C
CHEMISTRY; METALLURGY

Note(s) [2009.01]

  • In section C, the definitions of groups of chemical elements are as follows:
    • Alkali metals: Li, Na, K, Rb, Cs, Fr
    • Alkaline earth metals: Ca, Sr, Ba, Ra
    • Lanthanides: elements with atomic numbers 57 to 71 inclusive
    • Rare earths: Sc, Y, Lanthanides
    • Actinides: elements with atomic numbers 89 to 103 inclusive
    • Refractory metals: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W
    • Halogens: F, Cl, Br, I, At
    • Noble gases: He, Ne, Ar, Kr, Xe, Rn
    • Platinum group: Os, Ir, Pt, Ru, Rh, Pd
    • Noble metals: Ag, Au, Platinum group
    • Light metals: alkali metals, alkaline earth metals, Be, Al, Mg
    • Heavy metals: metals other than light metals
    • Iron group: Fe, Co, Ni
    • Non-metals: H, B, C, Si, N, P, O, S, Se, Te, noble gases, halogens
    • Metals: elements other than non-metals
    • Transition elements: elements with atomic numbers 21 to 30 inclusive, 39 to 48 inclusive, 57 to 80 inclusive, 89 upwards
  • Section C covers :
    • pure chemistry, which covers inorganic compounds, organic compounds, macromolecular compounds, and their methods of preparation;
    • applied chemistry, which covers compositions containing the above compounds, such as: glass, ceramics, fertilisers, plastics compositions, paints, products of the petroleum industry. It also covers certain compositions on account of their having particular properties rendering them suitable for certain purposes, as in the case of explosives, dyestuffs, adhesives, lubricants, and detergents;
    • certain marginal industries, such as the manufacture of coke and of solid or gaseous fuels, the production and refining of oils, fats and waxes, the fermentation industry (e.g., brewing and wine-making), the sugar industry;
    • certain operations or treatments, which are either purely mechanical, e.g., the mechanical treatment of leather and skins, or partly mechanical, e.g., the treatment of water or the prevention of corrosion in general;
    • metallurgy, ferrous or non-ferrous alloys.
  • In all sections of the IPC, in the absence of an indication to the contrary, the Periodic System of chemical elements referred to is the one with 18 groups as represented in the table below.
    • fig401
    • In the case of operations, treatments, products or articles having both a chemical and a non-chemical part or aspect, the general rule is that the chemical part or aspect is covered by section C.
    • In some of these cases, the chemical part or aspect brings with it a non-chemical one, even though purely mechanical, because this latter aspect either is essential to the operation or treatment or constitutes an important element thereof. It has seemed, in fact, more logical not to dissociate the different parts or aspects of a coherent whole. This is the case for applied chemistry and for the industries, operations and treatments mentioned in Notes (1)(c), (d) and (e). For example, furnaces peculiar to the manufacture of glass are covered by class C03 and not by class F27.
    • There are, however, some exceptions in which the mechanical (or non-chemical) aspect carries with it the chemical aspect, for example:
      • Certain extractive processes, in subclass A61K;
      • The chemical purification of air, in subclass A61L;
      • Chemical methods of fire-fighting, in subclass A62D;
      • Chemical processes and apparatus, in class B01;
      • Impregnation of wood, in subclass B27K;
      • Chemical methods of analysis or testing, in subclass G01N;
      • Photographic materials and processes, in class G03, and, generally, the chemical treatment of textiles and the production of cellulose or paper, in section D.
    • In still other cases, the pure chemical aspect is covered by section C and the applied chemical aspect by another section, such as A, B or F, e.g., the use of a substance or composition for:
      • treatment of plants or animals, covered by subclass A01N;
      • foodstuffs, covered by class A23;
      • ammunition or explosives, covered by class F42.
    • When the chemical and mechanical aspects are so closely interlocked that a neat and simple division is not possible, or when certain mechanical processes follow as a natural or logical continuation of a chemical treatment, section C may cover, in addition to the chemical aspect, a part only of the mechanical aspect, e.g., after-treatment of artificial stone, covered by class C04. In this latter case, a note or a reference is usually given to make the position clear, even if sometimes the division is rather arbitrary.
METALLURGY
C21
METALLURGY OF IRON
C21D
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)

Note(s) [2012.01]

