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Galvanized steel: characteristics, application, classification

Galvanized steel - it is steel wich differ high resistance to corrosion due to a thin coating layer of zinc alloy. The thickness of the zinc layer may vary, but it should not be lower than 0.02 mm. Zinc forms an oxide film on the surface which prevents oxygen from penetrating into the deeper layers of the metal, sot hat the likelihood of its oxidation decreases. In addition, galvanized iron has a more aesthetic appearance, so that it can be used without further painting or anti-corrosion treatment.

The main advantages of galvanized steel:

  • significant service life;
  • environmental safety;
  • high strength;
  • low cost;
  • ease of use;
  • ability to self-heal the coating in the event of scratches and pits.


Galvanizing of steel can be carried out by galvanic method, cold galvanizing, however, hot-dip galvanizing is most often used.

Hot-dip galvanizing is carried out in stages. First, the surface is degreased, then etched and rinsed. Finally, the steel sheet is immersed in a molten zinc bath. Zinc grades C0 and C1 are used, aluminum, lead and other metals are added to the bathroom. The process speed, temperature and quality of zinc are controlled by special devices. The result is a smooth, high performance metal surface that tolerates machining without loss of properties.


There are several classifications of galvanized steel, on which the further use of the metal depends.

Classification by groups:

  • CS - for cold stamping;
  • CP - for cold profiling;
  • FS - for further staining;
  • GP - general purpose.

Classification according to the ability to draw (steel of the CS group):

  • N - normal drawing;
  • D - deep drawing;
  • VD - very deep drawing.

Classification of the zinc layer thickness uniformity:

  • NT - normal thickness difference;
  • RT - reduced thickness variation.

Classification by coating thickness:

  • I - increased class (60-40 microns);
  • H - high class (40-18 microns);
  • U - usual class (18-10 microns).

Also on the surface there may be a crystallization pattern (CP) or it may be absent.


Galvanized steel sheets are used everywhere. Since galvanized steel sheets are resistant to corrosion, they are often used in industry: in heavy and chemical industries, instrumentation.

Galvanized steel sheet is amenable to mechanical processing, due to which it is used for the manufacture of stamped parts and deep-drawn products.

Galvanized steel is used in the automotive industry, for example, in the production of bodies or in the decoration of vans.

However, the main field of application of galvanized sheet is construction, as it is a durable and high-quality material. It is used in the construction of metal structures, which are light enough, while there is a small load on the walls and ceilings. Steel is suitable for the construction of hangars, garages, warehouses, roofs, etc.

Galvanized steel is used for the manufacture of a wide range of building products:

  • metal tiles;
  • corrugated board;
  • picket fence;
  • building profile;
  • strip;
  • water pipes;
  • gutters and air ducts;
  • brackets, etc.

Quality control

To determine how high-quality galvanized steel is, just look at it - the surface of the sheet should be flat, smooth, without cracks.

In sheets of cold stamping and general purpose, stains, sagging, roughness are allowed. In other types of galvanized sheet, defects should be absent.