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
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/28—Manufacture of steel in the converter
  • C21C5/42—Constructional features of converters
  • C21C5/44—Refractory linings
• • 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
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/28—Manufacture of steel in the converter
  • C21C5/42—Constructional features of converters
  • C21C5/44—Refractory linings
  • C21C5/441—Equipment used for making or repairing linings
  • C21C5/443—Hot fettling; Flame gunning
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/68—Temporary coatings or embedding materials applied before or during heat treatment
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/82—Descaling by thermal stresses
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
  • C22B9/006—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals with use of an inert protective material including the use of an inert gas
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/008—Using a protective surface layer
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/70—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using melts
  • C23C22/72—Treatment of iron or alloys based thereon
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F15/00—Other methods of preventing corrosion or incrustation

Definitions

• ABSTRACT Process for preventing the oxidation of hot metallic surfaces comprising coating the surfaces of the hot metal with a reducing agent which forms a protective pellicle, i.e., a thin skin or film, through which the state of the metal surface can still be observed during fabrication.
• the pellicle or film inhibits the formation of an oxide crust.
• the metal may be in solid or molten condition.
• the pellicle is formed by applying a reducing agent to the metal surface.
• the reducing agent may be applied as a cloud of fine particles, as a solution, or as vapors.
• the present invention concerns a new process for the protection of solid or liquid hot metallic surfaces.
• Processes which protect iron and steel parts by applying a protective or reduction layer before submitting them to treatment.
• these known layers are applied cold on the part which must subsequently be heated, and on the other hand, the known processes form a crust which masks the surface of the part.
• An object of the present invention is to protect not only solid but also liquid hot metallic surfaces from oxidation.
• a further object is simultaneously to minimize the formation of oxides.
• the process in accordance with the invention comprises applying,to the metallic surface to be protected, a product possessing reduction properties, which gives rise to a protective pellicle and can, as a result, be introduced and continuously applied, without modification of the manufacturing procedure already existing in the works of shop floors of the iron and steel industry, in forging or in foundry work.
• the process in accordance with the present invention is applicable to a metallurgical part in the course of transformation or working, for example, in the course of a rolling operation, without it being necessary to heat the part solely and separately before the application of the coating.
• the protected pellicle in accordance with the invention, reduces the oxides and minimizes the formation of calamine and leaves the hot surface visible so that one can observe with the naked eye the quality and state of the surface of the part in the course of lamina- .tion. As soon as a fault appears on the surface, it can be seen with the naked eye, since it is not masked by a crust of oxides, as in the case of known prior art processes.
• the protective composition of the present invention has particular applicability to cleaning and protecting of steel, which is subjected to temperatures of between 900C. and 1,200C during the usual rolling operation on a rolling mill.
• Steel bars being rolled frequently circulate at a speed of about 50 meter per second and their cross-sectional surface can be reduced from 3 feet X 3 feet to a one-sixth inch diameter wire after 25 passages between the cylinder.
• applicant's composition applied to a steel surface is able to permanently protect the metal surface throughout the rolling operation, no matter how great the cross-section reduction. Furthermore, using the heat produced in the rolling operation, it is not necessary to employ any exterior heat source in order to form the pellicle.
• the materials of this invention may be easily applied to the metal surface using already existing rolling mill equipment, without any other construction than mounting a transverse tube about 5 feet in length and an aerosol producing apparatus (such as a hopper, turbine, venturi or the like). No other special preferential circuit or general installation is required.
• the surface defects of the steel bar may be viewed as soon as they appear during the rolling operation, as the steel surface is kept permanently clean and protected against oxidation.
• the chemical forming materials of the present invention may be selected from a wide variety of materials which possesses the necessary chemical and physical properties required to insure the desired protective and reducing rolls of the present invention. That is, the materials to be employed in the process of the present invention are those which form a pellicle when'heated, suppress oxide formation on the surface of the metal to be protected and which form a film through which the surface of the metal can be observed. Such materials can comprise either mineral or organic components.
• SiO A1 0 CaO, MgO, Na, K, and B 0 b. SiO Na CO and B203;
• compositions illustrated in Examples 1-5, inclusive represent the initial compositions as applied to the hot metal surface, and not the final makeup of the coating.
• EXAMPLES 1-3 The following table illustrates three compositions which are particularly suitable for application to ferrous metals during a foundry rolling operation. In claims 1-5, all proportions are set forth in parts by weight.
• the following table illustrates two compositions which are particularly suitable for application to nonferrous metals during foundry rolling operations.
• Example 0210 810; A1 F 0; MgO T10 Be Na These materials are contacted with the hot metal surface in the same manner as described for the compositions of Examples 1-3.
• EXAMPLE 6 An organic composition particularly suitable for spraying onto metal billets during foundry rolling operations was prepared by mixing the following ingredients:
