Patent ID: 7419634

Claim:
A Fe—Ni based permalloy made of a hot rolled sheet comprising Ni: 70-85 wt %, C: not more than 0.015 wt %, Si: not more than 1.0 wt %, Mn: not more than 1.0 wt %, P: not more than 0.01 wt %, 5: not more than 0.005 wt %, O: not more than 0.006 wt %, Al: not more than 0.02 wt %, which is obtained by subjecting to a hot rolling a continuously cast slab having a cast texture that an area ratio of equiaxed crystal is not more than 1%, and having such magnetic properties that a maximum magnetic permeability μm is not less than 400000, an initial magnetic permeability ui is not less than 200000 and a coercive force Hc is not more than 0.006 (Oe), provided that Ni segregation amount C Ni s represented by the following equation is not more than 0.10 wt %: C Ni s=analytical value of Ni component (wt %) x Ci Ni s (c.p.s.)/Ci Ni ave. (c.p.s.) wherein Ci Ni s: a standard deviation of X-ray intensity (c.p.s.) Ci Ni ave.: an average intensity of total X-ray intensities (c.p.s.).