ON THE MECHANICAL PROPEKTIES OF STEEL. 



233 



Exr. XXIY.— Bar of Steel from Messrs. Osborn & Co., Sheffield. Elonga- 

 tions taken on 8 inches length. Mark on bar, " 5." Diameter of 

 specimen -714 inch. Area '4312 square inch. Reduced diameter 

 after fracture '72 inch. Area -4071 sqiiare inch. 



No. 



of 



Exp. 



Weight 

 laid on. 



Breaking strain per 

 square inch of section. 



Per unit of length. 



Elongation, 



Permanent 



set. 



Eemarks. 



1 

 2 

 3 



4 

 5 

 6 



7 



lbs. 

 28729 

 31849 

 33439 

 35014 

 38224 

 41344 

 44464 



lbs. 



tons. 



•0125 

 •0168 

 •0200 

 •0231 

 •0312 

 •0431 



103116 



46^03 



Specimen of tough- 

 ened cast steel 

 for shafts, piston- 

 rods, and machi- 

 nery purposes. 



•0525 Broke in neck. 



Results. — Here the breaking strain (P^) per square inch of section is 

 103,116 lbs., or 46-03 tons; and the corresponding elongation (?,)pcr unit of 

 length is -0431. By formula (13). — The work (h) expended in producing 

 rupture = 2222. 



Exp. XXY.— Bar of Steel from Messrs. Osborn & Co., Sheffield. Elonga- 

 tions taken on 8 inches length. Mark on bar, " 6." Diameter of 

 specimen -744 inch. Area -4347 square inch. Reduced diameter 

 after fractm-e ^734 inch. Area •4231 square inch. 



Results. — Here the breaking strain (PJ per square inch of section is 

 87,931 lbs., or 39-25 tons ; and the corresponding elongation (Z,) per unit of 

 length is -0243. By formula (13). — The work (m) expended in producing 

 rupture = 1068. 



