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Definition of thermal spraying

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Update time : 2019-02-14 16:07:18

  Thermal spraying is a process that USES a heat source to heat the spraying material to the state of melting or semi-melting, relies on the power of the heat source or the external compressed airflow, atomize the melting drops or push the melting particles into spray particle beams, and spray the pretreated workpiece surface at a certain speed to form a coating.
 

  Features of thermal spraying:

  Thermal spraying technology has two prominent characteristics: first, the composition of the powder is not limited, can be selected according to special requirements;The second is the process of thermal spraying workpiece temperature can be controlled, so as to reduce the deformation of oxidation and phase change, so that the performance of the material itself is not damaged or lost, these characteristics and thermal spraying coating with heat resistance, corrosion resistance, wear resistance, oxidation resistance, insulation, insulation and other special functions, so that thermal spraying technology has been rapidly developed.Should consider when choosing a coating technology economy and technical performance of the coating technology, in the whole system considering the surface coating or other surface modification and processing methods, to know the function of the surface requirements and service environment, base material (alloy, heat treatment, etc.) on the surface of the processing performance, must consider the coating's own technical problems and economy, the service life of coating and advantages, rather than just the production cost of coating.
 

   Application method of thermal spraying:

  According to the different heat source and spraying material state.Arc spraying is a method that arcs are generated between two wires that are connected to the positive pole and the negative pole of the power source. The heated molten part is atomized by the compressed air jet and sprayed onto the substrate to form a coating.Since this method is only suitable for spraying wire, so also known as arc wire spraying.
 

  Features:

  (1) the spraying material must be conductive.

 (2) the arc temperature is lower than the plasma temperature, but higher than the oxygen acetylene flame temperature.The compressed air pressure of atomized wire can be high, so the spraying layer is relatively dense.

  (3) since two wires are sent in at the same time, the spraying efficiency is high.

  2. Application:it is suitable for spraying large shafts and rollers as well as for long-term protection of large structural parts.

 

   Thermal spraying is how to heat the material:

  1. Thermal spraying is a method that USES a heat source to heat the spraying material, atomize, spray and deposit the melted or nearly melted particles on the surface of the substrate to form a special surface layer.At present, there are three main heat sources for spraying.One is arc heat source, two is plasma flame heat source, three is natural gas heat source.The thermal spraying methods can be divided into arc spraying, plasma spraying and flame spraying.

  2. spray welding (or spray welding) is the use of heat source to heat the material, spray onto the surface of the substrate, and then melt it to the surface of the substrate, forming a special surface layer method.At present, the heat source is mainly oxy-acetylene flame.