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PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS (refining metals in general C22B 9/00 )
Definition statement
This subclass/group covers:

all treatments of molten iron or steel, including the apparatuses specifically related thereto, e.g. converter, electric furnace.

References relevant to classification in this subclass
This subclass/group does not cover:
Ferrous alloy compositions
Cast iron alloys
Dephosphorising or desulfurising
Definition statement
This subclass/group covers:

Also the specific treating agents

Informative references
Attention is drawn to the following places, which may be of interest for search:
Dephosphorising or desulfurising of molten ferrous alloys
Special rules of classification within this group

In case the dephosphorising, desulfurising are more generally claimed and could also apply to ferrous alloys (incl. steel), C21C 7/064 should be attributed as well.

If the method of introduction is specifically claimed, the corresponding class in C21C 7/00 should be attributed

Removing impurities other than carbon, phosphorus or sulfur
Informative references
Attention is drawn to the following places, which may be of interest for search:
Removing impurities of ferrous alloys
General processes of refining metals
Special rules of classification within this group

In case the treatments to remove other impurities are more generally claimed and could also apply to ferrous alloys (incl. steel), C21C 7/04 or any appropriate class below should be attributed as well.

If the method of introduction is specifically claimed, the corresponding class in C21C7/00 should be attributed

Constructional features of mixers for pig-iron
Informative references
Attention is drawn to the following places, which may be of interest for search:
Stirring devices for molten metal
Manufacture of cast-iron
Definition statement
This subclass/group covers:

Treatment of pig iron to obtain non-spheroidal cast-iron.

References relevant to classification in this group
This subclass/group does not cover:
Cast-iron alloys (composition)
Informative references
Attention is drawn to the following places, which may be of interest for search:
Making of cast-iron alloys
Making spheroidal graphite cast-iron
Definition statement
This subclass/group covers:

Also the nodularising agents

Informative references
Attention is drawn to the following places, which may be of interest for search:
Cast-iron alloys
Making of cast-iron alloys
Manufacture of wrought-iron or wrought-steel
Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel [N: or stainless steel]
Definition statement
This subclass/group covers:

Also the manufacturing of stainless steels and ferro-alloys ; apparatuses, in particular converters, which are specifically dedicated to the steel processing are classified within this group as well

References relevant to classification in this group
This subclass/group does not cover:
Ferrous alloy compositions
Special rules of classification within this group

Indexing Codes C21C 5/00 to C21C 5/56 apply for additional information or in case no corresponding EC-subgroup exists.

Manufacture of steel in the converter [N: (C21C 5/005 takes precedence)]
Definition statement
This subclass/group covers:

Also the full plant lay-out.

Regulating or controlling the blowing
Definition statement
This subclass/group covers:

Converter processes in which the regulation or control of the blowing is claimed, be it from above, through the bath or a combination thereof, i.e. not specific to one of the methods ; the regulation or control can relate to the amount, the sequence, the composition etc of the gases.

Also post-combustion is considered as a means to control the blowing

Synonyms and Keywords

In patent documents the following abbreviations are often used:

Post-combustion
after burning
Blowing from above (C21C 5/35 takes precedence)
Definition statement
This subclass/group covers:

Regulation or control of blowing ONLY from above, i.e. through a lance

References relevant to classification in this group
This subclass/group does not cover:
Blowing through the bath (C21C 5/35 takes precedence)
Definition statement
This subclass/group covers:

Regulation or control of blowing only through the melt, i.e. through a tuyere or bottom

References relevant to classification in this group
This subclass/group does not cover:
Tuyere details
Removal of waste gases or dust
Definition statement
This subclass/group covers:

The treatment of the off-gas

Informative references
Attention is drawn to the following places, which may be of interest for search:
Separation
In particular of solids from gases or vapours by gravity, inertia or centrifugal forces
By filters
By liquids
By other means
Purifying or modifying the chemical composition of combustible gases containing CO
Offtakes or separating apparatus for converter waste gases or dust
Definition statement
This subclass/group covers:

The installation required for capturing and treating of the off-gas.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Arrangements for using waste heat, using or disposing of waste gas
Preventing escape from fumes from the area where they are produces, collecting or removing fumes therefrom
Devices for conducting smoke or fumes for factories or large buildings
Refractory linings
Definition statement
This subclass/group covers:

