Ni, Cu)
Mo
0 - 1
0.001-0.5
W
0 - 1
-
Ti
0 - 0.2
0.001-0.10
Zr
0 - 0.2
-
Hf
0 - 0.2
-
V
0 - 0.2
0.001-0.5 (one or both of V, Nb)
Nb
0 - 0.2
0.001-0.1 (one or both of V, Nb)
Ta
0 - 0.2
-
Sc
0 - 0.2
-
Y
0 - 0.2
-
Sn
0 - 0.02
-
As
0 - 0.02
-
Sb
0 - 0.02
-
Bi
0 - 0.02
0.0001-0.01 (one or more of Ca, Mg, Bi, REM)
Mg
0 - 0.005
0.0001-0.01 (one or more of Ca, Mg, Bi, REM)
Ca
0 - 0.005
0.0001-0.01 (one or more of Ca, Mg, Bi, REM)
REM
0 - 0.005
0.0001-0.1 (one or more of Ca, Mg, Bi, REM)
Fe and impurities
Balance
Balance (“unavoidable impurities”)
Formula (i)
≤ 3.00
0.002-3.0
Formula (ii)
≤ 0.80
0.315-1.2
Formula (iii)
≥ 0.80
2.1-4
Formula (iv)
0.003-0.02
0.001-0.1
Formula (v)
≤ 0.02
0
Formula (vi) for Ms
≥ 200
220.86-382.1
Martensite
≥ 85 vol%
Tempered martensite: ≥ 60 area%
Retained austenite
≤ 15 vol%
≤ 6 area%
Bainite
Balance
≤ 30 area%
Polygonal ferrite: ≤ 10 area%
Yield stress
≥ 1000 MPa
Inventive examples: 1004-1223 MPa
Tensile strength
≥ 1400 MPa
Broad teaching: ≥ 1300 MPa, preferably ≥ 1470 MPa
Inventive examples: 1476-1703 MPa
Yokoyama teaches a steel with a chemical composition ([0011]-[0012], [0016]-[0025], claims 1-5), microstructure ([0010]-[0011], [0026], claim 1), yield stress (inventive examples 1-4, 9-10 and 16-35 in Table 3), and tensile strength ([0002], [0009], [0014], [0036], inventive examples 1-4, 9-10 and 16-35 in Table 3) overlapping with the claimed steel, as shown in List 1. While Yokoyama does not explicitly disclose the values of formulas (i)-(vi), one can perform the calculations which result 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.
Yokoyama therefore reads on the limitations a steel sheet having a chemical composition consisting of, in mass%: C: 0.14 to 0.60%, Si: more than 0% to less than 3.00%, Al: more than 0% to less than 3.00%, Mn: 5.00% or less, P: 0.030% or less, S: 0.0050% or less, N: 0.015% or less, B: 0 to 0.0050%, Ni: 0 to 5.00%, Cu: 0 to 5.00%, Cr: 0to5.00%, Mo: 0 to 1.00%, W: 0 to 1.00%, Ti: 0 to 0.20%, Zr: 0 to 0.20%, Hf: 0 to 0.20%, V: 0 to 0.20%, Nb: 0 to 0.20%, Ta: 0 to 0.20%, Sc: 0 to 0.20%, Y: 0 to 0.20%, Sn: 0 to 0.020%, As: 0 to 0.020%, Sb: 0 to 0.020%, Bi: 0 to 0.020%, Mg: 0 to 0.005%, Ca: 0 to 0.005%, and REM: 0 to 0.005%,with the balance: Fe and impurities, and satisfying following formulas (i) to (v), wherein a value of Ms expressed by a following formula (vi) is 200 or more, a steel microstructure contains, in volume%:martensite: 85% or more, and retained austenite: 15% or less, with the balance, a yield stress is 1000 MPa or more, and a tensile strength of the steel sheet is 1400 MPa or more of claims 1 and 8 (the Examiner notes that claim 8 reads “a steel sheet having a chemical composition comprising” instead of “consisting of” of claim 1).
Regarding the average block size of martensite and bainite of claims 1 and 8, Yokoyama teaches an effective grain size must be 7 μm or less and preferably, 5 μm or less ([0029]). Yokoyama further teaches the effective grain size corresponds to the block size of martensite ([0029]). Yokoyama teaches inventive examples with effective grain size (De) of 2.5-3.0 μm (inventive examples 21, 30-31, 33, and 35 in Table 3. 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.
Yokoyama therefore reads on the limitation an average block size of martensite and bainite: 3.0 μm or less of claims 1 and 8.
Regarding the average axial ratio of martensite and bainite of claims 1 and 8, Yokoyama does not explicitly disclose an average axial ratio of martensite and bainite: 1.0004 to 1.0100.
Lu teaches the effect of carbon content on the c/a ratio of as-quenched martensite in Fe-C alloys (Title). Lu is considered analogous art since it is similarly concerned with the axial ratio of as-quenched and tempered martensite in the steel art (Section 4 Conclusion, “This equation can be used to estimate carbon content in as-quenched martensite and tempered martensite by using X-ray diffraction”) and Yokoyama has tempered martensite in its steel microstructure as shown in List 1 above.
