Classifications

• • C—CHEMISTRY; 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, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
• • C—CHEMISTRY; 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, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/62—Quenching devices
• • C—CHEMISTRY; 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, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/18—Hardening; Quenching with or without subsequent tempering
  • C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
  • C21D1/20—Isothermal quenching, e.g. bainitic hardening
• • C—CHEMISTRY; 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, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents

Definitions

• the invention relates to a method for the heat treatment of workpieces, in which the workpieces coming from a heating system are cooled.
• the workpieces are often cooled in an oil bath or salt bath, after which it is necessary to clean the workpieces after removal from the bath. This requires a lot of work.
• oil- or salt-containing wastewater is produced, which pollutes the environment and has to be partially landfilled.
• the invention has for its object to provide a heat treatment process that works much more environmentally friendly with less work and energy requirements.
• the method according to the invention is characterized in that the workpieces are used for cooling in a fluidized bed which is generated by at least one gas stream guided in a main flow direction, a fluidized bed medium being used which has a higher thermal conductivity than the material of the workpieces to be cooled, that the workpieces are moved during cooling relative to the gas stream generating the fluidized bed, while individual pulse-like gas jets are substantially perpendicular to the main direction of flow of the gas stream into the fluidized bed be initiated; and that the fluidized bed is kept at a substantially constant temperature in the fluidized bed during the treatment period of the workpieces.
• the gas flow conducted in the main flow direction usually consists of several substantially parallel partial flows which together produce the fluidized bed (also called “fluidized bed” or “fluidized bed”).
• the workpieces do not require any cleaning treatment after removal from the fluidized bed. This eliminates the disadvantages mentioned above with regard to energy consumption and environmental pollution. The discharge losses from the fluidized bed are also minimal.
• the operating parameters of the fluidized bed are selected so that cooling conditions result which even allow the processing of relatively large workpieces with complicated surfaces. Keeping the temperature constant ensures that the heat transfer conditions remain constant, with a sufficiently rapid heat transfer being promoted by the fact that the thermal conductivity of the fluidized bed medium is higher than that of the material to be cooled.
• the fluidized bed medium preferably consists of particles of metallic or non-metallic-inorganic character; Examples of this are aluminum alloys or carbides, insofar as they have a higher thermal conductivity than the generally metallic material of the workpieces to be treated.
• the invention ensures that a constant exchange of particles takes place on the workpiece surfaces also in the "slipstream zones", not only through the pulsed individual beams, but also through the movement of the workpieces. It can be vibration or long stroke movements.
• the direction of movement is not critical, however, if the movements are in the direction of flow, they must be faster than the gas flow.
• the method according to the invention is particularly well suited for the intermediate stage compensation of workpieces. So far, especially when using oil baths, special care had to be taken when cleaning the workpieces, since otherwise there was a risk that oil residues in the downstream holding furnace, in which the structural change takes place, would evaporate or burn and lead to uncontrollable pollutant emissions. This risk does not exist with the invention.
• the cooling conditions in the fluidized bed can be optimally adapted to the subsequent treatment in the microstructure conversion system.
• moisture preferably as water vapor
• This allows a higher heat transfer coefficient to be set. If necessary, this can shorten the residence time of the workpieces in the fluidized bed.
• the supply of moisture as water vapor ensures that no lumps form in the fluidized bed medium.
• the fluidized bed medium preferably has a constant radiation number over a wide temperature range, for example of about 600 ° C. This ensures rapid temperature compensation within the fluidized bed.
• a gas which generates the fluidized bed and has the same electrical charge sign as the particles of the fluidized bed medium. This avoids electrostatic charges, which may lead to the fluidized bed particles sticking together.
• the fluidized bed medium is regenerated during loading and unloading of the workpieces.
• the particle size of the fluidized bed medium can be kept constant and, if necessary, the particles can also be cooled. Since the regeneration takes place during loading and unloading of the fluidized bed, disturbances in the cooling process are avoided.
• the workpieces are preferably only cooled below the intended holding temperature to such an extent that the holding temperature is reached after removal from the fluidized bed by the heat flow from the core into the edge zones of the workpieces.
• the an Closing structural transformation system therefore, no heat supply to the workpieces is required. The latter was unavoidable with the well-known bath cooling system, because precise control was prohibited because of the steep temperature gradient, and therefore, due to caution, the workpieces were forced to undercool more.
• a particularly favorable use of energy results when the method according to the invention is applied to the intermediate stage tempering in that the heat emerging from the fluidized bed with the gas stream is used to heat the structural transformation system.
• the transport time of the workpieces from the heating system to the fluidized bed is dimensioned as a function of the radiation behavior of the workpieces.
• the workpieces then always enter the fluidized bed at the same temperature.
• the temperature differences within a batch or between individual workpiece sections can also be controlled.
• the process according to the invention can be carried out batchwise, that is to say in individual batches, or continuously, for example in continuous operation.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Crucibles And Fluidized-Bed Furnaces (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)
• Heat Treatment Of Articles (AREA)
• Furnace Details (AREA)
• Manufacturing Of Magnetic Record Carriers (AREA)
• Crystals, And After-Treatments Of Crystals (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6171029

Family Applications (1)

Country Status (10)

Cited By (3)

Families Citing this family (3)

Citations (7)

Family Cites Families (9)

• 1982
  • 1982-08-17 DE DE19823230531 patent/DE3230531A1/de not_active Withdrawn
• 1983
  • 1983-07-26 DE DE8383107322T patent/DE3366291D1/de not_active Expired
  • 1983-07-26 EP EP83107322A patent/EP0103705B1/fr not_active Expired
  • 1983-07-26 AT AT83107322T patent/ATE22329T1/de not_active IP Right Cessation
  • 1983-08-11 ZA ZA835890A patent/ZA835890B/xx unknown
  • 1983-08-15 JP JP58149098A patent/JPS5947322A/ja active Pending
  • 1983-08-15 DD DD83253963A patent/DD208993A5/de unknown
  • 1983-08-16 BR BR8304420A patent/BR8304420A/pt unknown
  • 1983-08-17 IN IN1013/CAL/83A patent/IN159134B/en unknown
  • 1983-08-17 KR KR1019830003840A patent/KR840005746A/ko not_active Application Discontinuation
• 1985
  • 1985-06-14 US US06/744,656 patent/US4612065A/en not_active Expired - Fee Related

Patent Citations (7)

Non-Patent Citations (2)

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