A method of evaluating a residual stress including a condition setting step of setting a processing condition of water jet peening for a processing target; an analysis step of analyzing a jet flow when a fluid is injected from a nozzle model to a processing target model in accordance with the processing condition, and obtaining a void fraction which is a volume fraction of babbles contained in a unit volume of the fluid, and a collapse fraction, which is a volume fraction of the bubbles which collapse in a unit time in the unit volume of the fluid, at each position on a surface of the processing target model; an impact pressure correlation value calculating step of obtaining an impact pressure correlation value, which is a product of the void fraction and the collapse fraction at each position; an experimental value acquisition step of obtaining an impact pressure experimental value.

A method of evaluating a residual stress including a condition setting step of setting a processing condition of water jet peening for a processing target; an analysis step of analyzing a jet flow when a fluid is injected from a nozzle model to a processing target model in accordance with the processing condition, and obtaining a void fraction which is a volume fraction of babbles contained in a unit volume of the fluid, and a collapse fraction, which is a volume fraction of the bubbles which collapse in a unit time in the unit volume of the fluid, at each position on a surface of the processing target model; an impact pressure correlation value calculating step of obtaining an impact pressure correlation value, which is a product of the void fraction and the collapse fraction at each position; an experimental value acquisition step of obtaining an impact pressure experimental value.

Methods and masks for manufacturing component of gas turbine engines are described. The methods include applying a mask to a protected surface of the component, the component having a designated surface to be treated by a shot peen operation. The mask includes a full masking portion configured to prevent a shot peen media from impacting the protected surface. A masking control region is arranged around the designated surface. The masking control region is configured to control an amount of force imparted to the component by shot peen media during the shot peen operation, wherein the masking control region extends from the full masking portion to the designated surface. The designated surface is shot peened with shot peen media to form a compressive stress region within the component proximate the designated surface and a tapering transition of compressive forces within the component proximate the masking control region.

Methods and masks for manufacturing component of gas turbine engines are described. The methods include applying a mask to a protected surface of the component, the component having a designated surface to be treated by a shot peen operation. The mask includes a full masking portion configured to prevent a shot peen media from impacting the protected surface. A masking control region is arranged around the designated surface. The masking control region is configured to control an amount of force imparted to the component by shot peen media during the shot peen operation, wherein the masking control region extends from the full masking portion to the designated surface. The designated surface is shot peened with shot peen media to form a compressive stress region within the component proximate the designated surface and a tapering transition of compressive forces within the component proximate the masking control region.

A surface treatment method includes: a first step of applying a plane wave-shaped shock wave to a workpiece to cause high-density transition to occur in a material structure of the workpiece; and a second step of applying a spherical wave-shaped shock wave or a pressure due to physical contact to the workpiece after the first step for plastic deformation of the workpiece.

A method for manufacturing a hollow spring member having a hollow steel spring rod having terminal sealed portions at both ends thereof. Each terminal sealed portion has a rotationally symmetric shape in which an axis passing through a center of the spring rod is an axis of symmetry. Each terminal sealed portion has an end wall portion including an end face; an arc-shaped smoothly curved surface between an outer peripheral surface of the spring rod and the end face, and a hermetically closed distal-end-center closure portion on the axis passing through the center of the spring rod. The method includes forming each of the end portions of the spring rod by forming a chamfered portion on an inner or outer peripheral side of the end portion of a hollow wire, the end portion having an opening portion at a distal end, heating the end portion of the hollow wire having the chamfered portion, and spinning the heated end portion to be gathered toward the axis from the outer peripheral side by a jig. The end wall portion, which includes the distal-end-center closure portion, is formed by the distal end of the end portion being joined together on the axis.

An article and a method of manufacturing the article is disclosed. The method includes providing the article including a substrate and a coating at least partially disposed on the substrate. The coating includes an outer surface. The coating further includes platinum and chromium. The method further includes applying cold work to the outer surface of the coating to produce a cold-worked layer extending from the outer surface of the coating to a cold work depth. The cold-worked layer includes approximately 45% cold work. The cold work depth is between about 30 microns to about 150 microns from the outer surface of the coating.

A coil spring jig includes a spring support portion where one end of a coil spring is capable of being placed, a plurality of displacement regulating portions extending along an axis of the coil spring from the spring support portion with the coil spring supported by the spring support portion as a reference, capable of abutting against an outer peripheral surface of the coil spring, and regulating displacement of the coil spring in a radial direction of the coil spring, and a lid portion supported by the displacement regulating portions and capable of keeping the coil spring in a compressed state by sandwiching the coil spring together with the spring support portion.

A method of manufacturing a hypoid gear includes face hobbing a gear blank and forming a green hypoid gear with gear teeth, heat treating the green hypoid gear to form a heat treated hypoid gear with heat treated gear teeth, and hard hobbing the heat treated gear teeth to form a hard finished hypoid gear. Critical non-tooth features on the heat treated hypoid gear are hard finished. Also, the critical non-tooth features on the heat treated hypoid gear can be hard finished prior to hard hobbing the heat treated gear teeth. The heat treating includes at least one of carburizing and induction hardening the green hypoid gear, a surface of the heat treated gear teeth has a hardness greater than or equal to 58 HRC, and the hard hobbing removes heat distortion from the heat treated gear teeth.

A method of manufacturing a hypoid gear includes face hobbing a gear blank and forming a green hypoid gear with gear teeth, heat treating the green hypoid gear to form a heat treated hypoid gear with heat treated gear teeth, and hard hobbing the heat treated gear teeth to form a hard finished hypoid gear. Critical non-tooth features on the heat treated hypoid gear are hard finished. Also, the critical non-tooth features on the heat treated hypoid gear can be hard finished prior to hard hobbing the heat treated gear teeth. The heat treating includes at least one of carburizing and induction hardening the green hypoid gear, a surface of the heat treated gear teeth has a hardness greater than or equal to 58 HRC, and the hard hobbing removes heat distortion from the heat treated gear teeth.