1、 Introduction

Laser cladding processing technology is a new surface modification technology emerging with the development of high-power lasers. It is a surface strengthening method that rapidly heats and melts alloy powder or ceramic powder with the surface of the substrate under the action of a laser beam, and after the beam is removed, self-excited cooling forms a surface coating with a relatively low dilution ratio and metallurgical bonding with the substrate material, thereby improving the wear resistance, corrosion resistance, heat resistance, oxidation resistance, and other properties of the substrate.

2、 Features

The cladding layer has a low dilution but strong adhesion, and is metallurgically bonded to the substrate. It can significantly improve the wear, corrosion, heat, oxidation, or electrical properties of the surface of the substrate material, thereby achieving the purpose of surface modification or repair, meeting the specific performance requirements of the material surface, while saving a large amount of material costs. Compared with surfacing, spraying, electroplating, and vapor deposition, laser cladding has the characteristics of low dilution, dense microstructure, good adhesion between the coating and the substrate, multiple suitable materials for cladding, and large variations in particle size and content. Therefore, the application prospects of laser cladding technology are very broad.

3、 Application

The laser cladding processing technology has a wide range of applications and fields of application. Basically, workpieces in the mechanical industry can be applied, and the application of laser cladding materials is relatively flexible. For example, iron based alloy powder is suitable for parts that require local wear resistance and are prone to deformation; Nickel based alloy powder and cobalt based alloy powder are suitable for local wear resistant, heat resistant, corrosion resistant, and thermal fatigue resistant components; Ceramic coatings have high strength, thermal stability, and chemical stability at high temperatures. The application of metal coatings formed by laser cladding processing technology in metal additive manufacturing is also evident, such as: 1. Manufacturing and remanufacturing of machine parts for electrical equipment. 2. Petrochemical equipment and components. 3. Other machinery industry equipment parts.

Metal materials used for laser cladding mainly include nickel based, cobalt based, iron based, titanium alloy, copper alloy, ceramic materials, etc.

The physical and electron micrographs of some metal powders are shown below (Changsha TIJO Metal Materials Co., Ltd.):

1

Brand:316L stainless steel powder

Features: Spherical powder, high alloying purity, good sphericity, high bulk density, good fluidity, and controllable particle size distribution

Purpose: Thermal spraying, laser cladding, laser sintering, 3D printing, additive manufacturing, metal powder injection molding, hot isostatic pressing sintering molding, etc

2

Brand:17-4PH stainless steel powder

Features: High strength, high toughness, high corrosion resistance, high oxidation resistance, excellent formability, excellent weldability, and good cutting performance

Purpose: Used for manufacturing shafts, steam turbine components, 3D printing, metal injection molding, hot isostatic pressing molding, etc