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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