  • Cementation by diffusion processes is classified in C23C.
  • Surface treatments of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass are classified in group C23F 17/00.
Subclass index
HEAT TREATMENT
General methods or devices 1/00, 11/00
of cast-iron, of iron alloys 5/00, 6/00
adapted for particular articles 9/00
MECHANICAL TREATMENT 7/00
COMBINED MECHANICAL AND THERMAL TREATMENTS 8/00
OTHER TREATMENTS 10/00
DIFFUSION PROCESSES FOR EXTRACTION OF NON-METALS 3/00
C21D 1/00
General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering [2006.01]
C21D 1/02
Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation [2006.01]
C21D 1/04
with simultaneous application of supersonic waves, magnetic or electric fields [2006.01]
C21D 1/06
C21D 1/08
with flames [2006.01]
C21D 1/09
by direct application of electrical or wave energy; by particle radiation [2006.01]
C21D 1/10
by electric induction [2006.01]
C21D 1/18
Hardening (C21D 1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D 1/62) [2006.01]
C21D 1/19
by interrupted quenching [2006.01]
C21D 1/20
Isothermal quenching, e.g. bainitic hardening [2006.01]
C21D 1/22
C21D 1/25
Hardening, combined with annealing between 300 °C and 600 °C, i.e. heat refining ("Vergüten") [2006.01]
C21D 1/26
Methods of annealing [2006.01]
C21D 1/28
Normalising [2006.01]
C21D 1/30
Stress-relieving [2006.01]
C21D 1/32
Soft annealing, e.g. spheroidising [2006.01]
C21D 1/34
Methods of heating (C21D 1/06 takes precedence) [2006.01]
C21D 1/38
Heating by cathodic discharges [2006.01]
C21D 1/40
Direct resistance heating [2006.01]
C21D 1/42
Induction heating [2006.01]
C21D 1/44
in heat-treatment baths [2006.01]
C21D 1/46
Salt baths [2006.01]
C21D 1/48
Metal baths [2006.01]
C21D 1/50
Oil baths [2006.01]
C21D 1/52
with flames [2006.01]
C21D 1/53
Heating in fluidised beds [2006.01]
C21D 1/54
Determining when the hardening temperature has been reached by measurement of magnetic or electrical properties [2006.01]
C21D 1/55
Hardenability tests, e.g. end-quench tests [2006.01]
C21D 1/56
characterised by the quenching agents [2006.01]
C21D 1/58
C21D 1/60
Aqueous agents [2006.01]
C21D 1/607
Molten salts [2006.01]
C21D 1/613
Gases; Liquefied or solidified normally gaseous material [2006.01]
C21D 1/62
C21D 1/63
C21D 1/64
with circulating liquids [2006.01]
C21D 1/667
C21D 1/673
C21D 1/68
Temporary coatings or embedding materials applied before or during heat treatment [2006.01]
C21D 1/70
while heating or quenching [2006.01]
C21D 1/72
during chemical change of surfaces [2006.01]
C21D 1/74
Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material [2006.01]
C21D 1/76
Adjusting the composition of the atmosphere [2006.01]
C21D 1/767
with forced gas circulation; Reheating thereof [2006.01]
C21D 1/773
under reduced pressure or vacuum [2006.01]
C21D 1/78
Combined heat-treatments not provided for above [2006.01]
C21D 1/82
Descaling by thermal stresses (mechanically B21, B23; chemically C23; electrolytically C25F 1/00) [2006.01]
C21D 1/84
Controlled slow cooling (cooling-beds for metal rolling B21B 43/00) [2006.01]
C21D 3/00
Diffusion processes for extraction of non-metals; Furnaces therefor (local protective coatings C21D 1/72) [2006.01]
C21D 3/02
Extraction of non-metals [2006.01]
C21D 3/04
Decarburising [2006.01]
C21D 3/06
Extraction of hydrogen [2006.01]
C21D 3/08
Extraction of nitrogen [2006.01]
C21D 3/10
Furnaces therefor [2006.01]
C21D 5/00
Heat treatment of cast-iron [2006.01]
C21D 5/02
improving the malleability of grey cast-iron [2006.01]
C21D 5/04
C21D 5/06
Malleabilising [2006.01]
C21D 5/08
with oxidation of carbon [2006.01]
C21D 5/10
in gaseous agents [2006.01]
C21D 5/12
in solid agents [2006.01]
C21D 5/14
Graphitising [2006.01]
C21D 5/16
Packing agents [2006.01]
C21D 6/00
Heat treatment of ferrous alloys [2006.01]

Note(s) [2006.01]

