JPS5841642A - Plastic working method - Google Patents

Abstract

PURPOSE:To execute plastic working of a metallic material with extremely high working efficiency, by detecting a phase transformation temperature by which the metallic material causes the largest plastic deformation, and executing the plastic working at said temperature, when heating and working the metallic material. CONSTITUTION:A metallic material to be worked 6 is supported by a fixed chuck 8 and a moving chuck 5, is heated electrically by electricity conductive chucks 8, 9, and its temperature is raised. To the material 6, slight tensile force is put by a cylinder 3, and its size varied as a temperature rises is detected by a length detector 7 connected to the moving chuck 5. It is inputted to a servo- unit 13 together with a signal of a tension length setting device 12, it is inputted to a working temperature controller 14 together with a detecting temperature by a detector 17 of the material 6 in that case, electrification is controlled so that the material 6 reaches a phase transformation temperature at which a degree of plasticity is highest, by a heating device 15, and after that, the material is worked by operating a moving lever 4 by the cylinder 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for plastically working metal materials in warm or hot conditions.

It is well known that when a metal material undergoes a phase transformation, it exhibits a superplastic phenomenon and is capable of significantly large plastic deformation.)
is beginning to be used industrially as a new plastic working method.

On the other hand, the phase transformation start temperature of metal materials is said to vary slightly depending on variations in the constituent elements, but it also varies depending on the heat treatment history and processing history, and it also varies depending on the heating or cooling rate until the phase transformation temperature is reached. be done. When attempting to control the heating or cooling of metal materials on an industrial scale within a relatively short range, conventional temperature measurement methods tend to cause temperature measurement delays and measurement errors, making it difficult to reproduce stable conditions. be. For example, in a radiation thermometer, the emissivity fluctuates depending on the surface condition of the material, and in a thermocouple method, it fluctuates depending on the way the temperature-measuring object and the thermocouple are connected.

On the other hand, the humidity range in which superplasticity appears is relatively narrow, so the timing at which the workpiece reaches such a temperature and the time at which the plastic processing method is applied to the workpiece must be matched. This method is particularly difficult to apply to products that are mass-produced on an industrial scale.

The present invention has been developed to overcome these technical difficulties, including internal factors such as the chemical composition of the workpiece and material history, as well as external factors in measurement.
It is possible to match the point at which the workpiece reaches the above-mentioned temperature and the point at which the plastic working method is applied extremely easily and with high precision, regardless of any factors, and the processing efficiency is greatly improved. ff+ has made it possible to do this!
IF:, which attempts to provide a processing method.

The drawings showing the embodiments of the present application will be described below.

FIG. 11 is a drawing schematically showing a mechanism for tensile working a rod-shaped workpiece as an example of plastic working of the workpiece. In this figure, 1 is the base, 2 is the (fixed chuck fixed to the base 1, the cylinder is exemplified as a 3-piece machining device, 4 is its advancing/retracting lever, and 5 is the extra edition at the tip of the additional punch 4. A movable chuck is a workpiece 6, which is made of non-austenitic steel or other various metal materials, and one end and a curved end of the workpiece are gripped by a fixed chuck 2 and a movable chuck 5, respectively.

Reference numeral 7 denotes a length detector shown as an example of a dimension detector, which is attached to the base 1, and its detection end is a movable part 7a.
is connected to the movable chuck 5. Reference numeral 8.9 denotes an energized chuck, which grips a portion of the workpiece side 6 that is close to the portion gripped by the chuck 2.5. Next, reference numeral 11 denotes an rIW temperature detector, which is designed to detect the temperature of the workpiece 6, and uses, for example, a radiation temperature needle. ν is a tensile length setting device, which is a device for setting the length of the workpiece 6 to be tensile processed in advance.

Reference numeral 13 indicates a servo unit, 14 indicates a processing temperature control device, and Takumi indicates a heating source.

Next, processing of the workpiece 6 using the above-described structure will be explained. First, the flow up of the workpiece 6 is controlled. That is, the workpiece 6 is heated by applying electricity from the heating power source to the workpiece side 6 via the current-carrying chuck 8.9. Then, as the temperature of the workpiece 6 gradually increases, its length also changes (elongates). The change in temperature is detected by the /II soakage detector 11. In addition, the change in length is determined by the change in the movable chuck 5.
is moved as shown by an imaginary line, and this movement is detected by the length detector 7. Note that this length measurement may be performed continuously or at any time.

In the process of increasing the temperature of the second material 6, the length of the workpiece 6 is elongated, and the length of the workpiece 6 changes as shown in FIG. 2, for example. During this process of change, if the structure of the workpiece 6 suddenly changes, this appears as a sudden change in length, as shown in the figure. Once this sudden change is detected, the process moves from row-temperature control to optimum processing temperature control. The above sudden change point can be detected by differentiating the measurement signal of the long elongation as shown in Fig. 8 (A) (an enlarged view of the sudden change in elongation in Fig. 2). This is done by obtaining a waveform of the change rate as shown and detecting the point where it becomes negative (or the point where it changes rapidly). These operations are performed by applying the detection signal of the detector 7 to the control device 14 through the servo unit 13, and by the device 1V14.

Next, optimal temperature processing control is performed as follows. If a sudden change in the length of the workpiece 6 is detected, the temperature detected by the temperature detector tic at that point is defined as quasi-temperature T1, and the temperature of the workpiece side 6 is increased by a predetermined ?M degree ΔT from that temperature. In order to increase the temperature, the power source 15 continues to energize the workpiece #A6 to give a predetermined thermal energy to the workpiece 6. The above-mentioned predetermined temperature ΔT depends on the material, dimensions, processing conditions, etc. of the workpiece side 6. ], and the predetermined thermal energy is determined according to the temperature ΔT.In this way, by additionally applying the predetermined thermal energy to the workpiece 6, the workpiece 6 becomes the optimum processing temperature T2.

