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 .
Election/Restrictions
Applicant’s election without traverse of Group I (Claims 1-3 and 6) in the reply filed on 05/11/2026 is acknowledged. Claims 4-5 are withdrawn. Claims 1-3 and 6 are examined herein.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-3 and 6 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites REM. Please spell out the full term of REM to improve claim clarity. Appropriate correction is required.
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.
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.
Claims 1-3 and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Takashima (US 2019/0161822) in view of Yokoyama (WO2020/162562, US 2022/0064771 is used as translation), and further in view of Kasuya (US 2017/0096723).
Regarding claims 1 and 2, Takashima discloses (Abstract; [0025] to [0064]) a steel sheet with a composition that overlaps with the instant claimed composition and therefore it would have been obvious to one of ordinary skill in the art to have selected amounts of each element from the ranges disclosed in Takashima to produce a steel composition that meets the recited composition in claim 1. The recited amount of O in claim 1 is a well-known impurity level oxygen in steel. It would be obvious to one of ordinary skill in the art to control the O level as low as possible in order to make a steel sheet having good mechanical properties.
Element
Claim 1
(mass %)
Takashima
(mass %)
Overlap
(mass %)
C
0.07-0.15
0.05-0.15
0.07-0.15
Si
0.01-2.0
0.0-1.6
0.01-1.6
Mn
1.5-3.0
1.3-2.4
1.5-2.4
P
0-0.02
0-0.05
0-0.02
S
0-0.02
0-0.005
0-0.005
Al
0.001-1
0.01-0.1
0.01-0.1
N
0-0.02
0-0.01
0-0.01
Co
0-0.5
0-0.1
0-0.1
Ni
0-1.0
0-0.05
0-0.05
Mo
0.0-1.0
0.005-0.5
0.005-0.5
Cr
0-2
0.005-1.0
0.005-1.0
O
0-0.02
impurity
impurity
Ti
0.0-0.5
0.005-0.1
0.005-0.1
B
0-0.01
0.0002-0.004
0.0002-0.004
Nb
0-0.5
0-0.5
0-0.5
V
0-0.5
0-0.05
0-0.05
Cu
0-0.5
0-0.3
0-0.3
Ta
0-0.1
0-0.01
0-0.01
Sn
0-0.05
0-0.1
0-0.05
Sb
0-0.05
0-0.01
0-0.01
Mg
0-0.05
0-0.01
0-0.01
Ca
0-0.05
0-0.005
0-0.005
Zr
0-0.05
0-0.1
0-0.05
REM
0-0.1
0-0.005
0-0.005
W
0-0.1
0
0
As
0-0.05
0
0
Fe + Impurities
Balance
Balance
Balance
Takashima discloses that the steel contains, by volume fraction, ferrite of 35% to 65%, residual austenite of 7% or less (including 0%), martensite of 20% to 60%, bainite of 20% or less (including 0%) (Abstract), which overlaps the recited area proportion of phases in claim 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). See MPEP 2144.05 I. Thus, the recited area fraction of phases is a prima facie case of obviousness over Takashima.
Takashima discloses examples that meet the recited composition of essential elements in claim 9 (Table 1, Steel A, B, C, E, F and H) and also meet the recited phase content in claim 9 (Table 3, Sample No. 1-8).
Takashima does not explicitly disclose that a ratio of the number of crystal grains of the ferrite and the bainite having an area of 6 µm2 or less to a total number of crystal grains of the ferrite and the bainite is 40% or more, a proportion of crystal grains of the ferrite and the bainite having an area of 50 µm2 or more is 5% or less, and a maximum Mn content in a region up to 0.5 µm from an interface between the ferrite and the martensite or the tempered martensite, in a direction perpendicular to the interface and toward an inside of the ferrite grains, is 0.30 mass% or more lower than an average Mn content of the steel sheet as recited in claim 1 and that an average aspect ratio of the crystal grains of the ferrite and the bainite having an area of 6 µm2 or less is 1.0 or greater and 2.0 or less as recited in claim 2.
