JPS5811486B2 - How to set the temperature inside a continuous heating furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for setting the temperature inside a continuous heating furnace.

In a continuous heating furnace, such as a continuous billet heating furnace, the production amount per unit time (rolling T/H
), the extraction pitch of the steel billet from the heating furnace is determined, and the furnace temperature is controlled so that the heating or soaking of the steel billet is completed at the scheduled time for extraction of the steel billet, which is determined by the extraction pitch. The heating pattern of the steel billets in the furnace is not strictly controlled; the furnace temperature is set in advance so that the steel billets reach a predetermined target temperature during extraction, and the combustion is controlled to reach the set temperature. was the norm.

However, with such conventional operation methods, it is difficult to achieve the target heat-rise pattern when heating a steel billet when it is necessary to set restrictions on the heat-rise pattern due to material reasons such as structural changes inside the billet during heating. It was difficult.

For example, the regulation of the heating pattern means that ■ The temperature transition of the billet is specified for the entire period from charging to extraction, ■ The time required for the temperature to change from one temperature range to another is specified, ■ For example, the time from when a certain temperature is reached until extraction is regulated, and billets with different regulations may be present in the furnace at the same time.

The present invention enables a furnace operator to intervene in a calculation device with a memory device to adjust the temperature at any time so that the steel slabs in the furnace are heated in a predetermined heat-up pattern under such constraints. The system calculates the optimum setting values that yield a pattern, and operates based on the optimum setting values. The temperature of the heated material is determined at appropriate time intervals, and the temperature of the heated material at the current time and the furnace temperature setting are used to calculate the temperature transition of the heated material from the current time to the scheduled extraction time using a heat transfer model. The calculated prediction is displayed on a display device, the furnace temperature set value is corrected according to the difference between the displayed predicted temperature transition of the material to be heated and the target temperature transition, and the temperature set value of the heated material is adjusted according to the corrected set value. A continuous method characterized by repeating calculation prediction and display of the temperature transition of the heating material until the temperature transition prediction matches the target temperature transition, and thereafter controlling the furnace temperature based on the corrected furnace temperature set value. This is a method for setting the temperature inside a heating furnace.

Hereinafter, the present invention will be explained in detail based on an example in which the present invention is applied to a continuous billet heating furnace.

FIG. 1 is a flowchart showing the operating procedure in an embodiment of the present invention, focusing on one piece of steel in the furnace.

In this case, the atmospheric temperature of each part of the furnace measured by a thermometer is stored in a storage device as furnace atmosphere data in a chronological manner at appropriate time intervals (block 2).

On the other hand, the position of the steel billet in the furnace is determined from the pusher stroke and number of extrusions in the case of a pusher type furnace, or from the number of times the drive skid is driven in the case of a walking beam type furnace, and is determined in chronological order based on the time it enters the furnace. (block ■).

Based on the above-mentioned stored furnace atmosphere temperature data and furnace position data, the temperature of the steel billet from the time the billet entered the furnace to the current time is measured at appropriate time intervals (for example, every 2 minutes).
Calculated using a known transfer model by an arithmetic unit,
The calculated steel billet temperature is stored in chronological order as billet temperature data (Block ■), and the temperature transition status is displayed on a display device (for example, a graphic CRT) (Block ■).
).

Now, in the present invention, at an arbitrary time during the heating of the steel billet, the temperature transition of the steel billet from that time to the scheduled extraction time is predicted as follows, and this prediction result is used as the target temperature transition. If it does not comply with the above, adjust the set value of the furnace temperature and the scheduled extraction time as necessary to make it comply.
Thereafter, the furnace temperature is controlled based on the corrected furnace temperature set value.

Now, for example, when a steel billet has passed through the preheating zone of the heating furnace and is in the heating zone, the furnace operator issues a calculation command to the calculation device and calculates the furnace temperature set value (block ■) at the relevant time (current time). The scheduled extraction time (
The steel billet temperature during the period up to block (■) (block ■) is divided into appropriate time intervals and calculated using a heat transfer model formula to predict the steel billet temperature transition (block ■).

The heat transfer model formula in this case is the same as the calculation of the actual steel billet temperature described above, and is determined from the furnace temperature set value instead of the furnace atmosphere temperature measurement value (which can be determined experimentally in advance). Use ambient temperature.

Then, the calculation result, that is, the prediction of the steel billet temperature transition is displayed on the display device together with the billet temperature transition record up to the above-mentioned current time (block 2).

The furnace operator looks at this display and compares it with the target temperature transition (block) set in advance for the steel slab.If the predicted temperature transition does not match the target temperature transition, the furnace operator Depending on the difference, the furnace temperature set value at the current time is revised to a higher or lower set value and then set again (block 0, ■).

Also, if necessary, set the scheduled extraction time earlier or later (correct and set again) (block ■).

Thereafter, the predicted temperature transition is again calculated (block 2), displayed, and compared with the target temperature transition (block 2).

Repeat this operation and when the temperature transition prediction (block ■) matches the target temperature transition (block ■), use the corrected setting value (block 0) at that time as the furnace temperature setting value (or scheduled extraction time), and from now on controls the temperature inside the furnace using the corrected set value (block 0).

The above is an operation procedure that focuses on one steel billet in the furnace. However, if there are different types of steel billets in the furnace that are subject to different regulatory conditions as described above, select the steel billet with the stricter conditions. Either the above operations are performed for , or the operations are performed so that both conditions are satisfied.

As described above, according to the present invention, when the target heat increase pattern of the material to be heated in the heating furnace is determined, the heat increase pattern of the material to be heated is predicted at any point during heating, and the target heat increase pattern of the material to be heated is predicted. By correcting the set value of the furnace temperature based on the prediction, the heating furnace can be operated so that the actual heating pattern matches the target heating pattern. It is extremely effective in controlling the heating of heated materials.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the operating procedure in one embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. The temperature of the open heated material from the time the heated material enters the furnace to the current time is determined at appropriate time intervals, stored and displayed, and the temperature of the heated material at the current time and the temperature of the heated material at the current time are determined. Using the furnace temperature set value, the temperature transition of the heated material from the current time to the scheduled extraction time is calculated and predicted using a heat transfer model, and this is stored and displayed on a display device. Temperature transition prediction is the goal of correcting the furnace temperature set value according to the difference between the temperature transition prediction of the heated material and the target temperature transition, and calculating and displaying the calculation prediction and display of the temperature transition of the heated material based on the revised setting value. A method for setting a furnace temperature in a continuous heating furnace, characterized in that the furnace temperature is repeatedly controlled until it matches the temperature transition, and thereafter the furnace temperature is controlled based on the corrected furnace temperature set value.