Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C1/00—Refining of pig-iron; Cast iron
  • C21C1/10—Making spheroidal graphite cast-iron
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C33/00—Making ferrous alloys
  • C22C33/08—Making cast-iron alloys
  • C22C33/10—Making cast-iron alloys including procedures for adding magnesium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C37/00—Cast-iron alloys
  • C22C37/04—Cast-iron alloys containing spheroidal graphite
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C37/00—Cast-iron alloys
  • C22C37/10—Cast-iron alloys containing aluminium or silicon

Definitions

• magnesium or a magnesium-containing alloy is added to the base iron, which corresponds in composition to untreated cast iron.
• the carbon is not separated out in the form of lamellar graphite, but as spheroidal graphite.
• the addition of magnesium which has a high affinity for oxygen and sulfur, reduces the oxides present in the melt, it forms magnesium oxide and binds the sulfur as magnesium sulfide.
• the magnesium oxides and sulfides rise to the surface over their residence time in the liquid iron and slag there. Magnesium treatment increases the surface tension of the melt, which means that the graphite tends to be spherical.
• the base iron is alloyed with rare earths and a significantly reduced but also regulated addition of magnesium.
• Another way to generate GJV is to add a titanium and cerium-containing magnesium alloy to set the desired vermicular graphite shape.
• magnesium is added to the base iron in the converter in pure form or in the form of an alloy, the magnesium content in the converter being lower than in the melt which is being poured and a final magnesium addition after the magnesium has been added to the converter or.
• -treatment of the melt pretreated with magnesium takes place during the transfer from the die casting furnace into the ladle.
• the raw materials preferably have a low sulfur content in order to keep the extent of desulfurization as low as possible.
• the base iron is then transferred to a converter or a magnesium treatment and / or transport pan.
• Magnesium is added to the base iron in the converter or in the magnesium treatment and / or transport pan, in pure form or in a magnesium-containing alloy, the magnesium content in the melt being lower than after the magnesium has been added in the converter or in the magnesium treatment and / or transport pan in the melt, which is poured into the molds.
• the next step is to fill the melt, which has been pretreated with magnesium, into a die-casting furnace at a molding and casting system, the melt being kept at the casting temperature. Subsequently, the melt pretreated with magnesium is poured into the ladle, with a final magnesium addition preferably in the form of a pretreatment alloy based on FeSiMg taking place during the transfer of the magnesium pretreated melt from the die casting furnace into the ladle.
• the structure of the structure can be matched to the metallurgical condition by the individual addition of magnesium for the final treatment in the melt pretreated with magnesium during the transfer into the ladle.
• the alloy is preferably also inoculated while the Mg is being added when it is transferred to the pouring ladle.
• This enables the inoculant to be added easily and can be adapted to small amounts of the melt, as a result of which small batches with the corresponding properties can be poured.
• the addition of the inoculant during the transfer or during the addition of magnesium can also react to a change in the metallurgical quality, the germ state of the melt by dynamically adjusting the amount of inoculant during the transfer.
• the amount of magnesium which is added to the casting ladle for the final treatment during the transfer is preferably monitored and regulated by means of thermal analysis.
• the thermal analysis must be carried out for each batch in order to ensure complete control. This means that the amount of magnesium that is supplied can be dynamically adjusted and immediately matched to the melt.
• the amount of inoculant added to the ladle for final treatment during transferring is also monitored and controlled by thermal analysis.
• the final addition of magnesium and / or addition of inoculant preferably takes place at most 120s before casting.
• the decay effect of magnesium and vaccination treatment is too high. In this case, process-reliable microstructure formation cannot be ensured.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

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Citations (5)

• 2018
  • 2018-12-14 EP EP18212500.5A patent/EP3666415A1/fr not_active Withdrawn

Patent Citations (5)

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