Abstract: A method for predicting a martensitic transformation rate and a method for setting processing conditions capable of improving the accuracy of a prediction of a martensitic transformation rate when a steel material is subjected to deformation processing as well as to heat treatment are provided. A method for predicting a martensitic transformation rate according to an embodiment includes predicting a rate of a transformation to a martensitic phase that appears when a steel material is subjected to deformation processing as well as to heat treatment in which a temperature of the steel material is changed, in which a martensitic transformation rate Vm is calculated by using a prediction formula, the method further including identifying parameters m and n of the prediction formula, and calculating the martensitic transformation rate at a predetermined temperature and a predetermined strain rate by using the prediction formula into which the identified parameters are substituted.

Abstract: A manufacturing method of a rare-earth magnet includes: manufacturing a sintered body having by performing pressing on a magnetic powder for a rare-earth magnet; and manufacturing a rare-earth magnet by putting the sintered body in a plastic working mold and by performing hot plastic working on the sintered body while pressing the sintered body to give anisotropy to the sintered body. The sintered body has a cuboid shape and includes at least one recessed side face that has a recessed portion curved inward. The plastic working mold includes a lower die, a side die forming a rectangular frame of four side faces, and an upper die slidable in the side die. The hot plastic working is hot upsetting.

Abstract: A production method includes producing a rare-earth magnet precursor (S?) by performing first hot working in which, in two side surfaces of a sintered body, which are parallel to a pressing direction and are opposite to each other, one side surface is brought to a constrained state to suppress deformation, and the other side surface is brought to an unconstrained state to permit deformation; and producing a rare-earth magnet by performing second hot working in which, in two side surfaces (S?1, S?2) of the rare-earth magnet precursor (S?), which are parallel to the pressing direction, a side surface (S?2), which is in the unconstrained state in the first hot working, is brought to the constrained state to suppress deformation, and a side surface (S?1), which is in the constrained state in the first hot working, is brought to the unconstrained state to permit deformation.

Abstract: A manufacturing method of a rare-earth magnet includes: manufacturing a sintered body having by performing pressing on a magnetic powder for a rare-earth magnet; and manufacturing a rare-earth magnet by putting the sintered body in a plastic working mold and by performing hot plastic working on the sintered body while pressing the sintered body to give anisotropy to the sintered body. The sintered body has a cuboid shape and includes at least one recessed side face that has a recessed portion curved inward. The plastic working mold includes a lower die, a side die forming a rectangular frame of four side faces, and an upper die slidable in the side die. The hot plastic working is hot upsetting.

Abstract: A production method includes producing a rare-earth magnet precursor (S?) by performing first hot working in which, in two side surfaces of a sintered body, which are parallel to a pressing direction and are opposite to each other, one side surface is brought to a constrained state to suppress deformation, and the other side surface is brought to an unconstrained state to permit deformation; and producing a rare-earth magnet by performing second hot working in which, in two side surfaces (S?1, S?2) of the rare-earth magnet precursor (S?), which are parallel to the pressing direction, a side surface (S?2), which is in the unconstrained state in the first hot working, is brought to the constrained state to suppress deformation, and a side surface (S?1), which is in the constrained state in the first hot working, is brought to the unconstrained state to permit deformation.

Abstract: A forward extrusion forging apparatus includes: a die having a hollow portion whose diameter is reduced at an intermediate position; and a punch that is positioned behind a workpiece placed in the hollow portion, slides in the hollow portion, and extrudes the workpiece ahead of the hollow portion so that the workpiece is forged. An extruding surface of the punch, which extrudes the workpiece, is recessed in a direction opposite an extruding direction in a manner such that a center portion of the extruding surface is most recessed.