Abstract: The present disclosure provides a method for manufacturing a gear capable of processing a projection formed on a tooth tip by shot peening while reducing time for manufacturing the gear. A method for manufacturing a gear includes: a process of hardening, by performing shot peening in which shot particles are jetted onto a tooth surface 1a of a gear base material, the tooth surface while applying residual stress to the tooth surface; a process of softening, by at least heating a tooth tip of the gear base material having the hardened tooth surface, the tooth tip; and a process of rotationally driving the gear base material having the softened tooth tip by engaging it with another gear.

Abstract: A method for producing a steel member includes carburizing the steel member, pearlitizing austenite, and performing quenching. The pearlitizing of the austenite includes performing a first pearlite precipitation treatment of cooling the steel member to a first temperature lower than an austenite transformation start temperature and higher than 680° C. and holding the steel member at the first temperature to pearlitize a part of the austenite formed in the carburizing of the steel member, and performing a second pearlite precipitation treatment of further cooling the steel member to a second temperature equal to or lower than 680° C. and higher than a nose temperature and holding the steel member at the second temperature to pearlitize the austenite retained in the first pearlite precipitation treatment.

Abstract: The present disclosure provides a method for manufacturing a gear capable of processing a projection formed on a tooth tip by shot peening while reducing time for manufacturing the gear. A method for manufacturing a gear includes: a process of hardening, by performing shot peening in which shot particles are jetted onto a tooth surface 1a of a gear base material, the tooth surface while applying residual stress to the tooth surface; a process of softening, by at least heating a tooth tip of the gear base material having the hardened tooth surface, the tooth tip; and a process of rotationally driving the gear base material having the softened tooth tip by engaging it with another gear.

Abstract: A method for producing a steel member includes carburizing the steel member, pearlitizing austenite, and performing quenching. The pearlitizing of the austenite includes performing a first pearlite precipitation treatment of cooling the steel member to a first temperature lower than an austenite transformation start temperature and higher than 680° C. and holding the steel member at the first temperature to pearlitize a part of the austenite formed in the carburizing of the steel member, and performing a second pearlite precipitation treatment of further cooling the steel member to a second temperature equal to or lower than 680° C. and higher than a nose temperature and holding the steel member at the second temperature to pearlitize the austenite retained in the first pearlite precipitation treatment.

Abstract: [Task] To provide a method that makes it possible to easily, inexpensively and accurately manufacture a machined part with a simple configuration and an excellent strength. [Means for Solution] In a method for manufacturing a machined part according to the invention, a dislocation is partially introduced (S3), through shot peening, only into a surface layer of a raw material 1 in a region 1a to be machined, graphite is partially deposited (S4), through heating, only in the surface layer of the region 1a to be machined, and then, the surface layer of the region 1a where graphite is deposited is removed, through machining (S5), only by an amount corresponding to a working margin 1c, thereby manufacturing a machined part 1?.

Abstract: The problem of the present invention involves providing a gear that has high tooth-root bending strength and for which there is no chipping of the tips of the teeth. Accordingly, the surface of the gear is carburized and the gear is strengthened by imparting residual stress, with the residual stress in the region with a surface depth of 5 ?m to 20 ?m being ?1000 MPa or less, and the residual stress in the region with a surface depth of 50 ?m to 150 ?m being ?1000 MPa or greater.

Abstract: [Task] To provide a method that makes it possible to easily, inexpensively and accurately manufacture a machined part with a simple configuration and an excellent strength. [Means for Solution] In a method for manufacturing a machined part according to the invention, a dislocation is partially introduced (S3), through shot peening, only into a surface layer of a raw material 1 in a region 1a to be machined, graphite is partially deposited (S4), through heating, only in the surface layer of the region 1a to be machined, and then, the surface layer of the region 1a where graphite is deposited is removed, through machining (S5), only by an amount corresponding to a working margin 1c, thereby manufacturing a machined part 1?.

Abstract: The problem of the present invention involves providing a gear that has high tooth-root bending strength and for which there is no chipping of the tips of the teeth. Accordingly, the surface of the gear is carburized and the gear is strengthened by imparting residual stress, with the residual stress in the region with a surface depth of 5 ?m to 20 ?m being ?1000 MPa or less, and the residual stress in the region with a surface depth of 50 ?m to 150 ?m being 1000 MPa or greater.

Abstract: The problem of the present invention involves providing a gear that has high tooth-root bending strength and for which there is no chipping of the tips of the teeth. Accordingly, the surface of the gear is carburized and the gear is strengthened by imparting residual stress, with the residual stress in the region with a surface depth of 5 ?m to 20 ?m being ?1000 MPa or less, and the residual stress in the region with a surface depth of 50 ?m to 150 ?m being ?1000 MPa or greater.