Direct laser synthesis and making process of hard alloy coating

Abstract

The present invention relates to a direct laser synthesis and making process of hard alloy coating, and belongs to the field of hard alloy making and applying technology. By means of the hard alloy forming material system and high-energy laser to produce special physical and chemical metallurgical and fast solidification characteristic, hard alloy coating is formed directly through reaction in melting bath. The hard coating is dense, gas hole free and without crack and other faults, combines metallurgically with the base material, has the components, micro structure and performance of the hard alloy and any required shape. The coating may be formed in the surface of various engineering metal parts, and may be used widely in hard alloy cutter, mold antiwear part, etc.

Description

Technical field: [0001] The invention relates to a new method for laser direct synthesis and manufacturing of cemented carbide coatings, belonging to cemented carbide manufacturing and application [0002] Technical field. Background technique: [0003] Cemented carbide is a refractory metal carbide (tungsten carbide, titanium carbide, tantalum carbide, niobium carbide, vanadium carbide, etc.) as the base, cobalt or nickel as the bonding metal, and alloy materials manufactured by powder metallurgy. High hardness, good wear resistance and corrosion resistance, good red hardness, high chemical and thermal stability, high compressive strength and low expansion coefficient. It is used in metal cutting tools, molds, mining, oil drilling, geological exploration and national defense and military industries. And other fields have been widely used. Cemented carbide is usually sintered and pressed into a specific shape by high temperature and high pressure, and then inlaid or welded on too...

AI Technical Summary

Problems solved by technology

Increasing the proportion of carbides in self-fluxing alloys within a certain range will improve the performance of metal matrix composite coatings, but usually when the proportion of carbides exceeds about 65%, the composite coatings obtained by laser cladding will have serious cracks and porosity and other defects, making it unusable

Laser direct cladding of WC / Co, TiC / Co, (WC-SiC) / Co, (WC-TiN-SiC) / Co, (WC-TiC-SiC) / Co, (WC-TiC-SiC) / Co , (WC-TiC-SiC) / Co, WC-TiC-TaC and other cemented carbide powders can obtain cemented carbide coatings, but there are often the following problems: (1) Laser cladding cemented carbide powders, especially small particles of hard alloys (2) When laser cladding small particles of cemented carbide powder, some carbide particles will dissolve into the molten pool, forming some brittle microstructures, resulting in larger Crack tendency; (3) When laser cladding larger particles of cemented carbide powder, the unmelted carbide particles are solidified and embedded on the metal matrix. Due to the great difference in the thermal physical parameters of the carbide and the matrix metal, there is a large difference between them. The compatibility of the material is poor, and the interface bonding is poor, which often causes the source of interface microcracks under heavy load.

Due to the above reasons, there is still no substantial technological breakthrough and application of laser cladding to prepare cemented carbide coatings.