How to check the hardness of tinplate?
1.What is tinplate?
Tinplate is a tin plate coated with tin on the surface, it is not easy to rust, also known as tin plated iron. The iron sheet is immersed in molten liquid tin to prepare. Tin is a metal that is less vivid than iron, neither oxidized by air nor reacted with water, so it has a moderately strong ability to resist corrosion. A thin layer of tin plated on the iron sheet can play a good maintenance effect. Tinplate tin box, tin box packaging, tin making factory, tin box packaging, tinplate, but once the plating layer is damaged, electrochemical corrosion occurs, because iron is more vivid than tin, iron will be used as the negative electrode of the primary battery oxidation reaction and loss, tin The existence will accelerate the corrosion rate of iron, so tinplate is different from white iron, it can only maintain the effect of iron if the coating is not missing.
Tinplate was first produced in Bohemia (now in Czech and Slovakia). The place has been rich in metal since ancient times, with advanced technology and know how to use water power to make machines, and tinplate has been produced since the 14th century. For a long period of time, this has been the world's leading producer of tinplate. At that time, tinplate was mainly used for making tableware and drinking utensils.
In the 17th century, Britain, France, and Sweden all hoped to establish their own tinplate industry, but because of the large amount of funds required, they have not been developed. Until 1811, Bryan. Don King and John. After Hall opened tinplate canned food, tinplate production developed on a large scale. Now the world produces about 250,000 tons of tin every year, more than 1/3 is used to make tinplate, most of which is used in the canned food industry.
2. Hardness test of tinplate
The tinplate hardness test used to be mostly table-top Rockwell hardness testers, and the general steel flat anvil was used to test the HR30T hardness.
For many years, because the national standard GB/T2520-2000 on tinplate began to use the internationally accepted HR30Tm hardness representation method, so the domestic has begun to choose a diamond anvil to test the HR30Tm hardness value of tinplate.
However, a HR30Tm hardness test requires a diamond anvil, and few Rockwell hardness testers made in China are available for purchase. Because suitable diamond anvils are difficult to buy, desktop hardness testers are more expensive. Therefore, the application of the HR30Tm hardness expression method in the domestic tinplate profession is not widespread. Especially in the use of tinplate manufacturers, although people always realize that the hardness of tinplate is very important, it is related to the quality of the processed products, to the production efficiency and enterprise efficiency. However, most companies have not re-tested the hardness of the tinplate materials they purchased.