JPH01136934A - Method for controlling temperature of wire rod in high frequency heating furnace - Google Patents

Abstract

PURPOSE:To secure drawn wire quality so that an aimed temp. is not out of an allowance range by putting the inlet position of a process at the time of starting wire drawing to the point and controlling the temp. of the wire rod at a tip part from here with high frequency electric power in accordance with the holding of working temp. CONSTITUTION:The wire rod 1 is worked at a deforming work process 2 and heat-treated at a high frequency heating process 3. The temp. control at the tip part from the point at the inlet position in the working process for the wire rod at the time of starting the wire drawing is execute with an arithmetic and controller 4 by setting the fixed value of plural terms 6a-6c in accordance with the holding heat of the working process, using a timer means 5 and changing the high frequency electric power with feed-forward control. After the working heat is fixed, the feed-back control is executed. By this method, the wire rod having good quality can be secured at a little waste wire.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of controlling the temperature of a drawn wire material, for example, in which heating is performed through a high-frequency heating process after a profile processing process.

(Prior Art) FIG. 3 is an explanatory diagram showing a processing and heating process for a drawn wire rod. In the figure, reference numeral 1 denotes a drawn wire rod, which is processed in a profile processing step 2 and then heat-treated in the next high-frequency heating step 3. Figure 3 (Al is the point at which the wire drawing starts, and P is the position of the wire rod 1 at the entrance of the processing step 2 at this time. Figure 3) is the point at which the above point P reaches the entrance of the heating step 3. , (C) shows the point when the same P point reaches the exit of the heating step 3.

The conventional temperature control of the wire 1 was to detect the temperature of the wire 1 at the exit of the heating process 3 from the beginning, and to control the set value of the high frequency power in the heating process 3 in order to make this the target temperature. . The control characteristic at the rise of the high-frequency power corresponding to each time (al to (C)) in FIG. 3 is as shown in E'' shown in FIG. , heating step 3
The temperature characteristics of the wire rod 1 on the exit side of
”, the allowable range for the target temperature H0 (, H
The temperature is controlled so that the temperature is 0±5°C.

(Problems to be Solved by the Invention) However, in the method described above, as shown in the characteristic diagram in FIG. becomes. This means that the wire rod 1 from the part immediately before point P to the second point onward is processed in processing step 2.
This is because the wire 1 was heated with the same high-frequency power E' as that of the wire 1 before the point P, even though the processing heat at the point P was also high. In this way, wire rod 1 has an allowable range (H0+
If there is a part that has been heat-treated above 5°C, the product quality will deteriorate, so in order to ensure the quality, it was necessary to use the wire 1 up to point d as the inspection line.

The present invention has been made in view of these problems, and aims to ensure that the temperature of the wire does not deviate from the target temperature tolerance range during wire drawing, to ensure quality, and to minimize the number of wire inspections. The present invention provides a method for controlling wire temperature in a high-frequency heating furnace.

(Means for Solving the Problems) In order to solve the above problems, the wire rod temperature control method in a high-frequency heating furnace of the present invention is such that when performing high-frequency heating after the completion of required processing, the wire rod temperature is The position at the entrance of the processing process is taken as a point, and from this point, the temperature control in the high-frequency heating process of the wire at the tip takes into consideration the processing heat of the above processing process, and controls the high-frequency power according to the processing heat. This is to control the temperature of the wire.

(Function) The present invention uses the method described above to control the temperature of the wire at the tip from the entrance position of the processing process of the wire at the start of wire drawing, that is, the heating control that takes into account the processing heat of the processing process. By controlling the high-frequency power according to the amount of processing heat, the temperature of the wire at the exit of the high-frequency heating process at the start is controlled to be within the allowable range in a short time.

(Example) A wire temperature control method in a high frequency heating furnace according to an example of the present invention will be described in detail below.

FIG. 1 is a block diagram of temperature control in the heating process in this embodiment, and FIG. 2 is a characteristic diagram showing changes in high frequency power and wire temperature over time in the same control.

In the figure, a wire rod 1 is processed in a profile processing step 2 in the same way as in the conventional example, and then heat treated in the next high-frequency heating step 3, and the same is true for time points a to c.

Here, the temperature control of the wire 1 in the heating step 3 is performed by the set output E of high frequency power by the arithmetic and control device 4. The control in the method of the present invention by the arithmetic and control unit 4 is such that at the start of wire drawing, feedforward control is performed in consideration of the influence of changing processing heat in processing step 2, and after the processing heat becomes constant, feedback control is performed. be.

