Method for controlling active magnesium in ductile cast iron
The present invention relates to a method for controlling if the amount of active magnesium in a treated melt is above or below a certain level which comprises the following steps:
- providing a thermal analysis cup with tellurium, a thermocouple, a metallic cap, and a controlled amount of a neutralizing mixture of sulfur and FeSi, said mixture comprising: a) from 0.07 to 0.25 wt% of FeSi in respect of the weight of the test sample of the treated liquid iron which is poured into it in the next step and b) a number of equivalents of sulfur which is the same as the number of equivalents of active magnesium which correspond to the said certain level to be determined,
- pouring into the thermal analysis cup treated melt
- recording a cooling curve
- identifying according to the shape of the curve, if the test sample has solidified at the graphite eutectic or at the carbide eutectic.
The present invention relates also to a thermal analysis cup for use in said method.
Authors:
Jon Garay, Ramón Suárez, Pello Larrañaga.
Keywords:
Pearlitic cast iron, iron foundry, improved mechanical properties, as cast, thermal cup, thermal analysis.