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Nondestructive test method for microhardness of metal surface layer subjected to laser shock processing

A laser shock strengthening and microhardness technology, applied in the direction of testing the hardness of materials, can solve the problems of surface integrity and surface topography, and achieve the effect of improving the surface topography and damage to the surface integrity, and the effect is good

Inactive Publication Date: 2015-12-09
JIANGSU UNIV
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Problems solved by technology

However, the traditional hardness measurement method mainly uses the hardness tester to press the indenter (diamond cone, steel ball or cemented carbide ball) into the surface of the sample in two steps. After the specified holding time, remove the main test force and measure The residual indentation depth, diagonal length or side length under the initial test force, calculate the hardness according to the measured value and the constants N and S, this method will cause indentations of different sizes on the surface of the metal parts, surface integrity and Surface topography is affected, which is undesirable in practical applications

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  • Nondestructive test method for microhardness of metal surface layer subjected to laser shock processing
  • Nondestructive test method for microhardness of metal surface layer subjected to laser shock processing
  • Nondestructive test method for microhardness of metal surface layer subjected to laser shock processing

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Embodiment Construction

[0015] The specific implementation of the present invention will be described in detail below in conjunction with the accompanying drawings and examples, but the present invention should not be limited to the examples.

[0016] The base material of the metal part used in this embodiment is 316L stainless steel, and its geometric size is 120mm×60mm×15mm. A square area of ​​30mm×30mm is selected in the middle of the surface for laser shock strengthening treatment.

[0017] An example of the surface hardness of a metal part after laser shock strengthening of an example measured using the above method, the steps are:

[0018] (1) Select 316L stainless steel metal parts after laser shock strengthening, first select 6 points on the surface of the impact area, and measure the S parameter value of Doppler broadening spectrum at each point after laser shock strengthening, which is regarded as S1, S2······S6, its values ​​are shown in Table 1, and the process parameters in the process o...

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Abstract

The invention relates to a nondestructive test method for microhardness of a metal surface layer subjected to laser shock processing. The method comprises aiming at a metal pipe subjected to laser shock processing, firstly measuring the parameter value S of a Doppler broadening spectrum of the surface of the metal piece, then using a hardness instrument to measure the microhardness of the corresponding position, and finally performing linear fitting on the measured hardness value and the parameter value S by employing least squares, so as to obtain the linear relation curve of the measured hardness value and the parameter value S. According to the method, for the metal piece which is subjected to laser shock processing and needs hardness measurement, the parameter value S of the surface Doppler broadening spectrum of a to-be measured position of the metal piece is firstly measured, and then the microhardness of the position can be estimated according to the relation curve of the parameter value and the hardness value. The method realizes nondestructive test of the microhardness of the metal surface layer subjected to laser shock processing, the disadvantage that the metal surface layer possesses impressions because of hardness instrument measurement is effectively avoided, and the metal surface integrity is guaranteed.

Description

technical field [0001] The invention relates to the field of laser processing, in particular to a nondestructive testing method for the microhardness of the metal surface layer after laser shock strengthening, and is especially suitable for nondestructive measurement of the microhardness of the surface layer of metal parts after laser shock strengthening. Background technique [0002] Laser shock strengthening technology is a new type of metal surface modification technology. It uses the shock wave mechanical effect induced by strong laser to process materials. It has the characteristics of high pressure, high energy, ultra-fast and ultra-high strain rate. The residual compressive stress layer formed by it is It can effectively eliminate the stress concentration inside the material and inhibit the initiation and expansion of cracks, and can significantly improve the fatigue life, corrosion resistance and wear resistance of metal parts. A large number of studies have proved th...

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Application Information

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IPC IPC(8): G01N3/40
Inventor 罗开玉景祥鲁金忠
Owner JIANGSU UNIV
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