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 .
Priority
Receipt is acknowledged of a certified copy of JP 2019-201427 filed November 6, 2019 as required by 37 CFR 1.55. Receipt is also acknowledged of WO 2021/090642, the WIPO publication of PCT/JP2020/038468 filed October 12, 2020.
Claim Status
This Office Action is in response to Applicant’s Remarks and Claim Amendments filed June 15, 2026.
Claims Filing Date
June 15, 2026
Pending
1-7
Withdrawn
4, 5
Under Examination
1-3, 6, 7
Response to Remarks filed June 15, 2026
Furuhashi in view of Venkatasurya
Applicant’s arguments, see p. 9, filed June 15, 2026, with respect to Furuhashi in view of Venkatasurya have been fully considered and are persuasive. The rejection of Furuhashi in view of Venkatasurya has been withdrawn.
The applicant persuasively argues Furuhashi requires 95% or more bainite (p. 9 para. 6) and the YS and TS of Furuhashi are lower than Venkatasurya (p. 9 para. 8, p. 11 para. 4), such that Furuhashi and Venkatasurya are fundamentally different (p. 9 para. 9).
Furuhashi discloses 95% or more bainite (Furuhashi [0012], [0050]) with YS around 700 MPa and TS around 1000 MPa (Furuhashi Tables 4-6). In contrast, when the steel of Venkatasurya undergoes coiling after hot rolling and before annealing the microstructure is undisclosed (Venkatasurya [0094]-[0101]). The final disclosed microstructure in Venkatasurya of 71% and 91% martensite and bainite is present after annealing, quenching, and partitioning (Venkatasurya [0099]-[0112]) with YS of 850 to 1100 MPa and the TS of at least 1180 MPa (Venkatasurya [0122]).
Furuhashi in view of Hayashi
Applicant's arguments filed June 15, 2026 with respect to Furuhashi in view Hayashi have been fully considered but they are not persuasive.
The applicant argues Hayashi holds after coiling to control precipitation and hydrogen trap sites (Hayashi [0044]) (p. 14 para. 1), which is not suggested by Furuhashi (p. 14 para. 2).
Both Furuhashi and Hayashi are directed to hot-rolled steel sheets (Furuhashi [0022]; Hayashi [0011]-[0011]) with substantially similar compositions (Furuhashi [0020], [0031]-[0046]); Hayashi [00099], [0022]-[0039]), bainite microstructures (Furuhashi [0012], [0048]-[0055]; Hayashi [0021]), tensile strength (Furuhashi [0007], [0011], [0030], [0045]; Hayashi [0008]-[0009], [0021]), elongation (Furuhashi Tables 4-6; Hayashi tables 2-1, 2-2, 2-3, 2-4), and processing of heating, hot rolling cooling, and winding (Furuhashi [0064]-[0074]; Hayashi [0010], [0040]-[0045]).
Furthermore, Hayashi is proper for use in an obviousness rejection because the reference is analogous art to the claimed invention by being in the same field of endeavor (MPEP 2141.01(a)(I)) of a hot-rolled steel sheet (Hayashi [0011]-[0011]) with a substantially similar composition to that claimed (Hayashi [00099], [0022]-[0039]), bainite microstructure (Hayashi [0021]), overlapping tensile strength (Hayashi [0008]-[0009], [0021]), and substantially similar processing of heating, hot rolling cooling, and winding followed by retaining between 500 and 580°C (400 to 700°C) for 2.0 hours or more (1 to 100,000 seconds, 0.0003 to 28 hours) (Hayashi [0010], [0040]-[0045]; applicant’s specification [0075]-[0091]).
The applicant argues the prior art does not suggest improved ductility, hole expansibility, and toughness by controlling the total density of L7 and L68 grain boundaries in bainite (p. 14 para. 3), the post-coiling of Hayashi adopted by Furuhashi achieves precipitation control of Nb, V, Cr, Ti, Mo, etc., and it is unclear whether this would contribute to the crystal orientation relationship in bainite (p. 14 paras. 7-8).
