Abstract
It is believed by many foundrymen that waste products increase at rainy season due to increase of hydrogen content of cast iron. The present uthor investigated the relation between percentage of waste products and humidity on every melting extending over a year in some foundries, and found that there is no definite relation between them. In labolatory, the auther repeated the process of melting and casting over 40 times under different conditions and analysed, each time, the evolved gases. Wet air or steam was blown upon the molton iron in different conditions. In few cases he detected H2 of less than 1%, but generally he found no H2 or CH4 in the evolved gases. Thus the humidity of melting atmosphere does not increase H2 at all and consequently can not be the cause of waste products. The influence of humidity upon the molding sand was not touched upon.
