A grain oriented electrical steel sheet includes a base steel sheet, an oxide layer, and a tension-insulation coating. When a glow discharge spectroscopy is conducted in a region from a surface of the tension-insulation coating to an inside of the base steel sheet, a sputtering time Fe.sub.0.5 at which a Fe emission intensity becomes 0.5 times as compared with a saturation value thereof and a sputtering time Fe.sub.0.05 at which a Fe emission intensity becomes 0.05 times as compared with the saturation value satisfy (Fe.sub.0.5−Fe.sub.0.05)/Fe.sub.0.5≥0.35. A maximal point of a Cr emission intensity is included between the Fe.sub.0.05 and the Fe.sub.sat. Moreover, a magnetic flux density B8 in a rolling direction of the grain oriented electrical steel sheet is 1.90 T or more.

A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when (α.sub.1 β.sub.1 γ.sub.1) and (α.sub.2 β.sub.2 γ.sub.2) represent deviation angles of crystal orientations measured at two measurement points which are adjacent on the sheet surface and which have an interval of 1 mm, the boundary condition BA is defined as |β.sub.2−β.sub.1|≥0.5°, and the boundary condition BB is defined as [(α.sub.2−α.sub.1).sup.2+(β.sub.2−β.sub.1).sup.2+(γ.sub.2−γ.sub.1).sup.2].sup.1/2≥2.0°, the boundary which satisfies the boundary condition BA and which does not satisfy the boundary condition BB is included.

Methods for producing non-oriented electrical steel sheets comprising steps including hot rolling a slab having a chemical composition comprising C: not more than 0.01 mass %, Si: not more than 6 mass %, Mn: 0.05-3 mass %, P: not more than 0.2 mass %, Al: not more than 2 mass %, N: not more than 0.005 mass %, S: not more than 0.01 mass %, Ga: not more than 0.0005 mass %, and the remainder being Fe and inevitable impurities, pickling without conducting hot band annealing or after conducting hot band annealing or self-annealing, subjecting to one or more cold rollings including an intermediate annealing therebetween and a finish annealing, and forming an insulation coating, an average heating rate from 500 to 800° C. in the heating process of the finish annealing is not less than 50° C./s, whereby a non-oriented electrical steel sheet having excellent magnetic properties is obtained even if hot band annealing is omitted.

The present invention provides a method for cutting an electromagnetic steel with a fiber laser, a method for producing an electromagnetic steel component wherein deterioration of magnetic properties is minimized and a rust-preventive effect is endowed, and a method for fabricating a core from the electromagnetic steel component cut by the fiber laser wherein an occurrence of varnish pool is suppressed. According to the present invention, an electromagnetic steel component is obtained by irradiating and cutting the electromagnetic steel sheet with a fiber laser while spraying an assist gas comprising an oxygen concentration of at least 50 volume percent, wherein the electromagnetic steel component is formed with an oxide film for preventing the occurrence of rust and minimizing degradation of magnetic properties to be caused by the heat of the fiber laser. The degraded magnetic properties of the electromagnetic steel component can be restored by the subsequent annealing treatment.

A grain-oriented electrical steel sheet according to the present invention has a steel sheet surface provided with grooves and includes two or more broken lines including the grooves having a length of 5 to 10 mm on a straight line intersecting a rolling direction on the steel sheet surface. In each of the broken lines including the grooves, the grooves are arranged at equal intervals, and a ratio of the length of the groove to a length of a non-groove is in a range of 1:1 to 1.5:1.

A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when (.sub.1 .sub.1 .sub.1) and (.sub.2 .sub.2 .sub.2) represent deviation angles of crystal orientations measured at two measurement points which are adjacent on the sheet surface and which have an interval of 1 mm, the boundary condition BA is defined as |.sub.2.sub.1|0.5, and the boundary condition BB is defined as [(.sub.2.sub.1).sup.2+(.sub.2.sub.1).sup.2+(.sub.2.sub.1).sup.2].sup.1/22.0, the boundary which satisfies the boundary condition BA and which does not satisfy the boundary condition BB is included.

Provided is a method for manufacturing a magnetostrictive torque sensor shaft mounting a sensor portion of a magnetostrictive torque sensor. The method includes conducting heat treatment on a shaft material including chrome steel or chrome-molybdenum steel by carburizing, quenching and tempering, and conducting shot peening on the shaft material after the heat treatment at least on a position where the sensor portion is to be mounted. The shot peening is conducted by firing shot with a particle size of not less than 0.6 mm and a Rockwell hardness of not less than 60 at a jet pressure of not less than 0.4 MPa for a jet exposure time of not less than 2 minutes.

A NdFeB magnet containing cerium and a manufacturing method thereof are provided. The manufacturing method includes steps of: refining a part of raw materials pure iron, ferro-boron, and rare earth fluoride in a crucible, adding a rest of the raw materials into the crucible and refining, casting a refined solution to a surface of a water-cooled rotation roller through a tundish and forming alloy flakes, processing the alloy flakes containing at least two different compositions with hydrogen decrepitation, milling powders, magnetic field pressing, vacuum presintering, machining and sintering, and obtaining the NdFeB magnet containing cerium. The NdFeB magnet containing cerium has a density of 7.5-7.7 g/cm.sup.3 and an average particle size of 3-7 m; comprises a main phase and a grain boundary phase distributed around the main phase. A composite phase containing Tb is provided between the main phase and the grain boundary phase.

An embodiment of the present invention provides a non-oriented electrical steel sheet, including Si at 2.0 to 4.0 wt %, Al at 1.5 wt % or less (excluding 0 wt %), Mn at 1.5 wt % or less (excluding 0 wt %), Cr at 0.01 to 0.5 wt %, V at 0.0080 to 0.015 wt %, C at 0.015 wt % or less (excluding 0 wt %), N at 0.015 wt % or less (excluding 0 wt %), and the remainder including Fe and other impurities unavoidably added thereto.

0.004([C]+[N])0.022 [Equation 1]

(In Equation 1, [C] and [N] represent a content (wt %) of C and N, respectively.)

The invention discloses an oriented silicon steel with excellent magnetic properties and a manufacturing method thereof. The present invention obtains the oriented silicon steel with excellent magnetic properties by controlling the area ratio of small crystal grains of D<5 mm in an oriented silicon steel finished product to be not more than 3%, and controlling the ratio 17/15 of the magnetic conductivity under the magnetic induction of 1.7 T and 1.5 T in the oriented silicon steel finished product to be 0.50 or more. In addition, by using a slab of the oriented silicon steel with suitable components and an optimized cold rolling step, the present invention effectively decreases the heating temperature of the slab and the production cost thereof, and simultaneously better controls the size and ratio of the crystal grains in the oriented silicon steel finished product and the magnetic conductivity in a certain range of magnetic induction, ensures that secondary recrystallization has good Goss texture orientation and finally, stably obtains the oriented silicon steel product with excellent magnetic properties.