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
  • C21C7/04—Removing impurities by adding a treating agent
  • C21C7/06—Deoxidising, e.g. killing
• • 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
  • C21C5/04—Manufacture of hearth-furnace steel, e.g. Siemens-Martin steel
  • C21C5/06—Processes yielding slags of special composition

Definitions

• the present invention has for its object :1 process according to which itis possible to manufacture iron and steel free from the 11n-- desirable elements phosphorus, arsenic, snl- At the some time lhe phur and the like.
• metal mannlocnlrcd according to the new process is: free from slugs inevitablev when deoxidized according" to the known processes and it is also lilac clccl-ric steel and electrolytic iron cnlirely safe against the risk of redshorlncss, that is to say free from other gcnrornpounds, I
• vapour of nzene which indeed has a very powerful reductive action, would react with the oxygen compounds of the bath according to the following equation 0,11 15Fe0 600 SH O 15Fe that is to say that from one volume vapour of benzene in the converter would result 9 volumes of. carbonic acid and steam.
• An essential feature of the invention therefore is the employment of a reducing gas burning without increase of volume. Hydrogen although it burns without increase of volume is not proper as a de oxidation-material because its reductive action at higher temperature decreases and at the temperature of liquid iron is imperceptibly small.
• the task of the carbon monoxide containing gas is therefore exclusively to reduce the ferrous oxide, not to burn phosphorus, manganese or other accompanaying elements which moreover have been removed by overblowing.
• second gas inlet is introduced, through which a gas of the above mentioned composition can be forced into the converter.
• the refining process is carried so far that the percentage of hosphorus has sunk to less than 0.01% and the percentage of manganese and silicon amount to no more than 0.02%. material as pure in phosphorus and sulphur as possible is used, the process then is the same as described in the basic process.
• the blast refining time must be fixed in several preliminary tests by means of chemical analysis.
• the charge is also melted and refined in the usual manner and then further refined (over-fined) for a long time.
• the determination of whether the refining-time is sufiicient is a ain made by means of chemical analysisn melting and refining in the open hearth furnace the time can be worked out according to the direct (ore)-or scrap-method or according to any other method.
• the liquid steel is brought into a converter as described above-only in this case of course the blast-inlet can be omitted-and is deoxidized by reducing gas being forced through the bath as above describe
• the bath can be worked in the well known manner with a double slag-la er.'
• Siemens-Martin steel can be carried out in a similar way.
• the pure iron thus obtained which is not only characterized by its purity but also by its homogenous texture, ductility and power of resisting corrosion, is suitable for extensive use in the technical world, and also with special advantage as a raw material for the man- Efacture of alloyed or unalloyed steel of any ind.
• the pure iron obtained by the process above described may be recarbonized if this should be desirable.
• recarbonization has been effected with the aid of manganese or other alloys containing a high percentage of carbon.
• the final step namely the recarburization is effected by means of gases or vapors having a carbonizing effect which gases are passed through the bath.
• gases or vapors having a carbonizing effect which gases are passed through the bath.
• the refining process for producing iron by blast and open hearth refining methods which, after initially refining a bath of m0lten iron in known manner, consists of the combined sequence of steps, namely, of first over-blowing the iron bath in order to introduce an excess of oxygen and thereby obtain a mixed bath of substantially pure iron and iron oxide, subsequently reducing the bath to practically pure iron by means of a noncarbonizing gas of substantially constant volume, which is actively reductive at the temperature of the bath including a mixture of carbon monoxide, carbon dioxide and nitrogen, and finally carburizing said bath by introducing a saturated hydrocarbon into the same until said bath contains a predetermined amount of carbon.
• the refining process for producing pure iron by blast and open hearth refining methods which, after initially refining a bath of molten iron in known manner, consists of the combined sequence of steps, namely, of first overblowing the iron bath in order to introduce an excess of oxygen and thereby obtain a mixed bath of substantially pure iron and non-carbonizing gas of substantially iron oxide, and subsequently reducing the bath to practically pure iron by means of a constant volume, which is actively reductive at the temperature of the bath including a mixture of carbon monoxide, carbon dioxide and nitrogen.
• the refining process for producing pure iron by blast and open hearth refining methods which, after initially refining a bath of molten iron in known manner, consists of the combined sequence of steps, namely, of first forming a new slag layer upon said bath in order to protect the same, then overblowing the iron bath in. order to introduce an excess of oxygen and thereby obtain a mixed bath of substantially pure iron and iron oxide, subsequently reducing the bath to practically pure iron by means of a non-caronizing gas of substantially constant volume, which is actively reductive at the temperature of the bath including a mixture of of oxygen and thereby obtain a mixed bath of substantially pure iron and iron oxide,
• pure iron by means of a non-carbonizing gas of substantially constant volume, which is actively reductive at the temperature of the bath including a mixture ofcarbon monoxide, carbon dioxide and nitrogen, and finally carburizing said bath by introducing a saturated hydrocarbon into the same until said bath contalns a predetermined amount of carbon.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=6040565

Family Applications (1)

Country Status (3)

Cited By (1)

• 1927
  • 1927-11-26 GB GB31898/27A patent/GB282365A/en not_active Expired
  • 1927-11-28 US US236371A patent/US1846234A/en not_active Expired - Lifetime
  • 1927-12-10 FR FR651612D patent/FR651612A/fr not_active Expired

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