Zinc Coating Enables Safer Transport of Goods

Researchers from Serbia with their colleagues from Slovenia have been developing a new type of transport container which will provide safer and more reliable transport.

The Innovation Centre of the Faculty of Mechanical Engineering, Belgrade, is participating in the Eureka project E! 5009 GALVAKONT – “The development of the production technology of hot-dip galvanised special transport containers”. The main objective of the project is to develop production technologies for special transport containers with a longer lifespan. The basic idea the research team had was to extend the working life of containers by using the technological process of hot-dip galvanizing and, in that way, to reduce the corrosion which is the main cause for containers’ relatively short life.

The current situation in the manufacturing of transport containers is such that existing containers are protected from corrosion by the process of dyeing. A Container’s lifespan is considerably shorter than expected and the two-component colours, which are used in this procedure, have a negative impact on the environment. The process of hot-dip galvanizing is the best known way to protect products of this type that are primarily exposed to different atmospheric and transport conditions. When zinc coated the resistance to mechanical damage is 8 times better than with epoxy coats and as much as 20 times better than the resistance of PVC and epoxy powder coats.

Two companies and two faculties from Serbia (The Innovation Centre of the Faculty of Mechanical Engineering, Belgrade, and Metal-Cinkara) and Slovenia (Faculty of Mechanical Engineering, University of Maribor, and Maksim Ltd.) have combined their knowledge for the successful implementation of project E! 5009. The researchers put special focus on the selection of materials, joining: welding/brazing procedures and techniques, hot-dip galvanizing bath chemistry and metallurgy of zinc coatings.

Hot-dip galvanized transport container

Transport containers enable transport of different types of goods and easy trans-loading, as well as protecting loads against atmospheric influences. Containers, used for the inter-modal transport of freights, are manufactured according to specifications from the International Standards Organization (ISO) and are suitable for multiple transportation methods such as truck, rail or ship. Besides the standard transport containers, there also are special containers for the transport of perishable goods, explosives and other dangerous materials. Besides special construction solutions, these containers also have the equipment needed for maintaining temperature and safety conditions. The container protected by hot-dip galvanizing must meet all consumer expectations in the international market, such as: high quality, compliance with legislation, functionality, widespread use, long working life, competitive pricing, optimal delivery, and others.

The first step researchers took was the selection of proper materials for these kinds of containers and finding proper zinc bath chemistry (a combination of zinc and alloying elements in a zinc bath), which will be most suitable for hot-dip galvanizing of selected materials. Special attention is paid to preventing the formation of dross, floating impurities which produce an uneven zinc coat.

The second step is to find out which joining techniques for the zinc coated, construction sub-parts of the container are the most suitable. Because of the dimensional limitations of the galvanizing kettle, hot-dip galvanizing is carried out in such a way that the individual construction sub-parts of the container are galvanized separately and joined afterwards. The process of hot-dip galvanizing was performed on a standard 20′ ISO container. The bath that is used for this process is larger than 12000mm. The single, hot-galvanized elements fuse into a whole on the assembly line where the container gets the desired shape and functionality for the transport of materials of larger dimensions. The main problem during fusion welding using carbon steel electrodes is embrittlement of the steel by liquid zinc. These welds are prone to cracking, and are one of the major problems that need to be solved.

As a result of previous research, a prototype of the ISO shipping container with a target carrying capacity of 7 tons was built and tested. In the process of hot-dip galvanizing, materials were exposed to temperatures of up to 450oC, making it necessary to analyse the behaviour of these materials at this temperature. It was especially essential to analyse the distortion of elements and sub-parts during the dipping in the bath. Therefore, unsteady thermo-elastic numerical analysis was done and the results will be used for process optimization.

The next steps within the project E! 5009 include the optimization of the production technology, which will be followed by transfer to the industrial level.  In this way, innovated containers for transport of larger materials will be produced and will meet all the requirements for such a product at the international level.  It is also important to note that the price of the innovated containers will not significantly differ from prices of the existing containers, which will in turn their competitiveness in the market”, says PhD Aleksandar Sedmak, CEO of The Innovation Centre of the Faculty of Mechanical Engineering, Belgrade.


Source:  www.inovacionifond.rs


Nov 1, 2012 in Serbia
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