JPS5864323A - Direct fire type coil annealing device - Google Patents

Abstract

PURPOSE:To heat a coil to a high temperature by a small temperature deviation, by providing a space of specified height between a furnace floor surface and a coil base plate, providing a part of burners within a range of height of this space, and heating a coil in a retort. CONSTITUTION:On the lower part and the middle part of a furnace body 1, a burner 2 is provided in the tangential direction of a retort 8. The retort 8 is fitted into a furnace floor 3 by a seal groove 13, and in the retort, pillar-like support fittings 10 are provided on the lower part in the center of a coil base plate 5 on which a coil 6 has been placed, and a space 11 of >=300mm. in the direction of height is formed between the surface of the furnace floor 3 and the coil base plate 5, so that the lower burner 2 is positioned within a range of height of the space 11. In this state, when the coil 6 is heated through the retort 8 by the burner 2, radiation heat 12 from the lower side furnace of the retort 8 heats the coil 6 from downward, a temperature deviation in the coil 6 is reduced, and it is possible to heat the coil 6 to a high temperature of >=1,000 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct-fired coil annealing device, and more specifically, the present invention relates to a direct-fired coil annealing device using combustion gas from a burner installed on the furnace wall.

Two direct-fire annealing devices are used to anneal a coil placed in a retort at the same temperature of IQOO°C or higher.

Note that the direct-fired coil annealing device refers to a coil annealing device that uses combustion gas from a burner as a heating source.

A conventional direct-fired coil annealing apparatus is illustrated in FIG. In the drawings, 1 is a furnace body, and 2 is a bath provided in the furnace body 1. 3 is a hearth, a coil support ring 4 is placed on this hearth 3, and the coil support ring 4 is connected to a coil base plate 5.
O7, which supports the coil 6 via the retort atmosphere gas circulation device, such as a base fan, is above the hearth 3 and is located on the coil support ring 4! It is located in the center.

A retort 8 is isolated from the combustion gas from the burner 2 in order to anneal the coil 6 placed therein under a predetermined protective atmosphere.

Incidentally, the coil 6 is heated by radiation from the retort 8 which is heated by the combustion action of the burner 2. As is generally well known, the heat transfer in the height direction of the coil 6 is overwhelmingly greater than the heat transfer in the radial direction.
Hearth 3 and coil base plate 5 for efficient heating in the shortest possible time
A base fan 7 provided in the coil support ring 4 between the two coils was operated to forcefully circulate ambient air gas from below, thereby promoting heating of the coil 6.

Coil annealing apparatuses having this retort internal atmosphere gas circulation device 7 are generally widely used, and most of them are low-temperature coil annealing furnaces with a heating temperature of about 600 to 900°C. Therefore, when performing annealing at a high temperature of 1000° C. or higher in such a coil annealing furnace, the heat resistance and durability of the retort atmospheric gas circulation device 7 become a major problem. Even if high-grade heat-resistant steel or special refractories were used as the constituent material of the atmospheric gas circulation device, its durability and maintainability were poor, and it could not be used as an actual industrial facility.

In addition, in the conventional direct-fired coil annealing apparatus, the distance between the hearth 3 and the lowest coil base plate 5 is usually 100 to 250 cm, which is enough to allow installation of the pace fan 7, and The base plate 5 is supported by a coil support ring 4 at its outer peripheral portion.

For this reason, when heating to a high temperature of 1000°C or higher using a conventional direct-fired coil annealing device, the pace fan 7 cannot withstand practical use, and it is difficult to apply a heating effect from the bottom of the coil, resulting in large temperatures. cause deviation.

Direct-fired coil annealing equipment inherently has a larger temperature deviation than coil annealing equipment that uses an electric heater as the heating source.Especially when the heating temperature is set to a high temperature of 1000'C or higher, the temperature deviation is It tends to get bigger. As shown in Fig. 2, other conventional direct-fired coil annealing equipment uses a hearth 3 and a coil base plate 5 to heat the lower part of the coil 6.
Some had an auxiliary heater 9 installed between them.

A direct-fired coil annealing furnace that also uses such an auxiliary heater 9 is disadvantageous when considering the cost required for heat treatment because the auxiliary heater 9 consumes a large amount of power. The problem is that equipment is required, which increases the complexity of the equipment and increases equipment costs.

The present invention was made in view of the above-mentioned circumstances, and uses the combustion heat from the burner to burn the coil placed in the retort to 100%.
The present invention provides a direct-fired coil annealing device that heats and anneales at a high temperature of 0° C. or higher with little temperature deviation.

