Surface requirements before coating

To ensure high quality of coating, quality of product’s surface must meet the requirements listed below. Failure to comply with relevant recommendations could lead to irreparable defects, poor coverage or increase cost of services.

Requirements for material and surface of base metal (according to GOST 9.301-86):

  • for coating it is exposed products of carbon steel, carbon structural steel and low alloy steel, cast iron, copper and its alloys;

  • on the surfaces should not be: rolled up the scale, burrs, bundles and cracks, including those that appeared after etching, polishing and other processing; corrosion damage, pores and cavities;

  • surface of cast and forged parts must be free of gas and shrinkage cavities, slag and flux inclusions;

  • surface of parts made of hot metal must be free from scale, pickling sludge, corrosion products of base metal and other contaminants;

  • surface parts after mechanical processing should be without oil layer, emulsion, metal chips, burrs, dust and corrosion products, without inclusions of particles of other material;

  • on the surfaces after heat treatment should not be nicks, bubbles, corrosion hotbeds, bundles, hogging;

  • welded and soldered joints on the parts must be cleaned and continuous around the perimeter. Not allowed presence of welds pores, fistulas, cracks and slag inclusions.


  •  

Guidelines for product construction:

  • the products should not have pockets, closed cavities that prevent free drainage of solutions. All cavities of products must be available for coating. If it is impossible to coat separate areas of products surfaces it should be discussed in documentation about the possibility of absence of coating in these cavities;

  • hollow products or articles of complex shape with narrow or blind holes and gaps are subjected for trial coating;

  • sharp corners and edges of products, except of technologically justified cases, shall be rounded the radius of at least 0.3 mm;

  • it is not allowed coatings of products (parts) that have some kind of soft solder, aluminum, glue or resin;

  • all assembled constructions must be mounted in a disassembled state.

For a mirrored surface coating product must be grounded (polished) up to Rz= 2,5.

Caution! Coating on suspensions has some technological peculiarities. The details that are coated on suspensions are fixed on hooks or with the help of wire for providing a reliable supply of electricity. As a result, the place of contact of details with coating suspension will have a minimum thickness. We ask to agree technological spaces for hanging where the thickness of the coating can be minimal.