JP2000087148A - Continuous annealing furnace for stainless steel strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous annealing furnace for stainless steel strip in which a catenary gradually descended toward the outlet side of a heating zone is formed to hardly damage the stainless steel strip. SOLUTION: In this continuous annealing furnace consisting of a preheating zone A, heating zone B and cooling zone D, the preheating zone and the cooling zone are horizontally disposed so that the former becomes high position, and the heating zone is inclined so as to gradually descend toward the outlet side and successively, disposed between the preheating zone and the cooling zone. A support roll 1 is disposed at the outlet part of the preheating zone and a connecting zone C having a pressure pad 12 is disposed between the heating zone and the cooling zone, and the stainless steel strip W in the heating zone, is transported as the catenary state with the supporting roll and the pressure pad.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a continuous annealing furnace for a stainless steel strip.

[0002]

2. Description of the Related Art Conventionally, continuous furnaces for continuously annealing stainless steel strip include a horizontal catenary type continuous annealing furnace and a vertical type continuous annealing furnace.

[0003]

However, in the former, the furnace is arranged horizontally and a large number of support rolls are arranged in the furnace. In addition, these support rolls have a large heat loss due to their water-cooled structure, and the stainless steel strip is likely to be scratched because it comes into contact with a large number of support rolls. There is a problem that there is. On the other hand, the latter furnace shape is an inverted U-shape, and the stainless steel strip carried in from the lower pre-tropical zone changes its direction to the upper top roll chamber, and is extracted from the downward heating zone to the cooling zone. Therefore, although there is no disadvantage of the former, the lower part of the heating zone (extraction port) due to the draft effect of the heating zone
Not only is it easy to disturb the furnace air in the final zone, but also the construction cost of the building is high due to the high furnace height, and
There is a problem in that a meandering adjustment mechanism is required in the top roll chamber and the equipment itself becomes expensive. Accordingly, an object of the present invention is to provide a continuous annealing furnace for a stainless steel strip that can solve the above-mentioned problems.

[0004]

In order to achieve the above object, the present invention provides a continuous annealing furnace for a stainless steel strip comprising a pre-tropical zone, a heating zone and a cooling zone, wherein the pre-tropical zone and the cooling zone are formed by the former. The heating zone is arranged horizontally so as to be at a high altitude, and the heating zone is inclined between the pre-tropical zone and the cooling zone so as to gradually descend toward the outlet side, and is connected to the pre-tropical outlet portion. A support roll is provided, and a joining band having a pressure pad is provided between a heating zone and a cooling zone. In the heating zone, the stainless steel strip is transported in a catenary state by the support roll and the pressure pad. It is.

[0005]

Next, an embodiment of the present invention will be described with reference to the drawings. Continuous annealing furnace T for stainless steel strip
Consists of a pre-tropical zone A, a heating zone B, a joint zone C, and a cooling zone D.

The pre-tropical zone A and the cooling zone D are arranged horizontally so that the former is higher than the latter. Further, the heating zone B is located between the pre-tropical zone A and the cooling zone D,
The heating zone B is provided with a joining band C at an exit portion of the heating zone B.

One support roll 1 is provided at the outlet of the pre-tropical zone A, and an exhaust port 2 is provided in the hearth near the charging port, and the exhaust gas is exhausted by the exhaust gas fan 3. It is sucked and exhausted from 2. The exhaust gas passes through a heat exchanger 4 and preheats combustion air of a direct fire burner 9 described below, and then is discharged from a chimney 5. In addition, 6 is a gas sealing device at the charging opening of the pre-tropical zone A, and 7 is a furnace pressure control valve.

The inside of the heating zone B is divided into a plurality of division zones by an upper partition wall 8a and a lower partition wall 8b, and each zone adjusts a combustion amount of a direct fire burner 9 provided in each of the zones. Thus, a predetermined heating pattern is obtained.

Reference numeral 10 denotes a furnace pressure detector for controlling the furnace pressure control valve 7, and reference numeral 11 denotes a stainless steel strip W radiation thermometer for controlling the combustion amount of the direct fire burner 9.

