Xke Oliio Journal of Science 



Vol. XXI JUNE, 1921 . No. 8 



STEEL MOLDING SAND IN OHIO. 



J. A. BOWNOCKER, 



Ohio State University. 



There are two types of molding sands, (1) those for steel 

 castings and (2) those for iron castings. The difference between 

 the two is primarily their refractory nature. Steel castings 

 require a sand that will not melt below 2,900° Fahrenheit, 

 while for iron castings 2,400° is Sufficient. 



Ohio is a leading producer of both grades of molding sand, 

 but this article considers only those suitable for steel purposes. 

 The chief requisites for a molding sand are refractory nature, 

 strength when in mold, vent or porosity and the surface left 

 on the castings. In steel casting, however, all of these 

 properties except that of fusibility may be regulated by the 

 sand producer or in the steel mill, and they need not, therefore, 

 be discussed in this paper. 



The minerals which compose the sandstones and con- 

 glomerates from which steel molding sands are made are 

 numerous, but silica or quartz in some form constitutes 95 

 per cent or more of the mass. Other common minerals present, 

 are feldspar, mica, and oxide of iron. The fusion temperatures 

 of these are about as follows: 



Silica 2,678° F. 



Orthoclase (feldspar) 2,167° 



Hematite 2,206°^ 



Magnetite 2,507°i 



Muscovite (mica) 2,246° 



Manifestly as the proportion of silica increases the fusion 

 point of the sand rises, while as the proportion of other common 

 minerals grows larger the fusion point is lowered. A high 

 silica percentage is therefore the first requisite of a sand for 

 steel molding purposes. 



1 Hsmatite and magnetite have no definite melting temperatures. 



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