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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 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 does not cover:

Ferrous alloy compositions

Cast iron alloys

Dephosphorising or desulfurising
Definition statement
This subgroup 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 C21C 7/00 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 subgroup covers:

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

References relevant to classification in this group
This subgroup 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 subgroup 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 carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel {or stainless steel}
Definition statement
This 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 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 {(C21C 5/005 takes precedence)}
Definition statement
This subgroup covers:

Also the full plant lay-out.

Regulating or controlling the blowing
Definition statement
This subgroup 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 subgroup covers:

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

References relevant to classification in this group
This subgroup does not cover:

Lance details

Blowing through the bath (C21C 5/35 takes precedence)
Definition statement
This subgroup 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 subgroup does not cover:

Tuyere details

Removal of waste gases or dust
Definition statement
This subgroup 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 subgroup 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 subgroup 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 subgroup 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 subgroup 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 ({C21C 5/005 takes precedence}; electric heating per se H05B)
Definition statement
This subgroup 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){(C21C 5/005 takes precedence)}
Definition statement
This subgroup 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 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 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 subgroup 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 subgroup 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