SU1310441A1 - Convector ring - Google Patents

Abstract

The invention relates to sheet-rolling production of tightly wound rolls of cold-rolled thin metal strip during annealing in bell-type furnaces with forced circulation of protective gas. The purpose of the invention is to improve the quality of annealed coils and the mechanical resistance of the ring. The goal is achieved by the fact that on the outer edge of a ring formed by two solid disks with a central hole, interconnected edges forming circular circulation channels, are fixed with one end of a protective screen plate tangentially to the ring. The gaps formed between the edge of the disk and the free end of the plates are at least half the height of the circulation channels. 2 Il. (L 4

Description

113

The invention relates to metallurgy, in particular, to sheet-rolling production, and can be used in the processes of annealing densely wound rolls of cold-rolled thin metal strip in bell-type furnaces with forced circulation of protective gas.

The purpose of the invention is to improve the quality of annealing and mechanical stability.

FIG. 1 shows a convector ring with a protective radiation screen; in fig. 2 - section A-A in FIG.

The convector ring consists of two disks 1, radial fins 2 connecting them, circulation tubes for the passage of heat-transfer gas, a central gas outlet 4, a radiation shield 5 formed by separate plates, and gas inlet sections into the convector ring 6 .

The height of the radiation shielding screen is determined by the height of the convector ring. The size of the inlet gas section into the convector ring (the width of the gap between the outer edge of the discs and the inner edge of the screen) is at least half the height of the circulating channels.

Suppose a convector ring has an outer diameter of 2300 mm. The height of the ring and the circulation channels Hbix located in it are, respectively, 70 and 50 mm. The height of the protective radiation shield is 70 mm, and the minimum width of the inlet gas section is 50 xO. mm

The outer diameter of the convector ring of the proposed design is 2300 +251 2 + 1, mm. (1.5 mm is the thickness of the material for the manufacture of the protective screen).

Annealing of tightly wound rolls using the convector ring of the proposed construction occurs in the following order.

A lower (first annealed coil) is placed on the supporting convector ring located on the stand of the bell-type furnace. A first intermediate convector ring is laid on the upper end of the roll. Then a second roll is placed on the specified convector ring, the second intermediate convector ring is placed on the upper end of the coil.

44

with

0

50

-thirty

35

40

45

Q

12

tso. The process of forming the foot continues until its height reaches a known permissible value. Then, the foot is slapped with a muffle, the protective gas supply valve is opened under the muffle, the circulation fan is turned on, a heating cap is installed and the burners of the furnace heating system are ignited.

From the heat exchanging muffle, heat is transferred to the annealed coils as follows.

Under the action of a running fan, the circulating protective gas is injected from the guide apparatus into an annular gap formed by the inner surface of the muffle and the outer side surface of the rolls. From the annular gap, the gas heated from the muffle through the inlet portions formed by the protective screen and the discs enters the circulation channels formed by the ribs and discs. In these channels, convection of heat from the gas through the ring disks to the ends of the annealed coils is prevented by convection. From the circulation channels, the gas enters the central exhaust channel and then through the internal cavities of the annealed coils enters the inlet of the circulation fan.

 In addition to convective heating of the metal by the circulating protective gas, heat transfer to the coils in the bell-type furnace occurs by radiation from the inner surface of the muffle. In this case, the radiative heat transfer occurs through the radiant protective gas of the annular gap to the side surfaces of the coils, and through the gap between the disks of convector rings to the outer portions of the end surfaces of the coils. The presence of a protective screen significantly reduces the radiant flux on the end surface of the roll. During the cooling period when the heating cap is removed, the circulating protective gas provides convective heat transfer from the load to the cooler muffle.

As a result of the use of convector rings of this design with a shielded outer edge with a constant, annealing cycle time improves the uniformity of heating of the coils, the amount of cm and the welded metal decreases, increasing

The life of the convector rings is lost.

Claims (1)

Invention Formula A convector ring, mainly for annealing of tightly wound tin rolls, containing two continuous disks, with central holes, interconnected by edges with the formation of circulation channels and a protective screen in the form of separate 104414 plates, characterized in that, in order to improve the quality of the annealed coils and the mechanical resistance of the ring, the plates are mounted tangentially relative to the ring and are fixed with one end on the outer ends of the ribs over the entire height of the ring with the formation of a gap between it and the less than half the height of circulation channels. 6 fig