A normal temperature nitriding process and processing device based on laser thermal-mechanical effect

Abstract

The invention provides a normal-temperature nitriding process and a processing device based on laser thermal-mechanical effect, comprising the following steps: at normal temperature, filling a closed box where a workpiece to be nitrided is placed with ammonia gas; outputting an output through a diffractive beam splitter A first laser beam and a second laser beam with different energies; several second laser beams are focused on the surface of the workpiece, and the ammonia gas is ionized to form free nitrogen atoms through the laser thermal effect; several of the second laser beams are distributed on the first laser beam and the first laser beam irradiates the surface of the workpiece, and the plasma generated by the laser carries nitrogen atoms and penetrates into the surface of the workpiece along the motion dislocation induced by the force effect. The invention utilizes the thermal effect and force effect of the laser to carry out surface strengthening treatment, and can obtain higher strength, hardness and fatigue performance than single strengthening treatment, and in addition, normal temperature nitriding can improve the defects of coarse grains caused by conventional high temperature nitriding.

Description

technical field [0001] The invention relates to the technical field of heat treatment or the technical field of surface nitriding, in particular to a normal temperature nitriding process and processing device based on laser thermal-mechanical effect. Background technique [0002] Nitriding technology, that is, a chemical heat treatment process in which nitrogen atoms are infiltrated into the surface of the workpiece in a certain medium at a certain temperature. The traditional gas nitriding is to put the workpiece in a sealed container, pass it through the flowing ammonia gas and heat it. After a long time of heat preservation, the ammonia gas thermally decomposes to generate active nitrogen atoms, which are continuously adsorbed to the surface of the workpiece and diffuse into the surface layer of the workpiece. , thereby changing the chemical composition and organization of the surface, and obtaining excellent surface properties. The Chinese invention patent discloses a h...

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Problems solved by technology

The above two patents use laser shock pretreatment to increase the dislocation density on the surface of the material, and then perform nitriding treatment to induce nitrogen atoms to penetrate into the material along the dislocations. However, this method also has certain defects: first, it is still the traditional nitriding treatment. If the time is too long, the high temperature of traditional nitriding will cause coarse grains, which will weaken the phenomenon of grain refinement brought about by laser shock strengthening, and affect the overall strengthening effect

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