COLLKCl'loNS IN KCoNoMlc Cllnl.ocJV AND MK I AIJ-I U'ti V. !<).') 



Tlie incrt'Mst' in stu'ii^lli diu' to liaiiiiiitTiiij; is not constant lor tin* fonr 

 classes, for whilst tiu' in«'reaso is f^roatost in the softest uiatrrial nnder 

 elastic stress it is jnst the reverse under ultimate stress as is also shown 

 by the auuoaled specimens. 



De8cri|itii>i:. 

 ;iiiiiiR>rtMl to 'J iiK-lii'M !«|iiure. 



0.8. 



o.c. 



0.4. 

 0.2. 



Totnl tni-an 



The general average shows 33.3 per cent, us the gain in strength of 

 the steel due to hammering Ginch ingots down to 2 inch s(|uare bans. 



Hammering also increases the du(;tilityof the material, as proved by 

 the specimens becoming more contracted in area at fracture, and also 

 by the increase in the ultimate exteusion. 



D<>8cription. 



Ilnminered to 2 inches 



square. 



Per cent. 



from 1. 6 to 3. 2 



from 2. 5 to 28. 4 



from 4. 2 to 52. 5 



0.2 1 from 11. 9 to 61.. J 



Total mean from 5. to 36. 3 



0.8. 

 0.6. 

 0.4. 



T'otitriution of area. 

 TTnanneali >i. .Vuiioaled. 



Ultimate extension. 



Pit cent. 

 from 2. 1 to 8. I 

 from 14. 9 to 40. 

 from 5. 2 to .')7. 

 from 27. no04. 1 



Unannealed. 



Per cent. 

 from 1. 1 to 2. 2 

 from 2. to 10. 2 

 from 3. 4 to 17. 9 

 from 11.6 to 22. 5 



Annealed. 



Per cent. 

 from 1.7 to 5.5 

 from 7. 2 to 12. 7 

 from 4. 3 to 19. 1 

 from 18. 2 to 22. 2 



from 4. 5 to 13. 2 from 7. 8 to 14. 9 



from 12. 3 to44. 



Series C. 



The mechanical eftects produced on steel bars containing l.d, (>,5, (M5 

 of carbon, by reducing to various sizes, viz, 3, 2.;, 2, 1.^, I and .A inch 

 square bars, some by hammering, others by rolling were next teste<l. 



In this .series, as in the preceding, and for the same reasons, spec- 

 imens in duplicate were prepared and tested as unannealed and an- 

 nealed. Six bars hammered from 3inch square to .^-inch square, and 

 six bars rolleil to the same sizes. 



