ES2326452B1 - MANUFACTURE OF PLUVIAL DROPS IN ALLOYS OF THE ALUMINUM-MAGNESIUM SYSTEM, AS ALTERNATIVE TO THE CONVENTIONAL PRODUCTS OF THE SECTOR. - Google Patents

Abstract

Rainwater downpipes manufacturing in aluminum-magnesium system alloys, such as alternative to conventional products in the sector.

The object of the invention is to manufacture the rainwater downpipe system, where they are included cuvettes, elbows, clamps, and the downspouts themselves, in any of the system alloys Aluminum-Magnesium 5XXX series, which present Mg content less than or equal to 3.5% by weight, presented in the annealing state, or after strain hardening in cold.

The innovation that these materials incorporate on conventional materials, currently used for the manufacture of these products, lies in its high lightness, derived from the combination of the elements Al and Mg, what which greatly simplifies the mounting of the downspout system, and in the improvement of structural properties, derived from power Mg hardener in solid solution, and the ability to deformation hardening presented by these alloys. TO all this must be added its good aptitude to weldability, and the excellent corrosion resistance properties in aqueous and marine environments. All these properties result superior to those presented by commonly used materials in the sector for the manufacture of the downspout system.

Description

Rainwater downpipes manufacturing in aluminum-magnesium system alloys, such as alternative to conventional products in the sector.

Object of the invention

The present invention, as expressed in the set forth in this specification, refers to manufacturing of rainwater downpipes in system alloys Aluminum-Magnesium, as an alternative to materials  Conventionals used for this purpose in their sector.

The evacuation of rainwater, which circulates at through the gutter of a roof, it is channeled by the downspouts of water to the corresponding drains. The junction between gutter and downspouts is made using accessories called, in the sector, "exits" or buckets. Well, the object of the invention it consists of manufacturing the rainwater downpipe system, where  cuvettes, elbows, clamps, and the pipes themselves are included downspouts, in any of the system's alloys Aluminum-Magnesium 5XXX series, with a content in Mg less than or equal to 3.5% by weight, presenting in the state of annealing, or after hardening by cold deformation. These Alloys have high resistance properties to corrosion in humid, aqueous, or marine environments, and high structural properties such as its resistance to plastic deformation, or specific stiffness. All these properties they are superior to those presented by the materials used commonly in the sector for the manufacturing of the system downspouts In turn, all this allows a remarkable simplification in the assembly of this downspout system, within the entire system of rainwater channeling, due to its lower weight.

Background of the invention

The evacuation of the rainwater that circulates to Through the gutter it is made through the water downspouts. There are many profiles of downspouts; round, square, rectangular, smooth or wavy, varying its thickness according to its section or diameter, the thickness being mostly commercialized in the sector of 0.5 and 0.6 mm. In the case of downspouts its diameters are usually 80, 100, and 120 mm, while the downpipes with square section usually have side length 80 and 100 mm. The union between downspouts is usually by overlapping two downspouts, when each downspout is arranged at one end "flared." The length of the downpipe is variable, although the most common is its commercialization in its format with length of 3 meters.

The water downspouts are arranged always in a straight line, avoiding possible elbows Mayos availability to cause traffic jams. Fixing the downpipe, at a certain distance from the wall, is done by "clamps" with hook. The maximum distance between these clamps must not exceed 2 meters.

The downspouts are manufactured from a coil, with bandwidth the development of the downspout, whose sheet is profile on a roller roll forming machine, or on a folder, until reaching the desired tube profile, to later join longitudinally the tube through two possible systems: "crimping" of its ends, or by welding longitudinal of its ends.

Currently, both the downpipe and its accessories, are being marketed by their sector in the following qualities:

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 Copper: In ½ hard state, referred to its maximum hardening capacity.

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 In a zinc based alloy, generally microalloyed with copper and titanium.

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 Construction steel galvanized.

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 Aluminum: 1XXX series, in lacquered state

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 PVC: Chloride polyvinyl.

Copper, zinc, and steel downspouts, usually manufactured by longitudinal welding of the ends of the bandwidth of the starting sheet, after its profiling. They can also be manufactured by "crimping" of the lateral ends of the sheet, after profiling the tube. Without However, the downpipes made of aluminum, of the 1XXX series, they are never welded by their lateral ends at the end of the tube, if not that its ends are always joined by "hooked up." The reason is because the aluminum downpipe, of the 1XXX series, they are usually marketed in the lacquered state, in various colors, the product being made from sheet metal previously lacquered, which cannot be subsequently welded to avoid the deterioration of the lacquer. Downspouts made of lacquered aluminum, 1XXX series, have some structural properties lower than other materials commonly used to manufacture this product, and that have been described above, along with poor resistance to corrosion in humid environments. Weaknesses that remain corrected with alloys Aluminum-Magnesium

Description of the invention

It's about manufacturing the downspout system of rainwater for buildings in those system alloys Aluminum-Magnesium, 5XXX series, presented a percentage by weight of Magnesium equal to or less than 3.5. The system  of rainwater downspouts includes the downspouts themselves and mounting accessories such as cuvettes, elbows, and clamps

System alloys Aluminum-Magnesium belong to the 5000 series, or also referred to as 5XXX. The interest of these alloys resides in the following factors:

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 High lightness derived from the combination of two light elements Mg and Al (? Mg = 1.74 g / cm3 and y Al = 2.70 g / cm3).