In response to applicant's argument that the prior art does not suggest improved ductility, hole expansibility, and toughness by controlling the total density of L7 and L68 grain boundaries in bainite, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
The prior art discloses a composition (Furuhashi [0020], [0031]-[0046]), microstructure (Furuhashi [0012], [0048]-[0055]), tensile strength (Furuhashi [0007], [0011], [0030], [0054]), and processing (Furuhashi [0064]-[0064]); Hayashi [0044]-[0045]) that is substantially similar to the claimed composition (claim 1) and the process to form the claimed hot-rolled steel sheet (applicant’s specification [0075]-[0091]), such that the claimed properties naturally flow from the disclosure of the prior art, including a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° about a <110> direction and a length L68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite being 0.35 to 0.60 um/um2.
In support, applicant’s specification recites obtaining a total density of L7 and L68 in the desired amount of bainite through the disclosed retention process temperature and time (applicant’s specification [0089]), which is render obvious by Hayashi [0044]-[0045].
For the above cited reasons, the rejection of Furuhashi in view of Hayashi is maintained.
Gaganov in view of Venkatasurya
Applicant’s arguments, see p. 9, filed June 15, 2026, with respect to Gaganov in view of Venkatasurya have been fully considered and are persuasive. The rejection of Gaganov in view of Venkatasurya has been withdrawn.
The applicant persuasively argues Gaganov and Venkatasurya are fundamentally different in their target steel sheet characteristics and products (p. 15 paras. 4-9).
Gaganov discloses at least 70 vol% bainite (Gaganov [0015], [0073]) with YS of at least 700 MPa (Gaganov [0007], [0015]) and TS of more than 780 MPa (Gaganov [0011], [0075]). In contrast, when the steel of Venkatasurya undergoes coiling after hot rolling and before annealing the microstructure is undisclosed (Venkatasurya [0094]-[0101]). The final disclosed microstructure in Venkatasurya of 71% to 91% martensite and bainite is present after annealing, quenching, and partitioning (Venkatasurya [0099]-[0112]) with YS of 850 to 1100 MPa and the TS of at least 1180 MPa (Venkatasurya [0122]).
Gaganov in view of Hayashi
Applicant’s arguments, see p. 17, filed June 15, 2026, with respect to Gaganov in view of Hayashi have been fully considered and are persuasive. The rejection of Gaganov in view of Hayashi has been withdrawn.
The applicant persuasively argues that Gaganov is directed to 3 mm or more thick plates (Gaganov [0003]), Hayashi is directed to a thin steel sheet (Hayashi claim 1) (p. 17 paras. 3-7), and the purpose of holding in Hayashi is to control precipitation of Nb, V, Cr, Ti, Mo, etc. (p. 17 para. 9)
Hayashi discloses after winding holding at 400 to 700°C for 1 to 100,000 seconds to control precipitation of oxides, sulfides, nitrides, and composite precipitates of Nb, V, Cr, Ti, and Mo (Hayashi [0044]). Hayashi also discloses that controlling the dispersion of oxides, sulfides, nitrides, complex crystallized particles, and complex precipitates of Nb, V, Cr, Ti, and Mo is different for thin steel sheets and thick steel sheets, which is thought to be due to the interactions between the dislocations and stress fields introduced by processing, including heat treatment methods (Hayashi [0015]). Therefore, the winding holding heat treatment process of Hayashi for thin steel sheets is not obvious to apply to the thick steel sheet of Gaganov.
Hayashi in view of Gaganov
Applicant's arguments filed June 15, 2026 with respect to Hayashi in view of Gaganov have been fully considered but they are not persuasive.
The applicant argues neither Hayashi nor Gaganov disclose the total density of L7 and L68 nor a method for achieving the total density (p. 18 para. 5) and Gaganov does not disclose rough rolling controls the total density of L7 and L68 grain boundaries in bainite (p. 19 paras. 5-11).
