DE2432426A1 - Corrosion resisting light tubular mast - has protective metal spray and synthetic resin seal on rust-proof steel - Google Patents

Abstract

Tubular mast, particularly for lights, of weather resistant steel has its surface roughened, and an aluminium layer sprayed on. It is covered with a layer of synthetic resin. Where a mast is exposed to particular corrosive action, e.g. sea air, the aluminium may be alloyed with magnesium or naganese. Masts may also have zinc coating 50 microns thick and then an aluminium coating of usual thickness of 100-300 microns. The metal may also be given greater density through mechanical pressure. The mast tube can be bent without damaging its protective coat and it can withstand mechanical stresses. The protection is given through the iron oxide forming on the steel surface and the aluminium layer whose pores are closed by the synthetic resin.

Description

Patent attorneys
DipUng. W. Meissner
Dipl.-Ing. PE Meissner

Mjr / Hk

4th July 1974

Mannesmann Aktiengesellschaft, 4 Düsseldorf, Mannesmannufer 2

KQrro sionsbeständijfyei; Rohrmas_t

The invention relates to a tubular mast, in particular a light mast, which consists of a weatherproof steel and its outer Surface is provided with a protective coating against corrosion.

Are known supports or masts made of conventional structural steels that are protected against corrosion by anti-rust coatings. However, these known paints have a temporary effect and must be renewed more or less often depending on the atmospheric conditions. They are also resistant to damage mechanical influences not very resistant.

Masts made of steel pipes are also known, the inner and outer surfaces of which are hot-dip galvanized for corrosion protection are. But even such a zinc layer provides temporary protection and corrodes with erosion, especially in one Industrial atmosphere, especially depending on the SOp content the air. They therefore usually have to be provided with an additional protective coating. Such masts require through the application the zinc layer after the hot-dip process is a costly great expense Steels cause galvanizing corrosion problems because of the accelerated iron-zinc reaction.

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Finally, supports or masts made of so-called weatherproof structural steels are also known. Forms on the surface of such steels under the influence of the atmosphere an iron oxide coating of dark brown color that adheres firmly and has protective layer properties Has. Impair in the first weathering phase such masts the environment by running rust water, or * Substances loosened from the rust layer.

The invention is based on the object for tubular masts or supports, in particular light masts, which are erected outdoors are a good-looking long-term protection against corrosion create that also resists damage from mechanical impacts. The object is achieved according to the invention in that the corrosion protection layer consists of a steel surface that has been roughened by blasting with corundum or chilled cast gravel Spray applied metallic base layer made of aluminum and a cover layer made of a synthetic resin that closes the pores consists.

The tubular masts invention have over previously known in the advantage that its inner surface is largely protected by the self-forming here Schutzrostschidt against corrosion and at the same time its outer surface against corrosion and mechanical damage. The protection of the outer surface is mainly based on the fact that the process-related pores of the aluminum spray coating are blocked on the one hand on the steel surface by the poorly soluble iron oxides formed here and on the other hand on the outer surface by the synthetic resin cover layer. This double effective corrosion protection guarantees a maintenance-free outdoor weathering time of the masts of more than 10 years.

The aluminum spray coating can be made of pure aluminum with 99 »5% Al exist. In the event that the masts are exposed to the action of a particularly humid and salty atmosphere., e.g. in the sea area, it is recommended with the further feature of the invention that the metallic base layer consists of a hydro-

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lysis-resistant, i.e. aluminum spray coating alloyed with magnesium or manganese consists. The thickness of the spray layer is expediently between 100 and 300 μm. A greater layer thickness is not Recommended, because the stresses caused by the spraying can have an effect that can cause the layer to flake off to lead. An underlying layer thickness is not recommended due to the reduced corrosion protection effect.

In addition to the significantly extended service life of the invention Another advantage is that masts can be deformed by bending without the Corrosion protection layer flaking off the mast surface. this has a particularly advantageous effect in the production of vc-n so-called Whippoles off. For masts that are not bent but on which the corrosion protection layer is damaged by external circumstances must be expected, the invention provides that the aluminum or aluminum alloy spray coating is also applied to a zinc spray layer covering the mast surface, the layer thickness of which is around 50 µm.

This zinc spray layer is effective because of the cathodic protective effect of the zinc 'on steel, so that if the aluminum sprayed layer is damaged, there is no under-rusting or rust formation.

Another improvement of the masts in terms of their surface finish is achieved according to the invention in that the metallic base layer is compacted by means of mechanical pressure is. The compaction can be achieved in such a way that, in the known manner, the spraying takes place in several layers the aluminum layer either the first or a further aluminum layer or the entire edition is treated by pressure rollers.

With the further feature of the invention it is proposed that the pore-sealing plastic cover layer consists of one on the Aluminum spray layer applied with or without a solvent

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acrylic, phenolic, polyurethane or vinyl resin. In some cases it is recommended, for example, for an improvement the surface smoothness and the optical appearance of the masts, that the top layer has fillers, e.g. aluminum or iron-mica pigments contains. In addition to the optical effect, this also ensures that the process-related continuous Pores no rusting or rust pox formation occurs.

In addition to the sealing with organic plastics, a Inorganic reaction sealing are used, acidified chloride and phosphate solutions being preferably used that react with aluminum to form oxide compounds of lower solubility.

- patent claims -

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Claims (6)

L2 Ί Case 9715 Λ £> ΛΛ Λ, ^ Α / ί »Λ Claims Tubular mast, in particular light mast, made of a weatherproof steel, the outer surface of which has a corrosion protection layer is coated, characterized in that the anti-corrosion layer consists of a layer applied by blasting by means of corundum or Chilled cast gravel roughened surface by spraying applied metallic base layer made of aluminum and one of its pores sealing cover layer consists of a synthetic resin. 2. tubular mast according to claim 1, characterized in that the base layer made of pure aluminum with 99.5? £ Al or one with magnesium or manganese-alloyed, hydrolysis-resistant aluminum spray coating consists, preferably in a layer thickness between and 300 μm, 3. Pipe mast according to claims 1 and 2 _9, characterized in that the aluminum or aluminum alloy spray coating is applied to a zinc spray coating covering the mast surface, the layer thickness of which is about 50 μm. 4. tubular mast according to claims 1 to 3, characterized in that the metallic base layer has been compacted by means of mechanical pressure _e 5. tubular mast according to claims 1 to 4, characterized in that that the plastic cover layer consists of one on top of the aluminum sprayed layer applied and cured, solvent-based or solvent-free acrylic, phenolic, polyurethane or Made of vinyl resin. 6. tubular mast according to claims 1 to 5> characterized in that the synthetic resin cover layer contains fillers, e.g. aluminum pigments or contains iron-mica pigments. 7 tubular mast according to claims 1 to 4 ₉ characterized in that that the pore-closing cover layer made of reaction materials ■ J / / g: of aluminum with chlorides such as eg. MgCl ₂ or ZnQlA ft is fixed or in a reaction of aluminum with phosphorus ^ whose salts are formed _o . S0S883 / 0590 ORIGINAL INSPECTED