Hardness Test of Tinplate

1. What is tinplate?

Tinplate is a sheet of iron with a layer of tin on the surface. It is not easy to rust and is also called tin-plated iron. It is made by dipping the iron sheet into molten liquid tin. Tin is a metal that is less active than iron. It is neither oxidized by air nor reacts with water, so it has a strong corrosion resistance.

A thin layer of tin is plated on the iron sheet to provide good protection. However, once the coating is damaged and electrochemical corrosion occurs, iron will be oxidized as the negative electrode of the primary battery and lost due to the more active iron than tin. The presence of tin will accelerate the corrosion rate of iron. Therefore, tinplate is different from tinplate. It can only protect iron when the coating is intact.

Tinplate was first produced in Bohemia (now in the Czech Republic and Slovakia). The area has been rich in metals since ancient times, with advanced technology and the ability to use water power to manufacture machines. Tinplate production has been going on since the 14th century. For a long time, this has been the main production area of ​​tinplate in the world. At that time, tinplate was mainly used to make tableware and drinking utensils.

In the 17th century, Britain, France and Sweden all hoped to establish their own tinplate industry, but due to the need for large amounts of capital, it was delayed in development. It was not until 1811 that Brian Donkin and John Hall started tinplate canned food that tinplate manufacturing developed on a large scale. Today, the world produces about 250,000 tons of tin per year, more than one-third of which is used to make tinplate, most of which is used in the canned food industry.

2. Hardness test of tinplate

In the past, the hardness test of tinplate mostly used a desktop surface Rockwell hardness tester, using ordinary steel flat anvils to test HR30T hardness.

In recent years, since the national standard GB/T2520-2000 for tinplate has begun to adopt the internationally common HR30Tm hardness expression method, China has begun to use diamond anvils to test the HR30Tm hardness value of tinplate.

The application of the HR30Tm hardness expression method in the domestic tinplate industry is not yet common. Especially for tinplate users, although people are aware that the hardness of tinplate is very important, it is related to the quality of processed products, production efficiency and corporate benefits. However, most companies do not re-test the hardness of purchased tinplate materials.

To test the hardness of tinplate, you can use a digital surface Rockwell hardness tester, which is very suitable for testing the hardness of tinplate. Its use will definitely bring obvious benefits to tinplate production and users.