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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 1-12 are pending and presented for examination on the merits.
Claim 1 is currently amended.
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 1-12 are rejected under 35 U.S.C. 103 as being unpatentable over US 2020/0087746 (A1) (also WO 2018/110676 (A1)) to Omura et al. (“Omura”).
US 2020/0087746 (A1) is a pre-grant publication of U.S. appl. ser. no.16/468,087, which is a 371 national stage application of PCT/JP2017/044989, published by WIPO as WO 2018/110676 (A1). The pre-grant publication will serve as an equivalent to and the translation for the WIPO publication.
Regarding claim 1, Omura discloses a grain-oriented electrical steel sheet. Title; abstract; para. [0001]. The steel sheet contains Si in an amount of 2.0-8.0% by mass (para. [0103], [0104]) and Sb in an amount of 0.005-1.500% by mass (para. [0110], [0112]), each encompassing the claimed ranges. The balance of the steel is Fe and inevitable impurities. Para. [0113].
The steel sheet comprises a steel substrate (electrical steel sheet base material) and a forsterite film on the steel substrate. Para. [0074]-[0076]. A Cr-depleted layer is located between the steel substrate and the forsterite film. Para. [0077]. A tension coating (also an insulating coating) is formed on the steel comprising the steel substrate and forsterite film (insulating coating layer positioned on the electrical steel sheet base material). Para. [0084], [0085], [0135].
Omura is silent regarding pore particle size in the insulating coating layer, subgrain boundary position in the steel substrate, subgrain boundary angle, and subgrain boundary area fraction in an ND cross section. 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 instant case, Omura discloses a method of manufacture where the grain-oriented electrical steel sheet is made by the following steps: heating a slab (para. [0115], [0116]); hot rolling (para. [0117]-[0119]); hot band annealing (para. [0120], [0121]); cold rolling (para. [0122], [0123]); decarburization annealing at a temperature of 750-900oC in an oxidizing atmosphere PH2O/PH2 of 0.25-0.60 (para. [0124], [0125]); applying an annealing separator (para. [0126], [0127]); final annealing comprising secondary recrystallization (para. [0128], [0128]); and flattening treatment and insulation coating at 750-900oC (para. [0133]-[0135]). An example line tension value during coating is 0.7 kgf/mm2 (para. [0039], [0049], [0057]), which falls within the line tension value of 0.20-0.70 kgf/mm2 in the instant specification (p. 24 – line 24 to p. 25 – lines 1-24). The line tension value is the same for each passing (e.g., para. [0049]), suggesting that the line tension stays consistent throughout the process, thereby satisfying Formula (Expression) 2 of the present invention (instant spec at p. 25).
The method of manufacture of the present invention includes steps of heating and hot rolling a slab (p. 21 – lines 20-24 to p. 22 – lines 1-9); annealing (p. 22 – lines 12-15); cold rolling (p. 22 – lines 16-21); carrying out primary recrystallization by decarburizing or nitriding at 800-900oC and an oxidation capacity PH2O/PH2 of 0.5-0.7 (p. 23 – lines 1-13); coating with annealing separator (p. 23 – lines 14-20); carrying out secondary recrystallization (p. 23 – lines 21-24 to p. 24 – lines 1-4); flattening annealing (p. 24 – lines 5-6); and coating with an insulating coating layer in which heat treatment is 550-1100oC (p. 24 – lines 7-16). Tension applied to the steel sheet during forming of the insulation coating layer is 0.20-0.70 kgf/mm2 (p. 24 – line 24 to p. 25 – lines 1-24).
Given that the manufacturing steps of Omura are identical or substantially identical to that of the present invention, one of ordinary skill in the art would have expected the claimed attributes of pore particle size in the insulating coating layer and subgrain boundary distribution, orientation, and area fraction to also exist in the prior art steel sheet because Omura applies a method of manufacture to a material composition that matches the corresponding method of manufacture and composition of the present invention.
