RU2128234C1 - Bell-type furnace - Google Patents

Abstract

FIELD: metallurgy, mechanical engineering, thermal treatment of strip in coils. SUBSTANCE: bell-type furnace has heating bell, muffle, stand with circulation fan, flat disc with hole for pile of coils that is manufactured with outer diameter equal to inner diameter of convector ring above top coil of pile. EFFECT: intensified process of heat transfer during periods of heating and cooling with simultaneous growth of uniformity of mechanical properties of annealed metal. 2 dwg, 1 tbl

Description

 The invention relates to a device for the heat treatment of strip and tape in tightly wound rolls and can be used in the metallurgical and engineering industries.

 Known bell furnace, including the cover of the foot of the rolls, which is a flat disk with a Central hole for the circulation of protective gas (US patent N 3832129, CL 432-77, 1974) [1].

 The disadvantage of this analogue is low productivity, increased energy consumption, reduced quality of the annealed metal due to the unevenness of the temperature field in the volume of the charge, associated with the non-uniform distribution of heat flow under the muffle of the bell furnace.

 The closest analogue is a bell furnace containing a stand, a circulation fan, a muffle, a heating cap, a cover in the form of a flat disk with a central hole with a passage area of 0.6-0.9 of the total area of the average cross sections of the circulation channels of convector rings installed between rolls [2].

 A disadvantage of the known bell furnace is the low productivity and reduced quality of the annealed metal, which is due to the heterogeneity of the temperature field over the volume of the charge due to the irrational distribution of the heat flux.

 The proposed bell furnace solves the technical problem of intensifying the heat transfer process during periods of heating and cooling while increasing the uniformity of the mechanical properties of the annealed metal, saving energy and increasing the performance of the bell furnace.

 A positive result is achieved in that in a bell-type furnace containing a heating bell, a muffle, a stand with a circulation fan, a cover of the stack of rolls in the form of a flat disk with a central hole with a passage area equal to 0.6 - 0.9 of the total area of the average cross sections of the circulation channels each of the convector rings placed between the rolls, installed at the top of the foot, the cover of the foot is made with an outer diameter equal to the inner diameter of the convector ring, and set it in the convector ring under the upper roll of the foot.

In the manufacture of a bell furnace with a cover of the foot of rolls in the form of a flat disk with a central hole and an outer diameter that allows you to install the cover on the upper roll of the foot according to the USSR patent N 1788981 C 21 D 9/663, F 27 B 11/00, 15.01.93, selected as the closest analogue, and when testing such a furnace, the following results were obtained: the spread of the yield strength Δσ _0.2 , along the stack height of the rolls during steel annealing 08Yu 50 N / mm ² ; the capacity of the bell furnace in the cycle of heating + cooling 0.56 t / h; specific fuel consumption of 63 kg / t.

 To substantiate the achievement of a positive result according to the claimed invention, experiments were conducted. In the bell furnace, a cover of the claimed design was used, placed in a convector ring under the upper roll, and a cover made according to the closest analogue, placed in the upper roll of the foot.

 The experimental data are summarized in table.

As shown by the experimental data, as a result of using the inventive bell-type furnace, the spread in the yield strength of 08Yu steel (Δσ _0.2 ) decreases by an average of 35 N / mm ² in comparison with the closest analogue, the furnace productivity increases by 8-10%, and fuel consumption decreases by 6-10%.

 In FIG. 1 shows the inventive bell furnace; in FIG. 2 - a flat disk with a hole.

 The bell furnace contains a stand 1, a heating cap 2, a muffle 3, convector rings 6, a flat disk 5 placed in the convector ring 6 under the upper roll 4, burners 7, a bench circulation fan 8, a flat disk 5 (see Fig. 2) from a sheet 5 mm thick with a central hole and an outer diameter equal to the inner diameter of the convector ring 6.

 Bell furnace works as follows.

 A stack of rolls 4 with convector rings 6 between rolls 4 and a flat disk 5 with a central hole placed in the convector ring 6 under the upper roll 4 are installed on the furnace bench 1 of the furnace. Then, the stack of rolls 4 is covered with a muffle 3 and a heating cap 2 with burners 7.

 In the process of heat treatment of the rolls 4 using a bench fan 8 circulate the protective gas in the half-muffle space. Shielding gas, heating from the muffle 3, gives off heat to the rolls 4, passing through an opening in the foot disk 5 and through the channels of convector rings 6.

List of sources used
1. US patent N 3832129, CL. 432-77, 1974.

 2. USSR patent N 1788981, C 21 D 9/663, F 27 B 11/00, 01/15/93.

Claims (1)

 A bell-type furnace mainly for annealing coils, including a heating bell, a muffle, a stand with a circulation fan, convector rings with circulation channels, a flat disk with a central hole with a passage area equal to 0.6 - 0.9 of the total cross-sectional area of the circulation channels of each convector rings, characterized in that the flat disk with the hole is made with an outer diameter equal to the inner diameter of the convector ring, and is installed in the channel of the ring under the upper roll of the foot.

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