1) Tin Tin plate original plate is very clean low-carbon (C<0.12%) mild steel, smelting of the residual non-metallic, mainly P,S,Si, contents and other contents, such as Cu,Cr,Mn must be strictly controlled, sometimes off impurities in molten steel in vacuum, this requirement is very high;
2) rolling, heating and cooling gradients must be strict, or easy to produce segregation;
3) cold rolling mill is 2mm thick hot-rolled plate (width of more than 1 m) at a speed of 30 meters per second, thin to 0.20 per cent of the steel substrate, in 24 hours of cold-rolling operation, product average thickness deviation shall not be larger than 5 μm, it can be said, like tons of rolling mill hydraulic pressure machine and the accuracy of the clock;
4) annealing temperature, speed control is not accurate, does not match the hardness of tinplate requirement;
5) Finally, in cleaning, plating, molten, passivated, oiled, and so any process, slightly lengthen or shorten the processing time, tinplate quality will be greatly decreased.