Patent ID: 11866812
Assignee: NIPPON STEEL CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  H | IPC C

Claim 1:
2. A forming method for an insulation coating of a grain oriented electrical steel sheet according to claim 1 characterized in that
the forming method for the insulation coating includes an insulation coating forming process of forming a tension-insulation coating on a steel substrate,
wherein, in the insulation coating forming process,
a solution including a metal phosphate and a silica for forming a phosphate-silica mixed tension-insulation coating is applied to an oxide layer of the steel substrate and the solution is baked at 850 to 950° C. for 10 to 60 seconds, so as to form the tension-insulation coating with an average thickness of 1 to 3 μm,
the steel substrate includes a base steel sheet and the oxide layer arranged in contact with the base steel sheet,
the base steel sheet includes, as a chemical composition, by mass %,
2.5 to 4.0% of Si,
0.05 to 1.00% of Mn,
0.02 to 0.50% of Cr,
0 to 0.01% of C,
0 to 0.005% of S+Se,
0 to 0.01% of sol.Al,
0 to 0,005% of N,
0 to 0.03% of Bi,
0 to 0.03% of Te,
0 to 0.03% of Pb,
0 to 0.50% of Sb,
0 to 0,50% of Sn,
0 to 1.0% of Cu, and
a balance consisting of Fe and impurities,
when a glow discharge spectroscopy is conducted in a region from a surface of the oxide layer to an inside of the base steel sheet, when a sputtering time at which a Fe emission intensity becomes a saturation value thereof on a depth profile is referred to as Fesat in unit of seconds, a plateau region of a Fe emission intensity where a Fe emission intensity stays for Fesat×0.1 seconds or more in a range of 0.40 to 0.80 times as compared with the saturation value is included between 0 second and the Fesat on the depth profile,
when a sputtering time at which a Cr emission intensity becomes a maximal value on the depth profile is referred to as Crmax in unit of seconds, a maximal point of a Cr emission intensity at which a Cr emission intensity at the Crmax becomes 0.01 to 0.03 times as compared with a Fe emission intensity at the Crmax is included between the plateau region and the Fesat on the depth profile, and
when a sputtering time at which a Si emission intensity becomes a maximal value on the depth profile is referred to as Simax in unit of seconds, a maximal point of a Si emission intensity at which a Si emission intensity at the Simax becomes 0.06 to 0,15 times as compared with a Fe emission intensity at the Simax is included between the Crmax and the Fesat on the depth profile.