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
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21B—MANUFACTURE OF IRON OR STEEL
  • C21B13/00—Making spongy iron or liquid steel, by direct processes
• • 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
  • C21C1/08—Manufacture of cast-iron
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01C—RESISTORS
  • H01C1/00—Details
  • H01C1/02—Housing; Enclosing; Embedding; Filling the housing or enclosure
  • H01C1/034—Housing; Enclosing; Embedding; Filling the housing or enclosure the housing or enclosure being formed as coating or mould without outer sheath
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01C—RESISTORS
  • H01C1/00—Details
  • H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
  • H01C1/148—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors the terminals embracing or surrounding the resistive element
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01C—RESISTORS
  • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
  • H01C17/28—Apparatus or processes specially adapted for manufacturing resistors adapted for applying terminals
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01C—RESISTORS
  • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
  • Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen

Definitions

• the present invention relates to a process for the production of improved cast iron and steel and more par ticularly to a homogeneous germination inoculation process for liquid cast iron and steel and the product obtained thereby.
• the iron and steel industry has carried out many tests to alter the cooling and crystallization of steel cast in ingot molds, particularly effervescent steel, by adding various materials, such as scales or iron ore, to the bath. The results are not conclusive either because the added material does not blend with the bath or the steel obtained is contaminated with undesirable inclusions after solidifying.
• an improved homogeneous germination inoculation is obtained by adding to the ingot molds or the casting ladle specific and controlled amounts of highly pure powdered sponge iron of a given composition, crystal structure and particle size.
• the powdered sponge iron inoculating agent particularly suitable for the homogeneous germination of cast iron and steel have particular characteristics which are defined within rather narrow limits.
• the characteristics of the sponge iron de pend upon the nature of the starting material and the operating conditions during the manufacture thereof.
• a material that may be prepared by the direct iron ore reduction process is described in US. patent application Ser. No. 444,607, filed Apr. 1, 1965. This process includes the following successive steps:
• This material which may be the product of step 2 or step 5 above, has the following characteristics.
• FeO total iron 77.0 to 99.0%. FeO 0.0 to 100.0%. Fe O 0.0%. Sn, Zn, Cu, As etc Indeterminable traces. Mn $0.271. Ni, Cr, Co 0.0 to 0.01%. Si, S, P 0.0l%. Ogygen (in the form of FeO) 0.0 to 22.0%.
• Particle size 40 to 2,000 microns (preferably 40 to 400 microns). Apparent density 2.3 to 3.0.
• the amount of inoculating agent which should be added to liquid cast iron or steel baths may be as high as 5.0% by weight, depending upon the Foo content thereof and the required characteristics of the final product.
• the elemental particles consisting of reticular piling of number of atoms according to the bodycentered cubic system have a homogeneous germinative action owing to the structure analogy thereof with the major constituent of the bath both by epitaxy during the solidification and by modification of bath concentration in the vicinity of each inoculating graint Among the specific effects resulting from such an inoculation is the degassing of the cast iron and steel. It
• the endothermicity of the reaction together with the mass cooling due to the inoculating agent causes an immediate and sensible lowering of dissolved gas solubil ity while carbon monoxide bubbles ascending to the surface swirl along a large proportion of the gases.
• degassing should be carried out by adding an amount of finely divided carbon to the inoculating agent to start the reactions.
• the treatment of the present invention is applied to quarter hard steels, such as the effervescent steels for deep stamping, high magnetic permeability steels or some alloy steels of austenitic nickel-chromium 18/8 grade, wherein it is difficult to lower the carbon content to values under 0.05% on account of peroxidation hazards, this outstanding reactivity of the iron powder with respect to carbon permits the simultaneous degassing and decarburization under excellent conditions without other bath elements being affected at casting temperature, especially silicon and manganese.
• each elemental particle of inoculating agent liberated by dissociation of the powdery aggregates causes the initiation of homogeneous crystallization due to mass cooling, a change in the iron concentration in the vicinity of the particles and epitactic rearrangement from the particles.
• the finely divided state of the iron powder has a positive effect upon germination and the growth rates of the germs while imparting to the finished product a finer structure with smaller intercrystal interstices corresponding to the absence of microporosities.
• the dendritic segregation process is considerably altered due to the shortening of the solidification front and the final product is sounder and less liable to internal stresses.
• the inoculation according to the present invention has a very important influence on the crystal texture itself of the cast iron and steel.
• the ferritizing effect of these iron powders on cast iron results from the evolution of some amount of nitrogen and hydrogen, which gases are stabilizers for iron carbides in the form of cementite and perlite.
• a 1.5% by weight inoculation of pure sponge iron containing 24.0% of FeO causes the direct formation of from 12.0% to more than 20.0% of ferrite according to the operating temperature.
• the treatment is far more effective where it is carried out on spheroidal-graphite cast irons, ferritization being then facilitated to such an extent that it is possible in many cases to avoid the subsequent thermal ferritizing treatment of castings with all the hazards; of deformation involved, especially for thin castings.
• This homogeneous germination inoculation procedure permits the casting of effervescent steel ingots having heights exceeding 1.8-2.0 meters, and the use of continuous casting in blooms or slabs.
• the second effervescence affects the molten metol core to a rather great depth by a thermosiphon effect due to the endothermicity of the reactions and heat absorption by the cold iron powder introduced into the bath, involving gas bubbles and, should the occasion arise, inclusions towards the top.
• the reaction takes place at high speed and pure iron grains then act as homogeneous germs of equiaxed crystallization.
• the solidification front of dendrites being shortened, the accelerated solidification is carried out without austenitic grains becomng larger. Effervescence is then quickly blocked and segregation occurs no longer as consolidation proceeds.
• the amount of sponge iron used with effervescent steels may run as high as 5% of the ingot weight according to the FeO content thereof, but excellent results are achieved with much smaller amounts of about 0.2% to 0.7%.
• sponge iron containing 36.3% of ferrous oxide to a 5-ton steel ingot, 8 minutes after casting, a decrease of 0.02% of initial carbon, of 0.1% of manganese and of 0.01% of sulphur in the ingot top is noted which results in a higher homogeneity of the mass. Further, total solidification time is reduced by a fourth to a third.
• a process for the homogeneous germination inoculation of liquid cast iron and steel which comprises adding thereto up to approximately 5% by weight of non-pyrophoric powdered sponge iron prepared by the reduction of iron ore and containing from 77.0% to 99.0% of free and oxidized iron, the oxygen in the form of FeO being present from 022% by Weight.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=26161575

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (1)

Family Cites Families (1)

• 1965
  • 1965-01-18 FR FR2307A patent/FR1449616A/fr not_active Expired
  • 1965-07-08 FR FR23977A patent/FR88294E/fr not_active Expired
• 1966
  • 1966-01-05 GB GB502/66A patent/GB1138631A/en not_active Expired
  • 1966-01-05 US US518784A patent/US3370939A/en not_active Expired - Lifetime
  • 1966-01-14 ES ES0322166A patent/ES322166A1/es not_active Expired
  • 1966-01-17 BE BE675222D patent/BE675222A/xx unknown
  • 1966-01-18 NL NL6600612A patent/NL6600612A/xx unknown
  • 1966-01-18 DE DE19661508229 patent/DE1508229B1/de active Pending

Non-Patent Citations (1)

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