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
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
• • 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
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/0037—Rotary furnaces with vertical axis; Furnaces with rotating floor

Definitions

• the present invention relates to a method of heat treatment, especially case-hardening, of articles with varying requirements as to heat treatment time.
• the invention also relates to a heat treatment instal- lation particularly suited to carrying out said method,
• continuous case hardening up to now pusher type installations have been used, in which the articles to be hardened are placed on metal skidding pallets, which are inserted through a feed-in opening at one end of the heat treatment furnace, and after heat treatment has been completed, are taken out through an exit opening at the opposite end of the furnace.
• the articles are heated to the heat treatment temperature and kept at this temperature as long as is required to achieve the desired carbonization depth.
• the method is based on the principle: first in - first out, and presupposes that all the articles inserted at the same time into the furnace are to have the same carbonization depth and therefore the same heat treatment time. If the assortment of articles in the heat treatment installa ⁇ tion contains articles requiring different carboniza ⁇ tion depths, which is often the case, these cannot be mixed in the furnace, since those articles requiring a short heat treatment time cannot be taken out before those requiring a longer treatment time. The result will be low utilization of capacity, when a few articles are to have a long heat treatment time and the available furnace space cannot at the same time be used for articles requiring a shorter treatment time.
• the purpose of the present invention is to achieve a method which makes it possible to better utilize available capacity by making it possible to treat at the same time articles which are to have differing carbonization depths.
• An installation particularly suited to carrying out the method according to the invention comprises a ring furnace known per se with a rotatable carrier for the articles and is characterized in that the discharge opening from a separate heating-up furnace is connected directly to the input opening of the ring furnace.
• all the articles are heated in the heating-up furnace to the heat treatment temperature of the heat treatment furnace.
• the articles to be heat-treated for 1.5 hours can be inserted into the heat treatment furnace after the articles to be treated for 3.5 hours, and be taken out before these, without requiring a change in the temperature or atmosphere of the heat treatment furnace.
• a ring furnace this can be done quite simply.
• Each article is time-monitored, preferably via a computer system, and is advanced to the exit point from the ring furnace after heat treatment has been completed.
• 1 designates a feeding station for articles to be case-hardened.
• the articles are placed on metal skidding pallets 2, on which the artic ⁇ les are then transported through the installation.
• the pallets are transferred to a conveyor 4 and are conveyed thereon through a washing station 5 and back to the conveyor 3 via a conveyor 6, and from there to a conveyor 7, by means of which the skidding pallets 2 are fed into the heat treatment furnace 8.
• the pallets are advanced to a heating up furnace 9, in which the articles are heated up to their heat treatment temperature, e.g. ca 900°C.
• the heating-up furnace 9 is attached directly to a ring furnace 10, in which the pallets after heat ⁇ ing of the articles are placed on a turn-table (as is indicated by the arrows in the figure). Regardless of the order in which the pallets are fed into the furnace 10, anyone of the pallets can now be removed by virtue of the fact that the turn-table can be advanced as many steps as are desired in either direction in order to place the selected pallet at the outlet 11 of the furnace 10. .
• the articles After treatment has been completed in the ring furnace 10, the articles are.transferred to a diffusion furnace 12 and from there either directly to a packing robot 13 or to an oil bath 14. From the oil bath 14, the articles are conveyed via conveyors 3 and 4 once again through the washing station 5 and finally to a tempering furnace 15, from which the articles are conveyed out to the conveyor 3»
• the heat treatment installation shown and described is suitably controlled by a computerized control system which keeps track of where each indi ⁇ vidual pallet is at each moment and times the various operations, so that all of the articles receive the proper heat treatment period independently of the order in which they are fed into the installation.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Articles (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=20357207

Family Applications (1)

Country Status (5)

Cited By (2)

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• 1984
  • 1984-10-02 SE SE8404926A patent/SE450389B/sv not_active IP Right Cessation
• 1985
  • 1985-09-30 DE DE8585905124T patent/DE3567479D1/de not_active Expired
  • 1985-09-30 WO PCT/SE1985/000377 patent/WO1986002104A1/en not_active Ceased
  • 1985-09-30 JP JP60504523A patent/JPS62500529A/ja active Pending
  • 1985-09-30 EP EP19850905124 patent/EP0198871B1/de not_active Expired

Non-Patent Citations (1)

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