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 .
Response to Amendment and Status of Claims
Applicant’s amendments to the claims, filed July 13, 2026, are acknowledged. Claim 1 is amended. No new matter has been added.
Claims 7-10 remain withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention Group II, drawn to a method of manufacturing a high-strength steel material, there being no allowable generic or linking claim.
Claims 1-5 and 7-10 are pending, and Claims 1-5 are currently considered in this office action.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-5 are rejected under 35 U.S.C. 103 as being unpatentable over Yin (previously cited, CN 101701326 A, English Machine translation provided) in view of Suh (previously cited, KR 20120071582 A, English Machine Translation provided) and Lee (previously cited, KR 20140098900 A, English Machine Translation provided).
Regarding Claim 1, Yin discloses a high-strength steel material having excellent temperature strain aging impact properties (Abstract), the steel material comprising:
Element
Claim 1 (wt%)
Yin, para. [0008]
C
0.04-0.14
0.09-0.14
Si
0.05-0.60
0.2-0.4
Mn
0.6-1.8
1.1-1.6
Sol. Al
0.005-0.06
silent
Nb
0.005-0.05
0.02-0.05
V
>0 to 0.006
0.007-0.06
Ti
0.001-0.015
0.001-0.005
Cu
0.01-0.4
0.20-0.35
Ni
0.01-0.6
0.15-0.40
Cr
0.01-0.2
0.002-0.15
Mo
0.001-0.3
0.002-0.10
Ca
0.0002-0.004
silent
N
0.001-0.006
silent
P
>0 and <0.02
0.007-0.015
S
>0 and <0.003
0.0015-0.003
balance
Fe, inevitable impurities
Fe, inevitable impurities
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). See MPEP § 2144.05.I.
While Yin discloses only discloses V as low 0.007% and fails to disclose the claimed range of greater than 0 and up to 0.006%, it is the examiner's position that the amounts in question are so close that it is prima facie obvious that one skilled in the art would have expected them to have the same properties. Titanium Metals Corp. v. Banner, 227 USPQ 773 (see MPEP 2144.05.I). Additionally, Applicant has not made a showing of criticality or unexpected results for the claimed range.
Yin fails to disclose the claimed elements of sol. Al, N and Ca.
Suh teaches including 0.005-0.06wt% sol. Al in order to obtain deoxidation while balancing for toughness and including 0.002-0.006% N in order to prevent solid solution strengthening and unwanted precipitate formation from Ti and Al additions which can reduce the toughness, while balancing for strain aging (para. [0028]-[0029]; para. [0032]-[0033]).
Lee teaches including up to 0.05% Ca and within the range satisfying 1.5≤Ca/S≤2.5 in order to prevent the formation of MnS inclusions by forming CaS precipitates, thereby preventing deterioration of the impact toughness, while balancing the formation of CaO (para. [0059]-[0061]). Yin discloses 0.0015-0.003 S, such that one of ordinary skill in the art would add Ca in the range of 0.00225-0.0075%, respectively.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have included 0.005-0.06wt% sol. Al and 0.002-0.006% N, as taught by Suh, and 0.00225-0.0075% Ca, as taught by Lee, for the invention disclosed by Yin. One would be motivated to add these ranges of sol. Al, N and Ca in order to obtain deoxidation while balancing for toughness, in order to prevent solid solution strengthening and unwanted precipitate formation from Ti and Al additions, which can reduce the toughness, while balancing for strain aging, and in order to prevent the formation of MnS inclusions by forming CaS precipitates, thereby preventing deterioration of the impact toughness, while balancing the formation of CaO, respectively (see teachings above).
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). See MPEP § 2144.05.I.
Yin further discloses a yield strength of ≥355MPa and a tensile strength of ≥490MPa or more, and therefore a yield ratio within the claimed range of 0.65-0.73 (Abstract; see also para. [0028], example steel comprises 355.22MPa yield strength and 516.04 MPa tensile strength and therefore a yield ratio of 0.688).
Yin fails to disclose the 5% strain aging DBTT temperature.
