JPH06297031A - Drawing method - Google Patents

Abstract

PURPOSE:To produce a steel wire having a stable quality with a smaller labor power by successively drawing a wire rod with a drawing die through pinch rollers after forming a borax coating film. CONSTITUTION:The surface ruggedness of a hot rolled wire rod 1 which is mechanically descaled is uniformly adjusted and the borax coating film is formed. After that, an electric signal that is detected with a piezoelectric element 14 which is attached on the drawing die 13 is measured by separating the frequency of <=300kHz from the frequency of >=300kHz by a signal processor while drawing the wire rod with the drawing die 13 and outputted by contrasting them with a signal in the stable state. Then, after forming the borax coating film, successively the wire rod is drawn by the drawing die 13 through the pinch rollers 12 which are mounted on the inlet side of a die box 11 of a wire drawing mill within 20sec as continuously blowing warm wind. In this way, trouble such as die wear, disconnection, are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate wire drawing process in which wire rod is subjected to descaling and pre-drawing treatment and continuous wire drawing is carried out from the wire rod to the final heat-treated wire diameter. This is a method for manufacturing the intermediate drawn wire of (1) at low cost.

[0002]

2. Description of the Related Art The role of the intermediate wire drawing process of a wire is to process a steel wire so that stable processing can be performed in the next process. Is being investigated so that it can be processed in a more efficient manner.
This is becoming an even more important issue due to the serious labor shortage. In other words, there is an increasing tendency to reduce the labor force by making the process continuous and saving labor. In addition, many steel cord products have a product wire diameter of 1 mm or less, and the processing conditions are extremely strict in terms of area reduction and lubrication. In order to perform stable working under such conditions, it is an important factor to make the quality of the steel wire in the intermediate drawn material uniform.
In order to efficiently manufacture products of uniform quality, for example, a worker at the site can judge by sensing a slight change in the color of the steel wire during wire drawing, or stop the wire drawing and use a magnifying glass to clean the surface of the steel wire. It requires careful observation and experience of workers in the field, and it is a very difficult problem in the current situation where the number of skilled workers is small.

In order to solve such a problem, for example, a technique (Japanese Patent Laid-Open No. 58-221611) for detecting a surface flaw by using a cold eddy current flaw detector in a wire drawing process has been proposed. However, in the technology for detecting flaws with an eddy current flaw detector, in order to carry out maintenance to scrape off only the flawed portion with a tool such as a cutting tool, it is necessary to slow down the wire drawing speed during that time, and productivity is reduced. It has caused a significant decrease,
In some cases, more manpower may be required to maintain the flaw.

In this way, the quality of the products to be shipped can be improved by the method of detecting the defects and guaranteeing the quality, but at the same time, the yield and the productivity are deteriorated, so that the skilled labor force is insufficient. Under the present circumstances where further cost reduction is required, it is a heavy burden on the manufacturer, and it is not an effective means for simultaneously improving quality and reducing manufacturing cost. Furthermore, since it is difficult to detect defects such as seizure and die marks in the longitudinal direction of the wire by detection by eddy current flaw detection, it is necessary for a worker in the field to visually observe the steel wire after all.

Further, researches have been conducted to detect the occurrence of die wear and seizure flaws at the time of wire drawing by using a piezoelectric element. However, since the wire drawing line of an actual machine is greatly affected by noise, it is put to practical use. The current situation is that it has not arrived.

[0006]

When the method for detecting after a flaw is generated as described above is adopted, it is impossible to improve the productivity at the same time when the labor force is insufficient. In other words, in order to efficiently draw a wire rod and obtain a stable quality steel wire with a small labor force, it is necessary to stabilize the wire drawing lubrication state and grasp the change in the lubrication state before an abnormality occurs. is necessary.

As a result of a detailed investigation on the lubrication state during wire drawing, it was found that the wire drawing die is vibrating due to mechanical vibration and vibration of the steel wire itself in addition to vibration due to the lubrication state. . And the vibration due to the lubrication state is
It was found to be due to the contact between the steel wire and the wire drawing die. The vibration caused by the contact between the steel wire and the die is described in detail below. When the steel wire is drawn by the wire drawing die, the lubricant forms a lubricating film to prevent direct contact between the steel wire and the wire drawing die. However, the steel wire and the wire drawing die are not completely separated by the lubrication film even in a good lubrication state, and there is a portion that locally contacts depending on the unevenness of the surface of the steel wire. It was found that the vibration of the wire drawing die due to this local contact well reflects the state of the wire drawing lubrication.

