JPS5952937B2 - Line speed control method for continuous annealing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a line speed control method for continuous annealing equipment suitable for continuously annealing strips of various sizes.

The conventional continuous annealing equipment for the 1-+7 series was designed to continuously produce strips of a specific type, such as steel plates for tinplate, with a uniform material and with few material restrictions and a narrow control range for strip temperature. It was being used.

In recent years, due to the diversification of products, production costs, and production yields, continuous annealing of strips of various types and sizes has become desirable.For this reason, continuous annealing equipment has a wide control range for strip temperature and can be used in accordance with material constraints. , equipment has become available that allows the operating conditions for heating, soaking, cooling, etc. to be changed arbitrarily.

However, when continuously annealing strips of various types and sizes, it is necessary to perform annealing under optimal conditions for each strip and at the maximum capacity of the equipment in terms of production costs and production yields. Therefore, judgments regarding operating conditions, constraints, etc. for a given strip, calculation of line speed for maximum production volume, etc. are complicated, and there is a problem that operation is difficult with conventional control methods.

In other words, in order to continuously anneal strips of each steel type and size to achieve the desired uniform quality, the optimum one is selected from a variety of uniform patterns, the scorching temperature, cooling rate, etc. are calculated for each strip, and then these It is necessary to calculate the line speed and operate the continuous annealing equipment in order to maximize the production of strips, but there are many points that are difficult to judge by the operator alone, especially when determining the material, etc. For strips and the like that have large restrictions, operation cannot be performed by an operator.

The present invention has been made in view of the above circumstances, and its purpose is to calculate the line speed and control the continuous annealing equipment based on the line speed so as to maximize the production amount of a predetermined strip. The present invention provides a line speed control method for continuous annealing equipment that can control strips of various types and sizes under optimal conditions.

That is, the present invention focuses on the heating, soaking, and cooling capacities in the heating zone, soaking zone, and cooling zone that constitute continuous annealing equipment, annealing conditions such as furnace temperature, strip width, strip thickness, temperature, etc. A relational expression between the characteristics of and the maximum capacity line speed is calculated, and from this relational expression, the maximum capacity line speed of each band is calculated for each predetermined strip, and the line speed is controlled based on the minimum value of these maximum capacity line speeds. This is a line speed control method for continuous annealing equipment characterized by the following.

The present invention will be explained below with reference to the drawings.

As shown in Fig. 1, strips 1 of various types and sizes are heated by radiant tubes, electric heaters, etc., and are kept cooled by a heating zone 2 and soaking zone 3, which keep the temperature uniform, and cooling tubes, plenum chambers, electric heaters, etc. It passes through the first cooling zone 4, the second cooling zone 5, and the third cooling zone 6 in order and is continuously annealed.

In this continuous annealing, the optimal one is selected for each strip from a variety of heat patterns (Xl,...Xi...Xn) as shown in Figure 2, and the soaking temperature, cooling rate, etc. are calculated. By operating according to the heat pattern, continuous annealing of strips of various sizes is possible.

In the present invention, a process computer dynamically selects heat patterns for individual strips, calculates soaking temperatures, cooling rates, etc., and calculates optimal line speeds for effectively using continuous annealing equipment. Let's do it.

First, to obtain the heat pattern Xi shown in Figure 2, various strip data (standards, steel type, chemical composition, material, plate size, coil weight, etc.) managed by the host computer are transmitted to the process computer. This calculator calculates the heat pattern based on the standard, steel type, etc.

Once the heat pattern is determined, the soaking temperature Ts of the strip
Cooling rate CR is calculated from chemical components and materials.

Once the annealing conditions such as the heat pattern Xi, soaking temperature Ts, cooling gray (CR), etc. of a predetermined strip are calculated in this way, the maximum capacity line speed in each section of the continuous annealing equipment is then determined.

Maximum capacity line speed L81M of heating zone 2 is calculated from equation (1).

LSIMAX=fl (Ql, W, D, 'r,,
(1) Ql: Heating capacity of radiant tube or electric heater, etc. W Strip width D Strip thickness T1: Strip temperature on exit side of heating zone Tz1: Furnace temperature of heating zone Maximum of heating zone 3 Capacity line speed LS2Mml below (2
) is calculated from the formula.

L32MAX=f2 (Q2. W, D, T1.
T2. TZ2゜t)
......(2) Q2: Heating and soaking capacity of radiant tube or electric heater, etc. W Nistrip width D Nistrip plate thickness T1: Strip temperature on the soaking area input side T2: Strip temperature on the soaking area exit side Tz2 : Temperature inside the soaking zone furnace t: Soaking time Maximum capacity line speed L in the first to third cooling zones 4 to 6
83MAX' = L85MAX is as follows (3) to (5)
Calculate from the formula.

LS3MAX=f3(Q3.W, D, T2.T3.Tz
3゜CR,t)・
...(3) LS4MAX-T4 (Q4.W, D, T3.
T4. Tz4゜CR,t)
...(4) LS5MAX=f5 (Qs,
W, D, T4. T5. Tz5゜CR,
t) ...(5)
Q3. Q4. Q5: Cooling and heat retention capacity of cooling tube, plenum chamber, electric heater, etc. W Nistrip width D Nistrip plate thickness T2. T3. T4. T5: Strip temperature on the exit side of each cooling zone CR: Cooling rate t: Holding time Therefore, the maximum capacity speed of each section calculated above LSIMAX = LS5MAX and the maximum line speed LSM of the equipment constrained by the mechanical and electrical system. The maximum capacity line speed LS in one helicopter can be determined from the following equation (6).

LS=MIN(LSlMAx, LS2MAX, LS3M
AX.

LS4MAX, LS5MAX, LSM)
...(6) Equations (1) to (5) for calculating the maximum capacity line speed can be calculated theoretically by heat transfer calculations, empirically from experimental data, or a combination of both. Obtainable.

As explained above, according to the present invention, the maximum capacity line speed of each unit is calculated and the line speed is controlled based on the minimum value of these maximum capacity line speeds, so continuous annealing operation for a wide variety of sizes is optimized. It has remarkable effects that can be controlled by conditions.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of continuous annealing equipment, and FIG. 2 is an explanatory diagram showing a heat pattern in the continuous annealing equipment. 1... S) IJ tube, 2... Heating zone, 3... Soaking zone, 4-6... First to third cooling zone.

Claims (1)

[Claims] 1. Obtain in advance the relational expressions between the annealing conditions and strip characteristics and the maximum capacity line speed for each unit constituting the continuous annealing equipment, calculate the maximum capacity line speed of each unit from the relational expressions, and calculate the maximum capacity line speed of each unit. A line speed control method for continuous annealing equipment, characterized in that the line speed is controlled based on a minimum value of the line speed.