METHOD OF PRODUCTION OF INGOTS MADE OUT OF MOTTLED CAST IRON WITH AUSTENITIC-BAINITE STRUCTURE Russian patent published in 2005 - IPC

FIELD: metallurgy; production of ingots made out of mottled cast iron with austenitic-bainite structure.

SUBSTANCE: the invention is dealt with metallurgy, in particular, with development of a method of production of mottled cast irons with globular graphite, which may be used for manufacture of components being worn under action of increased loadings. The method provides, that the mottled cast iron is melted down in the induction furnace, the liquid melt at pouring into a ladle is modified with magnesium-bearing addition alloys for formation of the ball-shaped graphite impurities in the ingots and during casting into a sandy-argillaceous mold expos it to inoculating modification. The ingots after crystallization are pulled out from the molds at the temperature of 900-1000°C, transposed to a furnace with temperature of 950-1000°C and keep there during 10-30 mines. After the aging the ingot is exposed to quenching in an isothermal bath at the temperature of 300-320°C within 1-1.5 hour. At that they use the cast iron of following chemical composition, (in mass %): carbon - 3.2-3.4, silicon - 3.0-3.3, manganese - 0.3-0.4, magnesium - 0.04-0.07, molybdenum - 1.5-1.7, nickel - 2.2-2.6, sulfur - 0.01-0.012, phosphorus - 0.06-0.08, iron - the rest. The invention allows to obtain a mottled cast iron with globular graphite and austenitic-bainite structure, high impact resistance, strength, hardness, wear resistance and quasi-isotropy.

EFFECT: the invention ensures production of a mottled cast iron with globular graphite and austenitic-bainite structure resistant to wear under action of increased loadings.

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