JPS5817243B2 - Operating method in reheating furnace - Google Patents
Operating method in reheating furnaceInfo
- Publication number
- JPS5817243B2 JPS5817243B2 JP53124336A JP12433678A JPS5817243B2 JP S5817243 B2 JPS5817243 B2 JP S5817243B2 JP 53124336 A JP53124336 A JP 53124336A JP 12433678 A JP12433678 A JP 12433678A JP S5817243 B2 JPS5817243 B2 JP S5817243B2
- Authority
- JP
- Japan
- Prior art keywords
- slab
- temperature
- charging
- slabs
- hot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
Description
【発明の詳細な説明】
本発明は、再加熱炉における操業方法に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a reheating furnace.
近年省エネルギ対策の一環として連続鋳造機で、鋳造さ
れた連鋳鋼片を所定寸法に切断して得られたスラブ(約
800℃)を冷却させることなく温片スラブのままで再
加熱炉に装入するいわゆるホットチャージ圧延が実施さ
れている。In recent years, as part of energy-saving measures, continuous cast steel slabs are cut into specified dimensions using a continuous casting machine, and the resulting slabs (approximately 800°C) are loaded into a reheating furnace as hot slabs without cooling. So-called hot charge rolling is being carried out.
しかしこの場合温片スラブの再加熱炉への装入温度は、
連続鋳造後の経過時間およびスラブ寸法等によって種種
異なり、通常300〜650℃程度の差異があってこれ
ら温度差を有する温片スラブを同一のヒートパターンで
操業されている複数の再加熱炉で加熱することは、最低
温度のスラブを基準としての再加熱のため高温スラブに
は必要以上の熱量を付与することになりエネルギの有効
利用の点から考えるとはなはだ不経済であった。However, in this case, the temperature at which the hot slab is charged into the reheating furnace is
The temperature difference varies depending on the elapsed time after continuous casting and the slab dimensions, etc., and the temperature difference is usually between 300 and 650 degrees Celsius.The heated slabs with these temperature differences are heated in multiple reheating furnaces operated with the same heat pattern. This was extremely uneconomical from the point of view of effective use of energy, since reheating was performed based on the slab with the lowest temperature as a standard, which resulted in applying more heat than necessary to the high-temperature slab.
本発明は上述の問題点に鑑みてなされたものであり、以
下本発明の一実施態様を示す図面に基づいて説明する。The present invention has been made in view of the above-mentioned problems, and will be described below based on the drawings showing one embodiment of the present invention.
まず、第1図フローチャートに示す如く製品の製造仕様
条件を加味してスラブ寸法、スラブ加熱温度等の圧延ス
ケジュールを決定し、該圧延スケジュールに基づいて再
加熱炉に順次供給すべき温片スラブの装入予定本数およ
び再加熱炉に装入された温片スラブがどのようなピッチ
で再加熱炉から抽出されるかを推定するとともに、前記
両推定値と連続鋳造機でのスラブの切断時刻の推定値と
に基づき連続鋳造機でのスラブ切断時刻から再加熱炉に
装入するまでのトラックタイムを決定する。First, as shown in the flowchart in Figure 1, a rolling schedule including slab dimensions, slab heating temperature, etc. is determined taking into consideration the manufacturing specification conditions of the product, and based on the rolling schedule, hot slab slabs to be sequentially supplied to the reheating furnace are determined. In addition to estimating the number of slabs to be charged and the pitch at which the warm slabs loaded into the reheating furnace will be extracted from the reheating furnace, the above estimated values and the cutting time of the slabs in the continuous casting machine are estimated. Based on the estimated value, the track time from the time when the slab is cut in the continuous casting machine until it is charged into the reheating furnace is determined.
つぎに上記トラックタイムと連続鋳造機で鋳造された連
鋳鋼片を切断する各温片スラブの切断時点での温度とを
把握して次に示す伝熱計算により温片スラブの再加熱炉
に装入する時点の温度θinを算出する。Next, we ascertain the above track time and the temperature at the time of cutting each hot slab that cuts the continuously cast steel slabs cast by the continuous casting machine, and use the following heat transfer calculation to load the hot slabs into the reheating furnace. The temperature θin at the time of input is calculated.
すなわち上述した順序で算出した温片スラブの連続鋳造
機での切断時刻と該時刻での温片スラブ温度、さらに再
加熱炉への温片スラブの装入時刻およびスラブ寸法によ
り上記0式に示す伝熱方程式に基づいて温片スラブの再
加熱炉への装入温度θinを算出する。In other words, it is shown in the above equation 0 based on the cutting time of the hot slab slab in the continuous casting machine calculated in the above order, the hot slab temperature at that time, the charging time of the hot slab slab to the reheating furnace, and the slab dimensions. The charging temperature θin of the hot slab into the reheating furnace is calculated based on the heat transfer equation.
