DETERMINATION OF DISSOLVED CARBON IN LOW- CARBON STEELS BY THERMOELECTRIC-POWER MEASUREMENTS - APPLICATION TO THE DETERMINATION OF THE AMOUNT OF CARBON IN SOLID-SOLUTION AT VARIOUS STEPS OF A CONTINUOUS ANNEALING

In order to control the service properties of continuously annealed ex tra-soft thin steel sheets. it is necessary to determine the carbon co ntent in solution leaving annealing. Among the various methods that ma y be used (internal friction of electrical resistivity), the thermoele ctric power is especially fast and simple. On samples containing vario us carbon contents in solution, measurements of thermoelectric power v ary linearly with respect to measurements of the height of the Snoek p eak of internal friction. Dosing the carbon content in solution was th en developed in extra-soft steels, using a method that frees itself fr om the influence of other addition elements (mainly manganese) and var ious microstructural modifications. The method was applied to the stud y of the over-ageing mechanism of continuously annealed extra-soft ste els.