Why canned products like to use tinplate cover for packaging?
For the tinplate cover, we will not be unfamiliar, because it can be seen everywhere in our lives. The main packaging material for cans and glass bottles is tinplate. Because tinplate is a high-precision product, it is the most advanced product in the cold-rolled steel industry. because:
1) The original tinplate is a very pure low carbon (C<0.12%) mild steel. The residual non-metals in the smelting process mainly refer to P, S, Si, content and other metal contents, such as Cu, Cr, Mn, etc. Be strictly controlled. Sometimes it is necessary to remove impurities in the molten steel in a vacuum, which is technically demanding;
2) During hot rolling, the gradient of temperature rise and temperature drop must be strictly controlled, otherwise segregation is easy to occur;
3) Cold rolling is a steel substrate in which a 2 mm-thick hot-rolled sheet (having a width of usually 1 m or more) is rolled at a speed of 30 m per second to a thickness of about 0.20. In the 24-hour cold rolling operation, the average thickness error of the product shall not exceed 5 microns. Therefore, it can be said that the rolling mill has a pressure similar to that of a 10,000-ton hydraulic press, and the accuracy of the timepiece;
4) The annealing temperature and speed control are not accurate, and the hardness of the tinplate does not meet the requirements;
5) Finally, in any process such as cleaning, electroplating, reflow, passivation, oiling, etc., the processing time is slightly extended or shortened, and the quality of the tinplate is greatly reduced.
In short, this high-speed, high-precision and extremely powerful equipment, its products not only have good internal quality, but also have a surface finish, which is destined to be a highly demanding high-precision high-tech product.