Regarding claims 2 and 3, Omura is silent regarding the subgrain boundary ratio of crystal grain length in TD direction to crystal grain length in ND direction, Goss crystal grain location, and ratio of subgrain boundary average particle diameter to Goss crystal grain average particle diameter in the ND plane. However, such attributes are expected in Omura given that it teaches a material composition and method of manufacture that aligns with the present invention, as noted above.
Regarding claims 4-6, Omura is silent regarding the formation of a fine grain interfacial layer from the surface of the steel sheet toward the inside and the average grain diameter, residual stress, and layer thickness of the fine grain interfacial layer. However, such features are expected in Omura given that it teaches a material composition and method of manufacture that aligns with the present invention, as noted above.
Regarding claim 7, Omura teaches that the steel sheet comprises a steel substrate (electrical steel sheet base material), a forsterite film (base coating layer) on the steel substrate, and a Cr-depleted layer between the steel substrate and the forsterite film. Abstract; para. [0074]-[0077]. A tension coating (also an insulating coating) is formed on the steel comprising the steel substrate (electrical steel sheet base material) and forsterite film (base coating layer). Para. [0084], [0085], [0135]. Thus, the base coating layer is located between the electrical steel sheet base material and the insulating coating layer.
Regarding claims 8 and 9, Omura is silent regarding the residual stress and layer thickness of the base coating layer. However, such features are expected in Omura given that it teaches a material composition and method of manufacture that aligns with the present invention, as noted above.
Regarding claims 10 and 11, Omura is silent regarding the residual stress and layer thickness of the insulating coating layer. However, such features are expected in Omura given that it teaches a material composition and method of manufacture that aligns with the present invention, as noted above.
Regarding claim 12, Omura is silent regarding the residual stress of the electrical steel sheet base material. However, such feature is expected in Omura given that it teaches a material composition and method of manufacture that aligns with the present invention, as noted above.
Response to Arguments
Applicant's arguments filed 07/16/2026 have been fully considered, but they are not persuasive.
Applicant argues that the claimed invention is not obvious over Omura because the claim is directed to a different structure and different technical mechanism than Omura. Applicant states that Omura uses line tension in with respect to the continuous annealing and sheet passing and that the insulation coating is applied only after the continuous annealing step, whereas the claimed invention is made by controlling the tension during the forming of the insulation coating layer and adjusting the minimum and maximum tension values so that pore-related stress concentration limits subgrain boundary formation.
In response, the line tension applied by Omura is not limited to the continuous annealing step. Omura discloses that the tension coating (insulating coating) is formed in a tension coating baking treatment. The tension coating baking treatment includes steps of applying a coating liquid, drying and baking the coating, and then performing a step of sheet passing in which a line tension is applied (para. [0049], [0057], [0058]). An example line tension in the coating baking treatment is 0.7 kg/mm2 (e.g., para. [0057], [0058]), which falls within the range disclosed in the present specification (pp. 24-25 – bridging paragraph). The tension coating baking treatment occurs after final annealing (secondary recrystallization) and is therefore separate from a continuous annealing step (e.g., para. [0056]-[0058], [0063], [0064], [0084]-[0086], [0096], [0124]-[0129], [0133]-[0135]). This is consistent with the method of the present invention in which the tension is controlled during formation of an insulation coating.
Applicant argues that the Cr-based oxide film at the interface between forsterite film and steel substrate would not inherently produce pores of the claimed size in the insulating coating layer.
In response, the interface region between the forsterite film and steel substrate is a Cr-depleted layer (para. [0077]). The oxide film refers to a dense oxide film at the interface between forsterite film and the steel substrate (para. [0010]). The oxide is formed during continuous annealing during which a line tension is applied, and the oxide is formed before the tension coating is formed (e.g., para. [0010], [0139]). A line tension is applied during a tension coating baking treatment step that takes place after the continuous annealing (para. [0039], [0049], [0057], [0139]), as noted above. Thus, the pores expected in Omura are not correlated to the oxide film produced during continuous annealing but are correlated to the insulating film and its method of production, which aligns with present invention.
Conclusion
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/VANESSA T. LUK/Primary Examiner, Art Unit 1733
September 03, 2026
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