Sentence Examples

  • In the former case there is no later chance to remove sulphur, a minute quantity of which does great harm by leading to the formation of cementite instead of graphite and ferrite, and thus making the cast-iron castings too hard to be cut to exact shape with steel tools; in the latter case the converting or purifying processes, which are essentially oxidizing ones, though they remove the other impurities, carbon, silicon, phosphorus and manganese, are not well adapted to desulphurizing, which needs rather deoxidizing conditions, so as to cause the formation of calcium sulphide, than oxidizing ones.
  • If this carbon is all present as graphite, so that in cooling the graphite-austenite diagram has been followed strictly (§ 26), the constitution is extremely simple; clearly the mass consists first of a metallic matrix, the carbonless iron itself with whatever silicon, manganese, phosphorus and sulphur happen to be present, in short an impure ferrite, encased in which as a wholly distinct foreign body is the graphite.
  • The iron of the original ferrite matrix, it will have changed this matrix from pure carbon (more accurately 0.40 X I oo --96 4 = 0.415%), a rail steel, because it is of just such a mixture of ferrite and cementite in the But this matrix is itself equivalent to a steel of about 0.40% of ratio of 90.4:6 or 94% and 6%, that such a rail steel consists.
  • 2) 100.0 The constitution and properties of such a series of cast irons, all containing 4% of carbon but with that carbon shifting pro o v,,3 950 R portion of ferrite and cementite respectively in the matrix, DEF, KS and TU reproduced from fig.
  • Second, though the brittleness should be lessened somewhat by the decrease in the extent to which the continuity of the strong matrix is broken up by the graphite skeleton, yet this effect is outweighed greatly by that of the rapid substitution in the matrix of the brittle cementite for the' very ductile copper-like ferrite, so that the brittleness increases continuously (RS), from that of the very grey graphitic cast irons, which, like that of soapstone, is so slight that the metal can endure severe shock and even indentation without breaking, to that of the pure white cast iron which is about as brittle as porcelain.