Bell-type furnace and a method for heat-treating material to be treated

• Main Authors: POETKE,WOLFGANG,DR, LAIGUDDIN,SAHIBZADA,DR.. SAEED-UR RAHMAN
• Format: Patent
• Language: English; German
• Published: 05.06.1986
• Edition: 4
• Subjects: CHEMISTRY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS

In a bell-type furnace (1) for the soft-annealing of sheet-metal coils (6a, 6b, 6c) arranged one above the other in layers with a protective bell (3) placed over the sheet-metal coils and delimiting a treatment chamber (30), with a heating bell (2) surrounding the protective bell with a clearance, and with at least one burner (4) arranged near to the bottom of the heating bell (2), opening into the annular space (20) between the two bells (2, 3) and intended for the production of the annealing heat, to avoid overheating of individual coils (6a, 6b) at excess heating temperatures at least that section of the treatment chamber (30) which accommodates the bottom coil (6a) is surrounded by at least one layer (11, 12) of thermally insulating material. To shorten the process time for the soft-annealing of the sheet-metal coils (6a, 6b, 6c), the protective-gas atmosphere is heated with the aid of this bell-type furnace (1) to a limiting value about 40 DEG C above the annealing temperature. When this limiting value is reached, the heat output of the burner (4), of which there is at least one, is reduced in order to introduce the annealing phase.