JPH06277743A - Continuous warm working method for deformed metallic bar - Google Patents

Abstract

PURPOSE:To efficiently form a deformed metallic bar having a complicated cross-sectional shape by preliminarily heating a base stock in rear of a die, applying the preliminarily heated base stock with retaining rear pressure and, at the same time, applying a product in front of the die with drawing front tensile force. CONSTITUTION:The base stock 1 before working is clamped by caterpillar type connecting shoes 4 and 4' and the base stock in rear of the working die 3 is applied with retaining rear pressure deltab of 0.5 to 1.0 yielding stress, the base stock 2 after working is clamped by similar caterpillar type connecting shoes 5 and 5' and the worked base stock in front of the die is applied with front drawing tensile force deltaf of 0.5 to 1.0 after working yielding stress. A high frequency heating coil 7 by which the base stock 1 is preliminarily heated in front of the die 3 is provided and a mechanism 9 by which a high frequency oscillator 8 is controlled so as temperature of the base stock 2 being worked is stably retained in a range of 300 to 400 deg.C is also provided. Accordingly, problems such as die filling and breaking prevention are resolved since the base stock is easily warm worked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies a combination of a force for pushing a raw metal rod behind a die and a force for pulling out a worked metal rod at the front of the die, and the raw material temperature at the time of working is kept at a warm temperature. The present invention relates to an excellent continuous warm working method for efficiently forming a deformed metal rod having a complicated cross-sectional shape by adding a heating temperature in advance in addition to a working heat generation temperature to form a region.

[0002]

2. Description of the Related Art Conventionally, in order to continuously process a metal rod into an irregular cross section, a method of drawing the metal rod forward through a die having a predetermined shape has been generally used. Since it reduces the surface area, it is necessary to combine several dies with a drawing machine and a heat treatment furnace in order to process the cross-sectional material into the desired irregular cross-sectional shape, which complicates the processing process and adjusts the work. A great deal of skill is needed. As a result, metal rods with irregular cross sections are very expensive.

[0003] For example, as a method for manufacturing a deformed wire made of a noble metal, as described in Japanese Patent Publication No. 1-26761, when manufacturing a deformed wire that requires an accurate shape and size, the apex of the apex angle is set. There is a method in which it can be provided on a forming roll and processed efficiently. This is used for soft metals and cannot be applied to high strength materials or materials with low ductility.

Further, as a cross-section reduction or profile cross-section processing of non-ferrous metals, for example, Wire Journal, 4-
Known as the Linex method by 1976, P64, this means sandwiches a flat plate material (not shown) between upper and lower grippers and utilizes the frictional force with the material to make a circular product from the die hole. Although it is introduced as a simple extrusion processing method, this method has a large bending after processing and often needs to be corrected later and the metal flow is disturbed, resulting in deterioration of product quality and When applied to difficult-to-process materials with low ductility, it is limited to processing when the extrusion ratio is relatively small.

As described above, when the conventional methods are applied to high-strength materials or difficult-to-process materials with low ductility, it is difficult to obtain a large area reduction rate at one time, or product quality defects occur. To do. In order to increase the cross-section reduction rate, it is necessary to repeat the processing, but in that case, in order to prevent the increase of the processing force caused by the repeated processing and the occurrence of fracture due to the decrease of the material ductility, annealing is performed several times during the process. It was necessary to go through complicated steps such as having to carry out.

Therefore, a skilled engineer is indispensable for manufacturing a metal rod having an irregular cross section having a complicated shape, and in addition, equipment cost and processing cost are inevitably enormous. Further, if the shape is complicated, there are many shapes that cannot be realized even if the processing is repeated several times. Recently, a technique of combining extrusion and drawing has been proposed as a method for coping with these problems. According to the method disclosed in Japanese Patent Laid-Open No. 3-254311, in which two pairs of connecting shoes are used to combine pushing and drawing of a material with respect to a die, this is an effective technique for large reduction of surface area, but has a simple shape. In any case, in the case of complicated deformed shapes such as fins, it is easy for shape instability to occur due to friction with the shoe and strong pressing with the wheel.
It cannot be applied to high-strength materials or difficult-to-process materials, and it is nothing but providing technology for processing simple deformed bars.

That is, a method for operating a high-strength material or a difficult-to-machine material, which is difficult to form a complicated cross section having a markedly irregular outer shape, has not been given. As described above, the manufacturing of a metal rod having an irregular cross section having a complicated shape requires a great deal of cost and is an essential requirement for a skilled technician, and the shape that can be manufactured is also greatly limited.

[0008]

SUMMARY OF THE INVENTION The present invention is extremely efficient in the production of deformed section metal rods with complex shapes, which is very time-consuming in the prior art, without the need for a skilled technician. Technology to do so.

[0009]

DISCLOSURE OF THE INVENTION The present inventors have made various studies to solve the above-mentioned drawbacks of the prior art and to make it possible to apply such a means to a deformed metal rod having a complicated shape. As a result, the material at the back of the die is preheated and the preheated material is pushed back to give a backward pressure, while the product in front of the die is simultaneously subjected to drawing front tension and greatly reduced surface area in the warm heating area. I found the technology to do.

