78 



Tables 48-50. 



MECHANICAL PROPERTIES. 



TABLE 48. — Steel Wire — Specification Values. 



(After I. A. S. B. Specification 3S12, Sept., 1917, for High-strength Steel Wire.) 



I'^iier 1. A. 3. ts. specincation 3S12, Sept., 1917, tor High-strength Steel Wire.) 

 S. A. E. Carbon Steel, No. 1050 or higher number specified (see Carbon steels above). Steel used to be manufac- 

 tured by acid open-hearth process, to be rolled, drawn, and then uniformly coated with pure tin to solder readily. 



Note. — Number of 90° bends specified above to be obtained by bending sample about 4.76 mm (0.188 in.) radius, 

 alternately, in opoosite directions. 



_ (Above specification corresponds to U. S. Navy Department Specification 22W6, Nov. i, 1916, for tinned, galvan- 

 ized or bright aeroplane wire.) 



TABLE 49. — Steel Wire — Experimental Values. 



(Data from tests at General Electric Company laboratories.) " Commercial Steel Music Wire (Hardened).' 



• For 4.55 mm wire drawn cold to indicated sizes. t For 4.55 mm (0.018 in.) wire annealed in H2 at 850° C. 



TABLE 60. — Semi-steel. 



Test results at Bureau of Standards on is5-mm shell, Jan. 1919. 



Microstructure — matri.x resembling pearlitic steel, embedded in which are flakes of graphite. 



Composition-Comb. C 0.60 to 0.76, Mno.88, P0.42 to 0,43, S 0.077 to 0.088, Si 1.22 to 1.23, graphitic C 2.84 to 2.94. 



Metal. 



Semi-steel : 



Graph. C 2.8s 

 Comb. C o. 76 



Graph. C 2.92 

 Comb. C 0.60 



Tension 

 kg/mm2 



19.8 

 14.9 



55 



Tension 

 lb/in2 



11,200 

 6,000 



28,200 

 21,200 



55 



Compression 



kg/mm^ 



24.3 

 i3.3 



72.6 

 61.4 



._ O 



55 



Compression 



Ib/in- 



34,SOo 103,000 



I 

 26,000 87,300 



Hardness. 



Brinell 



(0)3000 



kg 



176 

 170 



Sclero- 

 scope. 



Tension specimens 12.7 mm (0.5 in.) diameter, 50.8 mm (2 in.) gage length; elongation and reduction of 

 area negligible. 



Compression specimens 20.3 mm (0.8 in.) diameter, 61.0 mm (2.4 in.) long; failure occurring in shear. 



Tension set readings with extensometer showed elastic limit of 2.1 kg/mm^ or 3000 lb/in'. 



Modulus of elasticity in tension — 9560 kg/mm^ or 13,600,000 lb/in''. 

 Smithsonian Tables. 



