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Outline
Indent Level
Color Curly Brackets (indicating CPC extensions to IPC) References Date Revised

CPC
COOPERATIVE PATENT CLASSIFICATION
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MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS ; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS ; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHER TREATMENTS( cementation by diffusion processes C23C; surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F 17/00 ; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B )
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General methods or devices for heat treatments, e.g. annealing, hardening, quenching, tempering( furnaces in general F27 ; electric heating per se H05B )
C21D 1/02
.
Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
C21D 1/04
.
with simultaneous application of supersonic waves, magnetic or electric fields
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C21D 1/06
.
Surface hardening
C21D 1/08
. .
with flames
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C21D 1/09
. .
by direct application of electrical or wave energy ; by particle radiation
C21D 1/10
. . .
by electric induction
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C21D 1/18
.
Hardening( C21D 1/02 takes precedence ) ; Quenching with or without subsequent tempering( quenching devices C21D 1/62 )
C21D 1/185
. .
{
from an intercritical temperature
}
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C21D 1/19
. .
by interrupted quenching
C21D 1/20
. . .
Isothermal quenching, e.g. bainitic hardening
C21D 1/22
. . .
Martempering
C21D 1/25
. .
Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
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C21D 1/26
.
Methods of annealing
C21D 1/28
. .
Normalising
C21D 1/30
. .
Stress-relieving
C21D 1/32
. .
Soft annealing, e.g. spheroidising
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C21D 1/34
.
Methods of heating( C21D 1/06 takes precedence )
C21D 1/38
. .
Heating by cathodic discharges
C21D 1/40
. .
Direct resistance heating
C21D 1/42
. .
Induction heating
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C21D 1/44
. .
in heat-treatment baths
C21D 1/46
. . .
Salt baths
C21D 1/48
. . .
Metal baths
C21D 1/50
. . .
Oil baths
C21D 1/52
. .
with flames
C21D 1/53
. .
Heating in fluidised beds
C21D 1/54
.
Determining when the hardening temperature has been reached by measurement of magnetic or electrical properties
C21D 1/55
.
Hardenability tests, e.g. end-quench tests( investigating chemical or physical properties of materials in general G01N )
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C21D 1/56
.
characterised by the quenching agents
C21D 1/58
. .
Oils
C21D 1/60
. .
Aqueous agents
C21D 1/607
. .
Molten salts
C21D 1/613
. .
Gases ; Liquefied or solidified normally gaseous material
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C21D 1/62
.
Quenching devices
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C21D 1/63
. .
for bath quenching
C21D 1/64
. . .
with circulating liquids( in general F28D )
C21D 1/667
. .
for spray quenching
C21D 1/673
. .
for die quenching
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C21D 1/68
.
Temporary coatings or embedding materials applied before or during heat treatment
C21D 1/70
. .
while heating or quenching
C21D 1/72
. .
during chemical change of surfaces
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C21D 1/74
.
Methods of treatment in inert gas, controlled atmosphere, vacuum, or pulverulent material( production of gases C01 , C10 )
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C21D 1/76
. .
Adjusting the composition of the atmosphere
C21D 1/763
. . .
{
using a catalyst
}
C21D 1/767
. .
with forced gas circulation ; Reheating thereof
C21D 1/773
. .
under reduced pressure or vacuum
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C21D 1/78
.
Combined heat-treatments not provided for above
C21D 1/785
. .
{
Thermocycling
}
C21D 1/82
.
Descaling by thermal stresses( mechanically B21 , B23 ; chemically C23 ; electrolytically C25F )
C21D 1/84
.
Controlled slow cooling( cooling-beds for metal rolling B21B 43/00 )
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Diffusion processes for extraction of non-metals ; Furnaces therefor( local protective coatings C21D 1/72 ; furnaces in general F27 )
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C21D 3/02
.
Extraction of non-metals
C21D 3/04
. .
Decarburising
C21D 3/06
. .
Extraction of hydrogen
C21D 3/08
. .
Extraction of nitrogen
C21D 3/10
.
Furnaces therefor
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Heat treatments of cast-iron
C21D 5/02
.
improving the malleability of grey cast-iron
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C21D 5/04
.
of white cast-iron
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C21D 5/06
. .
Malleabilising
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C21D 5/08
. . .
with oxidation of carbon
C21D 5/10
. . . .
in gaseous agents
C21D 5/12
. . . .
in solid agents
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C21D 5/14
. . .
