Potassium ferrocyanide is often used as an arc stabilizing component in the coating, but this substance decomposes at a high temperature and evolves cyanogen gas. Hence the effects of the gas on the welding phenomena and deposited metal must be taken into consideration. In this work, the effects were studied and the following results were obtained.
(1) As the quantity of this component in the coating increases, a distinct increase of nitrogen content in the deposited metal and a slight increase of carbon content takes place, but apparent specific gravity and the quantityt of oxide inclusion decrease. These phenomena seam to be due to the action of cyanogen.
(2) As the quantity of this component in the coating increases, also the terminal voltage which is necessary for the same quantity of welding current decreases.
(3) Examining the microstructures of deposited metal, it was confirmed that the braunite or the eutectoid of iron and Fe
4N appears in iron containing more than 0.07% N.
It is to be concluded that the existence of a large quantity of this component in the coating is not desirable, as the increase of nitrogen content and the decrease of apparent specific gravity cause tremendous defects.
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