CHEMICAL AND PHYSICAL PROPERTIES, ETC. 219
silicon, and manganese. In getting this iron to a fluid condition it will be so full of gas and run so sluggish that the casting, if obtained at all, will be full of blow holes. Add silicon to this iron and a good sound casting will result.
The physical properties of cast iron may be said to consist of density, tenacity, elasticity, strength, toughness, brittleness, and chill. These may all differ in having characteristic qualities in different brands or classes of iron. The first of these elements is to be attributed to what is called the '' grain,'' and the degree of density is the basis of grading our iron by fracture from No. i (our most open, large-grained iron) up through Nos. 2, 3, 4, 5, 6 to 10; the latter two being almost as close-grained as a piece of glass, and generally called c' white iron.'' A cubic foot of white iron weighs about sixty pounds more than a cubic foot of No. i iron. '' White iron '' will sink in a ladle of liquid No. i iron, whereas a piece of No. i would float on its surface.
Tenacity of cast iron is that element which resists a pulling apart of its body or a separation of its molecules, as by a tensile strength test.
Elasticity is that quality which permits cast iron to stretch or bend and then return to its original position or shape when the load is removed. Should the load be so great that the iron will not return to its original shape, it partakes of what is called a permanent set, or has overreached its limit of elasticity, a point which, when attained in cast iron, is very close to the breaking load.lement iron free from every contamination, but iron with about 2 per cent. of carbon and free from sulphur, phosphorus,teel Institute Journal, 1893, Vol. i, p. 168.ion of manga j: which was added being found in the form of oxide in the so-The philosophical explanation of this extraordinary effect i my opinion, to be found in the fact that the f erro-manganesu .ğR. C. Hindiey, M. Hoskins, Harvard College, Havemeyer University, Henry Hiels Chemical Co., Isabella Furnace, Iron Gate Furnace, Iroquois Iron Co., Illinois Steel Co., Jefferson Iron Co., Kittan-ning Iron & Steel Co., C. A. Kelly Plow Co., Lebanon Furnace, Longdale Iron Co., Lackawanna Iron & Steel Co., Logan Iron........................ 16,720 " t-