Graphitising
C21D 5/16
. . . .
Packing agents
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Heat treatment of ferrous alloys
C21D 6/001
.
{
containing Ni( C21D 6/004 takes precedence )
}
C21D 6/002
.
{
containing Cr( C21D 6/004 takes precedence )
}
C21D 6/004
.
{
containing Cr and Ni
}
C21D 6/005
.
{
containing Mn
}
C21D 6/007
.
{
containing Co
}
C21D 6/008
.
{
containing Si
}
C21D 6/02
.
Hardening by precipitation
C21D 6/04
.
Hardening by cooling below 0 degrees Celsius
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Modifying the physical properties of iron or steel by deformation( apparatus for mechanical working of metal B21 , B23 , B24 )
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C21D 7/02
.
by cold working
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C21D 7/04
. .
of the surface
C21D 7/06
. . .
by shot-peening or the like
C21D 7/08
. . .
by burnishing or the like
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C21D 7/10
. .
of the whole cross-section, e.g. of concrete reinforcing bars
C21D 7/105
. . .
{
of concrete reinforcing bars
}
C21D 7/12
. . .
by expanding tubular bodies
C21D 7/13
.
by hot working
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Modifying the physical properties by deformation combined with, or followed by, heat treatment( hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D 1/02 )
.
{
of ferrous alloys( C21D 8/02 to C21D 8/12 take precedence )
}
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C21D 8/02
.
during manufacturing of plates or strips( C21D 8/12 takes precedence )
NOTE
-
In this group classification is made according to the most important feature in one subgroup only; for other features indexing codes of M21D are added

C21D 8/0205
. .
{
of ferrous alloys
}
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C21D 8/021
. .
{
involving a particular fabrication or treatment of ingot or slab
}
C21D 8/0215
. . .
{
Rapid solidification; Thin strip casting
}
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C21D 8/0221
. .
{
characterised by the working steps
}
C21D 8/0226
. . .
{
Hot rolling
}
C21D 8/0231
. . .
{
Warm rolling
}
C21D 8/0236
. . .
{
Cold rolling
}
C21D 8/0242
. . .
{
Flattening; Dressing; Flexing
}
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C21D 8/0247
. .
{
characterised by the heat treatment
}
C21D 8/0252
. . .
{
with application of tension
}
C21D 8/0257
. . .
{
with diffusion of elements, e.g. decarburising, nitriding
}
C21D 8/0263
. . .
{
following hot rolling
}
C21D 8/0268
. . .
{
between cold rolling steps
}
C21D 8/0273
. . .
{
Final recrystallisation annealing
}
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C21D 8/0278
. .
{
involving a particular surface treatment( C21D 8/0294 takes precedence )
}
C21D 8/0284
. . .
{
Application of a separating or insulating coating
}
C21D 8/0289
. . .
{
Application of a tension-inducing coating
}
C21D 8/0294
. .
{
involving a localised treatment
}
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. .
to produce plates or strips for deep-drawing
NOTE
-
In this group classification is made according to the most important feature in one subgroup only; for other features indexing codes of M21D are added

C21D 8/0405
. . .
{
of ferrous alloys
}
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C21D 8/041
. . .
{
involving a particular fabrication or treatment of ingot or slab
}
C21D 8/0415
. . . .
{
Rapid solidification; Thin strip casting
}
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C21D 8/0421
. . .
{
characterised by the working steps
}
C21D 8/0426
. . . .
{
Hot rolling
}
C21D 8/0431
. . . .
{
Warm rolling
}
C21D 8/0436
. . . .
{
Cold rolling
}
C21D 8/0442
. . . .
{
Flattening; Dressing; Flexing
}
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C21D 8/0447
. . .
{
characterised by the heat treatment
}
C21D 8/0452
. . . .
{
with application of tension
}
C21D 8/0457
. . . .
{
with diffusion of elements, e.g. decarburising, nitriding
}
C21D 8/0463
. . . .
{
following hot rolling
}
C21D 8/0468
. . . .
{
between cold rolling steps
}
C21D 8/0473
. . . .
{
Final recrystallisation annealing
}
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C21D 8/0478
. . .
{
involving a particular surface treatment( C21D 8/0494 takes precedence )
}
C21D 8/0484
. . . .
{
Application of a separating or insulating coating
}
C21D 8/0489
. . . .