In response to applicant's argument that neither Hayashi nor Gaganov disclose the total density of L7 and L68 grain boundaries in bainite as recited in claim 1, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
With respect to hot rolling, which includes rough rolling, Gaganov discloses hot rolling conditions that form a fine-grain austenite microstructure prior to finish rolling, which achieves optimized toughness and fracture elongation properties of the flat steel product (Gaganov [0064]-[0065]). Similar to Gaganov, applicant discloses hot rolling forms uniform prior austenite grains (applicant’s specification [0080]) and realizes an average grain size and aspect ratio of prior austenite grains (applicant’s specification [0081]). Both Gaganov and applicant’s specification recognize the relationship between hot rolling conditions and (prior) austenite. “Expected beneficial results are evidence of obviousness of a claimed invention”. MPEP 716.02(c)(II).
The applicant argues it is unclear if the characteristics of Hayashi would be maintained with the combination (p. 18 paras. 6-8, p. 20 paras. 1-2), where Hayashi is directed to thin steel sheets (claim 1), and Gaganov is directed to 3 mm or more thick plates (Gaganov [0003]) (p. 19 paras. 1-4).
Arguments presented by the applicant cannot take the place of evidence in the record. MPEP 716.01(c)(II).
Evidence to substantiate how the difference in thickness between Hayashi and Gaganov would result in different characteristics based on hot rolling (Hayashi [0010], [0041]) using process conditions that form fine-grained austenite microstructure prior to finish rolling to achieve optimized toughness and fracture elongation (Gaganov [0064]-[0065]). Hayashi is directed to delayed fracture (Hayashi [0014]), which is related to optimizing fracture elongation.
With respect to thickness, applicant’s specification discloses a sheet thickness of 0.6 to 8.0 mm ([0073]). Hayashi discloses a “thin” steel sheet ([0009]). While Hayashi does not disclose a thickness, applicant alleges “thin” refers to a thickness of less than 3 mm (Remarks p. 17 para. 5), which is within the scope of applicant’s invention. Gaganov’s disclosed thickness of at least 3 mm ([0003]) is also within the scope of applicant’s invention. This supports the obviousness of applying the hot rolling conditions of Gaganov during the hot rolling process of Hayashi.
The applicant argues Gaganov discloses rough rolling at 950°C to 1250°C with 50% or more reduction to refine austenite grains (Gaganov [0027]), but Hayashi is silent to austenite grain control (p. 19 paras. 5-11).
In order for a reference to be proper for use in an obviousness rejection under 35 U.S.C., the reference must be analogous art to the claimed invention. A reference is analogous art to the claimed invention if: (1) the reference is from the same field of endeavor as the claimed invention (even if it addresses a different problem); or (2) the reference is reasonably pertinent to the problem faced by the inventor (even if it is not in the same field of endeavor as the claimed invention). MPEP 2141.01(a)(I).
In the instant case, Hayashi and Gaganov are both analogous art proper for use in an obviousness rejection because they are from the same field of endeavor as the claimed invention as evidenced by being hot-rolled steel sheets (Hayashi [0010]-[0011]; Gaganov [0068], [0083]-[0086]) with overlapping chemical composition (Hayashi [0009], [0022]-[0039]; Gaganov [0017]-[0030], [0039]-[0058], Table 1 Steel B), microstructure (Hayashi [0021]; Gaganov [0015], [0073], [0084]-[0085], Table 3 No. 16), and tensile strength (Hayashi [0008]-[0009], [0021]; Gaganov [0075], [0092], Table 3 No. 16) that are manufactured by substantially similar processes including heating, hot rolling, cooling, and winding (Hayashi [0010], [0040]-[0045]; Gaganov [0061]-[0070], Table 2a No. 16)).
For the above cited reasons, the rejection of Hayashi in view of Gaganov is maintained.
Claim Rejections - 35 USC § 103
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.
Claims 1-3, 6, and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Furuhashi (JP 2006-022390 machine translation) in view of Hayashi (JP 2005-068548 machine translation).
