Zinc Coating

What you need to know: • Same Day delivery • Low and flexible prices • Superior coating depth ( median coating: 80μm) • One of the deepest kettles in Eastern Europe with the practical measures: L= 7 m, W = 1,1 m , H= 2,8 m In its lengthy activity in the metallic construction sector, Ecokapa&Avaco Group has gathered a great deal of experience about our customers’ needs in terms of corrosion protection. In our surveys, the clients emphasized the necessity of using a modern, efficient and especially long-lasting anti-corrosive protection technology. Many customers want to go a step further from the traditional paint-based surface protection method, and so to ensure their investment for the future. This is where we come in.

The Hot-Dip Galvanizing Process

By hot-dip galvanizing we understand a process where the steel gets allied, after being treated first, degreased and pickled, in a melted Zinc bath, having as result the steel surface’s covering with a Zinc coating. Briefly: hot-dip galvanization represents the best currently available protection system of steel against corrosion. It offers multiple characteristic advantages that every client should be aware of. Why Hot Dip Galvanizing? Since the advent of electro-chemical covering technology, hot-dip galvanization has kept its edge as a proven superior technology, given that it boasts many advantages.Especially for long-term anticorrosive solutions, hot dip galvanizing has been proven to outshine any competing technology. Electro-chemical coatings unfortunately have some major disadvantages that include a long duration of the galvanizing procedure, a relatively poor adherence of the Zinc to the piece (no Zn-Fe alloy created and a surface covering only 14 microns deep), an therefore a reduced life cycle for the coat of Zinc and the underlying metal. The importance of the ZN-Fe alloy should not be underestimated, for it guarantees that the layer of zinc adheres to the underlying surface and does nor peel off or allow for corrosion from indentations in the material that commonly occur during handling and transport. For the customer, this means increased maintenance costs in the future. Our usage of base covering and coating, offers both enhanced protection and aesthetic appeal. In some instances, companies have lower standards, offering single coatings with a layer of varnish. This type of product may at first be visually pleasing, but unfortunately, it does not stand the test of time. The zinc coating thickness practiced by Avaco&Ecokapa Group ensures that the metallic elements stay protected and do not lose their mechanical properties for many decades. For example, the chart below illustrates the lifetime in years in accordance with the depth of the zinc layer. image1 Hot-dip galvanization is: • Reliable • Resistant • Needs no maintenance • Time saving • Safe • Environmentally safe • Low price method, when taking the product life cycle into account • The best method for dealing with apertures and tags • Easy to control • The possibility to galvanize larger pieces than the dimension of the bath by alternating immersions • Aesthetic aspect of the zinc oxide crystals • And last but not least: 80 years of worry-free usage of the metallic structure.