Lee teaches a 5% strain aging DBTT of -40C or less, such as -59C to -65C, in order to produce steel which can be used for marine structures (para. [0007]; see Table 3 values, -59 to -65). Lee teaches wherein Ti, Ca, and Ti/N ratio contents, as well as a reduction ratio of 40% or more in the first rolling in the austenite recrystallization zone, secures the 5% strain aging DBTT of -40C or less (para. [0104]).
Yin, Suh and Lee discloses these requirements to achieve the 5% strain aging DBTT of -40C or less taught by Lee. Specifically, Lee requires a Ca content of 0.05% or less with a Ca/S ratio of 1.5-2.5 (Lee, para. [0061], see teachings applied by Lee above), a Ti amount of 0.003-0.02% (Lee, para. [0042]-[0043]; see Yin, Abstract, 0.001-0.005 Ti), a Ti/N ratio of 1.5-4.5 (Lee, para. [0045]; Yin, Abstract, 0.001-0.005 Ti; Suh, see teaching applied above and para. [0032], 0.002-0.006 N; thus Yin and Suh comprise Ti/N ratios of 0.16-2.5). Yin further comprises a rolling reduction of 60% or more in the first rolling reduction in the austenite recrystallization zone (Abstract; para. [0011]), which overlaps with the 40% or more reduction required by Lee.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have comprised a 5% strain aging DBTT of -40C or less, such as -59C to -65C, as taught by Lee, and by utilizing the Ca amounts, Ca/S ratio, Ti amounts, Ti/N ratio, and rolling reduction of 40% or more in the recrystallization zone of the first rolling, as taught by Lee, for the invention disclosed by Yin, Suh and Lee. One would be motivated to do this in order to produce a steel which is suitable for a marine structure, and because Yin, Suh and Lee comprise the features which achieve the 5% strain aging DBTT of -40C or less (see teachings above by Lee).
Yin discloses ferrite and pearlite, but fails to disclose the claimed microstructure.
However, Yin in view of Suh and Lee disclose the same composition (see above), and Yin discloses the same manufacturing (hot-rolling) method as the instant invention (see below).
hot-rolling method
instant specification, para. [0020]
Yin
citation
Reheating steel slab
1080-1250C
1200-1250C
[0009]
Rolling end temperature
780C or more
810-830
[0011]
cooling
air cooling or water cooling
laminar (water) cooling; air cooling
[0012]; [0026]; [0032]
Normalizing heat treatment
850-960C
905-915C
[0013]
It would be obvious to one of ordinary skill in the art that the steel of Yin, Suh and Lee comprise the claimed microstructure, as well as the claimed yield ratio and 5% strain aging DBTT temperature, because Yin, Suh and Lee disclose the same composition and Yin discloses the same hot-rolling method as the instant invention (see above). When 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.
Regarding Claim 2, Yin discloses wherein Nb is 0.02-0.05% (Abstract).
Regarding Claim 3, Lee discloses wherein the 5% strain aging DBTT temperature is from -59 to -65C, which reads on the claimed range of -54C to -61C (see teachings above; Lee, 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). See MPEP § 2144.05.I.
Additionally, Yin, Suh and Lee disclose the same composition and Yin discloses the same hot-rolling method as the instant invention (see above), and it would be obvious to one of ordinary skill in the art that the steel of Yin, Suh and Lee comprise the claimed 5% strain aging DBBT temperature. When 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.
Regarding Claim 4 and Claim 5, Yin fails to disclose (Claim 4) the claimed ferrite grain size and (Claim 5) the claimed carbonitrides; however, Yin, Suh and Lee disclose the same composition and Yin discloses the same hot-rolling method as the instant invention (see above), and it would be obvious to one of ordinary skill in the art that the steel of Yin, Suh and Lee comprise the claimed ferrite average crystal grain size of 15um or less (Claim 4) and claimed weight ratio (0.01wt% or more) and size (300nm or less) of carbonitrides (Claim 5). When 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.
