Method of producing ductile iron
Process for producing ductile iron by treating liquid iron with an initializer which is a ferrosilicon alloy comprising an effective amount of barium sufficient to inactivate the oxygen activity of the liquid iron. This is followed at a predetermined time thereafter by treating the liquid iron with a magnesium containing nodularizer, followed by treating the liquid iron with a eutectic graphite nucleation-inducing inoculant, and casting the iron.
1. A process for the production of ductile iron comprising:
treating liquid iron with an initialiser which is a bariumferrosilicon alloy wherein the bariumferrosilicon alloy delivers an amount of barium effective to deoxidize the iron through the formation of barium oxides,
followed at least two minutes thereafter by treating the liquid iron with a magnesium containing nodulariser,
followed by treating the nodularized liquid iron with a eutectic graphite nucleation-inducing inoculant, and
casting the iron.
2. A process as claimed in claim 1 , wherein the bariumferrosilicon alloy is by weight percent
46-50Si, 7-11 Ba
the balance being Fe and any unavoidable impurities which may be present.
3. A process as claimed in claim 1 , wherein the Mg-containing nodulariser (ii) is Mg metal, MgFeSi alloy, Ni—Mg alloy, or Mg—Fe briquettes.
4. A process as claimed in claim 1 , wherein treatment with the Mg-containing nodulariser is carried out between about 1 and 10 minutes after treatment with the initialiser.
5. A process as claimed in claim 1 , wherein, the amount of initialiser added is calculated to deliver at least 0.035% barium by weight of the liquid iron.
6. A process as claimed in claim 1 , wherein the amount of Mg-containing nodulariser is calculated to result in from 0.025 to 0.035% residual Mg in the liquid iron.