Regarding claims 1 and 7, Furuhashi discloses a hot-rolled steel sheet ([0022]) with an overlapping composition ([0020], [0031]-[0046]), microstructure ([0012], [0048]-[0055]), and tensile strength ([0007], [0011], [0030], [0054]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Feature
Claims 1 and 2
Furuhashi Disclosure
Furuhashi Citation
C
0.030 to 0.200
0.05 to 0.20
[0032]
Si
0.05 to 2.50
0.1 to 2.0
[0033]
Mn
1.00 to 4.00
1.0 to 3.0
[0034]
Sol. Al
0.001 to 2.000
0.001 to 0.20
[0037]
Ti
0.030 to 0.200
0.01 to 0.30
[0042]
P
0.020 or less
0.10 or less
[0035]
S
0.020 or less
0.010 or less
[0036]
N
0.010 or less
0.020 or less
[0038]
Nb
0 to 0.200
0.005 to 0.200
Opt. 0.01 to 0.30
[0042]
B
0 to 0.010
0.001 to 0.010
-
-
V
0 to 1.00
0.005 to 1.00
-
-
Mo
0 to 1.00
0.005 to 1.00
Opt. 0.01 to 0.50
[0043]
Cu
0 to 1.00
0.005 to 1.00
-
-
W
0 to 1.00
0.005 to 1.00
-
-
Cr
0 to 1.00
0.005 to 1.00
Opt. 0.01 to 0.50
[0043]
Ni
0 to 1.00
0.005 to 1.00
-
-
Co
0 to 1.00
0.005 to 1.00
-
-
Ca
0 to 0.010
0.0005 to 0.010
-
-
Mg
0 to 0.010
0.0005 to 0.010
-
-
REM
0 to 0.010
0.0005 to 0.010
-
-
Zr
0 to 0.010
0.0005 to 0.010
-
-
Fe
Remainder
Balance
[0040]
Bainite
80.0 or more
95 or more
[0048]-[0055]
Ferrite
10.0 or less
2 or less
[0055]
Microstructure remainder
10.0 or less
5 or less
[0048], [0055]
Tensile Strength
780 MPa or more
980 MPa or more
[0030], [0054]
The limitation of a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° about a <110> direction and a length L68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite is 0.35 to 0.60 um/um2 has been considered and determined to recite a property of the claimed hot-rolled steel sheet that results from the claim 1 composition undergoing the disclosed processing (applicant’s specification [0075]-[0091]). The process of the prior art is substantially similar (Furuhashi [0064]-[0074]).
In the disclosed process controlling the rough rolling and the rolling reduction in the final three stages of finish rolling realized the average grain size and aspect ratio of the prior austenite grains (applicant’s specification [0079]-[0081]). Furuhashi discloses an overlapping prior austenite average grain size and aspect ratio (Furuhashi [0013], [0048], [0051]-[0059]). Further, the cooling temperature achieves a desired amount of bainite (applicant’s specification [0087]). Furuhashi achieves an overlapping amount of bainite ([0048]-[0055]). Achieving an overlapping structure (prior austenite grains and bainite amount) supports the substantial similarity of applicant’s and Furuhashi’s processes.
Applicant
Furuhashi
Heating
1200°C or higher
1.0 hour or longer
[0077]-[0078]
Heating
1050 to 1300°C
[0064]
Hot Rolling
Rough rolling 1000°C or higher
Reduction more than 65%
[0079]-[0081]
-
Hot Rolling
Finish rolling 860 to 980°C
Reduction in final 3 stages less than 25%
[0082]-[0084]
Hot Rolling
Finish rolling 780 to 1030°C
[0066]
Cooling
570 to 620°C
20°C/s or higher
[0085]-[0088]
Cooling
Ar3 to 700°C
10°C/sec or more
[0067]-[0068]
Winding and Retaining
500 to 580°C
2.0 hours or more
[0089]-[0091]
Coiling
700°C or less
[0069]
With respect to processing, Furuhashi is silent to retaining at 500 to 580°C for 2.0 hours or more after coiling.
Hayashi discloses a hot-rolled steel sheet ([0010]-[0011]) that is wound then heat treated between 500 and 580°C (400 to 700°C) for 2.0 hours or more (1 to 100,000 seconds, 0.0003 to 28 hours) ([0044]-[0045]).
