Abstract
In this paper we would like to reveal the relationship between the intensity of plastic deformation and corrosion resistance of tinplates; causes of the corrosion and damage during long-term storage.
At present, majority of the tins produced are so-called two-part metal tins produced by drawing the cup and the lid of the tin, which are joined by beading. The technology of drawing in the production of cups has high demands on plastic quality of thin tinplates. During the drawing there occurs considerable plastic deformation of base steel material, but also of the surface tin-plated layer. The thickness of tinplates is reduced, keeping the required tensibility. Requirements on the inside and surface cleanness of the strips, their close dimension tolerance and ideal evenness increase.
Experiments oriented to investigating the causes of cracking of meat tins have shown clearly, that materials were damaged by corrosive mechanical damage. The corrosion was caused by increased aggressiveness of the meat filling, as well as by reduced protective efficiency of the tin coating in areas of major plastic deformation where tensile stress prevails. It is possible to remove the latter of the causes by improving the technological conditions for closing the tins (by reducing the tensile stress in the area of the lid radius) and increasing the resistance of protecting layers. Nowadays, thin tinplates are protected from the inside by plastic coating, which prevents them from corrosion in the critical areas of the tin.
Keywords: thin|tin-plated steel sheets|corrosion|cracking of meat tins|
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