386 



CAST IRON. 



tensile tests. This value, as given by bending tests, has 

 been called the coefficient of bending strength, and is 

 u'ivi-n by 



w.a.i 



' ~ b.d-.2 



In the following table are quoted results of tests on 

 rectangular bars of cast iron, showing the values of the 

 coefficient of bending strength for different grades of 

 iron : 



CROSS BREAKING TESTS OF CAST IRON. 



In addition to the experimental results given in the 

 above table, Mr. Millar earned out a number of tests, in 

 order to determine the effect upon the strength of the bar, 

 of the condition of the metal in the ladle previous to 

 pouring It was found that where the metal was run at a 

 very high temperature it had a somewhat lower breaking 

 strength than when run at a dull heat ; while, on the other 

 hand, the deflection was slightly higher. 



The deflection of a cast-iron beam of the usual pro- 

 portions (2in. deep by lin. wide) may be taken very 

 approximately as j^th of an inch for each l,0001bs. of 

 central load. 



