What kind of construction is flame spraying?

       Flame spraying refers to the use of the high temperature of the gas combustion flame to melt the spray material (wire or powder), and spray it with a compressed air stream to form a coating on the surface of the workpiece.

 

        As a new type of surface protection and surface strengthening process, flame spraying technology has developed rapidly in the past 20 years and has become a very active branch in the field of metal surface engineering. With the flame as the heat source, the metal and non-metal materials are heated to a molten state, formed into a mist under the impetus of high-speed airflow, and sprayed on the substrate. When the ejected tiny molten particles hit the substrate, they plastically deform and stack up as flakes.

 

        Introduction

        Flame spraying uses fuel gas acetylene, propane, methyl acetylene propadiene (MPS), hydrogen or natural gas, and combustion-supporting gas oxygen as heat sources. The spray material enters the flame through a certain transmission method and is heated to a molten or softened state. Then, it is sprayed onto the substrate by means of gas or flame acceleration. According to the different spraying materials, it can be divided into wire flame spraying and powder flame spraying.

 

        wire

 

        Wire flame spraying uses the heat source of oxyacetylene combustion to continuously heat and melt the sprayed wire, evenly send it into the flame, and then atomize it into particles by high-pressure gas, which is directly sprayed on the surface of the pretreated workpiece to form continuous deposition. Metal and alloy coatings. This process method is one of the most commonly used thermal spraying technologies in China. Mainly spray zinc, aluminum, zinc-aluminum alloy materials, and carry out long-term anti-corrosion treatment for large steel structures.

structure

 

        Wire flame spraying is sprayed with a wire flame spray gun. The spray source is the nozzle. The wire goes through the center of the nozzle. The tip of the wire is continuously heated to its melting point by an annular flame formed around the nozzle and hood. It is then atomized into spray particles by compressed air passing through the air hood. The accelerated airflow is sprayed onto the mold substrate, cooling the molten particles to a plastic or semi-molten state, while also undergoing some degree of oxidation. As the particles collide with the substrate, they flatten and bond with the substrate, and then the particles that collide with the substrate also flatten and bond with the particles of the substrate, thereby building up into a coating.

 

        Features

 

        The wire is conveyed by the rotation of the air turbine or motor in the spray gun, the speed of which can be adjusted to control the wire feeding speed. Using the air turbine spray gun, it is difficult to fine-tune the wire feeding speed, and its speed is difficult to be constant due to the influence of compressed air, but the spray gun is light in weight, suitable for manual operation; The adjustment can also be kept constant, and the spraying automation is high, but the heavy spray gun is only suitable for mechanical spraying.