MIXTURES FOR WHITE IRON CASTINGS AND EFFECTvS OF ANNEALING THEM.
There are castings, such as arc used for base plates in crushers, dies, etc., that arc best made of all white Iron. In making mixtures for such work the thickness of the casting as well as the character of the iron should be considered, as if this is not done castings that were desired to be white can be so thick as to cause the resulting iron to be mottled or i*ruy. It must also be remembered that there is a difference in the strength of white irons, and that such casting can be made from burnt or oxidi/.rtl iron, which will be weaker than those made of regular clean or unburned iron. Then ajj'ain, charcoal in»n can )»,ivr stronger white iron than coke or anthracitr iron. To i^ivc an approximate idea of the silicon in white iron mixtures, for making white castings, the following Table 59 is presented. The sulphur is supposed to In-held at .10 to .15, manganese .50 to .75, and phosphorus .25 to .50. If sulphur or manganese are higher than shown, then the silicon could be increased, or vice versa. The following analysis is supposed to be that existing in the castings, and which would mean that the silicon should be .10 to ,20 percent, higher and the sulphur two to three* points lower in the iron charged for making the easting":ould contain. All that can be done is to illustrate the fundamental principles involved, and these, as here stated, taken in connection with the effect re-melting of iron has in increasing or decreasing the chemical properties of a mixture, as outlined- in Chapter XLV., page 302, will permit any founder making a study of this chapter to intelligently formulate a mixture which will work well for any thickness of castings to be used for electrical purposes.castings in the cupola that would stand the tests of the United States Government for gun carriage work rightfully belongs to Messrs. Robert Poole & Son Co. of Baltimore, Md., and Muirkirk pig iron made by me. This was in 1893. The War Department at first refused to accept cupola iron as gun iron, but when it was fully demonstrateduois 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-