In addition, the joining band C is provided with
A well-known pressure pad 12 for ejecting gas inward to levitate and support the stainless steel strip W is provided, and an exhaust port 13 is provided on the ceiling. Then, the stainless steel strip W forms a catenary state by the support roll 1 of the heating zone B and the pressure pad 12 of the joining band C. In addition, 14 is an opening adjustment door.

In the cooling zone D, a hearth roll 15 is provided, and a known cooling means (not shown) is provided.

Next, an operation method of the continuous annealing furnace T will be described. First, a stainless steel strip (hereinafter, referred to as a steel strip) W is passed through as shown in FIG. 1, and the exhaust gas fan 3, each direct-fire burner 9, and the cooling means of the cooling zone D are driven to map each zone. The operation is started so that the heat curve shown in FIG. In this case, the steel strip W is radiantly heated in the pre-tropical zone A by the exhaust gas flowing from the heating zone B and is preheated to about 200 ° C., and subsequently in the heating zone B to about 1200 ° C. by the direct fire burner 9. It is heated, cooled to about 80 ° C. by the cooling means in the cooling zone D, and subjected to an annealing treatment.

The pressure pad 12 is a steel strip W
Is floated and supported, and a catenary is formed with the support roll 1 provided at the outlet of the pre-tropical zone A. The position of the catenary is such that the lowest point SAG of the catenary is on the outlet side of the heating zone B. Like that. As a result, the supporting load of the pressure pad 12 is the steel strip W between the lowermost point SAG and the pressure pad 12 and between the pressure pad 12 and the hearth roll 15, so that the necessary steel strip levitation force (gas ejection amount). Can be small. In addition, pressure pad 1
Since No. 2 is located on the cooling part side outside the heating zone B, the ejected gas has a relatively low temperature and a high density, so that the driving power of the pressure pad 12 can be reduced. In addition,
The splicing band C may be partitioned and installed in the heating zone B.

[0014]

As is apparent from the above description, according to the present invention, the heating zone has the inlet portion higher than the outlet portion and gradually descends toward the outlet portion, and
The stainless steel strip is transported in a catenary state, that is, in a non-contact state, in the heating zone by the support roll provided at the outlet of the pre-tropical zone and the pressure pad provided at the joint band, and the stainless steel strip is less damaged by the support roll In addition, since only one support roll having a water cooling structure is used, heat loss is small. Further, since the heating zone is inclined, the space length required for installation is shorter than that of the horizontal furnace, and the furnace height can be reduced to about 1/4 as compared with the vertical continuous annealing furnace.

Further, in the heating zone, the exhaust gas rises due to the draft effect. However, the height is low as described above, and the pre-tropical zone connected to the inlet of the heating furnace is horizontally arranged, so that the draft effect is low. It is possible to reduce the intrusion of cold air from the charging opening based on the draft, and the furnace temperature and the atmosphere in the furnace are not disturbed. Therefore, there is an effect that the gas sealing device is sufficient for the sealing device provided in the pre-tropical charging section.

[Brief description of the drawings]

FIG. 1 is a schematic view of a continuous annealing furnace for a stainless steel strip according to the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a heat curve.

[Explanation of symbols]

A: Pre-tropical, B: Heating zone, C: Joint zone, D: Cooling zone, T
... Continuous annealing furnace, 1 ... Support roll, 2 ... Exhaust port, 8
a, 8b: partition wall, 9: direct fire burner, 12: pressure pad, 15: hearth roll, W: stainless steel strip.

Claims (1)

[Claims] 1. A continuous annealing furnace for a stainless steel strip comprising a pre-tropical zone, a heating zone and a cooling zone, wherein the pre-tropical zone and the cooling zone are horizontally arranged such that the former is at a higher elevation, and Between the cooling zone and the cooling zone, the heating zone is inclinedly connected so as to gradually descend toward the outlet side, and a support roll is disposed at the pre-tropical outlet portion, and the heating zone and the cooling zone are connected to each other. A continuous annealing furnace for a stainless steel strip, wherein a stainless steel strip is conveyed in a catenary state by the support roll and the pressure pad in a heating zone by disposing a joining band having a pressure pad therebetween.