Therefore, if the vibration due to the machine, the vibration of the steel wire itself and the unevenness of the irregularities on the surface of the steel wire in the longitudinal direction can be minimized, the vibration state of the die can be made constant, and the lubrication can be performed. If it becomes possible to detect the change in vibration of the wire drawing die when the state changes,
It was confirmed that changes in the wire drawing lubrication state could be judged. As a result of many experiments, it was found that the change of the wire drawing lubrication state can be known by using the piezoelectric element to detect and evaluate the vibration of the die by converting it into an electric signal.

That is, according to the present invention, the surface texture of the steel wire is made uniform and the vibration of the die due to the surface texture is stabilized, so that only the change in the vibration caused by the lubrication state is evaluated and before the abnormality occurs. (EN) A wire drawing method capable of efficiently manufacturing an intermediate wire drawing material with a small labor force by notifying a worker of a change in a wire drawing lubrication state.

[0010]

According to the present invention, the surface irregularities of a hot-rolled wire which has been mechanically descaled by a mechanical descaler are uniformly adjusted, a borax film is attached, and then a wire drawing die is used. While the electrical signal detected by the piezoelectric element attached to the wire drawing die, the signal processing device measures the frequency of less than 300 kHz and the frequency of 300 kHz or more in distinction, and in the wire drawing method of outputting in comparison with the signal in the stable state, After depositing the borax film, while continuously blowing hot air, the wire is drawn with a wire drawing die within 20 seconds via a pinch roller attached to the entrance side of the die box of the wire drawing machine. The main point is the wire drawing method.

[0011]

As described above, according to the present invention, by making the surface texture of the steel wire uniform and stabilizing the vibration of the die due to the surface texture, the piezoelectric element is provided with a lubrication state which has been considered difficult until now. Is a wire drawing method capable of notifying an operator of a change in the wire drawing lubrication state before an abnormality occurs. Therefore, the present invention comprises a step of making the surface of the wire uniform, a step of stabilizing the vibration of the die, and a configuration for detecting and evaluating the vibration of the die.

Each component will be described below. Mechanical descaling of hot-rolled wire by mechanical descaling is performed by batch-type pickling, which causes a difference in the degree of pickling between the lower side and upper side of the coil, and in the case of borax, drops accumulate on the lower side. This is because a good borax film cannot be formed uniformly. It is necessary to treat with a single wire in order to make the surface condition of the wire material uniform. Further, in batch type pickling, the workability is not improved because the wire rod coil is treated as it is, and it becomes impossible to achieve labor saving by performing the descaling and wire drawing process continuously by treating with a single wire. This is because.

Next, the reason why the surface irregularities of the wire are adjusted uniformly is to stabilize the vibration state of the die. For example, if the surface condition differs in the longitudinal direction of the wire rod, the vibration of the wire drawing die fluctuates. Since the piezoelectric element attached to the wire drawing die detects the vibration state of the die, if the vibration state is not stable, the detection signal and the lubrication state will be consistent even if the signal detection conditions of the piezoelectric element are set. Because I will not do it. As a means for homogenizing, after bending, the surface is adjusted by brushing, then unevenness of several microns is introduced by corroding the surface with acid, or mechanically on the wire surface by shot peening or a belt sander. It is also possible to introduce irregularities of a few microns. The size of the unevenness should be decided according to the processing conditions and the required characteristics of the product, but empirically, unevenness of several microns is effective for stabilizing the lubrication state.

The borax film treatment of the wire is performed because in mechanical descaling, the wire is processed in a single wire rather than in a coil unit, so that the film formation must be completed in a short time. In addition to borax, there is a chemical conversion coating such as bonderite as a lubricating coating treatment material for the wire rod, but a coating that involves a chemical reaction takes a long time to form the coating, and thus is not suitable for the method of treating with a single wire.

