14 



MK. .1. MI'IR ON THE RECOVERY OF IRON FROM OVERSTi; .UN 



yielding as is usually associated with a yield-point occurred. Before this stress of 

 29 tons per square inch was reached, the stretching was not sufficient to cause the 

 skin of oxide to spring off in the manner characteristic of a yield-point, and the 

 removal and gradual re-application of a load of 28 tons was found to show compara- 

 tively little semi -plasticity of the material. Thus the specimen cannot be said to 



Diagram No. IV. (Slow recovery with time). 



tons 



\ 



Extensions -diminished AS explained on p*ge 12. 

 Scale -.- 1 unit of an inch. ? ( _f 



Curve No. 1 primary test of specimen. 

 2 after load removed from No. 1. 

 3 about 2 days after No. 1. 

 ^~~ 7 l. 



5 - ,, 17 l. 



> been thoroughly overstrained until after 29 tons per square inch had been 

 The primary loading was continued beyond this amount until a stress of 

 MS {)er square inch of original area was attained. 

 Curve No. 1, Diagram IV, illustrates, so far, the primary loading of this specimen. 



iHMhml manner in which this specimen yielded was perhaps, directly or indirectly, 

 by a small flaw which ran up the centre of the bar (see p. 4). 



