Vermicular graphite cast iron surface laser melting-solidifying method

Abstract

The invention relates to a vermicular graphite cast iron surface laser melting-solidifying method. Preheating treatment is conducted on vermicular graphite cast iron first, then a prepared laser absorption layer is evenly sprayed on the surface of the vermicular graphite cast iron, and laser melting-solidifying is conducted. According to the vermicular graphite cast iron surface laser melting-solidifying method, preheating treatment is conducted on a sample through a laser first, after pretreatment, the inside temperature gradient of laser melting-solidifying can be lowered, thermal stress isreduced, and the possibility that a melting-solidifying layer generates a crack is lowered to some extent. A spraying method is adopted, thus the laser absorption layer can be laid on the surface of the vermicular graphite cast iron more evenly, and the laser absorption layer fully acts with the laser and a substrate better. An obtained laser melting-solidifying layer is higher in hardness and hasgood abrasion resistance, corrosion resistance and impact resistance in a high temperature work environment. The laser absorption layer used in the vermicular graphite cast iron surface laser melting-solidifying method acts on the surface of the vermicular graphite cast iron, a better decarburizing effect is achieved, air holes of the melting-solidifying layer, the surface quality and other defects are controlled significantly, and mechanical properties, oxidation resistance and other advantages are enhanced.

Description

technical field [0001] The invention belongs to the technical field of laser processing, and in particular relates to a surface coating method of laser melting after surface preheating of vermicular graphite cast iron. Background technique [0002] The graphite form of vermicular graphite cast iron is between spherical and flake, which is a transitional form. Due to its combination of two structures, vermicular graphite cast iron not only has the toughness, wear resistance and strength of ductile iron, but also has the same anti-vibration, thermal conductivity and casting performance as gray cast iron, and better plasticity and fatigue resistance than gray cast iron. It has become the material of choice for key components of engines such as ingot molds, glass molds, exhaust pipes, cylinder heads, and cylinder blocks. [0003] In actual production and use, compacted graphite cast iron is often subjected to thermal cycle loads and cyclic mechanical loads, which lead to defect...

AI Technical Summary

Problems solved by technology

[0005] The technical problem solved by the technology of the present invention: overcomes the deficiencies of the prior art, and provides a method of laser melting on the surface of vermicular graphite cast iron, which adopts the method of spraying, so that the laser absorbing layer can be more evenly spread on the surface of vermicular graphite cast iron, and the laser The absorption layer has a better effect on the laser and the substrate, and the obtained laser fused layer has higher hardness, and has good wear resistance and corrosion resistance under high temperature working environment; The surface of graphite cast iron has a better carbon removal effect, so that the pores of the fused layer, poor surface quality and other defects have been significantly controlled and the advantages of mechanical properties and oxidation resistance have been enhanced.

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