Abstract: A method of producing a steel material includes a step of adding Ca to molten steel with an amount of Ca adjusted within a range satisfying the formula (1) below: 0.5 ? { Ca · y ? / ? 100 - ( [ S · W ? / ? 100 ) · 40.08 ? / ? 32.07 } ? 56.08 40.08 ( [ Al 2 ? O 3 ] · W ? / ? 100 ) ? 1.5 ( 1 ) where Ca is the amount [kg] of Ca added, y is an yield [%] of Ca, [S] is a concentration [% by mass] of S in the steel before addition of Ca, [Al2O3] is an amount [% by mass] of Al2O3 in the steel before addition of Ca, and W is a weight [kg] of the molten steel.

Abstract: The location where forsterite is present is checked in a region from which light excited by an electron beam is emitted when a material containing forsterite is irradiated with an electron beam. The material is preferably a grain oriented electrical steel sheet having a forsterite layer. In addition, it is preferable that the accelerating voltage be 10 kV or more when an electron beam is radiated when the material is a grain oriented electrical steel sheet having a tension coating layer on the forsterite layer.

Abstract: A method of producing a steel material includes a step of adding Ca to molten steel with an amount of Ca adjusted within a range satisfying the formula (1) below: 0.5 ? { Ca · y ? / ? 100 - ( [ S · W ? / ? 100 ) · 40.08 ? / ? 32.07 } ? 56.08 40.08 ( [ Al 2 ? O 3 ] · W ? / ? 100 ) ? 1.5 ( 1 ) where Ca is the amount [kg] of Ca added, y is an yield [%] of Ca, [S] is a concentration [% by mass] of S in the steel before addition of Ca, [Al2O3] is an amount [% by mass] of Al2O3 in the steel before addition of Ca, and W is a weight [kg] of the molten steel.

Abstract: The location where forsterite is present is checked in a region from which light excited by an electron beam is emitted when a material containing forsterite is irradiated with an electron beam. The material is preferably a grain oriented electrical steel sheet having a forsterite layer. In addition, it is preferable that the accelerating voltage be 10 kV or more when an electron beam is radiated when the material is a grain oriented electrical steel sheet having a tension coating layer on the forsterite layer.

Abstract: An apparatus for taking residual solid matter out of an extrusion head of an extruder includes a grasping device for grasping residual solid matter in the extrusion head, and a moving device for moving the grasping device between a grasping position in the extrusion head and an exhausting position on one side of the extrusion head. In order to remove the residual solid matter from the grasping device even if the solid matter firmly adheres to the grasping device, the apparatus further includes a disengaging device for urging the residual solid matter to disengage it from the grasping device when the grasping device has arrived at the exhausting position and released the residual solid matter. A control device is provided for controlling the grasping device, the moving device and the disengaging device.