Tinplate (commonly known as tinplate) refers to the surface of the steel plate coated with a thin layer of metal tin. Tinplate is the low carbon steel rolled into about 2mm thick steel plate, after pickling, cold rolling, electrolytic cleaning annealing, leveling, edge cutting processing, and then after cleaning, electroplating, softening, passivation treatment, oiling after cutting into tinplate plate finished products, tinplate tin plating for high purity tin (Sn> 99.8%). Tin layer can also be coated by hot dip plating method, the tin plate obtained by this method is thicker, with a large amount of tin, tin plating without purification treatment.

Classification:

1,Equal thickness tin plate: cold rolled tin plate with the same amount of tin plating on both sides.

2, Difference thickness tin plate: cold rolled tin plate with different amount of tin plating on both sides.

3, Level 1 tinplate: after online inspection of tinplate, in normal storage conditions, suitable for the surface of the whole steel plate for conventional painting and printing, shall not have the following defects: (1) through the thickness of the pinhole steel plate; ② the thickness exceeds the standard deviation; ③ To be affected by scars, pits, wrinkles, rust and other surface defects; (4) Shape defects that affect the use.

4, Secondary tinplate: the surface quality is lower than the first tinplate, allowing inclusion, wrinkle, scratch, oil, indentation, burr, burning point and other small area more obvious surface defects or shape defects, do not ensure that the whole steel plate can be routinely painted and printed.

Process:

Tinplate is generally manufactured according to the following processes:

1. Hot rolling: in the continuous tropical rolling mill, the slab is hot rolled at a higher rolling temperature to produce hot rolled steel plate and continuous strip coil after shearing;

2. Pickling: Pickling line is used to remove the oxide sheet on the surface of strip steel before cold rolling. This kind of high pressure cold rolling is needed for the production of thin tin plate required by the market. Good pickling effect will also improve the surface quality and cleanliness of steel plate to meet the needs of subsequent tin plating process;

3. Cold rolling: after pickling, the strip is cold rolled on the cold rolling machine to achieve the specified thickness. In order to ensure product quality, it is important to ensure uniform thickness, good surface quality and meet the requirements of flatness during cold rolling. These quality characteristics will be reflected in the final product quality of tinplate;

4, Annealing: cold rolling will make the strip grain structure along the direction of cold rolling elongation, so that the strip becomes hard and brittle. However, during the annealing process, the cold-rolled strip is reheated and held at a certain temperature in a reducing atmosphere for a period of time to form new undeformed grains so that the material properties meet the specified requirements for use. There are two types of annealing: hood annealing (batch annealing) and continuous annealing;

5, Flat rolling or secondary rolling: flat rolling or secondary rolling is usually the final processing. This rolling process can make the strip slightly cold hardening, increase some toughness and eliminate the yield plateau phenomenon. Moreover, cold rolling and secondary rolling can make the strip meet the required surface finish and improve the flatness and shape quality.