Hereunder is given a report of the investigation made of the corrosion of various kinds of steels of commercial type owing to the action of molten salts used as heat exchange medium in chemical industries, not the salts used for heat treatment in metal industries. Study was made also of the effects of carbon and silicon ingredients on the corrosion resistance. The following molten salts were used: The results obtaind are as follows: (1) In the salts (a) and (b), increase in chromium content of

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... teels, largely improves corrosion resistance of the steels. Rimmed steel is better than killed steel. means that the corrosion rate increases with carbon content up to about 0.16%, then decreases. Silicon also increases the corrosion rate up to about 0.2-0.4%, and then decreases it. Aluminized steel shows the resistance as well as stainless steels. (2) Chlorides such as salts (c) and (d) are more be undesirable. In molten chlorides, chromium alloying to steels is not so effective as in nitrate salts.