FMP coatings for power transmission line bearings

MODERN MATERIALS FOR “COLD” GALVANIZING THE BEST CORRESPONDENCE OF THE PRICE AND QUALITY TECHNOLOGICAL SUPPORT

FMP METHOD OF «COLD GALVANIZING» for metalwears of power transmission line bearings protection

High corrosion strength and durability of power transmission line bearings is one of conditions of continuous power supply. However at operation they are exposed to serious climatic loadings - to influence of precipitation, solar radiation, aggressive atmosphere with wide limits of temperature and humidity fluctuations which lead to corrosion and gradual destruction of constructions. High-grade anticorrosive protection will help to prevent it.

Modern way of reliable metalwears protection in power engineering is the method of "cold" galvanizing; which consists in drawing on metal varnish-and-paint compositions, containing, as an anticorrosive pigment, zinc powder of special quality. Manufactured zinc-rich coatings combine advantages of zinc metal and varnish-and-paint coatings. An example to this is coating system ZINOL + ALPOL, recommended by FMP for protection of constructions in power engineering (see fig. 1).

Coating ZINOL (2 layers) + ALPOL (1 layer), total coat thickness is 120 - 140 µm.

Fig.1 Protective coating scheme of power transmission line bearings

Coating ZINOL, containing up to 96 % of zinc mass, in this system, is similar to zinc metal coating on its electrochemical behavior, therefore, similarly to it, carries out effective cathodic steel protection (see figure 2).

Coating ALPOL based on aluminium powder, owing to the flaky particle form of an aluminium pigment, screens ZINOL surface, providing additional anticorrosion protection. The combination of tread and barrier protection in coating ZINOL + ALPOL is the guarantee of its high reliability and durability in comparison with other ways of protection. Coating ZINOL + ALPOL protects metalwears from corrosion for more than 15-20 years and it is recommended at building of new objects and repair of operating ones without breakup of them.

Materials of FMP production are technological, plain and easy-to-use. They are applied by means of airless and compressed-air spraying with application of standard equipment. Materials are applied in a wide range of the Russian climatic conditions, at negative temperatures and high humidity.

Advantages of “cold” galvanizing before standard protection methods

Parameter	“Cold” galvanizing according to ZINOL + ALPOL scheme	Hot-dip galvanizing	Common coatings
1. Application basis	Plant, construction site, field environment	Only at a plant	Plant, construction site, field environment
2. Equipment for coating application	Standard equipment for lacquer coatings	Special processing lines. The Enterprise has in the unlimited set.	Standard equipment for lacquer coatings
3. Requirements to protected constructions	Any construction	There are construction size and type restrictions	Any construction
4. Protective action mechanism	Combine cathode + barrier protective mechanism	Cathode	Barrier
5. Prediction of service life period in agressive atmosphere, polluted by sulphur dioxide and hygroscopic salts	More than 15 years *	Less than 12 years	2-4 years
6. Method serviceability	Maintainable,including galvanized constructions repair	Not maintainable	Maintainable
7. Overall performance of the method as applied to power transmission line bearings	Primality, availability, universality at high coating working lives	Have technological restrictions. Short coating working life in agressive atmosphere	Short coating working lives

* parallel testing of All-Russian Research Institute for Rail Transportation and State Unitary Enterprise – Research Center for Testing and Refining Automotive Vehicles showed, that FMP coating working life is twice as much as hot-dip galvanizing in aggressive atmospheric conditions is twice as much as.


Fig. 2 Change of potential of protective coatings of different type in atmospheric conditions.

Branch certification and testing

The method “cold” galvanizing with application of coating ZINOL + ALPOL has passed the full branch certification which has confirmed its application efficiency in electric-power branch:

• high protective behavior of the coating have been confirmed by numerous testing results in key branch institutes of Russia: Melnikov Central Research and Project Institute of Building Constructions, All-Russian Research Institute for Construction and Operation of Pipelines, Research Institute for Reinforced Concrete, All-Russian Research Institute for Rail Transportation, State Unitary Enterprise – Research Center for Testing and Refining Automotive Vehicles;
• coating application is introduced into addition to Construction regulations 2.03.11-85 “Anticorrosion building constructions protection”, section 5 “Metal Constructions” and recommended for application by “Gosstroy”, Russia;
• in comments to Rules electrical installation mechanism (7th issue), Rostechnadzor has mentioned application of the method of “cold” galvanizing with using zinc-rich coatings, included into addition to Construction regulations 2.03.11-85 for protection of metal units of air transmission facilities bearings and switch-gear metalworks.

APPLICATION EXPERIENCE