Regarding the average axial ratio of martensite and bainite, it would have been necessary and obvious to look to the prior art for exemplary axial ratios used in steels with martensite structures. Lu provides this teaching showing a relationship between the c/a ratio of martensite and the carbon content in steels (Abstract, the c/a ratio of martensite reads on the claimed average axial ratio of martensite). Lu teaches steels with less than 0.6 wt% carbon form tetragonal martensite and show a linear relationship between carbon content and c/a ratio (Section 4 Conclusion). Lu teaches a relationship of c/a = 1 + 0.031 wt%C and that this equation applies to both as-quenched and tempered martensite (Section 4 Conclusion). Lu teaches the lattice parameters, and therefore the resulting c/a ratios, are measured using high-resolution X-ray diffractomer (Abstract and Section 2 Experimental Procedure). Using the carbon content in the steel sheet of Yokoyama to calculate the axial ratio using the relationship taught by Lu, the c/a ratio of the martensite in the steel of Yokoyama is 1.0047-1.0093, which is within the claimed range. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the steel sheet of Yokoyama would necessarily possess a c/a ratio within the claimed ranges given the carbon content of the steel of Yokoyama and the corresponding axial ratio of martensite, as taught by Lu.
Modified Yokoyama therefore reads on the limitation an average axial ratio c/a of martensite and bainite, measured by an X-ray diffraction method: 1.0004 to 1.0100, wherein a and c denote a-axis and c-axis lattice constants in a tetragonal crystal structure, respectively of claims 1 and 8.
Modified Yokoyama therefore reads on all the limitations of claims 1 and 8.
Claims 2-3 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over JP 2016/050343 A of Yokoyama (as cited in IDS mailed 07/21/2022 with reference to machine translation), in view of “The effect of carbon content on the c/a ratio of as-quenched martensite in Fe-C alloys” of Lu, as applied to claim 1 above, and further in view of WO 2016/177420 A1 of Heller (as cited in prior office action with reference to machine translation),
Regarding claim 2, modified Yokoyama teaches the steel sheet of claim 1 as described above.
Yokoyama teaches the number density of Fe carbides in tempered martensite needs to be 1×106/mm2 or more ([0027], claim 1).
However, modified Yokoyama does not explicitly disclose wherein an average particle size of iron carbides included in the steel microstructure is 0.005 to 0.20 μm of claim 2.
Regarding the average particle size of iron carbides, it would have been necessary and obvious to look to the prior art for exemplary particle sizes of iron carbides used in steels with overlapping composition and microstructure to the steel sheet of modified Yokoyama. Heller provides this teaching showing a teaches a flat steel product and is considered analogous art since Heller teaches a steel with chemical composition, microstructure, and yield stress overlapping with the steel of Yokoyama (Abstract). Heller teaches the steel sheet contains iron carbides with a size of less than 500 nm ([0018], 500 nm is 0.5 μm). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to form the steel sheet of modified Yokoyama, and adjusting and varying the iron carbide particle size, such as within the claimed ranges, as taught by Heller, in order to form a conventional steel sheet using known and tested particle sizes of iron carbides predictably suitable for steels with optimized strength.
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 Yokoyama therefore reads on the limitation wherein an average particle size of iron carbides included in the steel microstructure is 0.005 to 0.20 μm of claim 2.
Regarding claims 3 and 7, modified Yokoyama teaches the steel sheet of claims 1 and 2 as described above.
Heller teaches the steel sheet is coated with a Zn coating with a hot dip coating step to protect the steel sheet against corrosive attacks ([0148], claim 6, a coating is considered a plating layer and is understood to be on a surface of a steel sheet which reads on the claimed plating layer on a surface of the steel sheet).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the steel sheet of modified Yokoyama to include the plating layer of Heller to protect the steel sheet against corrosive attacks, as taught by Heller.
Modified Yokoyama therefore reads on the limitation wherein the steel sheet includes a plating layer on a surface of the steel sheet of claims 3 and 7.
Response to Arguments
Applicant’s arguments with respect to claims 1-3 and 7-8 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.
Regarding the argument for using the reference of Lu, which is used similarly in the 103 rejections in this Office action, Applicant argues that Lu merely describes the c/a ratio of as-quenched martensite and that, in contrast, the martensite contained in the steels of the present invention and Heller includes tempered martensite (remarks, page 17).
In response, the new grounds of rejection rely on Yokoyama instead of Heller, as cited in this Office action. Yokoyama teaches an ultra-high strength cold-rolled steel sheet has a steel structure of polygonal ferrite is 10% or less, bainite is 30% or less, retained austenite is 6% or less, tempered martensite is 60% or more (Abstract), and therefore the martensite in the steel of Yokoyama is tempered martensite. As described in this Office action, Lu teaches the equation for calculating a c/a ratio using carbon content applies to tempered martensite (Section 4 Conclusions) in addition to the “as-quenched martensite” recited in the title of the journal article. Therefore, the equation taught by Lu is relevant to the steel sheet of Yokoyama given the overlap in the type of martensite and carbon content of the steel sheets.
Citation of Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
WO 2018/108653 A1 (using US 2020/0071785 A1 as its English translation) of Ahrenhold is considered relevant since it teaches a hot-rolled flat steel product with overlapping chemical composition and microstructure with the instant invention, a tensile strength of 800-1500 MPa, and a yield strength of > 700 MPa (Abstract).
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 nonprovisional extension fee (37 CFR 1.17(a)) 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 -Friday: 8:30 am - 5 pm.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Keith Hendricks can be reached on (571) 272-1401. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/Keith D. Hendricks/Supervisory Patent Examiner, Art Unit 1733
/M.A./Examiner, Art Unit 1733