A method for shot peening a gas carburised steel

A shot peening, medium technology, used in heat treatment equipment, heat treatment process control, manufacturing tools, etc.

Inactive Publication Date: 2013-01-09
SINTOKOGIO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] However, in these studies, only focusing on the mean value of the hardness on or near the material surface
Therefore, the methods used in these studies are difficult to apply to gas-carburized steels with a soft layer on the surface, because the residual stress is affected by the plastic deformation caused by the impact of the blasted medium and the mechanical properties of the processed steel involving the suppression of plastic deformation. Effect of characteristics

Method used

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  • A method for shot peening a gas carburised steel
  • A method for shot peening a gas carburised steel
  • A method for shot peening a gas carburised steel

Examples

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Embodiment Construction

[0033] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0034] figure 1 is a graph showing the distribution of hardness of processed steel used in Examples. The abscissa indicates the depth (microns) from the steel surface, and the ordinate indicates the Vickers hardness. Gas carburizing steel is used for the processed steel. In the figure, "TP.A" and "TP.B" represent steels that have been tempered at 180°C and 180°C, respectively.

[0035] figure 2 It is a table which shows the conditions and the result of the shot peening used in the Example. A compressed air shot peening system is used. A blasting medium having a hardness of 700 HV to 1,000 HV and a diameter (average diameter) of 0.2 mm to 1.0 mm is used.

[0036] The "maximum σ" in the table R ” represents the maximum compressive residual stress in the processed steel. By using a microstress analyzer available from Rigaku Corporation (X-ray tube: Cr-Kα; diffracti...

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Abstract

The present invention is to provide a method for shot peening for producing a high compressive residual stress in a gas carburized steel that has a soft layer. In this method, a depth where the maximum compressive residual stress is generated is estimated and the hardness on the surface or near the surface is not used. The depth where the maximum compressive residual stress is generated is estimated by multiplying the depth where the maximum stress is generated under contact stresses caused by the collision of shot media by the constant K. A processed steel that comprises a gas carburized steel and that has a hardness at that depth that exceeds 750HV is used. Shot media that have a hardness that is greater than that of the processed steels at that depth by 50HV or more are shot onto the processed steels to produce a high compressive residual stress in the processed steels.

Description

technical field [0001] The invention relates to a method for performing shot peening. In particular, the invention relates to a method for shot peening gas carburized steel. Background technique [0002] Traditionally, shot peening has been known to generate compressive residual stress and increase hardness to improve the fatigue strength of gears (see author Japan Shot Peening Technology Association; Metal Fatigue and Shot Peening; Publisher Gendai Kogaku-sha; 2004). Furthermore, in order to achieve high fatigue strength aimed at reducing component weight, a method for increasing the compressive residual stress produced by shot peening is known (see Kazuyoshi Ogawa and Takashi Asano; Shot peening of hardened steel Theoretical prediction of the resulting compressive residual stresses; Journal of JSSR, No. 48 (2003) pp. 31-38). [0003] However, in these studies, only the average value of the hardness on or near the material surface was focused. Therefore, the methods used...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D7/06C23C8/80C21D1/06C23C8/22C21D11/00
CPCC23C8/80C21D11/00C21D7/06B24C1/10
Inventor 小林祐次辻俊哉
Owner SINTOKOGIO LTD
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