According to one embodiment, a wet-area device includes a main part, a first layer, and a second layer. The first layer is provided on an outer surface of the main part. The second layer is provided on an outer surface of the first layer. A hardness of the second layer is greater than a hardness of the first layer. The first layer includes a first unevenness at a side of the outer surface of the first layer. The first unevenness includes a plurality of recesses and a plurality of protrusions. The second layer includes a second unevenness at a side of an outer surface of the second layer. The second unevenness includes a plurality of recesses and a plurality of protrusions. The second unevenness is arranged along the first unevenness. An average height of the first unevenness is less than an average length of the first unevenness.

A precise and efficient cold-extrusion forming method for an unsymmetrical ferrule blank, comprising pipe-cutting blanking, surface phosphorus saponification treatment, ferrule cold-extrusion forming, and turning post-treatment. In the step of surface phosphorus saponification treatment, firstly, shot blasting pretreatment is performed on the surface of a ferrule blank by using a shot blasting machine; and then, the process steps of washing, phosphorization, washing, saponification, and drying are completed in sequence. In the step of ferrule cold-extrusion forming, automatic material feed is performed by using an automatic feeding machine, and the material is conveyed to a cold-extrusion punch press for cold-extrusion. The method features low equipment investment cost, short technological process, and low energy consumption.

A blasting processing method using shot media. A particle diameter distribution of the shot media before forming an operating mix is bimodal and substantially continuous, and both a first particle group corresponding to a first peak and a second particle group corresponding to a second peak are aggregates of particles in a shape having an angular part.

A method of manufacturing a magnetostrictive torque sensor shaft (100) to which a sensor portion (2) of a magnetostrictive torque sensor (1) is mounted. The method includes heat treatment step of subjecting an iron-based shaft member to a carburizing, quenching, and tempering process, and a shot peening step of performing shot peening using a steel shot media having a Vickers hardness at least equal to 1100 and at most equal to 1300 and being free of boron, at least in a position on the shaft member, after the heat treatment step, to which the sensor portion is to be attached.

A shot peening method is disclosed. One method includes performing a first shot peening for applying residual stress to a surface of an object formed of a metal material at a first depth, and performing a second shot peening for applying residual stress to the surface of the object at a second depth deeper than the first depth after the first shot peening. The first shot peening is performed before the object is used at a high temperature and the second shot peening is performed after the object is used at the high temperature, and after a cracking caused by stress due to thermal expansion and contraction of crystal grains occurs in the object. The cracking being deeper than the first depth and shallower than the second depth.

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.

A shot peening method includes performing first shot peening for applying residual stress to a surface of an object formed of a metal material at a first depth, and performing second shot peening for applying residual stress to the surface of the object at a second depth deeper than the first depth after the first shot peening.

According to one embodiment, a wet-area device includes a main part, a first layer, and a second layer. The first layer is provided on an outer surface of the main part. The second layer is provided on an outer surface of the first layer. A hardness of the second layer is greater than a hardness of the first layer. The first layer includes a first unevenness at a side of the outer surface of the first layer. The first unevenness includes a plurality of recesses and a plurality of protrusions. The second layer includes a second unevenness at a side of an outer surface of the second layer. The second unevenness includes a plurality of recesses and a plurality of protrusions. The second unevenness is arranged along the first unevenness. An average height of the first unevenness is less than an average length of the first unevenness.

A particle diameter distribution of shot media before forming an operating mix is bimodal and substantially continuous, and both a first particle group corresponding to a first peak and a second particle group corresponding to a second peak are aggregates of particles in a shape having an angular part.

In order to provide a method for hardening a metal sheet material by means of which a particularly hard and scratch-resistant surface is produced on the metal sheet material, it is proposed that the method comprises the following: applying at least one peening stream to the metal sheet material, wherein at least one peening stream is applied to a front side of the metal sheet material and/or a rear side of the metal sheet material, respectively.