ここで θ(t 、X) :材料温度
t ニスラブ切断からの経過時間
X ニスラブの厚方向座標(0≦×≦H/2)ρ :材
料密度
C:材料比熱
λ :材料熱伝導率
H:温片スラブ厚
上記0式における初期条件
θ(O,X)−θ0・・・・・・・・・ ■ただしθ0
:連続鋳造終了時スラブ温度
および境界条件
(i)スラブ中心
(11)スラブ表面
ただしε:雰囲気との輻射率
θair :雰囲気温度
を上記0式に示す伝熱方程式に代入整理するとスラブの
再加熱炉への装入温度θinは
で求められる。Here, θ (t, X): Material temperature t Elapsed time from cutting the varnish slab Single slab thickness Initial condition θ (O,
: Slab temperature and boundary conditions at the end of continuous casting (i) Slab center (11) Slab surface, where ε: Emissivity with the atmosphere θair : By substituting the ambient temperature into the heat transfer equation shown in equation 0 above, the slab reheating furnace is obtained. The charging temperature θin is determined by:
ここてtinはスラブ切断から再加熱炉に装入するまで
の経過時間である。Here, tin is the elapsed time from cutting the slab to charging it into the reheating furnace.
さらに上記■式により求めた各温片スラブの再加熱炉へ
の装入温度θ団が近似であるものを集めて再加熱炉数と
同数の温片スラブ群に分割して、これらの各温片スラブ
群毎に所要圧延温度に加熱するための各再加熱炉ごとの
ヒートパターンを決定する。Furthermore, we collect the hot slabs whose charging temperature θ group to the reheating furnace obtained by the above formula A heat pattern for each reheating furnace for heating each slab group to the required rolling temperature is determined.
またさらに再加熱炉装入前の実際の温片スラブの表面温
度を測定し、温片スラブの装入平均温度を推定すること
により前記したように各ヒートパターンで操業なさしめ
ている再加熱炉の中から前記装入平均温度に対応するヒ
ートパターンを有する再加熱炉を選択して各温片スラブ
を装入し、所要圧延温度に加熱する。Furthermore, by measuring the actual surface temperature of the hot slab before charging into the reheating furnace and estimating the average charging temperature of the hot slab, the temperature of the reheating furnace operated under each heat pattern as described above can be estimated. A reheating furnace having a heat pattern corresponding to the average charging temperature is selected from among the reheating furnaces, each hot slab is charged therein, and heated to a required rolling temperature.
なお、上記温片スラブの装入平均温度とは、温片スラブ
毎に保有する表面部温度と中心部温度との温度差が時間
の経過に伴って変化することがら各温片スラブ毎にその
全体温度からみた平均温度をいい、これら温片スラブの
表面温度からの平均温度の推定は、伝熱計算によって求
められる表面温度と平均温度との関係から求められる。Note that the above-mentioned average charging temperature of hot slabs refers to the temperature difference between the surface temperature and center temperature of each hot slab that changes over time. It refers to the average temperature seen from the overall temperature, and estimation of the average temperature from the surface temperature of these warm slabs is obtained from the relationship between the surface temperature and the average temperature determined by heat transfer calculation.
即ち連続鋳造機で切断されたスラブは時間の経過と共に
温度降下するが、前記伝熱方程式■〜■において、θo
、、H9tを種々仮定することによって表面温度と平均
温度の関係が求められ、第2図はその一例であって厚さ
の異なるスラブを800°Cに加熱後の表面温度とスラ
ブ平均温度との関係を伝熱方程式によって求めたもので
ある。In other words, the temperature of a slab cut by a continuous casting machine decreases over time, but in the heat transfer equations
,,H9t, the relationship between the surface temperature and the average temperature can be obtained. Figure 2 is an example of this, and shows the relationship between the surface temperature and the slab average temperature after heating slabs of different thicknesses to 800°C. The relationship was determined using a heat transfer equation.
上記のように、スラブ1個毎にスラブ表面温度を実測し
て伝熱計算でそのスラブ平均温度を推定することにより
、各スラブをどのヒートパターンの再加熱炉に装入する
かを決定するのは、各スラブをより完全に目標温度に加
熱するために行なうものである。As mentioned above, by actually measuring the slab surface temperature for each slab and estimating the slab average temperature using heat transfer calculations, it is possible to determine which heat pattern to charge each slab into the reheating furnace. This is done to more completely heat each slab to the target temperature.
すなわち伝熱計算で求めたスラブの装入時点での推定温
度に基づき、その推定温度に近似しているスラブ群をそ
のままその推定温度に対応したヒートパターンに設定さ
れた再加熱炉に装入しても、目標とする加熱温度に加熱
することができるように思われるが、実際には、鋳片の
切断から再加熱炉に装入させるまでの間に発生するスラ
ブ運搬時のトラブルなどにより計算通りにならないスラ
ブもあるからである。In other words, based on the estimated temperature at the time of charging the slabs determined by heat transfer calculation, a group of slabs that approximate the estimated temperature are directly charged into a reheating furnace set to a heat pattern corresponding to the estimated temperature. Although it seems possible to heat the slab to the target heating temperature even if the slab is cut, in reality, calculations are difficult due to troubles that occur during transportation of the slab from the time the slab is cut until it is charged into the reheating furnace. This is because there are some slabs that do not fit into the street.
