JPH0711347A - Automatic combustion controlling method in continuous type heating furnace - Google Patents

Abstract

PURPOSE:To efficiently heat steel material group having particularly different heating condition, related to an automatic combustion control method in a continuous type heating furnace. CONSTITUTION:A soaking temp. of the steel materials are set at the average value or higher of the soaking temp. in each steel material at the front and the rear parts of this steel material and the soaking time of this steel materials are set at the average value or longer of the soaking time in each steel material at the front and the rear parts of this steel material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control method in a continuous heating furnace in a multi-product, high-production operation mode, and particularly to efficiently and continuously connecting a plurality of types of steel materials having different heating conditions in the same heating furnace. The present invention relates to an automatic combustion control method in a continuous heating furnace that conveys and heats the material to a furnace.

[0002]

2. Description of the Related Art Conventionally, as a "combustion control method in a continuous heating furnace for efficiently transporting and heating a plurality of types of steel materials having different heating conditions in the same heating furnace", Japanese Patent Publication No.
In a continuous heating furnace for heating two or more kinds of steel materials having different heating conditions in the same heating furnace as disclosed in Japanese Patent No. 78691, a group of steel materials having the same heating conditions previously charged and then charged next. From the set furnace temperature of the previous steel material group in each zone, the furnace set temperature calculated from each heating condition and the predicted combustion amount calculated from the set furnace temperature of the previous steel material group with different heating conditions Calculate the change time required to change to the set furnace temperature of the next steel group, and calculate the steel interval in the furnace between the previous steel group and the next steel group required to change the set temperature by the change time and the transport speed of the steel group. Calculate, determine the charging timing of the next steel group to be the steel interval in the furnace, charging the next steel group to the heating furnace at the charging timing, along with the movement of the steel group of the heating furnace, Set the combustion amount of the zone where the previous steel material group passed to the next steel material group There are combustion control method to be changed to bring temperatures.

[0003]

In order to efficiently operate the heating furnace in a multi-product, high-production operation mode, the heating furnace is operated continuously regardless of the heating conditions of the steel materials to be heated. A furnace is preferred. In order to operate the heating furnace continuously, depending on the heating conditions (extraction temperature, charging temperature, soaking temperature, soaking time, etc.) of the steel materials to be heated, the previous steel material group and the next steel material group are There is an interval between and heating. However, in the above-mentioned conventional method, under different heating conditions, the interval between the steel materials is secured, so that the conveyance pitch of the steel materials in the heating furnace becomes slow, which leads to a decrease in the production amount and deterioration of the fuel consumption rate.

Therefore, an object of the present invention is to provide a combustion control method for a continuous heating furnace in which a plurality of types of steel materials having different heating conditions are efficiently and continuously conveyed and heated in the same heating furnace. To do.

[0005]

DISCLOSURE OF THE INVENTION The present invention is to advantageously solve the above problems, and its purpose is to provide a continuous heating furnace for heating two or more kinds of steel materials having different heating conditions in the same furnace. In a continuous heating furnace that can control the furnace temperature independently in each zone, the temperature at which the steel material is maintained at a constant temperature after being heated in the furnace (hereinafter referred to as the soaking temperature) is the average of the soaking temperatures of the front and rear steel materials. It is characterized in that it is set to a value equal to or higher than the value, and the time for holding the steel material at a constant temperature after heating in the furnace (hereinafter referred to as soaking time) is set to be equal to or more than the average value of the soaking times of the front and rear steel materials. It is an automatic combustion control method in a continuous heating furnace.

A detailed description will be given below with reference to the drawings. First, FIG. 3 is a diagram showing a heat pattern setting method.
In the continuous heating furnace, the heat pattern is set according to the following procedure.

The in-furnace time of the material is calculated from the total extraction pitch of each steel material in the heating furnace. (The in-furnace time of the material is defined as T) (T = about 100 to 300 minutes).

[0008]

[Equation 1]

The soaking time (T ') is subtracted from the in-furnace time (T) of the material. _Let that time be T _o (heating time).
The soaking time (T ') is determined in terms of quality. (T '= 30
~ 90 minutes) (T _o = 40-300 minutes).

The furnace temperature of each zone is calculated based on the equation (t = αe ^βx + b) so that the soaking temperature (t ′ ° C.) is reached within the heating time (T _o = T−T ′). {T: temperature of slab, x
= In-furnace position, β = f (max furnace temperature, soaking temperature, conversion tropical furnace temperature)}, soaking temperature (t ') is determined in terms of quality. (T
= About 700 to 1300 ° C)

Next, a method for setting a heat pattern according to the present invention for each steel material that is continuously heated will be described. Figure 1
[Fig. 3] is a diagram showing the present invention. FIG. 2 is an example of a heating furnace charging sequence. When the charging order is as shown in FIG. 2, in the conventional method, the heat pattern of the general material in FIG. 2 becomes the heat pattern shown in ′ in FIG.
The set furnace temperature of each zone fluctuates greatly in the order
It was not possible to charge continuously with
It was heating at intervals.

On the other hand, according to the method of the present invention, it is possible to continuously charge the heating furnace by setting an average heat pattern with. That is, the average value of each soaking time and soaking temperature of and is calculated, and T = (T + T) / 2 t = (t + t) / 2 The value is set as the soaking temperature and soaking time. And

At this time, if the average value is out of the range of soaking temperature or soaking time set for the quality of the steel material,
Set it to the closer of the upper and lower limits within that range.
Alternatively, + α may be added to the average value of the soaking temperature or soaking time on the stable side in operation.

[0014]

According to the method of the present invention, in a continuous heating furnace in which a plurality of types of steel materials having different heating conditions are continuously conveyed and heated in the same heating furnace, it is necessary to secure a space between the steel materials. It is possible to continuously charge and heat steel materials. As a result, the transportation pitch in the heating furnace was increased, the production capacity was improved, and the fuel consumption rate was improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a heat pattern according to the method of the present invention.

FIG. 2 is a view showing a charging order of steel materials.

FIG. 3 is a diagram illustrating a method of setting a heat pattern.

Claims (1)

[Claims] 1. A continuous heating furnace that heats two or more types of steel materials having different heating conditions in the same furnace, and an automatic combustion control method for the continuous heating furnace in which each furnace temperature can be controlled independently, The temperature at which the steel is kept at a constant temperature after heating (hereinafter referred to as the soaking temperature) is set to be equal to or higher than the average value of the soaking temperatures of the steel materials before and after the steel material, and after the heating of the steel material in the furnace. An automatic combustion control method in a continuous heating furnace, characterized in that the time (hereinafter referred to as soaking time) held at the constant temperature is set to be equal to or more than the average value of the soaking time of each steel material before and after the steel material.