This technique was the fate of the conventional method,
It is possible to almost completely prevent buckling and breakage during processing of a deformed metal rod having a complicated shape and to efficiently form a desired complicated shape with a high surface reduction rate.

The term "complex shape" as used herein does not mean a simple triangle, quadrangle, or polygon, but rather has a plurality of protruding portion shapes called fins described in FIG. 3. For example, its height H is In the case of (a), the radius r of the inscribed circle is
On the other hand, in the rectangular cross section as in the case of (b), it is assumed that the radius is 0.2 to 0.8 with respect to the radius r of the inscribed circle.

That is, the gist of the present invention is to provide two pairs of connecting shoes at the front and rear of the die, press the material into the die, and perform processing by combining drawing with the material, and preheat the material behind the die. To 300 to 400 while applying a pushing backward pressure of 0.5 to 1.0 times the yield stress and a pulling forward tension of 0.5 to 1.0 times the post-working yield stress in front of the die. A continuous warm working method for a deformed metal rod is characterized in that the mold filling property of a complex shape is improved in one pass by working in a temperature range of ° C.

In this case, either the pushing rear pressure or the pulling front tension is controlled to a constant value, and the preheating temperature is also controlled. It is a processing method.

[0014]

In FIG. 1, the material 1 before processing is gripped by the endless track type connecting shoes 4, 4'and the rearward pressure σ _b is applied to the material 1 behind the processing die 3 to give the same endless track connecting shoe 5. , 5 ', an example of a continuous machining apparatus for a deformed metal rod having a complicated shape that grips the material 2 after machining and gives a drawing front tension σ _{f in} front of the die. On the other hand, a high-frequency heating coil 7 that heats the material 1 in advance is provided in front of the die so that the material 2 being processed is 300 to 400
A mechanism 9 for controlling the high-frequency oscillator 8 is provided so as to be stabilized in the temperature range of ° C. In this case, not only the processing speed and surface reduction rate, but also the processing heat generation varies depending on the load balance between the pushing rear pressure and the pulling front tension. The raw material 1 is preheated when passing through the high frequency heating coil 7 in front of the die 3 so as to be in a temperature range of 400 ° C.

In this figure, a pair of connecting shoes 4,
An endless track type extrusion device in which 4'is continuously arranged and connected is installed at the rear of the working die 3 and a rear pressure σ _b for pushing the raw material 1 is applied. On the other hand, in the front of the processing die 3, a front tension σ _f
Is applied to the deformed metal rod 2 at the same time as the rearward pressure σ _b .

At this time, a load control method is adopted in which the rearward pressure σ _b is constant, and the frontal tension σ _f shares a part necessary for machining, and conversely, the frontal tension σ _f is constant. In the load control method, one of the rear pressure σ _b and the method of sharing a part necessary for processing is used.

Using this apparatus, the coiled or linear material 1 is continuously fed to the endless track type extrusion apparatus and processed. When the deformed metal rod 2 after processing is rewound into a coil shape in a situation where the product shape does not have a problem such as twisting or indentation,
Alternatively, it is possible to arbitrarily set up a work process, such as a case of cutting a fixed length straight.

In the present invention, preheating the material at the rear of the working die and applying the pushing rear pressure results in higher compressive stress than in the case of processing only by the pulling front tension, and 300 to 400 ° C
Since the temperature is controlled to the warm working temperature range, good metal fluidity makes metal die filling into a die having a complicated shape extremely effectively.

Here, the reason why the rearward pressure σ _{b is set} to 1.0 times or less of the yield stress σ _y1 before processing the material is in order to prevent buckling of the material metal rod, and 0.5 The reason for setting the value more than twice is that the backward pressure σ _b has a weaker degree of acting as the mold filling property _if it is less than this, and it is necessary to increase the area reduction rate. Further, the material 1 is preheated and the temperature at the time of working is set to 300 to 400 ° C. because the deformation resistance of the worked metal rod 2 is small and the metal fluidity to the die 3 having a complicated shape is good. This is because it is shown.

Further, the drawing front tension σ in front of the die 3
_{When f} is appropriately combined, a large surface reduction rate can be easily imparted by combining the processed metal rod 2 with the rear pressure σ _b ,
Allows for desired mold filling. Here, the reason why the forward tension σ _f is 1.0 times or less of the yield stress σ _y2 after the material is processed is to prevent fracture, and of course, it is set to 0.5 times or more. This is because it is intended to positively utilize the heat generated during the die processing due to the surface reduction processing. The yield stress mentioned here refers to the yield point or 0.2% proof stress described in JIS Z2241. Further, the bending of the metal rod 2 after processing can be made extremely small by sufficiently applying the tension.

As described above, since warm working can be easily realized by combining the die front tension σ _f and the back pressure σ _b and preheating, die filling of complex-shaped dies, prevention of breakage, and suppression of bending. As described above, many problems that were difficult to solve by the conventional techniques have been solved.