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 Mg hardening power in solid solution, by replacement in the Al network, without excessive prejudice of its ductility.

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 Hardening capacity by deformation;

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 Good aptitude to weldability

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 Good resistance to corrosion, particularly in marine atmospheres.

Among its most frequent applications are find:

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 Ornamental elements and decorative;

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 Packaging bodies of two pieces, and the lid of the two-piece containers.

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 Home appliances domestic.

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 Conventional lampposts of street lighting.

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 In boats and boats.

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 Cryogenic tanks

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 Crane components

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 Vehicle structures (high-end motorcycle chassis, etc, ...).

The average densities of alloys of Al-Mg system, with contents below 3.5% Mg they range between 2,697 and 2,689 g / cm3. They are all values very similar and close to the density of Al (\ rho_ {Al} = 2.70 g / cm3), which significantly reduces the weight of the different elements of the rainwater downpipe system, facilitating its assembly.

1. Solid solution hardening

These alloys have the property of hardening in solid solution, and they are denoted with the letter "OR". In this sense they enter into competition with the 3XXX series, in which the Mn is the main hardener alloy element in solid solution But it happens that Mg is a hardener in solid solution more effective than Mn, since for every 0.8% Mg requires 1.25% Mn. In addition, the amount of Mg tolerable for getting precipitation hardening is greater than the amount of Mn. Said hardening by solid solution is due to the size difference between Al (solvent) and Mg (solute). This is quantified based on the concentration of solute (Mg dissolved) and by the degree of crystallographic decoupling between its respective cells.

Analyzing the phase diagram Al-Mg, it is noted that Al can dissolve at Ambient temperature 1.8% - Mg balance weight. Unlike most Al alloys (series 2XXX, 6XXX and 7XXX, that harden by precipitation, the possibility of exploring the precipitation hardening by the compound β (Mg 5 Al 8) is ruled out, due to the susceptibility to stress corrosion (SCC) that grants such precipitation. In In this sense, commercial alloys with Mg may contain solid solution at most 5.5% by weight of Mg, which allows obtaining 5.5-1.8 = 3.3% by weight of Mg supersaturating at Al. But in cold deformed samples, there is also the possibility of precipitation of β (Mg 5 Al 8) at temperatures equal to or greater than 65 ° C (typical of exposure solar) when Mg contents are above 3.5% -weight. So it is important to consider the possibility of loss of corrosion resistance due to precipitation induced by deformation during operation in service in those terms.

Elastic limits, breaking loads and total ductilities, of alloys of usual compositions of most common Al-Mg system, after annealing of homogenization, are those presented in Table I.

TABLE I Frequent series alloys 5XXX

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Bold it indicate those with Mg <3.5% by weight

one

2. Cold deformation hardening

The strain hardening potential cold of these alloys is well known, consisting of warp by cold lamination, plus the profiling that would provide it with tubular geometry, also cold. It is distinguished for each of them states ¼ hard, ½ hard, ¾ hard, and the "full-hard". All these states do reference to the breaking load R_ {m} obtained in a succession of cold deformations until reaching "full-hard" state.

The way to designate that these alloys have been hardened by deformation is to accompany them by the letter "H" (hardened). After this letter usually come 1 or 2 digits additional:

The first digit designates:

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 H1, indicates that it has been only hardened to achieve the desired resistance, without resort to a supplementary heat treatment. The number that follow H1 -if there is- the degree of hardening is required by deformation.

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 H2, indicates that it has been hardened by deformation more than necessary, and subsequently partially restored / recrystallized to reach the level of desired acrimony This level is indicated by the digit that is place next to H2.

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 H3, indicates that they were hardened by deformation and stabilized. The tratment of stabilization is applied to prevent softening by aging at room temperature. The tratment of stabilization, which improves ductility, consists of low TT temperature (T <100ºC) for stress relief; the heat itself of component manufacturing heat treatment can arrive to provide stabilization. The digit following H3 indicates the residual acidity level.

Regarding the "second digits", which designate the level of strain hardening, may vary between 1 and 9. The number "8" indicates a residual acidity equal to which would be obtained with a 75% reduction due to cold deformation after annealing of softening.

