A mechanical impact method and device for effectively reducing laser cladding cracks

A technology of laser cladding and mechanical impact, which is applied in the coating process and coating of metal materials, can solve the problems that affect the large-scale application of laser cladding, the formation of cracks in molded parts, and the cladding layer cracks, etc., to achieve the suppression of thermal cracks and the generation and expansion of cold cracks, the increase in strength, and the effect of refining the structure

Active Publication Date: 2017-08-11
YANSHAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, since the melting, solidification and cooling of the material are carried out under extremely fast conditions, it is easy to form defects such as cracks, pores and inclusions in the molded parts.
The most difficult problem to solve in laser cladding is the crack problem of the cladding layer, which has seriously affected the large-scale application of laser cladding in industrial production.

Method used

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  • A mechanical impact method and device for effectively reducing laser cladding cracks
  • A mechanical impact method and device for effectively reducing laser cladding cracks
  • A mechanical impact method and device for effectively reducing laser cladding cracks

Examples

Experimental program
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Effect test

Embodiment 1

[0029] A laser cladding coating of Fe90 self-fluxing alloy powder + TiC powder is performed on a 20CrMnTi steel shaft substrate with a diameter of 20mm, and the self-fluxing alloy alloy powder used is cladding (chemical composition percentage Wt%: 13.6Cr, 1.6 B, Si1.2, Mo0.8, C0.8, Fe balance), add TiC with a mass fraction of 5%, mix well with a three-dimensional mixer, dry it in a dryer, and add it to the powder feeder stand-by. Carry out turning treatment on the surface of the substrate, clean the surface fatigue layer, holes, cracks, etc., clean the surface with acetone or alcohol, and clamp the workpiece with the three-jaw chuck of the CNC bed. Apply mechanical shock to the single pass of the workpiece that has been cladding, and input the relevant parameters in the CNC system. The shaft surface linear speed is 250mm / min, the overlap rate is 40%, the powder feeder speed is 80g / min, and the gas The flow rate is 5l / min, the laser power is 2.5kw, and the spot diameter is 3mm....

Embodiment 2

[0031] The method is the same as in Example 1, except that the mechanical impact frequency is 300 Hz, L1 is 10 mm, and L2 is 15 mm during laser cladding. by Picture 9 It can be seen that the structure is uniform, the arrangement is orderly, the crystal grains are more refined, and the pores basically disappear.

[0032] It can be seen from the above two embodiments that with the aid of mechanical shock, the number of various defects (pores, cracks, etc.) in the cladding layer is suppressed, so that the performance of the cladding layer is improved. The coating can effectively reduce cracks in the cladding layer and improve the structure of the cladding layer.

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Abstract

A mechanical impact device for effectively reducing laser cladding cracks mainly includes: a powder-feeding high-power semiconductor laser cladding device, a numerical control device and a mechanical impact assembly. In the present invention, the workpiece to be clad is clamped with a three-jaw or four-jaw chuck, powder is fed to the workpiece by a preset powder feeding method, and a mechanical impact of a certain frequency is applied to a single pass of laser cladding to obtain a cladding layer with excellent quality . The mechanical vibration caused by the impact can effectively break the dendrites that are preferentially precipitated in the molten pool, the grains are refined, the plasticity of the solidified crystals is improved, and thermal cracks are avoided. Secondly, the hammering effect of the mechanical impact hammer on the cladding single pass , can partially balance the residual tensile stress generated during the cooling process of the molten pool, reduce the appearance of cold cracks, and obtain a cladding layer with excellent quality.

Description

Technical field [0001] The invention relates to a material processing method and device, in particular to a laser cladding material processing method and device. Background technique [0002] Laser cladding technology is a rapidly developing surface processing technology and an emerging technology for material processing. Using a high-energy laser beam, the metal powder and the substrate are quickly melted and cooled quickly, and the two interact, and finally a surface with high hardness and high wear resistance that is difficult to obtain by conventional methods is obtained. However, since the melting, solidification and cooling of the material are carried out under extremely fast conditions, defects such as cracks, pores, and inclusions are easily formed in the molded part. The most difficult problem in laser cladding is the crack of the cladding layer, which has seriously affected the large-scale application of laser cladding in industrial production. Summary of the inventio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C24/10
Inventor 郑丽娟王好平谢亮黄浩杜文连王祺
Owner YANSHAN UNIV
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