That is, the gist of the present invention is to provide a coil annealing apparatus in which a furnace body is provided with burners in one stage or in multiple stages, and a coil in a retort is heated by combustion gas from the burner. A columnar support is provided, a space in the height direction of 3 ooami is formed between the hearth and the coil base plate, at least some burners are provided in the furnace body within the height range of the space, and the coil There is a direct-fired coil annealing device characterized in that the coil is heated at a high temperature of 1000° C. or higher. □Next, the present invention will be explained in detail with reference to FIGS. 3 and 4.

In the drawings, 1 is a furnace body, and 2 is a burner, which are provided in the lower and intermediate portions of the furnace body 1 in the tangential direction of the retort 8. Moreover, the burner 2-1 provided at the lower part is provided in the furnace body 1 within the same height range as the height of the space formed between the hearth 3 surface and the coil base plate 5, as will be described later.

10 is a columnar support, and a coil base plate 5 on which the coil 6 is placed.
A space 11 in the height direction is formed between the coil bed plate 5 and the hearth 30.

Due to the space 11 between the hearth 3 and the coil base plate 5, the radiant heat 12 from the side surface of the retort 8 passes through the lower surface of the coil base plate 5, causing the coil 6 to move downward, as shown in FIG. Heat it up as well. This space 1 is heated from below.
1 must be at least 3001m in height. If this height is low, there will be less force acting from below the coil 6.
Since the temperature deviation becomes large when the coil 6 is annealed at a high temperature of 1000° C. or higher, the length is set to 300 m or higher.

Further, in the present invention, since at least some of the burners 2-1 are provided within the same height range as the height of the space 11, radiant heat 12 from the lower side of the retort 8 heated by the burners 2-1 is provided. The heat is input from below the coil, and the coil 6
heating efficiently from the height direction. This heating also reduces the temperature deviation within the coil 6.

Furthermore, the combustion gas from the burner 2-1 naturally flows upward along the retort 8 as a combustion gas flow, also heating the retort 8 (7)-4 surface. Due to these effects and the combustion gas of the burner 2, even when the coil 6 in the retort 8 is heated to a high temperature of 1000°C or higher, for example 1100°C, there is little temperature deviation.

Since the present invention is as described above, the coil can be annealed at a high temperature of 1000° C. or higher with little temperature deviation using combustion gas from the burner.

Further, the bottom portion of the retort 8 is placed in the seal groove 13 to prevent combustion gas from entering the retort 8. Note that an atmospheric gas supply pipe (not shown) is provided in the retort 8 to supply atmospheric gas.

Next, examples will be shown.

A silicon steel strip with a plate thickness of 0.3 mm and a plate width of 950 m is coated with an annealing separator and then wound to form a silicon steel coil with an outer diameter of 1600 am. , and were heated to 1170° C. in a high-temperature direct-fired coil annealing furnace according to the present invention.

In a conventional annealing furnace, the gap between the three sides of the hearth and the coil bed plate 50 is 2.
20, the base 7 is stopped, and the annealing furnace according to the present invention has an outer diameter of 550 mm and a height of 35 C1n+ on the upper surface of the hearth 3.
Place a columnar support lO made of heat-resistant steel with a thickness of 1' on top of it.
The i'OM coil base plate 5 and coil 6 were mounted and annealed.

During this annealing, in both annealing furnaces, the upper part of the outer periphery of the lower coil (corresponding to the highest temperature part of the coil)
Table 1 shows the temperature deviation between the lower coil and the central part of the inner circumference of the coil (corresponding to the lowest temperature part of the coil) at various times after reaching 170°C.

From Table 1, it can be seen that according to the present invention, even when annealing is performed at a high temperature of 1170° C., the material can be heated efficiently and annealed with little temperature deviation.

Table 1

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional direct-fired coil annealing device, FIG. 2 is an explanatory diagram of another conventional direct-fired coil annealing device, and FIG. 3 is an example of the direct-fired coil annealing device of the present invention. FIG. 4 is a detailed explanatory diagram of the present invention. l: Furnace body 2: Burner 3: Hearth 5: Coil base plate 11: Height space

Claims (1)

[Claims] In an annealing apparatus in which a furnace body is provided with burners in one or multiple stages, and a coil in a retort is heated by combustion gas from the burner, a columnar support is provided at the lower center of a coil bed plate on which the coil is placed, and the furnace 300 mm between the floor and the coil base plate
A coil i is formed by forming a space in the height direction of at least 1 in, and at least some burners are provided within the height range of the space.
A direct-fired coil annealing device characterized by heating at a high temperature of 1O'oo°C or higher.