JPH04202625A - Method f0r positioning of slab in vertical induction heating furnace - Google Patents

Abstract

PURPOSE:To permit uniform heating in the breadthwise direction of a slab even if the breadthwise dimension of the slab is different by coinciding the central part of a slab to be heated with the central part of an induction heating coil. CONSTITUTION:The position of the height H from a working floor FL of the central part HC of an induction heating coil 2 is set, and it is inputted to an arithmetic and control unit 7 for the quantity of strokes every time the breadthwise dimension W of a slab 3 to be heated is charged thereto. In this way, the position P of the height at which the central part SC of the slab 3 should be coincided with the central part HC of the coil 2 can be operated by a prescribed formula. Then, by outputting a control signal corresponding to the above position P of the height to the unit 7, the quantity of a stroke S from a working floor FL is measured by a position detector 6 while an elevation device 5 is raised and is inputted to the unit 7, and the deviation S(P-S) is operated by comparison. At the point of time when this deviation S becomes zero, the elevation device 5 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for positioning a steel billet in a vertical induction heating furnace.

<Prior Art> Conventionally, a batch-type heating furnace for heating steel slabs has a vertical heating furnace 1 in which a plurality of induction heating coils 2 are arranged in the height direction of the furnace, as shown in FIG. A type induction heating furnace is used. In this vertical induction heating furnace, a steel billet 3 is placed vertically in the width direction on a billet making stand 4 provided below the furnace, charged into the furnace by an elevating device 5, and subjected to M'4 heating. A method is adopted in which the steel billet 3 is heated to a predetermined temperature while controlling the power input to the coil 2 (for example, in Japanese Patent Publication No. 62-12
(See Publication No. 286).

The reason why the induction heating coil 2 is divided into multiple parts is that heat dissipation in the height direction of the heating furnace 1, that is, in the width direction of the steel slab 3, is different, so by dividing the coil, the heat dissipation is compensated for. This is what I am trying to do.

<Problem to be solved by the invention> By the way, in the above-mentioned conventional vertical induction heating furnace,
Since the stroke of the lifting device 5 is generally set to be constant, the widthwise center SC of the charged steel billet 3 and the induction heating coil 2 are connected to each other as shown in FIG. When there is so-called heating symmetry, in which the central portion HC in the height direction coincides, the temperature distribution in the width direction of the steel slab 3 can be made almost uniform, as shown in FIG. 5(a). can.

However, as shown in FIG. 4(b) or (C), the steel piece 3
When the width dimensions of the three induction heating coils 2a differ,
, 2b, and 2c, the heating symmetry described above is disrupted, resulting in temperature unevenness in the width direction. As a result, temperature irregularities ΔT and ΔT occur in the width direction as shown in FIG. 5(b) or (C).

The present invention was made to solve the above problems, and an object of the present invention is to provide a method for positioning a steel billet in a vertical induction heating furnace that reduces temperature unevenness in the width direction.

<Means for Solving the Problems> The present invention provides a method for heating a steel billet erected in the width direction using a vertical induction heating furnace in which a plurality of induction heating coils are arranged in the height direction inside the furnace. A method for positioning a steel billet in a vertical induction heating furnace, the method comprising: adjusting the widthwise center of the steel billet to match the heightwise center of the heating coil array. It is.

<Function> According to the present invention, the widthwise center of the steel billet and the heightwise center of the induction heating coil array are always aligned, so even if the width of the steel billet differs, heating is possible. Heating can be performed while maintaining symmetry, and thereby the steel piece can be heated with little temperature unevenness in the width direction.

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the steel billet positioning device of the present invention.

In the figure, 6 is a position detector that detects the stroke amount of the lifting equipment W5, and it measures the distance that the top of the steel slab 3 rises from the working floor surface FL, with O being the point where the top of the steel slab 3 coincides with the working floor surface F. It shall be.

7 is a stroke amount calculation control device that calculates the stroke amount of the lifting device 5.

8 is a stroke position adjusting device that adjusts the stroke amount of the lifting device 5.

Next, the operation of the steel billet positioning device configured as described above will be explained.

First, the height position H (fixed value) of the central portion 11c of the induction heating coil 2 from the work floor FL is set in advance in the stroke amount fi calculation control device 7. And the steel piece 3 that should be heated
By inputting the width dimension W each time the steel billet 3 is charged, the height position P at which the center SC of the steel billet 3 should coincide with the center HC of the induction heating coil 2 is calculated based on the following formula (1). Ru.

P = H+ (W / 2) −−m−−−−−
------- (1) By outputting a control signal corresponding to this height position P to the stroke position W adjustment device 7, while raising the lifting device 5, the position detector 6 detects the working floor surface F. The stroke amount S from the front is measured and inputted to the stroke amount calculation control device W7, and the deviation ΔS is compared and calculated using the following equation (2).

Δs = p −s −−−・−−−−−=
・−・−・−・−・−・(2) When this deviation ΔS becomes O, that is, when it is determined that the measured value S of the stroke amount matches the calculated height position P, the lifting device 5 stop.

As a result, the center part SC of the steel piece 3 is aligned with the induction heating coil 2.
Therefore, the steel piece 3 can be arranged symmetrically with respect to the induction heating coil 2.

In addition, regarding the height position P determined by the above formula (1), it is desirable to make a slight correction if it is known in advance that there is a difference in the heat dissipation distribution in the height direction of the heating furnace 1. .

In addition, when the stroke amount of the lifting device 5 is large, that is, when the width dimension W of the steel billet 3 is quite small, the billet charging table 4
will be directly heated by the coil 2c,
The billet charging table 4 needs to be made of a material such as a heat-resistant alloy with excellent heat resistance, but since this alloy is expensive, the coil 2c is further divided into two parts, as shown in FIG.
c' and 2C'' may be controlled individually as appropriate.

When the steel billet positioning device of the present invention was used to heat a steel billet with a radius of 1100+ui, the temperature distribution T in the width direction for a heating temperature of 1200''C was as high as 60℃ in a conventional example with a constant stroke. However, in the example of the present invention in which the centers of the coil and the steel piece were aligned, the temperature could be kept within 20°C.

<Effects of the Invention> As explained above, according to the present invention, the center of the steel billet to be heated is made to coincide with the center of the induction heating coil, thereby achieving uniform heating in the width direction of the steel billet. This makes it possible to improve product quality and save energy.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the configuration of an embodiment of the steel billet positioning device of the present invention, Fig. 2 is a schematic diagram showing a modified example of the induction heating coil used for implementing the present invention, and Fig. 3 is the configuration of a conventional example. 4(a)-(C) and 5(a)-(
C) is an explanatory diagram of the operation of the conventional example. l... Heating furnace (vertical induction heating furnace), 2... Induction heating coil, 3... Steel billet, 4... Steel billet charging stand. 5... Indication device, 6... Position detector, 7.
...Stroke amount calculation control device. 8... Stroke position adjustment device. Patent applicant: Kawasaki Steel Corporation Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A method for positioning a steel billet when heating a steel billet erected in the width direction using a vertical induction heating furnace in which a plurality of induction heating coils are arranged in the height direction of the furnace, the method comprising: 1. A method for positioning a steel billet in a vertical induction heating furnace, comprising adjusting the center portion of the steel billet in the width direction to coincide with the center portion in the width direction.