In other words, the structure has the highest degree of plasticity. When such a state occurs, the power supply from the power source 15 to the workpiece 6 is stopped. For example, the above-mentioned control may be performed using a control device [
It is set to 14. In addition, in the process of temperature increase control and optimum processing temperature control, by applying a light tensile force to the workpiece 6 through the cylinder 3, even if the workpiece 6 has a high degree of plasticity, it remains soft. Even if it is, it is possible to prevent bending due to the weight.

2. Once the workpiece 6 has reached the structural state with the highest degree of plasticity, processing is carried out next. That is, the advancing/retracting rod 4 in the cylinder 3 is moved back to pull the workpiece 6, thereby enlarging it. In this case, by inputting the signal detected by the length detection device 7 and the signal output from the tension length setting device 12 to the servo unit B, and operating the cylinder 3 under the control of the servo unit B, The workpiece 6 can be stretched to a dimension preset on the setting device 2. Moreover, since the workpiece 6 has a structure with the highest degree of plasticity, the above-mentioned stretching process can be carried out by only requiring a small stretching force.

The length of the workpiece 6 in each of the above steps was detected by the length detector 7, but the detection can be done by directly detecting the movement of the advancing/retracting rod 4 in the cylinder 3, or by directly detecting the movement of the advancing/retracting rod 4 in the cylinder 3. This may be done by detecting the amount of

Next, various aspects of the above-mentioned processing are as follows.

(a) The process of temperature change in which the above operations are applied to the workpiece includes, in addition to the temperature raising process due to heating as described above, a temperature decreasing process due to cooling of the heated workpiece. The dimensional change may be a positive or negative process.

(b) In the case of heating the workpiece, in addition to the above-mentioned direct current heating, well-known methods such as furnace heating (FFJI) F-air heating, induction heating, etc.) can be applied.

(e) After detecting a sudden change in the dimensions of a workpiece, the following method is used to bring the workpiece into the most plastic structural state by applying a small amount of predetermined energy to the workpiece. There is a method like this.

(1) After detecting a sudden turning point of dimensional change, a constant electric power is supplied for a predetermined appropriate time depending on the material, dimensions, and processing conditions.

(2) Control the temperature increase rate of the workpiece at a constant rate and continue such temperature increase for a predetermined time 1. (8) Correct the temperature detector at the reference rate T1 and set the target value to adjust Controlled by the detection value of the detector.

(This is a relative temperature control based on the reference temperature T1, and the temperature increase ΔT is a small value of 0 to 50°C, so the control can be performed with high precision.) (4) The above-mentioned r
When the process of temperature change is a temperature-lowering process, the above energy is a negative value (cooling), and the control method is the same as (2) and (8) above or any other arbitrary method. is possible.

(5) The value of the energy may be 00 (the case where the temperature is maintained for a certain period of time).

(d) Processing of the workpiece does not necessarily have to be carried out in the most plastic structural state; by the time the sudden change in dimension is detected, the workpiece has already reached a very plastic structural state. Therefore, processing may be performed at that point.

(fl) When manufacturing a tapered rod by processing a workpiece, the workpiece may be given an 11-degree gradient in its axial direction prior to the tension processing. ! P! As a means for creating a gradient in plasticity, for example, a method such as cooling a part of the workpiece can be used1.The gradient in plasticity that is imparted can be used to create a tapered rod with a desired shape after tensile processing. It is advisable to set appropriate conditions to ensure that

As described above, in this invention, when plastically working the workpiece 6, a sudden change in the dimensions of the workpiece 60 is detected, and the time point and the time when the plastic working means are applied to the workpiece 6 are determined. Since the timings of the above are matched, it is possible to plastically work the workpiece 6 in a state in which it is very easy to be plastically worked, which has a great effect on extremely improving the working efficiency.

Moreover, in the present invention, when detecting the point in time when the workpiece 6 is in a state where it is highly susceptible to plastic working as described above,
As described above, since it captures the property caused by the internal state of the workpiece 6, which is the dimensional change of the workpiece 60, it is extremely clear that the workpiece 6 is in a state where it is extremely susceptible to plastic working as described above. can be captured accurately. In other words, it has the advantage of being able to reliably detect not only the external appearance of the workpiece but also the internal structural state of the workpiece. This is effective in ensuring the above-mentioned improvement in processing efficiency.

In addition, even if the property determined by the internal state of the workpiece 6 is captured as shown in "-", in the present invention, the dimensional change is captured as the VI: quality, so the workpiece 6 is It is possible to detect the above-mentioned sudden change point regardless of the material, and the method of the present invention has the advantage of being widely applicable to various workpieces made of different materials.

[Brief explanation of the drawing]

The drawings show an example of the present application, and Fig. 1 is a diagram showing an example of a processing mechanism for a workpiece, Fig. 2 is a graph showing the relationship between time, temperature, and elongation, and Fig. 8 is an enlargement of elongation. Figures and graphs showing changes in elongation rate. 6...Work material, 7...Length detector. (11) 220- Figure 2 Figure 3

Claims (1)

[Claims] When performing warm or hot plastic working by applying a temperature change to the workpiece, measure the change in the dimensions of the workpiece that has been subjected to the temperature change, and find the point at which the measured value suddenly changes. □ A plastic working method, characterized in that the above-mentioned workpiece is plastically worked at an altitude exceeding the temperature or humidity at the time of detection.