However, these structure features depend on the steel composition and the method of making the steel. Takashima discloses a method of making the steel sheet, comprising: heating the slab to 1150-1270°C, hot-rolling to manufacture a hot-rolled sheet with a finish rolling temperature of 850-950 °C, cooling the hot-rolled sheet to 700 ºC or less at a cooling rate of 75 ºC/s ore higher, coiling the hot rolled steel sheet at temperatures of 300-600° C, cold rolling the steel sheet at a reduction rate of 25% to 85%, annealing the cold rolled sheet at 760 to 900° C for 15-1200 seconds ([0085] to [0110]), which overlap the processing temperature and time recited in claim 4.
The difference between the method of Takashima and the method of instant Specification is that Takashima does not disclose that finish rolling is performed using a rolling mill having four or more stands wherein a ratio of sheet thickness reduction in each of stands ranging from an (n-3)-th stand to the n-th stand is set to 30% or greater and that the holding time in a temperature range from the coiling temperature to the coiling temperature - 50ºC is 2 to 8 hours as recited in claim 4.
Yokoyama teaches a method of making a steel sheet having composition and phase content overlapping the composition and phase content of Takashima ([0079] to [0178]). Yokoyama discloses that finish rolling is performed using a rolling mill having a plurality of stands wherein a ratio of sheet thickness reduction in each stand is 37% or less to make a steel sheet having excellent formability and toughness ([0019]; [0020]; [0165]). Thus, it would be obvious to one of ordinary skill in the art to perform finish rolling using a rolling mill having a plurality of stands wherein a ratio of sheet thickness reduction in each stand is 37% or less as taught by Yokoyama in the process of Takashima in order to make a steel sheet having excellent formability and toughness as disclosed by Yokoyama. The finish rolling reduction ratio disclosed by Yokoyama overlaps the recited finish rolling reduction ratio in claim 4. 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.
Takashimain in view of Yokoyama does not disclose the holding time in a temperature range from the coiling temperature to the coiling temperature - 50ºC is 2 to 8 hours as recited in claim 4. Kasuya teaches a method of making a steel sheet having composition and phase content overlapping the composition and phase content of Takashima ([0008] to [0024]). Kasuya discloses that the holding time at the coiling temperature is 3 hours or more and air cooling to room temperature is performed afterwards to make a steel sheet having high tensile strength and ductility ([0026]; [0027]; [0090] to [0093]). Thus, it would be obvious to one of ordinary skill in the art to perform holding at a coiling temperature for 3 hours or more followed by air cooling to room temperature as taught by Kasuya in the process of Takashima in order to make a steel sheet having high tensile strength and ductility as disclosed by kasuya. Air-cooling disclosed by Kasuya meets the recited colling rate of 0.1 ºC/s or higher as recited in claim 4.
In view of the fact that Takashima in view of Yokoyama and Kasuya teaches a steel composition that meets the recited composition in claim 1 and a method of making the steel sheet with processing parameters overlapping the processing conditions recited in claim 4, one of ordinary skill in the art would expect that the steel sheet disclosed by Takashimain view of Yokoyama and Kasuya to meet the limitation that that a ratio of the number of crystal grains of the ferrite and the bainite having an area of 6 µm2 or less to a total number of crystal grains of the ferrite and the bainite is 40% or more, a proportion of crystal grains of the ferrite and the bainite having an area of 50 µm2 or more is 5% or less, and a maximum Mn content in a region up to 0.5 µm from an interface between the ferrite and the martensite or the tempered martensite, in a direction perpendicular to the interface and toward an inside of the ferrite grains, is 0.30 mass% or more lower than an average Mn content of the steel sheet as recited in claim 1 and that an average aspect ratio of the crystal grains of the ferrite and the bainite having an area of 6 µm2 or less is 1.0 or greater and 2.0 or less as recited in claim 2. “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.
Regarding claims 3 and 6, Takashima discloses that the steel sheet contains zinc coating layer ([0107]; [0108]), which meets the limitation recited in claims 3 and 6.
Conclusion
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/XIAOWEI SU/Primary Examiner, Art Unit 1733
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