Response to Arguments
Applicant’s arguments, filed July 13, 2026, have been fully considered; however, the arguments appear to be directed to the previous Final rejection mailed October 15, 2025 over Suh in view of Lee and Yoo (and Okano). Applicant does not appear to provide arguments directed to the current rejection (Non-Final rejection mailed April 13, 2026) over Yin in view of Suh and Lee. Therefore, the arguments are deemed moot as they are not relevant to the current ground(s) of rejection.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Kondo (previously cited, US 20140352850 A): teaches a microstructure comprising 80-95% ferrite, 5-20% bainite, and up to 8% other phases which include pearlite, residual austenite and martensite, and further comprising carbonitrides of Nb and/or Ti with an average size of 1-10nm (Abstract; para. [0016]).
Kondo discloses a composition comprising:
Element
Claimed (wt%)
Kondo (wt%)
Citation
C
0.04-0.14%
0.02-0.08%
Abstract
Si
0.05-0.60%
0.20-1.0%
Abstract
Mn
0.6-1.8%
0.8-2.3%
Abstract
Sol. Al
0.005-0.06%
0.010-0.1%
Abstract
Nb
0.005-0.05%
Ti+Nb is 0.005-0.03%*
Abstract
V
>0% and <0.01%
0.005-1.0%
[0017]
Ti
0.001-0.015%
Ti+Nb is 0.005-0.03%*
Abstract
Cu
0.01-0.4%
0.05-1.5%
[0017]
Ni
0.01-0.6%
0.05-1.5%
[0017]
Cr
0.01-0.2%
0.05-1.50%
[0017]
Mo
0.001-0.3%
0.005-1.0%
[0017]
Ca
0.0002-0.004%
silent
N
0.001-0.006%
0.001-0.01%
[0016]
P
>0% and <0.02%
0.005-0.15%
[0016]
S
>0% and <0.003%
0.002-0.015%
[0016]
balance
Fe, inevitable impurities
Fe, unavoidable impurities
[0016]
Goto (previously cited, US 20170369962 A1): teaches a high toughness steel comprising 0.01-0.12% C, 0.05-0.5% Si, 1.0-2.2% Mn, 0-0.03% P, 0-0.005% S, 0.001-0.1% Al, 0-0.006% N, 0.01-0.1% Nb and 0.001-0.05% Ti, and a microstructure of 90% or more of bainitic ferrite with a grain size of 10um or less, wherein the remainder may include pearlite, bainite or martensite (Abstract; para. [0074]-[0077]).
Goto teaches wherein up to 75% of Nb is present in the form of 20nm precipitates of which are mainly carbonitrides, in order to ensure high strength while preventing decreases in yield strength after post-welding heat treatment (Abstract; para. [0078]-[0079]). Lee teaches up to 0.04% Nb (see para. [0040]-[0041] of Lee), such that there would be up to 0.03% (75% of 0.04%) of 20nm of Nb precipitates and which are Nb carbonitrides when the teachings of Goto are applied to the Nb contents taught by Lee, which reads on the claimed range of at least 0.01%.
Maruyama (US 20140178712 A1): teaches a steel comprising 0.04-0.09% C, 0-0.4% Si, 1.2-2% Mn, 0-0.1% P, 0-0.02% S, 0-1% Al, 0.02-0.09% Nb, 0.02-0.07% Ti, 0-0.005% N, 0.01-0.12% V, one or more of Cr, Cu, Ni and Mo 0.02-2% in total, 0.0003-0.01% Ca, and a balance of Fe, and 5% or less of pearlite, 0.5% or less martensite and austenite (one of ordinary skill in the art would appreciate this to be in reference to the MA phase), and a balance of ferrite, and further carbonitrides comprising a size of 20nm or less (Abstract; para. [0044]-[0047]33).
Suh (previously cited and cited above, KR 20120071582 A, English Machine Translation provided, further teachings): teaches a composition comprising
Element
Claimed (wt%)
Suh
Citation
C
0.04-0.14%
0.02-0.10%
[0022]
Si
0.05-0.60%
0.05-0.45%
[0024]
Mn
0.6-1.8%
1.2-1.8%
[0026]
Sol. Al
0.005-0.06%
0.005-0.06
[0028]
Nb
0.005-0.05%
silent
V
>0% and <0.01%
silent
Ti
0.001-0.015%
0.005-0.03
[0031]
Cu
0.01-0.4%
silent
Ni
0.01-0.6%
silent
Cr
0.01-0.2%
silent
Mo
0.001-0.3%
silent
Ca
0.0002-0.004%
silent
N
0.001-0.006%
0.002-0.006
[0032]
P
>0% and <0.02%
0-0.02
[0035]
S
>0% and <0.003%
0-0.005
[0035]
balance
Fe, inevitable impurities
Fe, inevitable impurities
[0016]
Suh discloses a microstructure comprising 50% or more acicular ferrite, and up to 50% polygonal ferrite and/or polygonal ferrite and pearlite (para. [0012], wherein 50% or more of the structure may be one of acicular ferrite; para. [0013]; para. [0044]). Suh discloses wherein the portion of the microstructure which is 50% or more acicular ferrite may also include bainitic ferrite, which additionally reads on the claimed amount of ferrite and a microstructure comprising bainite (para. [0012]).
