Laser strengthening process for metal leaf

Abstract

The invention relates to a metal leaf laser strengthening technology. After the surface of the metal required processing area is coated alloy extinction coating, the light beam with certain facula selected by the processed area is practiced laser processing. The laser location and moving in the processed area are realized the light beam three-dimensional motion by the digital control programming of the leaf local processed area shaped conductor. At the same time, the inert gases are used to protect the action area, and the average hardness of the local hardened layer reaches from HV four hundred and fifty to HV six hundred and fifty. And it is reduced with gradient from the outer to inner. The depth of the single side hardened layer is more than 0.25 millimeter. The width of the hardened band is adjustable, and it has no processed crack, deformation. The invention solves the deformation problem when the metal blaze is practiced induction hardening. And the hardness is higher than from ten percent to twenty percent of the induction hardening.

Description

technical field [0001] The invention relates to a metal surface laser strengthening process, which is suitable for the surface strengthening of rotating metal blades, especially for the surface strengthening of the blades of the steam inlet part of a steam turbine. Background technique [0002] Metal blades are one of the important parts in some machinery and equipment. The life and wear of the blades directly affect the normal operation of the equipment. Although the mechanism of fatigue damage has been understood, the problem of blade life has not been resolved due to many factors affecting blade life, and blade failure accounts for more than 30% of various equipment failures. For example: The thermal power 300,000-kilowatt feed water pump unit produced by Hangzhou Steam Turbine Group Co., Ltd. adopts NK50 / 60 condensing type, and its final stage adopts HK56-3 blades, which are responsible for converting the thermal energy of steam into mechanical ...

AI Technical Summary

Problems solved by technology

In order to improve the water erosion resistance of blades, there are mainly the following technological methods at present: (1) Flame quenching and strengthening: flame heating and quenching on the steam outlet side of the blades. (2) High-frequency induction heating and quenching: This process uses induction heating and then low-temperature tempering to produce tempered martensite with a thickness of 2-6mm, which can improve efficiency, but the induction heating equipment is complicated, especially the design of the induction coil (3) Partial coating: a layer of new alloy is covered on the partial position of the steam inlet edge of the blade. The process methods used include: brazing Stellite alloy sheet, thermal spraying, surfacing, electroplating, chemical transformation Membranes, coatings and coatings, etc.

This type of method has problems such as complex process, large residual stress, and easy peeling off of the covering layer.

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