The reason why the electric signal is detected by the piezoelectric element attached to the wire drawing die while drawing the wire is to faithfully convert the vibration of the die into an electric signal for processing. Since the wire drawing die is water-cooled in the die box, it is possible to attach a waveguide rod from the viewpoint of waterproofing. A waveguide rod is a jig that transmits vibration of a die so as not to be damped like a stethoscope. However, when the piezoelectric element is attached to the die box, it is difficult to accurately detect the vibration of the wire drawing die. This is because the wire drawing die is fixed by a rubber O-ring or the like so that the cooling water does not leak, and this rubber absorbs the vibration. That is, it is desirable to detect the signal directly from the wire drawing die as much as possible.

The reason why the signal detected by the piezoelectric element is measured by the signal processing device while distinguishing between frequencies below 300 kHz and frequencies above 300 kHz is to detect the lubrication state with high sensitivity from many noises. From the results of many tests, the noise due to the contact between the wire drawing machine gear and the steel wire and the hook of the wire drawing machine is often less than 300 kHz, and the signal due to the metallic contact between the die and the steel wire is over 300 kHz. Many frequencies are generated. Therefore, by detecting the signal with this frequency as a boundary, it becomes possible to separate the noise and the signal due to the lubrication state.

The reason for outputting the signal in comparison with the signal in the stable state is that the detected signal is affected by many factors such as steel type, wire drawing conditions during wire drawing, type of lubricant, and descaling method. This is because it is not possible to evaluate the lubrication state on a fixed basis. As a format to output in comparison,
In addition to the method of outputting the change in the signal from the start of wire drawing with a pen recorder, the difference or ratio of the signals for a certain period of time is output to a monitor or printer to know the fluctuation with the signal in the stable state. You can also In addition, it is necessary to comprehensively judge from a variety of situations to judge how much a change from the stable state is abnormal. In other words, in this method, in order to detect a sign that an abnormality occurs, even if the detection signal changes from the stable state, there is no change in the appearance of the actual wire drawing. Whether it needs to be taken or not needs to be judged by the material and wire drawing conditions.

In the above wire drawing method, after the borax film is adhered, it is introduced into the wire drawing machine within 20 seconds while continuously blowing hot air, that is, the lubricating ability of the borax film formed on the surface of the wire or the lubricant. This is to eliminate local fluctuation factors of the ability as a carrier. Fluctuations in the lubrication capacity of the wire in the longitudinal direction are the biggest cause of the discrepancy between the detected signal and the actual lubrication condition.Therefore, the handling of the wire after borax film formation should be the most careful to evaluate the lubrication condition. This is where you need it. The borax liquid on the surface of the wire is dried in a few seconds to form a borax film. Since this borax film begins to absorb moisture in the air immediately after its formation, it is desirable to draw the wire as soon as possible. As a result of a detailed investigation, when the borax film is left for more than 20 seconds after being deposited, the surface layer part of the borax film locally absorbs water and a part where the performance of the film is deteriorated occurs. Especially, if hot air is not blown to the wire rod, the local deterioration becomes large, so it is necessary to guide the wire rod to the wire drawing machine while blowing warm air. Furthermore, once the step of winding into a coil after the borax film is formed, the borax generated on the surface is locally dropped off due to the rubbing of the wire rods, so it is better not to include the step of winding into a coil. good. If it takes a long time to dry, it is possible to further shorten the time until the borax liquid dries by preheating the wire before the borax treatment.

The reason for passing through the pinch roller attached to the die box entrance side of the wire drawing machine is to stabilize the vibration due to the contact between the surface of the wire and the die. If there is no pinch roller at the entrance of the die box, the wire rod will enter the die box with a large swell, and the wire rod may come into contact with the entrance of the die, causing abnormal vibration of the die.