Apart from the lining itself, the equipment to make, apply or repair the lining, both of the vessel and of the taphole in particular.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Linings for furnaces in general, incl. making and repairing
Tapholes
Details or accessories
Definition statement
This subclass/group covers:

Lances, means for their handling ; supporting means for the converter ; cooling arrangements ; tapholes, their opening and sealing ; charging devices ; measuring and sampling devices ; support and transport devices for the converter ; cleaning and skull removal.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Lances injecting a gas jet ; injecting particulate material using a fluid jet
Trunnions in generalbearings and accessories in general
Devices or methods for removing incrustrations
Arrangements of controlling devices
Arrangements of monitoring devices
Charging of furnaces
Travelling or movable supports for the charge
Tapholes, opening and sealing
Measuring, testing in general of weight of vibrations or ultra-, infra- or sonic waves radiation pyrometry other temperature measurements
Specific techniques for measuring or analysing materials by determining their chemical or physical properties
Measuring the weight of the converter
Bottoms or tuyéres of converters
Definition statement
This subclass/group covers:

Porous plugs and tuyeres

Informative references
Attention is drawn to the following places, which may be of interest for search:
Treatment of fused masses in a ladle, incl. with gases
Tilting mechanisms for converters
Informative references
Attention is drawn to the following places, which may be of interest for search:
Pivotal connections in general ;
Bearings and accessories in general
Manufacture of steel in electric furnaces ([N: C21C 5/005 takes precedence]; electric heating per se H05B)
Definition statement
This subclass/group covers:

Any type of electric heating : AC, DC, induction or plasma, incl. accessories as burners.

The manufacturing of alloyed steels, incl. ferro-alloys.

The charging of the electric furnace.

Multiple hearth furnaces.

The general lay-out of the melt shop.

Informative references
Attention is drawn to the following places, which may be of interest for search:
Burners
Methods or apparatus for combustion using fluent fuel
Electrically heated hearth furnaces hearth furnaces in general and their accessories
Arrangements of elements for electric heating in or on furnaces
Electric heating elements or system
Electric heating in general
Special rules of classification within this group

specific Indexing Codes exist for the presence/absence of a foam or a molten heel in the electric furnace

Manufacture of steel by other methods (making liquid steel by direct processes C21B 13/00) [N: (C21C 5/005 takes precedence)]
Definition statement
This subclass/group covers:

Also methods starting from scrap (with/without preheating) not treated in electric (arc) furnaces

Treating molten ferrous alloys, e.g. steel, not covered by groups C21C 1/00 to C21C 5/00 (treating molten metals during moulding B22D 1/00, B22D 27/00; remelting ferrous metals C22B)
Definition statement
This subclass/group covers:

Treatments of refining or alloying by means of the treatment agents, the form thereof, purpose or the circumstances.

Metallic, carbonaceous or exothermic treatment agents.

Loose or compacted agents or cored wires.

Treatments in a ladle, under pressure or in a current of streaming metal ;

special treatments of the slag.

References relevant to classification in this group
This subclass/group does not cover:
Treating molten metals during moulding
Remelting of ferrous alloys
Informative references
Attention is drawn to the following places, which may be of interest for search:
Making tubes by bending sheet
Cored wires for welding, soldering
Removing impurities by adding a treating agent
Informative references
Attention is drawn to the following places, which may be of interest for search:
Removal of impurities from pig iron other than carbon, sulfur or phosphor
Dephosphorising; Desulfurising
Definition statement
This subclass/group covers:

Including specifically disclosed agents for desulfurising and dephosphorising

Informative references
Attention is drawn to the following places, which may be of interest for search:
Removal of phosphor or sulfur from pig iron
Decarburising
Definition statement
This subclass/group covers:

Including stainless steels

Informative references
Attention is drawn to the following places, which may be of interest for search:
Control and regulation of blowing in a converter
Treatment with gases (C21C 7/06, C21C 7/064, C21C 7/068 take precedence)
Informative references
Attention is drawn to the following places, which may be of interest for search:
Refining metals by treating with gases
Use of slags or fluxes as treating agents (C21C 7/06, C21C 7/064, C21C 7/068 take precedence)
Informative references
Attention is drawn to the following places, which may be of interest for search:
Refining metals by treating with fluxes
Handling in a vacuum
Informative references
Attention is drawn to the following places, which may be of interest for search:
Refining of metals by applying a vacuum
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Last Modified: 10/11/2013