{
Application of a tension-inducing coating
}
C21D 8/0494
. . .
{
involving a localised treatment
}
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.
during manufacturing of rods or wires
C21D 8/065
. .
{
of ferrous alloys
}
C21D 8/08
. .
for concrete reinforcement
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.
during manufacturing of tubular bodies
C21D 8/105
. .
{
of ferrous alloys
}
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.
during manufacturing of articles with special electromagnetic properties
NOTE
-
In this group classification is made according to the most important feature in one subgroup only; for other features indexing codes of M21D are added

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C21D 8/1205
. .
{
involving a particular fabrication or treatment of ingot or slab
}
C21D 8/1211
. . .
{
Rapid solidification; Thin strip casting
}
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C21D 8/1216
. .
{
the working step(s) being of interest
}
C21D 8/1222
. . .
{
Hot rolling
}
C21D 8/1227
. . .
{
Warm rolling
}
C21D 8/1233
. . .
{
Cold rolling
}
C21D 8/1238
. . .
{
Flattening; Dressing; Flexing
}
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C21D 8/1244
. .
{
the heat treatment(s) being of interest
}
C21D 8/125
. . .
{
with application of tension
}
C21D 8/1255
. . .
{
with diffusion of elements, e.g. decarburising, nitriding
}
C21D 8/1261
. . .
{
following hot rolling
}
C21D 8/1266
. . .
{
between cold rolling steps
}
C21D 8/1272
. . .
{
Final recrystallisation annealing
}
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C21D 8/1277
. .
{
involving a particular surface treatment( C21D 8/1294 takes precedence )
}
C21D 8/1283
. . .
{
Application of a separating or insulating coating
}
C21D 8/1288
. . .
{
Application of a tension-inducing coating
}
C21D 8/1294
. .
{
involving a localized treatment
}
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Heat treatment, e.g. annealing, hardening, quenching, tempering, adapted for particular articles ; Furnaces therefor( furnaces in general F27 )
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C21D 9/0006
.
{
Details, accessories not peculiar to any of the following furnaces( control devices C21D 11/00 )
}
C21D 9/0012
. .
{
Rolls; Roll arrangements
}
C21D 9/0018
. .
{
for charging, discharging or manipulation of charge
}
C21D 9/0025
. .
{
Supports; Baskets; Containers; Covers
}
C21D 9/0031
.
{
Rotary furnaces with horizontal or slightly inclined axis
}
C21D 9/0037
.
{
Rotary furnaces with vertical axis; Furnaces with rotating floor
}
C21D 9/0043
.
{
Muffle furnaces; Retort furnaces
}
C21D 9/005
.
{
Furnaces in which the charge is moving up or down( for wire, strip C21D 9/54 )
}
C21D 9/0056
.
{
Furnaces through which the charge is moved in a horizontal straight path( C21D 9/0043 takes precedence )
}
C21D 9/0062
.
{
Heat-treating apparatus with a cooling or quenching zone
}
C21D 9/0068
.
{
for particular articles not mentioned below
}
C21D 9/0075
.
{
for rods of limited length( of unlimited length C21D 9/52 )
}
C21D 9/0081
.
{
for slabs; for billets
}
C21D 9/0087
.
{
for chains, for chain links
}
C21D 9/0093
.
{
for screws; for bolts
}
C21D 9/02
.
for springs
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C21D 9/04
.
for rails( apparatus for heat treatment of railway rails on the spot E01B 31/18 )
C21D 9/06
. .
with diminished tendency to become wavy
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C21D 9/08
.
for tubular bodies or pipes
C21D 9/085
. .
{
Cooling or quenching
}
C21D 9/10
. .
shotgun barrels
C21D 9/12
. .
barrels for ordnance
C21D 9/14
. .
wear- or pressure-resistant pipes
C21D 9/16
.
for explosive shells
C21D 9/18
.
for knives, scythes, scissors, or like hand cutting tools
C21D 9/20
.
for blades for skates
C21D 9/22
.
for drills ; for milling cutters ; for machine cutting tools
C21D 9/24
.
for saw blades
C21D 9/26
.
for needles ; for teeth for card-clothing
C21D 9/28
.
for plain shafts
C21D 9/30
.
for crankshafts ; for camshafts
C21D 9/32
.
for gear wheels, worm wheels, or the like
C21D 9/34
.
for tyres ; for rims
C21D 9/36
.
for balls ; for rollers
C21D 9/38
.
for roll bodies
C21D 9/40
.
for rings ; for bearing races
C21D 9/42
.
for armour plate
C21D 9/44
.
for equipment for lining mine shafts, e.g. segments, rings, props
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C21D 9/46
.
for sheet metals
C21D 9/48
. .
deep-drawing sheets
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C21D 9/50
.
for welded joints
C21D 9/505
. .