[0020]

EXAMPLES Next, examples of experiments conducted on the present invention will be described. Example 1 First, as shown in FIG. 1, the equipment used in the example is a steel wire rod 1, a supply stand 2, a bending roller 3,
A wire brush 4, a pickling tank 5, a heating tank 6, a borax film treatment device 7, a hot air dryer 8, a dry continuous wire drawing machine 9-a to 9-h capable of continuous drawing in 8 stages, and a winding machine. 10 is a facility arranged in series. The pickling tank 5 uses 10% normal temperature hydrochloric acid, and the immersion time of the steel wire rod 1 is 15 seconds. If the time is shorter than this time or the acid concentration is low, it is not possible to introduce uniform unevenness on the surface of the steel wire rod 1. The heating tank 6 is filled with hot water of 80 ° C, and the steel wire rod 1 is heated to 80 ° C by passing through the tank.
This is because the temperature of the borax solution in the borax film treatment device 7 is set to 80 ° C. However, when the temperature of water becomes 60 ° C. or less, borax hardly dissolves in water, and borax film treatment is possible. Since it becomes impossible, the temperature of the borax liquid in the heating tank 6 and the borax film processing apparatus 7 is preferably about 80 ° C. The hot air dryer 8 is capable of generating hot air of 100 ° C., and the borax film is kept in the air until the steel wire rod 1 is guided into the die box 11 by the dry continuous wire drawing machine 9-a. Prevents absorption of water.

Dice box 1 of dry continuous wire drawing machine 9-h
1 is as shown in FIG. 2, and a pinch roller 12 for suppressing vibration of the steel wire is attached to the steel wire entrance. The piezoelectric element 14 was attached only to the final drawing wire die 13 and the vibration of the die was observed. The signal of the piezoelectric element 14 is processed by the signal processing device 15. The reason why the piezoelectric element 14 is attached only to the final stage is that the smoothing of the steel wire surface and the progress of die wear do not progress with only one die, and in the latter half of the die schedule, it becomes a set with several dies. This is due to the empirical judgment that they often proceed simultaneously. When it is possible to locally advance with one die, as a matter of course, it is necessary to attach the piezoelectric element 14 to all the dies.

Further, in the signal processing device 15, the ring-down value for calculating all the number of voltage amplitudes and the RMS value of the root mean square of the peak voltage of each amplitude are less than 300 kHz and 30.
Calculation is performed separately for 0 kHz or more, and the cumulative value of the measurement data is output in units of 1 second. Processing amount of steel wire rod 1 is 1 ton for each level
The wire was drawn one by one, and the lubricant was removed from the die box 11 when 500 kg had been drawn from the start of wire drawing, artificially causing poor lubrication, and a change in signal was observed. FIG. 3 shows the result of collecting the output data. It can be seen that if the lubrication is poor, that is, seizure or die wear occurs, the ring-down value of 300 kHz or more becomes significantly large. At the same time, regarding the RMS value, it was also observed that the RMS value of 300 kHz or more increased when seizure occurred and decreased when die wear occurred.

Example 2 The equipment used in Example 1 was used to observe how the signal changes by changing the constituent elements of the present invention, and to investigate whether the lubrication condition can be evaluated. . Table 1 summarizes the results. In Table 1, the pickling time is a means for introducing fine irregularities of about several microns on the surface of the wire after mechanical descaling,
This is an example in which the surface of the wire is corroded by an acid to introduce irregularities. If the pickling time is short, the irregularities introduced on the surface of the wire are insufficient, so the surface of the wire is not even.
Further, the hot air blowing time in Table 1 shows the time until the steel wire rod 1 is borax-treated by the borax film treatment device 7 and then drawn by the wire drawing die of the dry continuous wire drawing machine 9-a. It is a thing.

The level A is a level which is a standard of the present invention,
This is an example in which the most stable wire drawing and lubrication state can be obtained.
Levels B, E and F adjust the pickling time against Level A,
This is a modification of the surface roughness of the wire. At level B, a stable wire drawing lubrication condition was obtained because uniform unevenness was introduced on the surface of the wire, but at level E and F, surface unevenness was not sufficiently introduced, so the vibration condition of the wire drawing die. Is unstable and the detection signal does not match the lubrication state.

Levels C, D, G, H, and I are levels with different warm air blowing times. When the hot air blowing time becomes long, the borax film of the steel wire rod 1 absorbs water locally to deteriorate the lubricating ability and the property as a carrier of the lubricant, so that the vibration state of the wire drawing die can be stabilized. It will be difficult.
As can be seen from the levels C and D, if the hot air blowing time is 20 seconds or less, the vibration of the wire drawing die is stable and the detection signal and the actual lubrication state match, but like the levels G, H, and I. When the hot air blowing time is longer than 20 seconds, the vibration becomes unstable and the lubricating state cannot be detected.