It would have been obvious to one of ordinary skill in the art in the process of Furuhashi after coiling to heat treat between 400 and 700°C for 1 to 100,000 seconds (0.0003 to 28 hours) to precipitate oxides, sulfides, nitrides, and composites without coarsening causing a decrease in trapping ability and steel strength (Hayashi [0044]-[0045]).
The prior art discloses a composition (Furuhashi [0020], [0031]-[0046]), microstructure (Furuhashi [0012], [0048]-[0055]), tensile strength (Furuhashi [0007], [0011], [0030], [0054]), and processing (Furuhashi [0064]-[0074]; Hayashi [0044]-[0045]) that is substantially similar to the claimed composition (claim 1) and the process to form the claimed hot-rolled steel sheet (applicant’s specification [0075]-[0091]). Therefore, the claimed properties naturally flow from the disclosure of the prior art, including a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° about a <110> direction and a length L68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite being 0.35 to 0.60 um/um2.
Regarding claim 2, Furuhashi discloses an overlapping composition ([0042]-[0043]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claims 3 and 6, Furuhashi discloses in the microstructure an average grain size of prior austenite grains is 10 to 30 um (20 um or less), and a ratio ld/Sd between a long axis ld and a short axis Sd of the prior austenite grains is 2.0 or less (5.0 or less) ([0013], [0048], [0051]-[0059]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Claims 1-3, 6, and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Hayashi (JP 2005-068548 machine translation) in view of Gaganov (US 2017/0137911).
Regarding claim 1, Hayashi discloses a hot-rolled steel sheet ([0010]-[0011]) comprising an overlapping chemical composition ([0009], [0022]-[0039]), microstructure ([0021]), and tensile strength ([0008]-[0009], [0021]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Feature
Claims 1 and 2
Hayashi Disclosure
Hayashi Citation
C
0.030 to 0.200
0.01 to 0.3
[0022]
Si
0.05 to 2.50
2.0 max
[0023]
Mn
1.00 to 4.00
0.01 to 3.0
[0024]
Sol. Al
0.001 to 2.000
0.005 to 4.0
[0027]
Ti
0.030 to 0.200
0.001 to 3
[0032]
P
0.020 or less
0.1 max
[0025]
S
0.020 or less
0.05 max
[0026]
N
0.010 or less
0.01 max
[0028]
Nb
0 to 0.200
0.005 to 0.200
0.001 to 3
[0029]
B
0 to 0.010
0.001 to 0.010
0.0002 to 0.1
[0037]
V
0 to 1.00
0.005 to 1.00
0.001 to 3
[0030]
Mo
0 to 1.00
0.005 to 1.00
0.0001 to 3
[0033]
Cu
0 to 1.00
0.005 to 1.00
0.005 to 5.0
[0035]
W
0 to 1.00
0.005 to 1.00
0.005 to 5
[0034]
Cr
0 to 1.00
0.005 to 1.00
0.001 to 3
[0031]
Ni
0 to 1.00
0.005 to 1.00
0.005 to 5
[0036]
Co
0 to 1.00
0.005 to 1.00
-
-
Ca
0 to 0.010
0.0005 to 0.010
0.0005 to 0.01
[0039]
Mg
0 to 0.010
0.0005 to 0.010
0.0005 to 0.01
[0038]
REM
0 to 0.010
0.0005 to 0.010
0.0005 to 0.01
[0039]
Zr
0 to 0.010
0.0005 to 0.010
-
-
Fe
Remainder
Balance
[0009]
Bainite
80.0 or more
30 to 100%
[0021]
Ferrite
10.0 or less
-
-
Microstructure remainder
10.0 or less
-
-
Tensile Strength
780 MPa or more
980 MPa or more
[0008]-[0009], [0021]
The limitation of a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° about a <110> direction and a length L68 of a grain boundary having a crystal orientation difference of 68° about the <110> direction in the bainite is 0.35 to 0.60 um/um2 has been considered and determined to recite a property that results from applicant’s disclosed manufacturing process (applicant’s specification [0075]-[0091]). As presented in the following table, the processing of Hayashi overlaps with applicant’s disclosed heating, finish hot rolling, cooling then winding, and retaining conditions (Hayashi [0010], [0040]-[0045]).