以上述べたように本発明方法によれば、予め決定された
圧延スケジュールに基づいて再加熱炉に供給すべき温片
スラブの本数を求めるとともに該スラブの本数に対応さ
せるべく各温片スラブの連続鋳造機での切断時点での温
度とスラブ切断から再加熱炉装入までの経過時間とを杷
握して温片スラブの再加熱炉に装入する時点の温度を算
出した後、該装入温度が近似であるものを集めて温片ス
ラブを再加熱炉数と同数の温片スラブ群に分割し、かつ
これらの各温片スラブ群毎に所要圧延温度に加熱すべく
再加熱炉でのヒートパターンを決定し、さらに再加熱炉
装入前の各温片スラブの表面温度を実測した後、該温片
スラブの装入平均温度を推定して、各温片スラブを前記
装入平均温度に対応するヒートパターンを有する再加熱
炉に分割して装入せしめて所要圧延温度に加熱するよう
になさしめたために、温片スラブを必要以上に加熱せず
、必要かつ最少限の消費燃料で再加熱炉を操業できて省
エネルギ対策に効果があり、ひいては製品のコストダウ
ンにも寄与できる発明である。As described above, according to the method of the present invention, the number of hot slabs to be supplied to the reheating furnace is determined based on a predetermined rolling schedule, and each hot slab is successively supplied in order to correspond to the number of slabs. After calculating the temperature at the time of charging the hot slab into the reheating furnace by taking into account the temperature at the time of cutting in the casting machine and the elapsed time from cutting the slab to charging the reheating furnace, The warm slabs are collected to have similar temperatures and divided into the same number of hot slab groups as the number of reheating furnaces, and each of these warm slab groups is heated to the required rolling temperature using the reheating furnace. After determining the heat pattern and actually measuring the surface temperature of each hot slab before charging into the reheating furnace, the average charging temperature of the hot slab is estimated, and each hot slab is adjusted to the charging average temperature. Since the hot slabs are charged separately into a reheating furnace with a heat pattern corresponding to the required rolling temperature and heated to the required rolling temperature, the warm slabs are not heated more than necessary and the required and minimum fuel consumption is used. This invention enables the operation of a reheating furnace, which is effective in saving energy, and can also contribute to reducing product costs.
第1図は本発明方法を実施するため・のフローチャート
図、第2図は、スラブ表面温度と平均温度との関係図で
ある。FIG. 1 is a flowchart for carrying out the method of the present invention, and FIG. 2 is a diagram showing the relationship between slab surface temperature and average temperature.
Claims (1)
スラブを冷却させることなく再加熱して圧延機に供給す
るに際し、予め決定された圧延スケジュールに基づいて
上記連鋳鋼片に対する温片スラブ本数を求めるとともに
、その切断時点の温度と装入時点までの経過時間とを把
握して温片スラブ装入温度を算出し、該温片スラブ装入
温度が近似であるものを集めて再加熱炉数と同数の温片
スラブ群に分割し、これら各温片スラブ群毎に所要圧延
温度に加熱すべく複数の再加熱炉のヒートパターンを設
定し、他方、温片スラブの装入時の表面温度を実施する
ことによって該温片スラブの装入平均温度を推定して、
該装入平均温度に対応するヒートパターンに設定した前
記再加熱炉に温片スラブを装入することを特徴とする再
加熱炉における操業方法。1. When reheating the hot slab obtained from the continuous cast steel slab cast by a continuous casting machine and supplying it to the rolling mill without cooling, the hot slab for the continuous cast steel slab is reheated and supplied to the rolling mill based on a predetermined rolling schedule. In addition to determining the number of slabs, the temperature at the time of cutting and the elapsed time up to the time of charging are calculated to calculate the hot slab charging temperature, and the warm slabs whose charging temperature is approximate are collected and reheated. The hot slab slabs are divided into the same number of hot slab groups as the number of furnaces, and heat patterns of multiple reheating furnaces are set to heat each hot slab group to the required rolling temperature. Estimating the charging average temperature of the warm slab by performing surface temperature measurement,
A method of operating a reheating furnace, comprising charging a warm slab into the reheating furnace set to a heat pattern corresponding to the average charging temperature.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP53124336A JPS5817243B2 (en) | 1978-10-09 | 1978-10-09 | Operating method in reheating furnace |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP53124336A JPS5817243B2 (en) | 1978-10-09 | 1978-10-09 | Operating method in reheating furnace |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5550436A JPS5550436A (en) | 1980-04-12 |
JPS5817243B2 true JPS5817243B2 (en) | 1983-04-06 |
Family
ID=14882812
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP53124336A Expired JPS5817243B2 (en) | 1978-10-09 | 1978-10-09 | Operating method in reheating furnace |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5817243B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61161047U (en) * | 1985-03-28 | 1986-10-06 |
-
1978
- 1978-10-09 JP JP53124336A patent/JPS5817243B2/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61161047U (en) * | 1985-03-28 | 1986-10-06 |
Also Published As
Publication number | Publication date |
---|---|
JPS5550436A (en) | 1980-04-12 |
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