Table 870 657 



PROPERTIES OF MALLEABLE CAST IRON 



(From Proc. Amer. Soc. for Testing Materials, 31, pt. 2, 1931 ; Malleable Iron 



Research Institute.) 



Malleable iron is the product produced by the annealing or graphitization of " white iron " 

 castings in which all carbon should be present in the combined form, such that the final 

 structure of the malleable casting consists of ferrite and free carbon (temper carbon) 

 with practically no combined carbon as free cementite or pearlite. Where strength, 

 ductility, machineability, and resistance to shock are important, malleable iron castings are 

 of wide application. 



Chemical composition: C 1.00 to 2.00; Si 0.60 to 1.10; Mn < .30; P < .2; S .06 to .15%- 



Density: 7.15 to 7.45. Thermal expansion: 20°-400° C, about 0.000012 per C C. 



Sp. Ht. : Mean 2o°-ioo° C, 0.122 per g per °C; 2o°-200°, 0.125; 20 c -500°, 0.139; 

 2o°-70O°, 0.159. 



Thermal conductivity: Kt, 50 C, 0.145 g. cal./sec./°C/cm ; ioo C, 0.137; 200 C. 0.115. 



Tensile strength: 54,000 lbs. /in. 2 ; range 45,000 to 63,000; yield point 36,000 lb. /in. 2 



Elongation in 2 in. 18%. Modulus of elasticity in tension 25,000,000 lb. /in. 2 



Compressive strength : Material flows indefinitely. 



" Special " tensile 57,690 ; yield point 38,000 ; elongation 25% in 2 in. 



Ultimate shearing strength 48,000 lb. /in. 2 ; yield point 23,000 lb./in. 2 ; elasticity mod. 

 12,500,000 lb./in. 3 



Modulus rupture in torsion 58,000 lb./in. 2 ; yield point in torsion 24,000 lb./in. 2 



Brinell hardness 115, range 100 to 140. Charpy impact value 7.75 ft. lb. 



Note: If malleable iron is heated above its lower critical point (about 760 C), carbon 

 redissolves and the character of the iron changes. 



Resistivity: 28 to 37 microhms -cm 3 Rmo/Ro— I.I R 50 o/R = 2.3. 



Magnetizing force, H, gilberts/cm 2.5 5 



Induction, B, gausses (mean) 5800 7600 



Comparative machineability. Relative power required (means of planing, drilling, and 

 milling) : 



Dow metal, type E 19 Gun metal 55 Copper annealed 131 



Bearing bronze 36 Cast iron 60 Tool steel 1.03% C... 145 



Aluminum alloy no. 31. 2>7 Manganese bronze ... 61 Stainless Cr, iron, ann. 158 



Red brass 38 Malleable cast iron.. 70 Monel metal 165 



Sheet brass 41 Unleaded brass 85 Nickel "A" 193 



Smithsonian Tables 