Applicant
Hayashi
Heating
1200°C or higher
1.0hour or longer
[0077]-[0078]
Reheating
1100 to 1300°C
To prevent high rolling resistance and grain coarsening
[0040]
Hot Rolling
Rough rolling 1000°C or higher
Reduction more than 65%
Finish rolling 860 to 980°C
[0079]-[0084]
Hot Rolling
Not less than Ar point or higher
[0010], [0041]
Cooling then Winding
570 to 620°C
20°C/s or higher
[0085]-[0088]
Cooling then Coiling
Preferably 500 to 700°C
Preferably 20°C/sec to 1000°C/sec
[0042]-[0043]
Retaining
500 to 580°C
2.0 hours or more
[0089]-[0091]
Holding
400 to 700°C
1 to 100,000 seconds (0.0003 to 28 hours)
[0044]-[0045]
With respect to processing, Hayashi is silent to hot rolling rough rolling at 1000°C or higher with a rolling reduction of more than 65%.
Gaganov discloses a hot-rolled steel sheet ([0062]-[0070]) that is hot rolled with a rough rolling completion temperature of 1000°C or higher (950 to 1250°C) and a total reduction of more than 65% (at least 50%) ([0064]-[0065]).
It would have been obvious to one of ordinary skill in the art in the process of Hayashi during hot rolling to rough roll at 950 to 1250°C with a reduction of at least 50% so that recrystallization processes can proceed to completion in each rough-rolled slab to assure the formation of fine-grain austenite microstructure prior to finish rolling, which achieves optimized toughness and fracture elongation properties of the flat steel product (Gaganov [0065]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
The prior art discloses a composition (Hayashi [0009], [0022]-[0039]), microstructure (Hayashi [0021]), tensile strength (Hayashi [0008]-[0009], [0021]), and processing (Hayashi [0010], [0040]-[0045]; Gaganov [0064]-[0065]) that is substantially similar to the claimed composition (claim 1) and the process to form the claimed hot-rolled steel sheet (applicant’s specification [0075]-[0091]). Therefore, the claimed properties naturally flow from the disclosure of the prior art, including a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° and a length L68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite being 0.35 to 0.60 um/um2.
Regarding claim 2, Hayashi discloses an overlapping chemical composition ([0009], [0022]-[0039]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Regarding claim 3, Hayashi discloses the presence of prior austenite grain boundaries ([0013]).
The limitations of in the microstructure, an average grain size of prior austenite grains being 10 to 30 um, and a ratio ld/Sd between a long axis ld and a short axis Sd of the prior austenite grains being 2.0 or less have been considered and determined to recite properties that results from applicant’s disclosed manufacturing process (applicant’s specification [0075]-[0091]). As presented in the claim 1 rejection, the processing of Hayashi in view of Gaganov overlaps with applicant’s disclosed heating, finish hot rolling, cooling then winding, retaining (Hayashi [0010], [0040]-[0045]), and rough rolling conditions (Gaganov [0064]-[0065])
The prior art discloses a composition (Hayashi [0009], [0022]-[0039]), microstructure (Hayashi [0021]), tensile strength (Hayashi [0008]-[0009], [0021]), and processing (Hayashi [0010], [0040]-[0045]; Gaganov [0064]-[0065]) that is substantially similar to the claimed composition (claim 1) and the process to form the claimed hot-rolled steel sheet (applicant’s specification [0075]-[0091]). Therefore, the claimed properties naturally flow from the disclosure of the prior art, including in the microstructure, an average grain size of prior austenite grains being 10 to 30 um, and a ratio ld/Sd between a long axis ld and a short axis Sd of the prior austenite grains being 2.0 or less.
Regarding claim 6, Hayashi discloses the presence of prior austenite grain boundaries ([0013]).