Methods and Important Considerations for Clients

Many customers prefer hot-dip galvanization because of its low price comparative to other known methods of corrosion protection. In addition to this, it is also the best-known method of ensuring an optimal life span for your metallic elements, and leaves the customer worry-free in terms of future maintenance. The procedure is simple, but some precautions and specifications must be taken into consideration at the design phase for best results. The location of technical appertures 1. Preferably – completely open with the same diameter as the section at the top and bottom. 2 & 3. Holes must be made on both sides, unless the piece allows for complete openings 4. Has to be used with Poz.2 and Poz.3, if apertures in the top of the section are not allowed. Two semicircles separated by 180 ° in line with the cuts from poz.2 and poz.3. 5. The openings at both ends must be at least 30% of the pipe for more than 75 mm of the pipe and 45% of the surface of the pipe for 75 mm or less. Poz.2 semicircle A= 40 x R mm Poz.3 slot B = 18 mm – center hole–C = 75 mm diameter Poz.4 semicircle D = 40 x R mm image3 Beam with rectangular profiles for reinforcement image4 The location of the orifices for vertical rectangular profiles must conform to examples A and B in the direction of the arrows in the drawing. Each vertical rectangular profile must have two apertures in the top and bottom, at 180 degrees in line to the horizontal parts as shown by the arrows. The size of the openings at each end must represent 30% of the cross-sectional area. End plates – horizontal 1. Preferably – fully open 2 & 3. Similar variants – holes must be 30% of the inner surface of the tube. image4 Railings The drawing below illustrates the optimal project for the manufacture of a handrailrequiring zinc coating. 1. The ventilation holes must be as close as possible to the welding, but not less than a ø 9 mm diameter. 2. Inner holes must correspond to the diameter of the pipe for the best quality and lowest cost of galvanizing. 3. Vents in end sections or similar sections must be of minimum 12 mm diameter. 4 & 5. Any device used for lifting the assembly that obstructs the openings the ends of the horizontal handrail and vertical tubes must be attached after galvanizing. image5 The drawing below illustrates an acceptable alternative if no complete internal appertures (pipe diameter) are incorporated in railing project . 1. air vents should be as close as possible to the welding and should represent 25% of the diameter of the pipe , but should not have a smaller diameter than ø 9 mm. Two holes on each end , and each junction should be at 180 ° to each other as shown in the drawing . 2. Vents in end sections or similar sections must be of minimum 12 mm. 3 & 4 . Any device used for lifting the assembly that obstructs the openings the ends of the horizontal handrail and vertical tubes must be attached after galvanizing. image6 Many galvanizers prefer the ventilation system to be visible on the outside of the assemblage. This is necessary to verify proper ventilation and to see whether it was omitted by mistake. The decision to use pipes to replace structural sections in welded products must be made only after a careful balancing of the costs of zinc galvanizing, given that they maybe an inherent disadvantages for the customer image7 image8 The finished metallic element is to be immersed in liquid Zinc at 450oC. The expansion of the metal is inevitable, while the contortion is not, if: – Welding tensions are avoided; – Preferentially, symmetrical sections are chosen; – Expansion possibilities are allowed in the flat surfaces (sheets) by ribbed, pyramidal, radial stamps, etc. Please avoid the usage of materials with big thickness differences within the same piece, as these parts result in different expansion patterns in the molten Zinc, and this can lead to contortion. For the Zinc to flow freely and cover every part of the element, please consider providing ventilating apertures, and access to draining outlets. Kindly consider that the piece gets immersed in Zinc, so the technological apertures must allow the ventilation, penetration and draining of the Zinc from your work. The quality of galvanization is directly influenced by the number, the section and the placement of the apertures. image9 Caisson shaped section The following drawing shows the location of the apertures and the corners that have to be cut in order to permit evacuation of the molten zinc. Using the following formulas, the diagram shows the usual measures for apertures and cut angles. INTERNAL gussets – should be at a minimum distance of 900 mm Sections in the form of a caisson: H + W = 600 mm and larger – the aperture plus the cuts must be> than 25% of the surface of the tin ( I + G ) . Sections in the form of a caisson H + W less than 600 mm to 400 mm and – one must use 30 % . Sections in the form of a caisson H + W less than 400 mm to 200 mm and –one must use 40 %. Sections shaped in the form of a caisson H + W below 200 mm is left completely open – no internal plate end or gussets. The following table is only for square sections. For rectangular sections, please calculate the required area and consult the galvanizer on positioning the openings. Size of the box H+W Apertures ø A Corner openings Dim B 1200 200 150 900 150 125 800 150 100 700 150 75 600 125 75 500 100 75 400 100 50 300 75 50 image10 Please do not try to galvanize parts that have paint, Vaseline and/or welding dross/slab marks, because additional costs can be incurred for sandblasting, cleaning and supplementary pickling. In the worst case, the galvanization result can be deficient, and thus, leave room for corrosion. image11 Please ensure that your elements do not have closed corners or dead angles. You should enable the penetration of Zinc through access apertures in the areas with material superposition. Even for the metallic elements made of normal, opened profiles, it is essential to enable a loose, easy draining for the melted Zinc. image12 Modular design is recommended, given that big, complex pieces have to be disassembled before galvanization, and incur increased transport costs. image13 Please ensure that the section and the number of apertures matches at least the figures mentioned in the chart.image14 Profiles with closed, non-pitted contour lead to contortion or even explosion in the galvanizing bath image15 It is useful to imagine the flow of the Zinc throughout the element while designing it to not only fit the functional specifications, but also to permit galvanizing to ensure its long-term functionality. image16 The Si content of the Steel is extremely important for the final outcome of the galvanization procedure. The graph describes the thickness of the coat of zinc in relation to the % of Si contained in the steel treated.

Characteristics of the production unit

The production unit at Rosiori boasts all necessary equipment to handle any galvanization procedure, including an induction-heated galvanizing bath, produced by GH Induction Germany. The size of the galvanizing bath is: Practical dimensions: L = 7,0 m; W = 1,2 m; H = 3,2 m. L = 6,5 m; W = 1,1 m; H = 2,8 m. This ensures uniform galvanizing, in accordance with SR EN ISO 14001:2002; The end result is: up to 80 years of protection for your product by the Zinc coating, a very good adherence of the Zinc and a minimal thickness of the coating that starts from 50 microns.

Environmentally-Friendly Technologies

We pride ourselves on implementing the latest standards in hot dip galvanizing technology. We do this because not only is the state of the environment important to us as a company, but it is also important to you, our customer. It is a well known fact that by using hot-dip galvanizing, 6000 million tons of steels are saved from rust worldwide, every year – this, in itself being a huge contribution to sustainable construction and the conservation of energy. Abiding by the standards of the European Union on environmental safety is an essential component of the company’s way of doing business. We know that environmental dumping is seen by many of our competitors as being a cost advantage of business in Eastern Europe, but we trust that our clients concern for sustainability also informs their decision on which suppliers to choose. Disregard for the environment will eventually also show up on the bottom line, and we do not gamble with the future.