• the reducing, pellicle-forming materials are generally solid and may be used in the form of a cloud of very fine powder, the particles of which melt upon contact with the hot part of the liquid metal.
• the compositions of this invention may also be employed in conjunction with a suitableliquid carrier, for example, as a dispersion, in the form of a fog which also gives rise, on contact with the hot surface part or the liquid metal, to a protective reducing pellicle.
• the reducing agents can also be directly gasified so as to constitute an atmosphere which possesses the property of reducing oxides, and which is contacted with the hot metal surface in a reducing atmosphere to form a protective pellicle.
• the application of a process in accordance with the invention can be effected without having to modify the lamination train, i.e., the mechanical treatment applied to the parts in the course of transformation, when the parts are at the desired temperature.
• the protective and reducing pellicle in accordance with the invention maintains the surface of the part substantially free of oxides, leaving any possible superficial fault exposed to the naked eye and this, in spite of the large increase in surface observed in the course of lamination.
• the operation in accordance with the invention is thus comparable to sanding, grinding or chemical removal which permits suppression of masking or observation of surface faults.
• thermal treatment which consists in applying a coating on the final cold part before passing it to an oven or a vat.
• the treatement in accordance with the invention can be effected automatically without the intervention of a workman and it can be incorporated conveniently in existing manufacturing procedures without having to modify them.
• the treatment since the treatment is applied to a part in the course of hot working or transformation and not on the cold part, it does not necessitate subsequent heating of the part, for example, by passing it through an oven as a separate treatment step.
• a continuous process for forming a protective coating on hot ferrous metals during a hot foundry rolling operation comprising continuously contacting the hot ferrous metal, during hot rolling thereof, with a chemically reducing composition which forms a pellicle when heated, supresses oxide formation on the surface of the ferrous metal being coated and forms a film through which the surface can be observed, whereby said protective coating is formed upon contact of said composition with said ferrous metal, said chemically reducing composition having the following initial composition, in parts by weight, 17.5 parts CaO, 5.5 parts SiO 1.4 parts A1 0 0.5 part Fe O 1.6 parts MgO, 14 parts B, 0.5 part K and 0.3 part Na.
• a continuous process for forming a protective coating of hot ferrous metals during a hot foundry rolling operation comprising continuously contacting the hot ferrous metal, during hot rolling thereof, with a chemically reducing composition which forms a pellicle when heated, suppresses oxide formation on the surface of the ferrous metal being coated and forms a film through which the surface can be observed, whereby said protective coating is formed upon contact of said composition with said ferrous metal, said chemically reducing composition having the following initial composition, in parts by weight, 16.0 parts CaO, 4.5 parts SiO 3.6 parts A1 0 0.8 part F6 0,, 2.4 parts MgO and 17 parts B.
• a continuous process for forming a protective coating of hot ferrous metals during a hot foundry rolling operation comprising continuously contacting the hot ferrous metal, during hot rolling thereof, with a chemically reducing composition which forms a pellicle when heated, suppresses oxide formation on the surface of the ferrous metal being coated and forms a film through which the surface can be observed, whereby said protective coating is formed upon contact of said composition with said ferrous metal, said chemically reducing composition having the following initial composition, in parts by weight, 25.0 parts CaO, 7.0 parts S10 4.2 parts A1 0 1.2 parts Fe,O 3.2 parts MgO and 17 parts Na.
• a continuous process for forming a protective coating of hot ferrous metals during a hot foundry rolling operation comprising continuously contacting the hot ferrous metal, during hot rolling thereof, with a chemically reducing composition which forms a pellicle when heated, suppresses oxide formation on the surface of the ferrous metal being coated and forms a film through which the surface can be observed, whereby said protective coating is formed upon contact of said composition with said ferrous metal, said chemically reducing composition having the following initial composition, in parts by weight, 17 parts CaO, 5 parts SiO 5 parts Al, 2 parts Fe O 1.8 parts MgO, 37 parts TiO and 2.1 parts Na.
• a continuous process for forming a protective coating of hot ferrous metals during a hot foundry rolling operation comprising continuously contacting the hot ferrous metal, during hot rolling thereof, with a chemically reducing composition which forms a pellicle when heated, suppresses oxide formation on the surface of the ferrous metal being coated and forms a film through which the surface can be observed, whereby said protective coating is formed upon contact of said composition with said ferrous metal, said chemically reducing composition having the following initial composition, in parts by weight, 22 parts CaO, 4 parts SiO 4 parts A], 1.5 parts Fe O 1.8 parts MgO, 12 parts TiO 10 parts Be and 1.7 parts Na.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Other Surface Treatments For Metallic Materials (AREA)
• Chemical Treatment Of Metals (AREA)
• Metal Rolling (AREA)
• Forging (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (8)

Cited By (7)

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Citations (18)

• 1966
  • 1966-05-24 FR FR47309A patent/FR1489122A/fr not_active Expired
• 1967
  • 1967-05-09 BE BE698249D patent/BE698249A/xx unknown
  • 1967-05-22 DE DE19671558001 patent/DE1558001A1/de active Pending
  • 1967-05-22 LU LU53715A patent/LU53715A1/xx unknown
  • 1967-05-22 ES ES341388A patent/ES341388A1/es not_active Expired
  • 1967-05-23 GB GB23817/67A patent/GB1196043A/en not_active Expired
  • 1967-05-23 NL NL6707137A patent/NL6707137A/xx unknown
• 1970
  • 1970-01-30 US US00008099A patent/US3765205A/en not_active Expired - Lifetime

Patent Citations (18)

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