DETAILED ACTION
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 07/16/2026 has been entered.
Status of Claims
Claims 1-7 and 9-15 are pending. Of the pending claims, claims 1-7 and 9 are presented for examination on the merits, and claims 10-15 are withdrawn from examination.
Claims 1 and 2 are currently amended.
Status of Previous Claim Rejections Under 35 USC § 112
The previous rejection of claim 8 under 35 U.S.C. § 112(b) is moot in view of the canceled status of the claim.
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 1-4 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over US 2021/0343458 (A1) (also WO 2020/091039 (A1)) to Yashiki et al. (“Yashiki”) in view of US 2016/0322137 (A1) to Lee et al. (“US ʹ137”).
US 2021/0343458 (A1) is a pre-grant publication of U.S. application serial no. 17/259,837, which is a 371 national stage application of PCT/JP2019/0430241, published by WIPO as WO 2020/091039 (A1). The pre-grant publication will serve as the translation for the WIPO publication.
Regarding claim 1, Yashiki discloses a non-oriented electrical steel sheet. Abstract; para. [0048], [0049]. The steel sheet contains the following elements in percent by mass (para. [0014]-[0030], [0035]-[0037], [0052]-[0086]):
Element
Claim 1
US 2021/0343458 A1
Si
3.0 - 4.0
more than 3.7 and 5.0 or less
Al
0.3 - 1.5
0.05 - 0.45
Mn
0.1 - 0.6
more than 0.2 and 1.5 or less
Sn
Sn and/or Sb: 0.006-0.1
0 to 0.100
Sb
Sn and/or Sb: 0.006-0.1
0 to 0.100
C
0.0015 - 0.0040
0.0050 or less
Cr
0.01 - 0.03
0.5 or less
Cu
0.003 - 0.008
less than 0.200
Mg
0.0005 - 0.0025
0.002 or less
N
0.0003 - 0.0030
0.0030 or less
Fe & inevitable
balance
remainder
impurities
With respect to claimed Equation 1, Steel D has a calculated value of 0.03 and Steel I has a calculated value of 5.17. Table 1. Thus, the example steels have Equation 1 values ranging from 0.03 to 5.17, which encompasses the range defined by Equation 1. Steels M, N, and R have calculated Equation 1 values of 1.92, 1.77, and 1.77, respectively, which fall within the claimed range.
Furthermore, the quantities of Sn, Sb, Cr, Cu, and Mg in Yashiki overlap with the claimed Sn, Sb, Cr, Cu, and Mg ranges. Therefore, calculations based on these quantities, such as Equation 1, would also overlap the claimed range.
The overlap between the ranges taught in the prior art and recited in the claims creates a prima facie case of obviousness. MPEP § 2144.05(I). It would have been obvious for one of ordinary skill in the art to select from among the prior art ranges because there is utility over an entire range disclosed in the prior art.
Yashiki is silent regarding a claimed distribution density of AlN precipitates. However, it is well established that when a material is produced by a process that is identical or substantially identical to that of the claims and/or possesses a structure or composition that is identical or substantially identical to that of the claims, any claimed properties or functions are presumed to be inherent. Such a finding establishes a prima facie case of anticipation or obviousness. See MPEP § 2112.01.
In the present instance, Yashiki discloses a steel that has a chemical composition as claimed. In addition, Yashiki discloses a method of manufacture, wherein the steel is heated (para. [0100]-[0103]); hot rolled (para. [0102], [0103]); annealed (para. [0104]-[0106]); coiled (para. [0119]); pickled (para. [0107], [0108]); cold rolled (para. [0109], [0110]); final annealed (para. [0111]-[0114]); and coated with insulation coating (para. [0115], [0116]). The method of manufacture of the present invention includes steps of heating the slab, hot rolling, winding, annealing, cold rolling, final annealing, and forming an insulating film (instant spec at pp. 17-20). The parameters (e.g., heating temperatures, times, dew point, and soaking atmosphere) of Yashiki also match those parameters disclosed in the instant specification. Therefore, any claimed characteristics, such as oxide layer, oxide composition, and precipitate density, would also be expected in the prior art steels given the alignment between their composition and method of fabrication.