Suh discloses a DBBT of -50C or lower, wherein the DBBT does not increase more than 10C when subjected to a 5% strain aging treatment (Abstract; para. [0045]; see Table 3, wherein DBBT after 5% strain aging ranges from -59C to -76C in inventive examples). Thus, the DBBT of Suh after 5% strain aging (from -59C to -76C), reads on the claimed 5% strain aging DBTT temperature range of -54C or lower.
Yoo (previously cited, KR 20130073472 A, English Machine Translation provided): teaches a steel comprising 0.04-0.10 wt% C, 0.05-0.50 wt% Si, 1.4-2.0 wt% Mn, 0.01-0.05 wt% Al, 0.005-0.02 wt% Ti, 0.002-0.01 wt% N, 0.02wt% or less of P, and 0.005wt% or less of S, wherein the steel further comprises 0.02-0.07 wt% Nb, 0.05-0.3 wt% Mo, 0.3wt% or less of Ni, 0.0005-0.004 wt% of Ca, and additionally the elements V and Cr (Abstract).
Yoo teaches including up to 0.08% V in order to improve strength by forming VN precipitates while balancing for weldability and toughness, and up to 0.3% Cr in order to increase strength by the formation of martensite/austenite (MA) during rapid cooling, and as a less expensive substitute for Mo, while balancing for weldability (para. [0052]-[0055]).
Yoo also teaches wherein up to 5% (martensite-austenite constituent) MA additions to a ferrite/bainite structure increases the strength and plastic deformation capability of the steel plate, while balancing for ductile fracture resistance (para. [0079]; para. [0057]; see also para. [0043] and [0055]).
Lee (previously cited and cited above, KR 20140098900 A, English Machine Translation provided, further teachings): teaches an average ferrite crystal grain size of 10um or less, and wherein refining crystal grains improves strength and low-temperature and strain aging impact toughnesses (para. [0014]; para. [0064]; para. [0031]; para. [0040]; para. [0043]).
Okano (previously cited, JP 2901890 B2, English Machine Translation provided): teaches a steel comprising bainite, martensite and 2% or more ferrite, wherein Nb carbonitrides comprise a size of 50nm or less and are contained in an amount of 0.01-0.6% by volume in order to improve strength by effective precipitation strengthening while balancing for toughness (para. [0021]-[0024]). One of ordinary skill in the art would appreciate that 0.01-0.6vol% equates to at least 0.01wt% as the density of Nb carbonitrides is about equal to or greater than the density of the steel.
Perez (CA 2594631 A1): teaches a steel comprising 0.05-0.40% C, 0.5-1.6% Mn, 0-0.02% P, 0.005-0.03% S, 0-0.4% Si, 0-0.5% Cr, 0-0.05% Nb, 0-0.035% Ti, 0-0.09% V, 0-0.3% Cu, 0-0.04% Al, comprising a microstructure of ferrite plus bainite-pearlite, and a YS of 379.2-551.6 MPa and a UTS of 655 MPa or more (para. [0030]-[0033]; Claim 1).
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CATHERINE P SMITH whose telephone number is (303)297-4428. The examiner can normally be reached Monday - Friday 9:00-4:00 MT.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Keith Walker can be reached on (571)-272-3458. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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CATHERINE P. SMITH
Patent Examiner
Art Unit 1735
/CATHERINE P SMITH/Examiner, Art Unit 1735
/KEITH WALKER/Supervisory Patent Examiner, Art Unit 1735
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