By providing a mechanism for controlling either the rear pressure σ _b or the front tension σ _f to a constant value, the rear pressure σ _b and the front tension σ _f can be operated in a state close to the limit. By suppressing the fluctuations of both
It is possible to prevent breakage and buckling and process the cross-section of the metal rod uniformly in the longitudinal direction with high accuracy. Furthermore, it is desirable to dispose a cutting machine in the case of a product having a straight length like a deformed section steel wire and having a prescribed length.

As described above, the present invention makes it possible to form a deformed metal rod having a complex cross-section having a high reduction ratio and an effective complex shape without buckling or breaking of the metal rod, and particularly steel or high strength alloy. It is intended to provide a technique effective for continuously processing a metal rod having a deformed cross-section of a high strength material such as, or a difficult-to-machine metal material having low ductility.

[0024]

EXAMPLE FIG. 2 is a perspective view of a rectangular cross-section metal rod with fins, in which four-direction fins are continuously provided in the longitudinal direction. Since this shape makes it difficult to form fins, and the fin height is an extremely good measure for evaluating the mold filling property, the effectiveness of the present invention was judged based on this shape.

Material 1 has a yield stress of 60 kgf / mm ² and a diameter of 1.
A solid S53C rolled wire coil having a circular cross section of 0.2 mm was used, and a metal soap was added to the phosphate for lubrication. The withdrawal speed of the processed metal rod 2 is 30m / during initial processing.
With a min, a continuous machining mechanism that can control 70 m / min during steady machining was adopted.

The force applied to the raw metal rod 1 is a die back pressure σ _{b which} is 0.10 to 1.14 times the yield stress σ _y1 before working, and the yield after working of the worked metal rod 2. Various combinations of die front tension σ _f of 0.40 to 1.11 times the stress σ _y2 were given. The die used has the shape shown in FIG.
Rectangular shape 6 × 8mm, fin width W is 2mm, height H is 1.4
It was set to 0 mm, and if the fins were filled with the material, it was judged that the mold was sufficiently filled. Furthermore, in consideration of problems such as buckling and disconnection during processing,
It was judged by x.

At this time, the material is preheated to 100 to 300 ° C. or left at room temperature in the rear of the processing die, but the processing speed, the surface reduction rate, the extrusion pressure σ _b and the drawing tension σ _f are applied. Depending on the balance etc., the processing temperature changes depending on the amount of heat generated by the specified processing material. Therefore, attach a temperature sensor to the die outlet and feed this back to the high frequency heating transmitter to increase the processing material temperature to about 200 ~.
The control was carried out in the range of 400 ° C. Forward tension ratio σ _f ′
= Σ _f / σ _y2 and the rear pressure ratio σ _b ′ = σ _b / σ _y1
Table 1 shows the processing conditions of this example together with the results.

[0028]

[Table 1]

Test numbers A to I are full of molds, but A-
In Nos. 1 to I-1, since the temperature during processing was low, the fin height was less than 1.35 mm and the die was not sufficiently filled. For K, L and M, the material buckled behind the die and machining became impossible, and for N and O, the material broke at the front of the die and machining became impossible. In P to U, the fin height was less than 1.3 mm due to insufficient extrusion pressure or front tension, and the die was not filled. From these results, according to the processing in the area of the present invention, predetermined molding is possible, and the effectiveness of the present invention is shown.

[0030]

According to the present invention, there is a problem such as disconnection which occurs when a deformed metal rod is processed by simply applying a drawing force by a winder in front of a die of a conventional means to a material, and a steel having a straight rod shape. By overcoming the drawbacks of continuous processing of wires, it is possible to efficiently and continuously process deformed metal rods having complicated shapes, especially difficult-to-machine materials and high-strength materials. Moreover, according to the present invention, the bending and bending can be greatly suppressed, so that the precision machine parts can be optimally processed. The material to be processed is not limited to a solid material, and it is obvious that it can be applied not only to a hollow material but also to a material filled with a non-metallic substance or a dissimilar metal inside the tube, which is industrially valuable.

[Brief description of drawings]

FIG. 1 is an explanatory view of a continuous machining apparatus for a deformed metal rod that applies rear pressure and front tension of a machining die that constitutes the present invention.

FIG. 2 is a perspective view of a deformed metal rod with fins that can be used in the present invention.

3A and 3B are explanatory views of the shape of the present invention.

[Explanation of Codes] 1 Material 2 Work Material 3 Dies 4, 4 ', 5, 5'Endless Track Connecting Shoe 7 Material Heating Coil 8 High Frequency Transmitter 9 Temperature Control Mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takanari Miyaki 12 Nakamachi, Muroran City Nippon Steel Corporation Muroran Works

Claims (1)

[Claims] 1. When two pairs of connecting shoes are provided before and after the die and the material is pushed into the die and combined with drawing, when the material is preheated behind the die, the yield stress of the material is 0. Push back pressure of 0.5 to 1.0 times,
In front of the die, the yield stress after working is 0.5 to
A continuous warm working method for a deformed metal rod, characterized in that a work material is processed into a complicated cross-sectional shape in one pass in a temperature range of 300 to 400 ° C. while applying a pulling front tension of 1.0 times.