In addition to Yashiki’s method of manufacture, controlling the concentration of fine AlN precipitates is well known. US ʹ137 is directed to a non-oriented electrical steel sheet. Abstract; para. [0001]. To achieve high magnetic flux density and low iron loss, composite inclusions including either or both AlN and MnS having a size of at least 10 nm must have a distribution density of 0.02 unit per mm2 or less. Para. [0017], [0036]; claim 3. AlN suppresses crystal grain growth and deteriorates iron loss and should be includes in the steel in as small of an amount as possible. Para. [0042].
It would have been obvious to one of ordinary skill in the art to have operated Yashiki’s method in such a way that results in the fabrication of an electrical steel sheet in which AlN precipitates are minimized throughout the steel sheet, including in regions near the surface, because reducing their density improves at least iron loss property.
Regarding claim 2, Yashiki discloses S, Ti, Nb, and V in the steel in the following overlapping amounts (para. [0064]-[0071], [0074], [0075]):
Element
Claim 2
US 2021/0343458 A1
at least one of
S
0.0003 - 0.0030
0.0030 or less
Ti
0.0003 - 0.0030
less than 0.0050
Nb
0.0003 - 0.0030
less than 0.0050
V
0.0003 - 0.0030
less than 0.0050
Regarding claim 3, Yashiki discloses P, Mo, and Ni in the steel in the following overlapping amounts (para. [0062], [0063], [0078], [0079], [0084]):
Element
Claim 3
US 2021/0343458 A1
P
0.005 - 0.05
0.030 or less
Mo
0.001 - 0.01
0.5 or less
Ni
0.005 - 0.04
less than 0.500
Regarding claim 4, Yashiki discloses that the average grain size of the base metal is more than 40 µm and 120 µm or less (para. [0088]-[0090]), which encompasses the claimed range.
Regarding claim 9, Yashiki discloses that the final sheet thickness of the base metal is 0.10 mm to 0.35 mm (para. [0110]), which is identical to the claimed range.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Yashiki in view of US ʹ137, as applied to claim 1 above, and further in view of JP 2006-241563 (A) to Takeda et al. (“Takeda”) (abstract and computer-generated translation are in file as of 11/18/2025).
Regarding claim 5, Yashiki is silent regarding the existence of an oxide and its thickness on the steel sheet.
Takeda is directed to a non-oriented silicon steel sheet having excellent magnetic properties. Abstract. The steel sheet has an oxide layer on the surface, and the thickness of the oxide is 2-20 nm thick (para. [0010]), which overlaps the claimed range. By forming a surface oxide layer on the very surface of the steel sheet, the formation of an internal oxide layer and the absorption of nitrogen is prevented. Para. [0012], [0019], [0025]. The oxide layer is mainly formed of SiO2 and MnO2. Abstract; para. [0026].
Takeda teaches that an internal oxide layer deteriorates magnetic properties. Para. [0005]. Therefore, it would have been obvious to one of ordinary skill in the art to have grown an oxide layer having a thickness of 2 nm to 20 nm on the surface of the steel sheet of Yashiki because the surface oxide would avoid the creation of internal oxides that have negative effects on the magnetism of the steel sheet.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Yashiki in view of US ʹ137, as applied to claim 1 above, and further in view of US 2023/0021153 (A1) (also WO 2021/125683 (A2)) to Lee et al. (“US ʹ153”).
US 2023/0021153 (A1) is a pre-grant publication of U.S. application serial no. 17/787,023, which is a 371 national stage application of PCT/KR2020/017976, published by WIPO as WO 2021/125683 (A2). The pre-grant publication will serve as the translation for the WIPO publication.
Regarding claim 5, Yashiki is silent regarding the existence of an oxide and its thickness on the steel sheet.
