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EFFECTS OF VARIATIONS IN MANGANESE. 245
made of the same pattern peeling much more readily than others, with the use of the same grades of sand or facing and equal fluidity of metal, a phenomenon many have often been at a loss to understand. In regard to differences noticeable in the fluidity of the metal, there was little if any to be seen between the iron coming from either side of the cupola, but the addition of manganese to the molten metal in the ladle noticeably increased the fluidity.
Where founders desire a «* white iron " of the best strength obtainable in castings, heats Nos. 8 and 9 would show that it can be readily obtained by mixing ferro-manganese with good strong grades of low silicon pig or scrap iron. Of course, white iron can be obtained with the cheapest grades of old scrap, but this will be much weaker than when good iron and ferro-manganese are used. The amount of manganese seen in heats Nos. 8 and 9, with the low silicon iron, is sufficient to make a casting having a section from three to five inches thick all white, when cast without the use of chill. Where sections are heavier a greater percentage of manganese will be required. It will appear rather strange to many to note the high silicon charcoal iron used in heat No. 3, as it is rare that such brands of iron exceed 2.00 per cent, in silicon. This iron was obtained from the Jefferson Iron Co., Jefferson, Texas. The charcoal iron in heats Nos. 7 and 9 was kindly donated by the Seaman-Sleeth Co., Pitts-burg, Pa. Further information on the effects of manganese is found on pages 213 to 215.ng. All the bars poured with the iron .having manganese added in the cupola showed this effect to a greater or less degree. No doubt this is the cause of some castingsos. 4, 5, and 6, However, when we get to low silicon irons, as to.n. in ladle 1,772 Ibs. .100" -326 " I.IOO .242 3