A cryogenic laser peening device and processing method

Abstract

The invention provides a cryogenic laser peening device and processing method, comprising a laser emission system, a low temperature control device, a drying device, a pressure control device and a control system; the laser emission system is used to generate laser beams; the low temperature control The device includes a cryogenic box and a liquid nitrogen delivery system, the liquid nitrogen delivery system is used to deliver liquid nitrogen into the cryogenic box; a workpiece is installed in the cryogenic box, a hollow gland is placed on the workpiece, and the pressure The control device is used to apply pressure on the gland, and the laser beam passes through the gland to irradiate the surface of the workpiece; the drying device is used to dry the air inside the gland; the control system is used to control the delivery of liquid nitrogen system, laser emission system and pressure control device. The invention realizes that the cryogenic temperature can reach the liquid nitrogen temperature, the cryogenic temperature is controllable, the light transmittance is improved and the confinement effect is better, and the cryogenic laser shot peening strengthening effect is improved.

Description

technical field [0001] The invention relates to the field of laser shock processing, in particular to a cryogenic laser peening device and a processing method. Background technique [0002] As a new surface strengthening process, laser peening has the advantages of obvious grain refinement and influence on layer depth, which can effectively improve the fatigue resistance, wear resistance and corrosion resistance of metal materials, so it is widely used in aerospace, automobile and Ships and many other fields. However, the current laser peening technology is generally carried out at room temperature. During the peening process, the dynamic recovery of grains and the annihilation of some dislocations will occur. The strength of the material is greatly improved but the improvement of plasticity is not particularly obvious, so it cannot reach the level of aerospace alloys. Requirements. Cryogenic treatment, also known as ultra-low temperature treatment, mainly refers to the lo...

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Problems solved by technology

However, the high light transmittance glass used is prone to water mist on the side in the air, which seriously reduces the light transmittance and weakens the strengthening effect

In addition, the volume of fixtures and workpieces at ultra-low temperatures will have a cold shrinkage effect, resulting in insufficient clamping force and easy pressure release, resulting in a decrease in shock wave pressure and further reducing the strengthening effect

For the constrained layer used in the cryogenic laser peening process, the invention patent of high light transmittance cryogenic laser shock head and laser shock system discloses the use of liquid nitrogen as the constrained layer in the cryogenic laser peening process, but at room temperature Due to the boiling of liquid nitrogen, a large number of bubbles will be generated inside the liquid nitrogen, which will reduce the strengthening effect

[0004] Since cryogenic laser peening requires laser peening treatment of the workpiece in an ultra-low temperature environment, however, in most cases the cryogenic temperature cannot reach the temperature of liquid nitrogen (-196°C), and the surface of the workpiece in the liquid nitrogen environment will produce liquid Nitrogen vapor and water mist seriously affect the light transmittance, thus greatly reducing the effect of cryogenic laser shot peening

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