A study was made of copper-tin-lead-bearing bronzes with and without additions of zinc, phosphorus, nickel, and antimony. Tests made included wear resistance, resistance to impact, Brinell hardness, and resistance to repeated pounding at several temperatures.In general, the alloys with 4 per cent zinc and the alloys with 0.05 per cent phosphorus gave superior results in the tests as compared with the alloys with nickel and antimony. The alloys with 2 per cent nickel showed decreased wear resistance but increased resistance to pounding, and the alloys with 1 per cent antimony gave low resistance to impact, otherwise these additions were favorable from the standpoint of the other tests.
Foundrymen occasionally experience difficulties with steel castings in meeting ductility specifications of 24 per cent elongation and 35 per cent reduction of area if the steel is deoxidized with aluminum shortly before pouring the castings. Sound castings can usually be obtained in dry sand molds without the addition of " deoxidizers " immediately before pouring. Green sand molding is generally desired but porosity, as "pinholes," often occurs. Aluminum and other "deoxidizers" studied eliminated porosity but lowered the ductility. The mold conditions are probably the important variables responsible for pinholes. A sufficient amount of "deoxidizer," however, should be in the steel at the time of pouring to deoxidize the steel from the gases evolved from the moisture contained in the mold,,
A study was made of four heats of acid electric steel for castings in which two heats were in the so-called ' 'oven-educed" state while the others were in the normal condition as made according to general practice. The two types were investigated as regards temperature of the molten metal, structure, and physical and chemical properties.the tendency to skin over on the surface of the metal immediately after it is , .
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