The arithmetic and control device 4 has a timer means 5, a fixed value setting means 6, and a feedback control means 7, and the fixed value setting means 6 further includes a fixed value setting section 6a for periods 1 to 3.
~6C. In addition, this arithmetic and control device 4 includes:
As input signals, the target temperature H6 of the wire 1, the measured actual temperature H of the heated wire 1, the line speed V, the wire drawing start signal S, etc. are input. In addition, processing heat H1 of processing step 2 and room temperature H necessary for calculation processing to be described later.
It goes without saying that the number 5, etc. is input in advance.

Based on the input of the wire drawing start signal S, the timer means 5 starts a period 1 between time points a and b shown in FIG.
A period 2 between time points C, a certain period 3 after time C, and a period 4 thereafter are set, and the respective period setting outputs are input to the planting setting means 6 and the feedback control means 7. Here, the timer means 5 may be provided in a plural number according to the switching of the setting, or may be one which can be switched in plural times, and in short, each period after the input of the wire drawing start signal S It is fine as long as it is configurable.

The control action will be explained below.

First, when period 1 is set by the timer means 5,
This period is a period in which only the wire 1 that does not have processing heat from time a to time 3 is heated, and the first fixed value setting section 6a
Accordingly, the wire drawing speed V and the required heating temperature (target temperature H8
- room temperature H,) is set as a constant value power e1, where 6, = r (vl (H(1-Hb)
). Note that a rising period is required at time a, and after the set power e is stabilized, the actual temperature H of the wire 1 falls within the allowable range (±5
℃).

Next, at time point C, the setting by the timer means 5 becomes period 2, but in this period until the next time point C, during the heating step 3, the part of the wire 1 that holds the processing heat H8 and the processing heat H1 This is a period in which there are some parts in which the company does not hold any. The set power in period 2 is the weighted average of the set power el found in the above period 1 and the set power e2 found in period 3, which will be described later, based on the mixing ratio of the processing heat H1 holding portion, and is shown in Figure 2. As shown, it becomes a straight line with a slope that descends over time.
It is output from the second list price setting section 6b.

Next, when point P reaches the exit of heating step 3 at time C, the timer means 5 sets period 3.

During this period 3, for example, 3 seconds after the point P reaches the exit of the heating step 3, the fixed price is set to prevent hunting, and the wire drawing speed V and the required heating temperature are set from the third fixed price setting section 6C. (Target temperature H, - (normal temperature Hb + estimated processing heat H
1)) A constant power e2 is set with the parameter et = f (V+ (Ho-(Hb+Ha)))
is input as output power E to the heating process 3 side.

Then, after the regular price setting in period 3 is completed, the next period 4 begins, in which only the wire 1 having the processing heat H1 is heated, and the timer means 5 is set to a position where the feedback control means 7 is activated. Based on the output of the feedback control means 7, the heating control of the wire 1 in the heating step 3 is continued. Therefore, by comparing the actual temperature H of the wire 1 with the target temperature H0, the output power E is set according to the situation, and the actual temperature H is controlled to be kept constant.

By the way, as a result of implementing the method of the present invention under the conditions shown in the table below for materials with diameters of φ7 and φ91, the outlet temperature of the material heating process did not fall outside the allowable range (5 degrees Celsius above the target value).
Good quality products were manufactured with good yield.

Table (Effects of the Invention) As described above, the present invention provides a method for controlling the temperature of a wire rod in a high-frequency heating furnace. Since the temperature of the wire is controlled by controlling the high-frequency power according to the amount of processing heat, the wire temperature reaches a certain temperature at the start of wire drawing, and then heats up out of the allowable range. This invention has a great effect in that the tangent line is shortened to point D in FIG. 2, making it possible to secure wire rods of good quality.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the method of the present invention, Fig. 2 is a control characteristic diagram thereof, Figs. The figure is a control characteristic diagram in a conventional embodiment. 1 is wire rod, 2 is irregular processing process, 3 is high frequency heating process, 4
5 is a calculation control device, 5 is a timer means, 6 is a fixed value setting means, 7 is a feedback control means, and P is a point of the wire. Figure 2 X111%Ozu Figure 3 Figure 4

Claims (1)

[Claims] (1) When performing high frequency heating after completing the required processing,
At the start of wire drawing, the position at the entrance of the processing process of the wire is set as a point, and from this point the temperature control in the high-frequency heating process of the wire at the tip takes into account the processing heat of the above processing process, and adjusts the processing heat according to the holding of processing heat. 1. A wire temperature control method in a high frequency heating furnace, characterized in that the temperature of the wire is controlled by controlling high frequency power.