Machine molding ; Dry-sand and loam work Foundry appliances Foundry chemistry Cupola practice Mixing cast iron Malleable cast iron Steel casting Brass and alloy founding

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1915 Excerpt: ...the iron is very dirty, it may be charged every time. Whether the flux used is sufficient in quantity or not is generally shown by the fluidity of the slag, which should be as fluid as practicable. If it does not run freely, it is due to one of two causeseither the cupola is running cold on account of a low bed and improper melting conditions or insufficient flux is being used. A very great excess of limestone flux will also make a dull slag. When the slag is not sufficiently fluid, it runs out so sluggishly that it is very liable to pile up in the cupola to the level of the tuyeres. If this occurs, the cold blast will chill the slag, clogging the tuyeres, and the melting will be retarded or stopped entirely. 63. Necessity of avFroe Slag.--It is very important to obtain a good free slag--one that is fluid--so as to prevent it piling up any higher than the slag hole. If the slag does pile up, the cupola would be far better off if no flux had been used, as its use only increases the amount of material that must be removed in order to successfully continue melting. In fact, if a cupola can be made to run free and clean to the end of the heat without using a flux, it is only a waste of money to use it, since, besides the cost of the flux itself, it also requires some fuel to melt it. It is a good plan to leave the slag hole open after tapping the slag. It should be watched carefully to see that the slag does not rise to or above the tuyeres and flood them and the wind belt. This overflow interferes with and may stop the operation of the cupola and causes considerable additional labor in cleaning up. This danger is less if the slag is running thin and hot, than if it is thick and sluggish. FUEL COMBUSTION IN CUPOLAS 64. The Blast--In order to melt iron rapidly, ...