The limitations of in the microstructure, an average grain size of prior austenite grains being 10 to 30 um, and a ratio ld/Sd between a long axis ld and a short axis Sd of the prior austenite grains being 2.0 or less have been considered and determined to recite properties that results from applicant’s disclosed manufacturing process (applicant’s specification [0075]-[0091]). As presented in the claim 1 rejection, the processing of Hayashi in view of Gaganov overlaps with applicant’s disclosed heating, finish hot rolling, cooling then winding, retaining (Hayashi [0010], [0040]-[0045]), and rough rolling conditions (Gaganov [0064]-[0065])
The prior art discloses a composition (Hayashi [0009], [0022]-[0039]), microstructure (Hayashi [0021]), tensile strength (Hayashi [0008]-[0009], [0021]), and processing (Hayashi [0010], [0040]-[0045]; Gaganov [0064]-[0065]) that is substantially similar to the claimed composition (claim 2) and the process to form the claimed hot-rolled steel sheet (applicant’s specification [0075]-[0091]). Therefore, the claimed properties naturally flow from the disclosure of the prior art, including in the microstructure, an average grain size of prior austenite grains being 10 to 30 um, and a ratio ld/Sd between a long axis ld and a short axis Sd of the prior austenite grains being 2.0 or less.
Regarding claim 7, Hayashi discloses a hot-rolled steel sheet ([0010]-[0011]) comprising an overlapping chemical composition ([0009], [0022]-[0039]), microstructure ([0021]), and tensile strength ([0008]-[0009], [0021]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Feature
Claim 7
Hayashi Disclosure
Hayashi Citation
C
0.030 to 0.200
0.01 to 0.3
[0022]
Si
0.05 to 2.50
2.0 max
[0023]
Mn
1.00 to 4.00
0.01 to 3.0
[0024]
Sol. Al
0.001 to 2.000
0.005 to 4.0
[0027]
Ti
0.030 to 0.200
0.001 to 3
[0032]
P
0.020 or less
0.1 max
[0025]
S
0.020 or less
0.05 max
[0026]
N
0.010 or less
0.01 max
[0028]
Nb
0 to 0.200
0.001 to 3
[0029]
B
0 to 0.010
0.0002 to 0.1
[0037]
V
0 to 1.00
0.001 to 3
[0030]
Mo
0 to 1.00
0.001 to 3
[0033]
Cu
0 to 1.00
0.005 to 5
[0035]
W
0 to 1.00
0.005 to 5
[0034]
Cr
0 to 1.00
0.001 to 3
[0031]
Ni
0 to 1.00
0.005 to 5
[0036]
Co
0 to 1.00
-
-
Ca
0 to 0.010
0.0005 to 0.01
[0039]
Mg
0 to 0.010
0.0005 to 0.01
[0038]
REM
0 to 0.010
0.0005 to 0.01
[0039]
Zr
0 to 0.010
-
-
Fe
Remainder
Balance
[0009]
Bainite
80.0 or more
30 to 100%
[0021]
Ferrite
10.0 or less
-
-
Microstructure remainder
10.0 or less
-
-
Tensile Strength
780 MPa or more
980 MPa or more
[0021]
The limitation of a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° about a <110> direction and a length L68 of a grain boundary having a crystal orientation difference of 68° about the <110> direction in the bainite is 0.35 to 0.60 um/um2 has been considered and determined to recite a property that results from applicant’s disclosed manufacturing process (applicant’s specification [0075]-[0091]). As presented in the following table, the processing of Hayashi overlaps with applicant’s disclosed heating, finish hot rolling, cooling then winding, and retaining conditions (Hayashi [0010], [0040]-[0045]).
Applicant
Hayashi
Heating
1200°C or higher
1.0hour or longer
[0077]-[0078]
Reheating
1100 to 1300°C
To prevent high rolling resistance and grain coarsening
[0040]
Hot Rolling
Rough rolling 1000°C or higher
Reduction more than 65%
Finish rolling 860 to 980°C
[0079]-[0084]
Hot Rolling
Not less than Ar point or higher
[0010], [0041]
Cooling then Winding
570 to 620°C
20°C/s or higher
[0085]-[0088]
Cooling then Coiling
Preferably 500 to 700°C
Preferably 20°C/sec to 1000°C/sec
[0042]-[0043]
Retaining
500 to 580°C
2.0 hours or more
[0089]-[0091]
Holding
400 to 700°C
1 to 100,000 seconds (0.0003 to 28 hours)
[0044]-[0045]
With respect to processing, Hayashi is silent to hot rolling rough rolling at 1000°C or higher with a rolling reduction of more than 65%.
