The Davistown Museum

Stimpson, William C., Gray, Burton L. and Grennan, John. (1930). Foundry work: A practical handbook on standard foundry practice, including hand and machine molding with typical problems, casting operations, melting and pouring equipment, metallurgy of cast metals, etc. American Technical Society, Chicago. IS.

"Foundry work may be described as that branch of engineering which deals with the melting of metal and the subsequent pouring of this molten metal into molds to form castings. Castings are made in large quantities in two general classes of metals or their alloys. The largest and most important group of castings is made from the iron (ferrous) group of alloys, consisting of gray cast iron, malleable cast iron, carbon steel castings, and alloy steel castings. The non-ferrous group of castings includes those made of the copper-base alloys -- brass and bronze; aluminum alloys; zinc-base alloys; and the tin- and lead-base alloys. These several alloys are poured or forced, when melted, into molds of different types." pg. 1.
"There are two general types of molds -- sand and metal molds. Those in which nearly all the castings are made, when judged from a tonnage basis are sand molds. Metal molds are used in increasing numbers, particularly for making small castings in large quantities. Their outstanding use is in the production of die castings, which are usually made of zinc or aluminum alloys." pg. 1.
"Sand molding is divided into three classes or divisions, two of which, green sand molding and dry sand molding, are quite similar. Loam molding, the third method of sand molding, differs greatly from green and dry sand molding. Green and dry sand molding are again divided into three divisions: bench molding for small castings, floor molding for medium and fairly heavy castings, and pit molding for large castings." pg. 1-2.
"Foundry facing is the term given to materials applied to or mixed with the sand that comes in contact with the melted metal. ... The principle facings are graphite and sea coal." pg. 6.
"Core making supplements molding. It deals with the construction of separate shapes in sand which form holes, cavities or pockets, in the castings. Such shapes are called cores. They are held firmly in position by the sand of the mold itself or by the use of chaplets. Core sand is of different composition from molding sand. It is shaped in wooden molds called core boxes. Cores are baked in an oven before they can be used. the whole detail of their construction is so different from that of a mold, that core making is a distinct trade, but, like pattern making, closely connected with foundry work." pg. 79.
"The chief difference in the composition of steel and cast iron is in the amount of carbon they contain. When iron ore is smelted in a blast furnace, it changes from iron oxide to iron. The iron absorbs carbon from the coke in the blast furnace until the iron carries about 3.5 per cent carbon. ... Carbon is the most important element in cast iron. One of the important influences of carbon on cast iron is the effect on the melting point. Pure iron has a melting point of 2735º F., a temperature which is so high that it is very difficult to reach. The presence of 3.5 per cent carbon in pig iron reduces the melting point to 2075º F. For this reason, cast iron is easily and cheaply melted and therefore it can be produced more cheaply than any other form of iron. ...Carbon is found in cast iron in two different chemical forms. Iron and carbon form a chemical compound, which is called cementite. The chemical formula of this is Fe₃C. When cast iron is molten, the carbon is always chemically combined with the iron. When the cast iron cools, there are conditions that will cause this compound of iron and carbon to separate into its two constituents, iron and carbon. When the carbon is not chemically combined with the iron, it is called free carbon or graphitic carbon and the cast iron is known as gray cast iron. ... When the iron and carbon are chemically combined in the form of cementite, the cast iron is very hard and is known as white cast iron." pg. 166-168.
"Wonderful results have been obtained in the properties of steel by the addition of other elements. Nickel steel, nickel chromium steel, molybdenum steel, vanadium steel, manganese steel, silicon steel, stainless steel, high-speed steel, and other alloy steels give greater service under special conditions than ordinary carbon steel. ... Any change in the total carbon content of gray cast iron will cause a softening of the cast iron as the carbon increases and a relative hardening as the carbon decreases. ... For machinery castings 30 per cent of steel gives the strongest castings. Automobile cylinders are made with from 15 per cent to 20 per cent steel in the charge." pg. 172-174.
On nickel cast iron: "Nickel alone may be added to cast iron. Its softening effect is very similar to that of silicon. Chromium hardens cast iron. When nickel and chromium are both used, a finer grained cast iron ... is produced." pg. 175.
"Malleable cast iron is cast as a white cast iron and, by suitable heat treatment, the combined carbon is changed to free carbon. The resulting castings are strong and tough. ... Lighter castings are made with higher silicon content than are heavy castings. The quality of the castings is higher with a low carbon content." pg. 176.
"There are two outstanding alloys of copper, namely, brass and bronze. Brass is an alloy of copper and zinc, and a true bronze is an alloy of copper and tin. Lead, in varying amounts, is found in both brass and bronze. ... Brass is made in two ways. It may be cast into ingots and rolled and pressed into shape, or it may be cast into sand molds to form castings." pg. 179.
"The three common bronzes are called gun metal, bell metal, and bearing bronze. Gun metal is composed of 90 per cent copper, and 10 per cent tin. ... Bell metal is harder than gun metal and contains approximately 20 per cent tin. Small bells contain as high as 25 per cent tin. ... Bronze bearing metal contains copper, tin, and lead. A very common mixture is 80 per cent copper, 10 per cent tin, and 10 per cent lead." pg. 180.