摘要 |
A METHOD OF TINNING METAL STRIP Electrolytic tinning is performed in a tinning line having a series of tinning tanks through which metal strip moves while electrolysing current is passed, and having at at least one of the entry side and the exit side at least one buffer apparatus for storing a variable amount of the moving strip. In order that some speed variation in the tinning tanks can occur, allowing the use of lower capacity buffer apparatuses, the current passing in each tinning tank is adjusted during tinning for portions of the strip. The current is calculated for a given strip portion by (a) determination of a value for the thickness of the tin layer on entry to the tinning tank; (b) determination of a value for the desired thickness on exit from the tinning tank; (c) from the difference of these values determination of a value g for the desired increase in the tin layer thickness in the tinning tank; and (d) determination of the instantaneous required value of the current I in the tinning tank in dependence on the value g and the speed v of the strip through the tank. |