. Transactions. find any reliable method for determin-ing quantitatively the elongation of alloys at various methods have been suggested but they have proved of doubtfulvalue. The simplest way is to use the old method. Totest the alloy, a casting is made in a die having a comparatively largecore and thin wall. If the alloy can stand the casting stress, a perfectcasting will be obtained, otherwise the casting will show bad a comparative result is obtained, but for everj^day control itanswers the purpose. However, a simple and reliable method for deter-
. Transactions. find any reliable method for determin-ing quantitatively the elongation of alloys at various methods have been suggested but they have proved of doubtfulvalue. The simplest way is to use the old method. Totest the alloy, a casting is made in a die having a comparatively largecore and thin wall. If the alloy can stand the casting stress, a perfectcasting will be obtained, otherwise the casting will show bad a comparative result is obtained, but for everj^day control itanswers the purpose. However, a simple and reliable method for deter- CHARLES PACK 585 mining quantitatively the elongation of metals and alloys at varioustemperatures would prove of enormous value to all metallurgists engagedin the various phases of metal-casting research. It is interesting to note that the elongation of a metal or alloy atnormal temperatures is no indication as to the properties of that metal oralloy at higher temperatures. The writer has found many cases where. Fig. 8.—Cross-section op casting with two gating positions. an alloy showing little or no elongation at normal temperatures shows ahigh elongation at higher temperatures. The alloys of aluminum andcopper may serve to illustrate this point. It is well known that the addi-tion of copper to aluminum reduces the elongation of the aluminum aluminum alloy containing 12 per cent, copper will show less elon-gation than an alloy containing only 6 per cent, copper when tested atnormal temperatures. Nevertheless, the 12 per cent, copper alloy has
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
