Provided are a plated steel sheet and a method for manufacturing same, the plated steel sheet comprising: a base steel sheet; a Zn—Mg—Al plating layer provided on at least one surface of the base steel sheet; and an Fe—Al inhibition layer provided between the base steel sheet and the Zn—Mg—Al plating layer. The plating layer comprises, by weight %, 4 to 10% of Mg and 5.1-25% of Al and the remainder being Zn and unavoidable impurities with respect to components not including iron (Fe) diffused from the base steel sheet. The plating layer comprises a 24-50% MgZn.sub.2 phase in phase fraction. In the MgZn.sub.2 phase, an Al single phase is present in the ratio of 1-30% relative to the cross-sectional area of the total MgZn.sub.2 phase.

A method and apparatus for processing a metallic workpiece with defined edges (e.g., a gear) comprises media blasting of the workpiece by directing a first media against exposed surfaces on the workpiece to increase the root strength of the gear, the blasting causing the defined edges to be radiused or mushroomed, ceasing the media blasting, loading the workpiece into a finishing apparatus, and subjecting the workpiece to a finishing process with a second media, the exposed surfaces on the workpiece being subjected to the finishing process to reduce the radiused edges on the workpiece created from the media blasting. The process of moving the workpiece to the spindle-finishing apparatus from the media blasting may be performed automatically by a machine. Once the workpiece has been subjected to the finishing process with the second media, it may be removed from the spindle-finishing machine, washed, and rinsed with rust inhibitor whereby wear properties of the workpiece are enhanced.

A method and apparatus for processing a metallic workpiece with defined edges (e.g., a gear) comprises media blasting of the workpiece by directing a first media against exposed surfaces on the workpiece to increase the root strength of the gear, the blasting causing the defined edges to be radiused or mushroomed, ceasing the media blasting, loading the workpiece into a finishing apparatus, and subjecting the workpiece to a finishing process with a second media, the exposed surfaces on the workpiece being subjected to the finishing process to reduce the radiused edges on the workpiece created from the media blasting. The process of moving the workpiece to the spindle-finishing apparatus from the media blasting may be performed automatically by a machine. Once the workpiece has been subjected to the finishing process with the second media, it may be removed from the spindle-finishing machine, washed, and rinsed with rust inhibitor whereby wear properties of the workpiece are enhanced.

A device for double-sided processing through single shot peening includes: a shot peening system, a workpiece clamping mechanism for clamping a workpiece, and a rebound system. The workpiece is provided with a first through-hole, and the first through-hole directly faces a nozzle. The rebound system includes a reflecting surface, an open container, and a reflecting surface gripping unit. The reflecting surface includes an upper reflecting surface, a middle reflecting surface, and a lower reflecting surface. The middle reflecting surface is provided with a second through-hole. The upper reflecting surface and the lower reflecting surface are both made of flexible elastic materials and are both provided with waterproof layers. A partition plate is disposed in the open container and partitions the open container into a first cavity and a second cavity. The second cavity is provided with a filling liquid, and the partition plate is slidable in the open container.

A device for double-sided processing through single shot peening includes: a shot peening system, a workpiece clamping mechanism for clamping a workpiece, and a rebound system. The workpiece is provided with a first through-hole, and the first through-hole directly faces a nozzle. The rebound system includes a reflecting surface, an open container, and a reflecting surface gripping unit. The reflecting surface includes an upper reflecting surface, a middle reflecting surface, and a lower reflecting surface. The middle reflecting surface is provided with a second through-hole. The upper reflecting surface and the lower reflecting surface are both made of flexible elastic materials and are both provided with waterproof layers. A partition plate is disposed in the open container and partitions the open container into a first cavity and a second cavity. The second cavity is provided with a filling liquid, and the partition plate is slidable in the open container.

A steel wire which has excellent cold coiling workability, and which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present, embodiment containing, in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less, S: 0.020% or less, Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, and N: 0.0100% or less, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces/μm.sup.3.

A damper spring which has an excellent fatigue limit is provided. A chemical composition of the damper spring according to the present embodiment contains in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less, S: 0.020% or less, Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, and N: 0.0100% or less, with the balance being Fe and impurities. In the damper spring, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces/m3.

According to an aspect of the disclosure, there may be provided a peening apparatus for generating a compressive residual stress on a pipe member including at least one curved round portion and having a hollow inside formed therein in which a first fluid and a second fluid, which is in a gas phase, are accommodated, the apparatus including: a probe which is disposed such that it is submerged in the first fluid supplied to the hollow inside, and which is configured to apply a wave to the first fluid, wherein the first fluid and the second fluid have different acoustic impedances, so that the wave is totally reflected on a reflection surface where the first fluid and the second fluid are in contact, and forms a standing wave, and wherein a cavity generated and grown by the formed standing wave is exploded and emits a shock wave or microjet, which generates a compressive residual stress on the inner surface of the pipe member surrounding the hollow inside.

According to an aspect of the disclosure, there may be provided a peening apparatus for generating a compressive residual stress on a pipe member including at least one curved round portion and having a hollow inside formed therein in which a first fluid and a second fluid, which is in a gas phase, are accommodated, the apparatus including: a probe which is disposed such that it is submerged in the first fluid supplied to the hollow inside, and which is configured to apply a wave to the first fluid, wherein the first fluid and the second fluid have different acoustic impedances, so that the wave is totally reflected on a reflection surface where the first fluid and the second fluid are in contact, and forms a standing wave, and wherein a cavity generated and grown by the formed standing wave is exploded and emits a shock wave or microjet, which generates a compressive residual stress on the inner surface of the pipe member surrounding the hollow inside.

A peening method which can sufficiently improve fatigue properties of a lap fillet welded joint having a thin steel sheet as a base sheet, in which a knocking pin having a predetermined shape is continuously knocked as a series of knocking toward a direction inclined relative to the welding direction, the series of knocking is repeatedly performed in the welding direction, at that time, a knocking mark group made of a plurality of knocking marks formed by the series of knocking is superimposed on at least a part of an adjacent knocking mark group while an end part in the direction orthogonal to the welding direction of the knocking mark group is separated from an end part in the direction orthogonal to the welding direction of the adjacent knocking mark group.