In order to produce high quality and healthy boxes, the companies producing tin cans have to check the coating condition of the tin and whether there are pores on it. The tin is essentially obtained by flattening the steel containing less than one thousandth of a thousand carbon and then coating its surface by various methods. In the coating process, tin, sometimes chrome, are used. In this way, the percent 98 of the tin is made of iron and the percent 2 of the tin consists of a coating material such as tin or chromium.

The coating is applied to prevent corrosion and corrosion of the underlying steel. However, during this coating process there are still pores. In order to close these pores, lacquering is also applied to the tin can.

In the canning industry, hermetically sealed (ie, hermetically sealed and tightly closed) cans are generally made of tin and lacquered cans. Cans are usually made of cans with a thickness between 0,23 and 0,28 mm. The lid can be 0,02 mm thinner than the can used in the body.

In particular, acidic and dark colored foodstuffs interact with tin, causing discoloration and deterioration in canned food. This is caused by pores in the coating. Through these pores, foodstuffs easily reach steel and react.

There is an inverse relationship between the number of pores on the unit surface of the can and its strength to resist corrosion. In other words, the higher the number of pores, the lower the corrosion resistance of the can. When performing the porosity test, the cut cans of certain sizes are retained in sulfuric acid and special test solution and the pores formed are counted.

In advanced laboratories, studies are carried out to determine the pore and coating status of tin in tin cans. During these studies, standards and test methods published by national and international organizations are based. The standard used in this respect is:

• TS 13718 Cans