A precise and efficient cold-extension 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-extension. The method features low equipment investment cost, short technological process, and low energy consumption.

Provided is a method for modifying a surface of a Co-13 Cr alloy to obtain the Co-13 Cr alloy superior in fatigue strength. The method for modifying a surface of a Co-13 Cr alloy, comprising a step of shot peening of the Co-13 Cr alloy using a shot material including ZrO.sub.2.

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.

Articles of bulk-solidifying amorphous alloys such as a golf club face insert with improved durability and fatigue resistance, and more specifically articles of bulk-solidifying amorphous alloys subjected to a surface treatment, such as shot-peening, which creates deformations in the exterior surface, and methods of improving the durability and fatigue resistance of bulk-solidifying amorphous alloys using a surface treatment, such as shot-peening.

In some examples, a material may be subject to shot peening of a relatively long duration to improve cavitation erosion resistance of the material. For example, the material surface may be shot peened to cause grain reduction and an increase in hardness to a depth of 60 m or more, while the surface remains relatively smooth. As one example, the method may include treating a surface of austenitic stainless steel by impacting the surface with shot media for a treatment duration of 15 to 40 minutes at a shot peening intensity corresponding to an Almen strip type A intensity of 5A to 10A.

The invention relates to a method for manufacturing a coil spring and for determining a propelling condition for a shot medium. In a case where it is confirmed that the coating film remains in a third step, at least one or more of conditions of the shot peening treatment including a propelling speed of the shot medium, a propelling time of the shot medium, a material of the shot medium, and an average particle diameter of the shot medium are changed and the second step and the third step are repeated until the coating film does not remain. In a case where it is confirmed that the coating film does not remain in the third step, the condition of the shot peening treatment in the second step in which the coil spring is obtained with no remaining coating film is determined as the propelling condition for the shot medium.

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.

First, it is determined in a determination step by a determination unit whether there is a nitrided layer on a surface of a water-cooled hole of a mold, by using an eddy current sensor. Next, in a shot step, when it is determined in the determination step that there is no nitrided layer, the surface of the water-cooled hole of the mold is shot-peened under a shot condition set according to a base material of the mold, and when it is determined in the determination step that there is the nitrided layer, the surface of the water-cooled hole of the mold is shot-peened under a shot condition which maintains a state where there is the nitrided layer.

Methods for hardening a metal sheet material include applying at least one peening stream to the metal sheet material, wherein at least one peening stream is applied, in each case, to a front side of the metal sheet material and a rear side of the metal sheet material, respectively, at least at times simultaneously. In one example, the metal sheet material is a stainless steel material, wherein the at least one peening stream is generated from a peening material in which at least 50% by weight of the peening material has a largest particle diameter of at least 0.8 mm and wherein the metal sheet material has a mean final surface hardness after the application of the at least one peening stream of at least approximately 300 HV.

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 boron-free zirconia shot media having a Vickers hardness at least equal to 1100 and at most equal to 1300, at least in a position on the shaft member, after the heat treatment step, to which the sensor portion is to be attached. The surface of the shaft member, after shot peening, has a total error, including hysteresis error and angle error, of not more than 3%.