A laser melting method for the surface of vermicular graphite cast iron

Abstract

The invention relates to a laser melting method for the surface of vermicular graphite cast iron. First, the vermicular graphite cast iron is preheated, and then a prepared laser absorbing layer is evenly sprayed on the surface of the vermicular graphite cast iron to carry out laser melting. In the present invention, a laser is used to preheat the sample. After the pretreatment, the temperature gradient inside the laser melting can be reduced, the generation of thermal stress can be reduced, and the possibility of crack initiation in the fused layer can be reduced to a certain extent. The invention adopts the method of spraying, so that the laser absorbing layer can be more evenly laid on the surface of the vermicular graphite cast iron, and the laser absorbing layer can fully interact with the laser and the base material better. The obtained laser melting layer has high hardness, and has good wear resistance, corrosion resistance and impact resistance under high temperature working environment; The carbon effect makes the defects such as pores and poor surface quality of the fused layer obviously controlled and enhances the advantages of mechanical properties and oxidation resistance.

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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