{
Cooling thereof
}
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C21D 9/52
.
for wires ; for strips;
{
for rods of unlimited length
}
C21D 9/525
. .
{
for wire, for rods( C21D 9/54 takes precedence )
}
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C21D 9/54
. .
Furnaces for treating strips or wire
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C21D 9/56
. . .
Continuous furnaces for strip or wire
C21D 9/561
. . . .
{
with a controlled atmosphere or vacuum
}
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C21D 9/562
. . . .
{
Details
}
C21D 9/563
. . . . .
{
Rolls; Drums; Roll arrangements
}
C21D 9/564
. . . . .
{
Tension control
}
C21D 9/565
. . . . .
{
Sealing arrangements
}
C21D 9/567
. . . .
with heating in fluidised beds
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C21D 9/573
. . . .
with cooling
C21D 9/5732
. . . . .
{
of wires; of rods
}
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C21D 9/5735
. . . . .
{
Details
}
C21D 9/5737
. . . . . .
{
Rolls; Drums; Roll arrangements
}
C21D 9/58
. . . .
with heating by baths
C21D 9/60
. . . .
with induction heating
C21D 9/62
. . . .
with direct resistance heating
C21D 9/63
. . . .
the strip being supported by a cushion of gas
C21D 9/64
. . .
Patenting furnaces
C21D 9/66
. . .
Tower-type furnaces
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C21D 9/663
. . .
Bell-type furnaces
C21D 9/665
. . . .
inverted or side-facing
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C21D 9/667
. . . .
Multi-station furnaces
C21D 9/67
. . . . .
adapted for treating the charge in vacuum or special atmosphere
C21D 9/673
. . . .
Details, accessories, or equipment peculiar to bell-type furnaces
C21D 9/675
. . . .
Arrangements of charging or discharging devices
C21D 9/677
. . . .
Arrangements of heating devices
C21D 9/68
. . .
Furnace coilers ; hot coilers( cold coilers B21C )
C21D 9/70
.
Furnaces for ingots, i.e. soaking pits
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Modifying the physical properties by methods other than heat treatment or deformation
C21D 10/005
.
{
by laser shock processing
}
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Process control or regulation for heat treatments( controlling or regulating in general G05 )
C21D 11/005
.
{
for cooling
}
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C21D 2201/00
Treatment for obtaining particular effects
C21D 2201/01
.
Shape memory effect
C21D 2201/02
.
Superplasticity
C21D 2201/03
.
Amorphous or microcrystalline structure
C21D 2201/04
.
Single or very large crystals
C21D 2201/05
.
Grain orientation
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C21D 2211/00
Microstructure comprising significant phases
C21D 2211/001
.
Austenite
C21D 2211/002
.
Bainite
C21D 2211/003
.
Cementite
C21D 2211/004
.
Dispersions ; Precipitations
C21D 2211/005
.
Ferrite
C21D 2211/006
.
Graphite
C21D 2211/007
.
Ledeburite
C21D 2211/008
.
Martensite
C21D 2211/009
.
Pearlite
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C21D 2221/00
Treating localised areas of an article
C21D 2221/01
.
End parts( e.g. leading, trailing end )
C21D 2221/02
.
Edge parts
C21D 2221/10
.
Differential treatment of inner with respect to outer regions, e.g. core and periphery, respectively
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C21D 2241/00
Treatments in a special environment
Collapse
C21D 2241/01
.
under pressure
C21D 2241/02
. .
Hot isostatic pressing
C21D 2241/03
.
in zero gravity( e.g. in spce )
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C21D 2251/00
Treating composite or clad material
C21D 2251/02
.
Clad material
C21D 2251/04
.
Welded or brazed overlays
C21D 2261/00
Machining or cutting being involved
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C21D 2281/00
Making use of special physico-chemical means
C21D 2281/01
.
Seed crystals being used
C21D 2281/02
.
temperature gradient
This page is owned by Office of Patent Classification.
Last Modified: 10/10/2013