pt-BRes-ESen-US
| Login
 

Metalization Spraying

SURFACE PREPARATION 

Any coating, for better, that is, will never fulfill its intended purpose, if not firmly attached to the base material. Often failures occur with certain coatings because of their deployment of the base after a very short time of use or even immediately after the deposition. Thermal Spraying in the preparation of a surface is the most important steps to ensure a perfect adhesion to the substrate layer.

The type of material to be deposited, and the type of base generally determine the best method of preparation, to be employed.

APPLICATIONS IN RECOVERY AND PARTS IMPROVEMENT

Grow in the country anticorrosive applications using thermal spray processes or simply metalization.

In mechanical components subjected to high stresses, it is stated subjecting them to non-destructive testing prior to application of the coating. This is due to detect possible faults or defects that can reproduce the layer, broken rice, for example, a steel can not be repaired by the method of metallization.

In general, machine elements and other mechanical parts that are to be both a metalization coating for improving its surface characteristics as restoration dimensional require a machining work advance. This machining is intended or a lowering of the area to be coated to leave the necessary space for the specified layer thickness, or a uniform area has irregular wear caused by the use of part or to remove chemical contamination, oxidation and coatings .

For applications of coatings using equipment flame gas, using wire, it is customary to prepare the surface, machining a slight lal pitch thread, 5 mm and depth of thread with 0.2 to 0.3 mm. This thread is intended to increase the contact surface between substrate layer and creating a mechanical anchoring effect which assists the adhesion of the layer. Tip: a tool to open the thread must be sharp in order to cut the material without a sharp edge at the bottom of the fillet, thus, avoids the notch effect, which could cause cracking, with possible breakage of material Based on this place.

On one axis, another tip is to avoid metallize to the ends. It is customary to let them with a small strip without tearing down, thus forming a chamber where the coating is protected from mechanical shocks. A coated axis to the edge metallization layer may have easily chipped to any hit on the top. The figures below show the most appropriate ways to prepare an axis:



The next step is to eliminate any other fats and oils left on the work piece after machining or grinding.

Another application of preparation '' surface is abrasive blasting, where the plating should be done immediately after the operation. The most commonly used abrasives are aluminum oxide, steel grit angle, quartz sand and crushed.

In the field of blasting, in large structures exposed to the outdoors, where the abrasive recovery is very difficult to use sand used primarily for their low cost compared with other abrasives. However, wherever possible it is preferable to replace the second abrasive sand due to two factors: The first is that the sand has a high content of silica and mica which are impregnated on the surface sandblasted difficult the adhesion of any one wants to apply coating paint is or plating, the second factor is the downside risk to the health of the applicator caused by prolonged exposure of the vast dust formed. The jatistas should work with respiratory protection equipment.

Confined to work in places where they can easily collect the abrasive, it is stated using aluminum oxide or possibly angular steel grit. These abrasives are used for high performance, it does not break easily, allowing large number of reuse. And do not produce dust which is very good for the security of jatista.

Companies that make recovery or processing of parts usually have offices or rooms suitable for the service and there blasting primarily use aluminum oxide which offers higher production yields and allows for perfectly clean and activated surfaces.

Metallization by thermal spraying consists of a group of processes in which finely divided particles of coating materials, metallic or non-metallic surfaces are deposited on a previously prepared in the molten condition or semi-molten to1 form a coating. The heat necessary for the operation is generated in a metallizing gun and may be the burning of a fuel gas through the process gas flame (flame spray) or an electrical arc (are spray).

JACKET COLD?

A strong jet of air is spraying the molten metal by beating it against the surface is cooled so that the coating does not heat the part to avoid too much of their morphological structure.

PROCESS FOR GAS FLAME (FLAME-SPRAY)

In the process gas flame or f / ame spray, a metal wire or powder is melted by the heat of the flame generated by burning fuel gas (acetylene, natural gas / LPG or propane) and oxygen. Through a strong jet of air (compressed air) the melted particles are sprayed shocking on the workpiece surface, previously prepared.

PROCESS FOR ELECTRIC ARC (ARC-SPRAY)

In the electric arc process or air and spray, the electric arc is obtained in a spray nozzle where two wires come from the deposition material. Leads to a differential potential by opening the electric arc that melts the wires. A mechanical or electrical wires continually pull the same time a strong jet of compressed air is directed in the region spraying the molten metal against the workpiece surface.

 

CORROSION COATING

Grow in the country anticorrosive applications using thermal spray processes or simply metalization.

The low cost of equipment, easy to apply, the field of technology and efficiency in the results are decisive factors for use in applications metallization corrosion.

The coatings provide excellent corrosion protection, applying a layer of 0.3 mm zinc a metal frame corrosion duration is 30 to 40 years, under atmospheric action (see chart below):

One major advantage of this process is the possibility of applying layers of zinc, aluminum or an alloy of these metals is restricted as to its thickness, and also a fast, economical and which can run the equipment with moving parts of any size , no transfer of excess temperature.

In parts galvanized, applies to plating for repairs in areas where the galvanized coating can not, the parts that had to be cut or chopped any action that the galvanized coating and especially in the areas of weld seams.

Corrosion Applications, by plating, are successfully employed in ship hulls, bridges, frames, posts, gates hydropower, among other numerous pipes and metal structures subject to corrosion in rural atmospheres, industrial or marine. 


PREVENT MAJOR AREAS OF WEAR

Manufacturers use the metallization in order to obtain greater advantages to their products. Whether to increase the useful life of the workpiece, or to provide increased benefits in wear resistance and / or temperatures, or in parts required to have electrical conductivity, or those which must have resistance to interference radiofrequency, etc..