Obviously, each of the states of reference on behalf of sheet metal manufacturers Al-Mg, is associated with a series of possible thicknesses supply, which must be compatible with the standard ranges of  downpipe thicknesses. Then, in Tables II to VII, relate the most common supply states of sheet metal Al-Mg on behalf of the suppliers of the sector.

TABLE II Typical Mechanical Properties of 5005 Alloy (0.8 Mg)

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TABLE III Typical Mechanical Properties of 5050 Alloy (1.4 Mg)

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TABLE IV Typical Mechanical Properties of 5052 Alloy (2.5 Mg-0.25 Cr)

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TABLE V Typical Mechanical Properties of 5454 Alloy (2.7 Mg-0.8 Mn-0.12 Cr)

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TABLE VI Typical Mechanical Properties of 5154 Alloy (3.5 Mg-0.25 Cr)

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TABLE VII Typical Mechanical Properties of 5457 Alloy (1.0 Mg-0.30 Mn)

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Table VIII shows the properties specific structural elements of some of the system's alloys Al-Mg, after a hardening process by cold deformation, comparing them with the properties of some of the most used materials for the manufacture of elements of the rainwater downpipe system.

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3. Finishing and coating of base alloys To the

The aluminum finish is aesthetically nice on many products even if no treatment is done specific surface. Its protective oxide formed so natural, it is transparent and can be thickened by anodizing, and It can be raised, depending on the thickness, by anodizing to obtain a complementary protection without compromising the external appearance metallic

Aluminum accepts a wide variety of finishes to alter and reinforce certain surface appearances as require. You can create surface textures, from aspect rough to matte, until mirror-smooth finish. It can apply shades of colors through chemical processes, or anodized It is possible to apply paints, lacquers, and electrodeposition coatings.

The possibilities of coatings that admit aluminum alloys in general, and series alloys Al-Mg in any of its delivery states, in particular, they are:

Mechanical Finishes

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Burnish

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Surface textured

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Chiseled

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Chemical Finishes

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Chemical attack

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Polished

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Electrolytic Finishes

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Anodized

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 Type I architectural uses (> 18 µm thickness)

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 Type II architectural uses (10 µm> thickness> 18 µm)

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Coatings electrolytic

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Non-electrolytic coatings.

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Lacquered (they are not long durability)

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Coatings polymeric

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 Coatings of polyester

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 Plastisol

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 Acrylic paints Water

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 Polyester modified by silicones

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 Polyurethane aliphatic

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 Coatings of fluorocarbon

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in the form of pigments with curing in the air or by cooking.

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Plastic laminates They are films of plastic bonded to Al.

TABLE VIII Choice and selection of materials most suitable for rainwater downspouts

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Meaning of the indices :

E / \ rho: Specific flexural rigidity by unit of mass, of a beam requested in traction, of length L and of area A, variable.

R_ {m} / \ rho: Deformation resistance plastic beam of length L (of variable area A).

E 1/3 / \ rho: Specific flexural stiffness per unit of hollow beam mass of length L and thickness d.

The resulting indices are indicated in bold maximums among the candidate materials. The highest value in any column where a specific coefficient appears is It corresponds to the best material for that coefficient.

Claims (8)

1. Rainwater downpipe system, consisting of downpipes, cuvettes, elbows, and clamps, manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, characterized in that Magnesium intervenes in a chemical composition of these alloys percentage equal, or less, to 3.5% by weight with respect to the total alloy. These alloys can be presented in any of their delivery states, either in an annealed state (presenting hardening properties in solid solution) or in a hardened state by cold deformation. And the downpipes may have been manufactured by crimping processes, or by welding the lateral ends of the sheet bandwidth used in the previous profiling of said downspout. 2. Rainwater downspout system manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, according to claim 1, characterized in that Chromium and Manganese are involved in the chemical composition of said alloys in a percentage lower than 0.5 and 1%, respectively, by weight with respect to the total alloy. 3. Rainwater downspout system manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, according to claim 1, characterized in that in the chemical composition of said alloys the Chrome intervenes in a percentage less than 0.5% by weight with respect to the total alloy. 4. Rainwater downpipe system manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, according to claims 1 to 3, characterized by presenting an electrolytic finish by anodizing, with a thickness equal to or greater than 15 µm. 5. Rainwater downpipe system manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, according to claims 1 to 3, characterized by presenting a non-electrolytic coating, by lacquering. 6. Rainwater downpipe system manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, according to claims 1 to 3, characterized by presenting a non-electrolytic, polymeric coating. 7. Rainwater downpipe system manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, according to claims 1 to 3, characterized by presenting a coating, not electrolytic, by means of enamels in the form of pigments with air curing. 8. Rainwater downpipe system manufactured in those alloys of the Aluminum-Magnesium system, of the 5XXX series, according to claims 1 to 3, characterized by presenting a non-electrolytic coating, by means of plastic laminates adhered to the material.