US ʹ153 is directed to a non-oriented electrical steel sheet. Abstract. The steel is exposed to oxygen during manufacturing, and an oxygen concentration gradient may exist from the surface to the inner direction. Para. [0081]. The oxide layer may be 10-50 nm. Para. [0082]. The oxide contains O in an amount of 40-70 wt.%, Al in an amount of 25-55 wt.%, P in an amount of 0.01-0.1 wt.%, and Sn in an amount of 0.01-0.1 wt.%. Para. [0083]. The oxide suppresses nitrogen from diffusing to the base material, thereby improving magnetism. Para. [0082].
It would have been obvious to have added an oxide layer having a thickness of 10 nm to 50 nm on the surface of the steel sheet of Yashiki because the oxide layer would enhance the steel’s magnetic properties by blocking nitrogen from diffusing into the base steel.
Allowable Subject Matter
Claims 6 and 7 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: The closest prior art is Yashiki in view of US ʹ137 further in view of either Takeda or US ʹ153. With respect to Takeda, Takeda teaches that the oxide layer is mainly formed of SiO2 and MnO2 (abstract; para. [0026]) and therefore does not teach the proportions and ratios of Al and Si recited in claims 6 and 7. With respect to US ʹ153, US ʹ153 teaches the oxide contains O in an amount of 40-70 wt.%, Al in an amount of 25-55 wt.%, P in an amount of 0.01-0.1 wt.%, and Sn in an amount of 0.01-0.1 wt.% (para. [0083]) and therefore does not teach the proportions and ratios of Al and Si recited in claims 6 and 7.
Response to Arguments
Applicant's arguments filed 07/16/2026 have been fully considered, but they are not persuasive.
Applicant argues that Yashiki does not teach or disclose the claimed surface-region AlN precipitate distribution density and that the claimed density is not an obvious matter or routine experimentation.
In response, the argument is moot in view of the of citation to US ʹ137, which discloses that the distribution density of AlN (10 nm or larger) should be minimized to less than or equal to 0.02 units/mm2 to lower iron loss, as noted above. Because of the adverse effects of AlN, one of ordinary skill in the art would be motivated to control and minimize their amount to avoid deteriorating the magnetic properties of the steel sheet.
Applicant argues that Yashiki does not teach or suggest controlling Sn, Sb, Cr, Cu, and Mg so as to satisfy Equation 1.
In response, Table 1 of Yashiki discloses compositions of Steels M, N, and R, each of which has calculated Equation 1 values of 1.92, 1.77, and 1.77, respectively. These values fall within the claimed range. Thus, the limits of Equation 1 are taught in the prior art.
Applicant argues that Equation 1 is necessary for forming an appropriately dense oxide layer on the steel sheet and suppressing formation of fine AlN precipitates.
In response, this is not persuasive because the formation of an oxide layer for suppressing nitrogen absorption, and therefore the formation of AlN, is known in the art. Takeda teaches that by forming a surface oxide layer on the very surface of the steel sheet, the formation of an internal oxide layer and the absorption of nitrogen is prevented (para. [0012], [0019], [0025]). US ʹ153 teaches that the oxide suppresses nitrogen from diffusing to the base material, thereby improving magnetism (para. [0082]). Thus, there is no new discovery in the beneficial effects of an oxide layer.
The argument is further not persuasive because the data in the instant specification do not support the assertion. Specimen No. B2 has an Equation 1 value of 0.89 (Table 2), which falls within the claimed range of 0.66 and 2. However, Specimen No. B2 contains AlN precipitates in a distribution density of 6.3/mm2, which falls outside the claimed upper limit of 3/mm2. Therefore, it cannot be concluded that Equation 1 is critical when samples satisfying the equation produce steels with AlN precipitates that exceed the claimed permitted limit.
Conclusion
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/VANESSA T. LUK/Primary Examiner, Art Unit 1733
September 19, 2026
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