Gaganov discloses a hot-rolled steel sheet ([0062]-[0070]) that is hot rolled with a rough rolling completion temperature of 1000°C or higher (950 to 1250°C) and a total reduction of more than 65% (at least 50%) ([0064]-[0065]).
It would have been obvious to one of ordinary skill in the art in the process of Hayashi during hot rolling to rough roll at 950 to 1250°C with a reduction of at least 50% so that recrystallization processes can proceed to completion in each rough-rolled slab to assure the formation of fine-grain austenite microstructure prior to finish rolling, which achieves optimized toughness and fracture elongation properties of the flat steel product (Gaganov [0065]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
The prior art discloses a composition (Hayashi [0009], [0022]-[0039]), microstructure (Hayashi [0021]), tensile strength (Hayashi [0008]-[0009], [0021]), and processing (Hayashi [0010], [0040]-[0045]; Gaganov [0064]-[0065]) that is substantially similar to the claimed composition (claim 1) and the process to form the claimed hot-rolled steel sheet (applicant’s specification [0075]-[0091]). Therefore, the claimed properties naturally flow from the disclosure of the prior art, including a total density of a length L7 of a grain boundary having a crystal orientation difference of 7° and a length L68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite being 0.35 to 0.60 um/um2.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Hayashi (JP 2005-068548 machine translation) in view of Venkatasurya (WO 2017/108966 with citations from US 2019/0003007) as applied to claim 1 above, and further in view of Furuhashi (JP 2006-022390 machine translation).
In the event it is determined that the claimed prior austenite average grain size and ratio Ld/Sd do not naturally flow from the disclosure of Hayashi in view of Venkatasurya, then the below rejection in view of Furuhashi is applied.
Regarding claim 3, Hayashi discloses the presence of prior austenite grain boundaries ([0013]).
Furuhashi discloses a hot-rolled steel sheet ([0022]) in the microstructure an average grain size of prior austenite grains is 10 to 30 um (20 um or less), and a ratio ld/Sd between a long axis ld and a short axis Sd of the prior austenite grains is 2.0 or less (5.0 or less) ([0013], [0048], [0051]-[0059]).
It would have been obvious to one of ordinary skill in the art in the steel of Hayashi to have an average grain size of prior austenite grains of 20 um or less and a ratio ld/Sd of prior austenite grains of 5.0 or less so that voids are less likely to occur during bending, resulting in cracks (Furuhashi [0051]) and so that the variation in bendability in width direction of the coil becomes significant (Furuhashi [0052]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Hayashi (JP 2005-068548 machine translation) in view of Venkatasurya (WO 2017/108966 with citations from US 2019/0003007) as applied to claim 2 above, and further in view of Furuhashi (JP 2006-022390 machine translation).
In the event it is determined that the claimed prior austenite average grain size and ratio Ld/Sd do not naturally flow from the disclosure of Hayashi in view of Venkatasurya, then the below rejection in view of Furuhashi is applied.
Regarding claim 6, Hayashi discloses the presence of prior austenite grain boundaries ([0013]).
Furuhashi discloses a hot-rolled steel sheet ([0022]) in the microstructure an average grain size of prior austenite grains is 10 to 30 um (20 um or less), and a ratio ld/Sd between a long axis ld and a short axis Sd of the prior austenite grains is 2.0 or less (5.0 or less) ([0013], [0048], [0051]-[0059]).
It would have been obvious to one of ordinary skill in the art in the steel of Hayashi to have an average grain size of prior austenite grains of 20 um or less and a ratio ld/Sd of prior austenite grains of 5.0 or less so that voids are less likely to occur during bending, resulting in cracks (Furuhashi [0051]) and so that the variation in bendability in width direction of the coil becomes significant (Furuhashi [0052]). In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05(I).
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 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.
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/STEPHANI HILL/Examiner, Art Unit 1735
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