Level J is an example of wire drawing without a pinch roller. Without the pinch roller, the vibration state of the wire drawing die is affected by the vibration of the steel wire, so the lubrication state cannot be detected. Levels K and L are examples in which the boundary frequency of the detection signal by the piezoelectric element is changed. Even if the boundary frequency is 200 kHz or 400 kHz, it is not possible to detect the wire drawing lubrication state due to the adverse effects of noise or the detection signal becoming too weak.

FIG. 4 is a typical example of changes in the detection signal when the wire is drawn under conditions other than the present invention. Under the conditions deviating from the conditions of the present invention as shown in this figure, it was not possible to predict seizure due to poor lubrication that occurred in the latter half of wire drawing due to large variations in measured values. It is considered that this is because the vibration of the die includes not only the vibration due to the lubrication state but also the vibration due to the unevenness of the surface of the steel wire or the vibration of the wire.

[0028]

[Table 1]

Example 3 Using the equipment used in Example 1, a hard steel wire rod was continuously drawn for 20 tons under the conditions of the present invention. FIG. 5 shows the progress of wire drawing and changes in measurement data. At about 6 tons from the start of wire drawing, the ring-down value of 300 kHz or higher and the RMS value tended to increase. Since seizure may occur, the acid in the deteriorated pickling tank was replaced with a new one, and a new lubricant was added to the die box. The condition is stable. If such measures were not taken, it is probable that seizure had occurred. The ring-down value tended to increase after about 15 tons, but the RMS value was low, so it was judged that this was a sign of die wear, and wire drawing was interrupted to replace the die. As a result of this wire drawing, no defects such as flaws and fluctuations in wire diameter occur in the 20 ton intermediate wire drawn material, labor for flaw inspection and maintenance can be omitted, and production loss at the time of die replacement is minimized. I was able to suppress it.

[0030]

According to the present invention, the wire drawing work is stabilized by observing the wire drawing lubrication state, troubles such as die wear and wire breakage are prevented in advance, and stable quality steel wire is used with less labor. It is possible to produce in.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of equipment used in an example.

FIG. 2 is a detailed view of a die box 11 attached to a dry continuous wire drawing machine 9-h.

FIG. 3 is a diagram in which data representing a signal detected by the piezoelectric element 14 over time and a situation of wire drawing are overlapped, and when the detection frequency is 300 kHz or more, the ring-down value and the RMS are shown.
The value indicates that the lubrication state can be evaluated.

FIG. 4 is a diagram showing the data detected by the piezoelectric element 14 over time and the situation of wire drawing, in which the signals detected under conditions other than the present invention reflect the wire drawing lubrication state. It means not.

FIG. 5 is a diagram in which data representing a signal detected by the piezoelectric element 14 over time, a wire drawing situation, and a wire drawing processing amount are overlapped, which are more appropriate depending on a change in a detection signal in a large wire drawing experiment. This is an example in which the occurrence of flaws due to seizure, wire breakage, and wire diameter defects due to die wear are prevented by taking various measures.

[Explanation of symbols]

 1 Steel Wire 2 Supply Stand 3 Bending Roller 4 Wire Brush 5 Pickling Tank 6 Heating Tank 7 Borax Film Treatment Device 8 Hot Air Dryer 9-a to 9-h Dry Continuous Wire Drawing Machine 10 Winding Machine 11 Dice Box 12 Pinch Roller 13 Wire drawing die 14 Piezoelectric element 15 Signal processing device

Claims (1)

[Claims] 1. A mechanical descaler is used to uniformly adjust surface irregularities of a hot-rolled wire rod that has been mechanically descaled, a borax film is attached to the hot-rolled wire rod, and then the wire rod is drawn by a wire-drawing die while being attached to the wire-drawing die. The electric signal detected by the piezoelectric element is 300k
In a wire drawing method in which frequencies below 300 Hz and frequencies above 300 kHz are separately measured and output in comparison with a signal in a stable state, a borax film is adhered, and then hot air is continuously blown to the wire drawing machine within 20 seconds. The wire drawing method is characterized in that the wire is drawn by a wire drawing die through a pinch roller attached to the entrance side of the die box.