Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
  • B21B45/0269—Cleaning
  • B21B45/0275—Cleaning devices
  • B21B45/0278—Cleaning devices removing liquids
  • B21B45/0284—Cleaning devices removing liquids removing lubricants

Definitions

• the present invention relates to the degreasing of a cold rolled metal strip.
• the degreasing is carried out at the same time as the heating of the strip by a chemical effect of the fumes at high temperature and resulting from a sub-stoichiometric combustion, on the oil layer of the strip.
• This chemical effect results in rapid evaporation of the oil layer covering the strip, and its decomposition in the gas phase, into simple hydro-carbides, therefore comparable to those contained in the fuels used for heating the strip.
• This decomposition is facilitated by the presence of water vapor in the fumes.
• the final balance of the fumes is very close to that which normally results from combustion without the presence of oil on the tape.
• degreasing by chemical effect of fumes at high temperature can only be applied in its entirety in ovens heated with gas or using a light liquid fuel, such as kerosene or domestic heating oil.
• the present invention proposes to provide such a process.
• the process according to the invention is essentially characterized in that the heating and degreasing actions are separate: the heating being carried out in an enclosure provided with electrical means for supplying heat (for example resistors, infrared lamps, heating devices by induction, by conduction or others), and degreasing being obtained by the effect of an appropriate atmosphere in the heating enclosure.
• heat for example resistors, infrared lamps, heating devices by induction, by conduction or others
• the strip to be degreased is brought to the temperature generally necessary for carrying out the degreasing by smoke effect, that is to say from 450 to 600 ° C.
• the atmosphere of the heating enclosure is constituted, according to the invention, by fumes from the combustion of a gaseous fuel, produced outside or inside the enclosure, but whose essential purpose is not to participate in the heating of the band.
• sub-stoichiometric combustion is used, pre-mixed or not, with a rate of im burned between 0, 5 and 10%.
• the gas thus produced has, for an oven or an enclosure of medium industrial size, a flow rate of between 100 and 500 Nm 3 / hour, which represents approximately 5% of the flow rates practiced in gas-heated ovens.
• Unteldébit allows both to renew the gas responsible for eliminating the evaporated oil, and to maintain the furnace pressure at a value higher than the ambient pressure. Furthermore, such a flow rate makes it possible to maintain the oven at a certain temperature during its periods of shutdown.
• the temperature of the heating chamber does not exceed 1000 ° C., a temperature which, combined with that of the strip, allows rapid evaporation of the oil without causing an undesirable band oxidation effect, an effect which, in a gas-heated oven, occurs in a temperature range between 1000 and 1200 ° C.
• the fumes discharged from the heating enclosure can undergo a treatment with a view to burning the unburnt resulting from the sub-stoichiometric combustion and the evaporation of the oil.
• the fumes thus treated can, after burning, be used again to preheat air, which will subsequently be used during combustion, to produce the atmospheric gas of the heating and degreasing enclosure.
• the heating enclosure can be produced so as to obtain a small distance between the heating elements (or the walls of the enclosure) and the strip to be degreased.
• the aim of this short distance is to eliminate. both the absorption of the radiation by the fumes constituting the atmosphere of the furnace, and which include water vapor and carbon dioxide, and to favor the renewal of this atmosphere gas at the level of the strip by an effect convective resulting from a rapid flow.
• the oil heating and evaporation enclosure is preferably constituted in the form of a narrow chamber ensuring rapid passage and renewal of the atmospheric gas at the level of the bandaged.
• the method according to the invention applies particularly to all types of annealing ovens in which the electro-chemical degreasing of the strip can be replaced by a degreasing by flame, for example: annealing oven before galvanizing, before tinning, continuous annealing of black sheets, etc.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=9259773

Family Applications (1)

Country Status (5)

Cited By (6)

Citations (4)

Family Cites Families (1)

• 1981
  • 1981-06-23 FR FR8112289A patent/FR2508064B1/fr not_active Expired
• 1982
  • 1982-06-22 AT AT82401144T patent/ATE23369T1/de not_active IP Right Cessation
  • 1982-06-22 CA CA000405718A patent/CA1191434A/fr not_active Expired
  • 1982-06-22 EP EP82401144A patent/EP0069009B1/de not_active Expired
  • 1982-06-22 DE DE8282401144T patent/DE3274121D1/de not_active Expired

Patent Citations (4)

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