Metallurgy Of Cast Iron

CHAITKR I-VII.
UTILITY ()P TRANSVICRSIO, CRUSHING IMPACT AND SHOCK TICSTS.
The tests called for in our engineering and other scientific text hooks include transverset tensile and crushing strength, a few giving impact. Of all these, none can surpass in value for general use the transverse test, with its accompaniment of " deflection'' for foundry practice, simply because castings arc chiefly subjected to such strains. The utility of tensile tests will be found discussed on page 449. The quality of east iron to withstand crushing loads is also one often of much importance to the engineer and founder. The values found by the author from which the relation between crushing and tensile strength may be deduced lead him to affirm that the elements constituting a test in transverse, de-ileetiou and chill are, for general purposes, largely a good index as to the crushing strength. An iron having a high transverse strength combined with small deflection should prove tin* best to withstand crushing loads.
Impact tests on the side of bars are of little prae-tiral value in assisting to determine what eastings can stand in shocks or blows,* If there is any form of tests with test bars, to demonstrate the power of iron t<» withstand shocks or blows, there is much more
* This ha-, rt'frivwr to striking hist, bars until they break, and ui»t to stu;h U.';4s us are outlined on the next two pug'es.d, though not MO hard an No. i,