Classifications

• • 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
  • C21C1/105—Nodularising additive agents
• • 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
  • C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires

Definitions

• a treatment wire known from DE-OS 27 38 379 consists, for example, of a powdery core material made of magnesium alloys, such as Mg-Si-Mn or Mg-Fe-Si alloys, or calcium alloys, such as Ca-Si-Mn or Co-Si Fe alloys. These alloys can also contain rare earth metals.
• the powdered core material is usually compacted.
• a wire-like agent for treating metal melts in which between the outer jacket made of ferrous metal and core material made of relatively volatile metal, eg. B. magnesium, an insulating material made of z. B. iron powder is arranged.
• the core material should be added simultaneously with the melting of the jacket material and premature melting and evaporation of the magnesium core should be prevented.
• the known wires do not always meet the requirements of metallurgical practice. If manganese or iron alloyed magnesium silicon alloys are used, the reactivity of the magnesium is greatly reduced in such alloys and a larger L egleitersmenge required with often undesirable alloying elements. As far as treatment wires with coated magnesium wire are used, the rigidity of the wire often proves to be a hindrance. An uneven reaction sequence cannot be avoided by forming vapor bubbles of different sizes in the metal evaporated in the melt, such as magnesium.
• the invention has for its object to avoid the disadvantages mentioned when treating metal melts with wire-shaped additives.
• the medium of the melt should be offered in such a structure that the active substances develop in the finest form and are absorbed by the melt without any noteworthy losses.
• the composition of the wire-like and silicon-free treatment agent can be varied within wide limits, so that it can be used both for deoxidation and desulphurization of molten metals, as well as for alloying a molten metal, or to bring about a structural refinement of any kind in the melt.
• the wire-shaped loading is suitable for the treatment of cast iron melts h andlungsstoff for the manufacture of nodular iron.
• the components of the metal powder mixture are in the generally in a certain relationship to each other.
• the metal component A such as calcium, magnesium or rare earth metal
• the metal component B such as iron, nickel or manganese
• the metal component A is in a mixing ratio of 40 to 60 parts by weight to 60 to 40 parts by weight. In many cases it has proven advantageous to maintain a ratio of 50 to 50 parts by weight.
• the components of the metal powder mixture are of the same grain size. It has proven advantageous here to maintain a grain size of the metal powder of 0.02 to 1.0 mm.
• a preferred range is a grain size of 0.05 to 0.25 mm, in which range particularly favorable results are achieved with grain sizes of the metal powders of 0.07 to 0.16 mm.
• the casing made of ferrous metal enclosing the metal powder mixture generally has a wall thickness of 0.2 to 0.5 mm, a wall thickness of 0.3 mm being preferred.
• the mode of action of the wire-shaped treatment agent according to the invention can be imagined as follows for continuous immersion in the molten metal.
• the powder of the metal component with the higher melting or boiling point acts as a nucleus for the gas bubble formation of the powder component with the lower boiling point.
• a powder mixture of z. B. Magnesium and iron rise accordingly when immersed in a molten metal of z. B. above 1200 ° C comparatively many small Mg vapor bubbles in the melt and largely dissolve on their way to the metal surface. This ensures optimum Mg output.
• an iron metal-coated treatment agent made of magnesium powder and iron powder
• a magnesium yield of over 60% is achieved, and the graphite of the cast iron melt is completely spherical.
• the treatment is carried out with the same wire, but with powder filled with pure magnesium metal, the Mg output is approximately 2%.
• any formation of smoke or eruptions is surprisingly avoided, so that almost 100% of the z. B. added magnesium can be effectively implemented with the iron or steel melt.
• the treatment agent according to the invention can be used in a safe and reproducible manner to advantageously deoxidize, desulphurize, modify graphite shapes, such as vermicular or spheroidal graphite, or inoculate the molten iron or steel.
• a coated body with an outer diameter of 3.2 mm was made of a sheath made of mild steel tape (wall thickness of the iron sheath 0.3 mm) and a core made of a mixture of 50% metallic magnesium powder and 50% iron powder, both with a grain size of 0.07 down to - 0.16 mm, produced by means of a wire production machine. The product is mechanically compressed and deformed and a body is made in wire form.
• the magnesium content was 1.9 g.
• the feed speed was about 100 m / min.
• the treated iron melt had a magnesium content of 0.042% after the end of the test, which corresponds to a magnesium yield of 65.6%.
• the treatment was completely calm and without smoke development and without eruptions or without expelling melt components.
• the graphite in the casting was 100% spherical.

Landscapes

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

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (2)

Cited By (12)

Families Citing this family (1)

Citations (7)

• 1979
  • 1979-12-04 DE DE19792948636 patent/DE2948636A1/de not_active Withdrawn
• 1980
  • 1980-10-22 EP EP80201001A patent/EP0030043A3/fr not_active Withdrawn

Patent Citations (7)

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