  • When classifying in group C21D 6/00, any aspect of the method for the heat treatment of ferrous alloys which is considered to represent information of interest for search may also be classified in groups C21D 1/02-C21D 1/84. This can, for example, be the case when it is considered of interest to enable searching of heat treatment methods of ferrous alloys using a combination of classification symbols. Such non-obligatory classification should be given as "additional information".
  • When classifying in group C21D 6/00, any alloying constituent which is considered to represent information of interest for search may also be classified in groups C22C 38/02-C22C 38/60. This can, for example, be the case when it is considered of interest to enable searching of heat treatment of specific ferrous alloys using a combination of classification symbols. Such non-obligatory classification should be given as "additional information".
C21D 6/02
Hardening by precipitation [2006.01]
C21D 6/04
Hardening by cooling below 0° C [2006.01]
C21D 7/00
Modifying the physical properties of iron or steel by deformation (apparatus for mechanical working of metal B21, B23, B24) [2006.01]
C21D 7/02
by cold working [2006.01]
C21D 7/04
of the surface [2006.01]
C21D 7/06
by shot-peening or the like [2006.01]
C21D 7/08
by burnishing or the like [2006.01]
C21D 7/10
of the whole cross-section, e.g. of concrete reinforcing bars [2006.01]
C21D 7/12
by expanding tubular bodies [2006.01]
C21D 7/13
by hot working [2006.01]
C21D 8/00
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) [2006.01]
C21D 8/02
during manufacturing of plates or strips (C21D 8/12 takes precedence) [2006.01]
C21D 8/04
to produce plates or strips for deep-drawing [2006.01]
C21D 8/06
during manufacturing of rods or wires [2006.01]
C21D 8/08
for concrete reinforcement [2006.01]
C21D 8/10
during manufacturing of tubular bodies [2006.01]
C21D 8/12
during manufacturing of articles with special electromagnetic properties [2006.01]
C21D 9/00
Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor [2006.01]
C21D 9/02
for springs [2006.01]
C21D 9/04
for rails [2006.01]
C21D 9/06
with diminished tendency to become wavy [2006.01]
C21D 9/08
for tubular bodies or pipes [2006.01]
C21D 9/10
shotgun barrels [2006.01]
C21D 9/12
barrels for ordnance [2006.01]
C21D 9/14
wear-resistant or pressure-resistant pipes [2006.01]
C21D 9/16
for explosive shells [2006.01]
C21D 9/18
for knives, scythes, scissors, or like hand cutting tools [2006.01]
C21D 9/20
for blades for skates [2006.01]
C21D 9/22
for drills; for milling cutters; for machine cutting tools [2006.01]
C21D 9/24
for saw blades [2006.01]
C21D 9/26
for needles; for teeth for card-clothing [2006.01]
C21D 9/28
for plain shafts [2006.01]
C21D 9/30
for crankshafts; for camshafts [2006.01]
C21D 9/32
for gear wheels, worm wheels, or the like [2006.01]
C21D 9/34
for tyres; for rims [2006.01]
C21D 9/36
for balls; for rollers [2006.01]
C21D 9/38
for roll bodies [2006.01]
C21D 9/40
for rings; for bearing races [2006.01]
C21D 9/42
for armour plate [2006.01]
C21D 9/44
for equipment for lining mine shafts, e.g. segments, rings or props [2006.01]
C21D 9/46
for sheet metals [2006.01]
C21D 9/48
deep-drawing sheets [2006.01]
C21D 9/50
for welded joints [2006.01]
C21D 9/52
for wires; for strips [2006.01]
C21D 9/54
Furnaces for treating strips or wire [2006.01]
C21D 9/56
Continuous furnaces for strip or wire [2006.01]
C21D 9/567
with heating in fluidised beds [2006.01]
C21D 9/573
with cooling [2006.01]
C21D 9/58
with heating by baths [2006.01]
C21D 9/60
with induction heating [2006.01]
C21D 9/62
with direct resistance heating [2006.01]
C21D 9/63
the strip being supported by a cushion of gas [2006.01]
C21D 9/64
Patenting furnaces [2006.01]
C21D 9/66
Tower-type furnaces [2006.01]
C21D 9/663
Bell-type furnaces [2006.01]
C21D 9/665
inverted or side-facing [2006.01]
C21D 9/667
Multi-station furnaces [2006.01]
C21D 9/67
adapted for treating the charge in vacuum or special atmosphere [2006.01]
C21D 9/673
Details, accessories, or equipment peculiar to bell-type furnaces [2006.01]
C21D 9/675
Arrangements of charging or discharging devices [2006.01]
C21D 9/677
Arrangements of heating devices [2006.01]
C21D 9/68
Furnace coilers; Hot coilers (cold coilers B21C 47/00) [2006.01]
C21D 9/70
Furnaces for ingots, i.e. soaking pits [2006.01]
C21D 10/00
Modifying the physical properties by methods other than heat treatment or deformation [2006.01]
C21D 11/00
Process control or regulation for heat treatments [2006.01]