78 TABLES 48-50. 



MECHANICAL PROPERTIES. 



TABLE 48. Steel Wire Specification Values. 



(After I. A. S. B. Specification 3812, Sept., 1917, for 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 Hz at 850 C. 



TABLE 50. Semi-steel. 



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



Microstructure matrix resembling pearlitic steel, embedded in which are flakes of graphite. 



Composition-Comb. Co.6o 100.76, Mno.88, P 0.42 100.43, 80.077 to 0.088, Si 1.22 to 1.23, graphitic C 2. 84 to 2.94. 



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 2 or 3000 lb/in 2 . 



Modulus of elasticity in tension 9560 kg/mm 2 or 13,600,000 lb/in 2 . 

 SMITHSONIAN TABLES. 



