JP2816080B2 - Cold continuous processing of deformed metal bars with complex shapes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deformed metal rod having a complicated shape by applying a combination of a force for pushing a material metal rod behind a die and a force for drawing a processed metal rod in front of the die. The present invention relates to a continuous processing method for efficiently forming a sheet.

[0002]

2. Description of the Related Art Conventionally, in order to continuously process a metal rod into a deformed section, a method of drawing the die in front of a die through a die having a predetermined shape is generally used. To reduce the surface area, it is necessary to combine a number of dies, a drawing machine and a heat treatment furnace in order to process the cross-sectional material into the desired irregular cross-sectional shape. Extreme skill is required.

As a method for producing a deformed wire made of precious metals, as described in Japanese Patent Publication No. 1-26761, when producing a deformed wire requiring an accurate shape and dimensions, the apex of the apex angle is determined. There is a method that can be provided on a forming roll to enable efficient processing. This is used for soft metals and cannot be applied to high strength materials or materials with low ductility.

Further, as a method for reducing the cross section of non-ferrous metals and processing a deformed cross section, for example, Wire Journal, 4-
1976, P64, which is known as the Linex method. This means sandwiches a plate-shaped material (not shown) between upper and lower grippers and uses a frictional force with the material to form a circular product from a die hole. Although it is simply introduced as an extrusion processing method, this method has a large bending after processing and often needs to be corrected later, and the metal flow is disturbed and the product quality deteriorates, so high strength materials and However, when applied to difficult-to-process materials with low ductility, the processing is limited to the case where the extrusion ratio is relatively small.

As described above, when any of the conventional methods is applied to a high-strength material or a difficult-to-process material having a low ductility, it is difficult to obtain a large cross-sectional reduction rate at a time, or the product quality is poor. I do. In order to increase the cross-sectional reduction rate, it is necessary to repeat the processing, but in that case, in order to prevent the occurrence of breakage due to the increase in the processing force caused by the repetition of processing and the decrease in the ductility of the material, annealing several times in the middle And complicated processes.

Therefore, a skilled technician is indispensable for the production of a deformed metal bar having a complicated shape, and equipment costs and processing costs are unavoidably enormous in many cases. In addition, there are many shapes that cannot be realized even if processing is repeated several times if the shape is complicated.

Recently, as a method for solving these problems, a technique combining extrusion and drawing has been proposed. Japanese Patent Application Laid-Open No. Hei 2-229615 discloses a technique in which a wire is pressed against the outer periphery of a rotating wheel with a fixed shoe to apply a dice pushing force, and a pair of connecting shoes sandwiches the wire to apply a pulling force from the die. . This is an effective technology for large area reduction processing of high-strength materials, but not only for simple shapes, but also for fins and other complicated deformed shapes, which tend to cause scratches due to friction with the shoe and strong pressing with the wheel. Not suitable for high strength materials and difficult-to-machine materials.

Further, according to the method disclosed in Japanese Patent Application Laid-Open No. 3-254331, in which the material is pushed into and pulled out of the die by using two pairs of connecting shoes, friction with the fixed shoe as described above, Although there is an advantage such as no flaws appearing, it does not deviate from one that provides a simple deformed rod processing technique. That is, no method has been provided for operating particularly high-strength materials and difficult-to-work materials which are difficult to form a complex cross-section having significantly irregularities. As described above, the production of a deformed metal bar having a complicated shape is not only a great expense, but also an indispensable requirement for a skilled technician, and the shape that can be produced is greatly limited.

[0009]

SUMMARY OF THE INVENTION The present invention relates to the production of a metal rod having a complicated shape and a complicated cross section, which has been very troublesome in the prior art, and can be carried out extremely efficiently without the need for a skilled technician. Technology to provide

[0010]

Means for Solving the Problems 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 means to a deformed metal bar having a complicated shape. As a result, the inventors have found a technique for simultaneously applying a pressing rear pressure to a material behind a processing die and a pulling front tension to a product in front of the die. This technology almost completely prevents the buckling and breakage of the metal rod, which was the fate of the conventional method, and makes it possible to efficiently form a deformed metal rod having a complicated shape with a high area reduction rate. .

Here, the complex shape does not mean a simple triangle, a quadrangle, or a polygon, but has a plurality of protrusion portions called fins described with reference to FIG. In the case of the circle in (a), the radius r of the inscribed circle
On the other hand, in the case of a rectangular cross section as in the case of (b), this means a shape formed at a ratio of 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 a method for cold continuous working of a deformed metal rod having a complicated shape in one pass by combining indentation and extraction of a workpiece with respect to a die by using two pairs of connecting shoes. The indentation rear pressure of 0.2 to 1.0 times the yield stress before processing of the material at the rear and the yield stress of 0.1 to 1.times. A deformed metal having a complicated shape characterized by adding a zero-time drawing forward tension in an appropriate combination within the range of the following expression and controlling either the rear pressure or the front tension to a constant value. It is in the cold continuous working method for bars. To _{0.95σ f '+ 1.7σ b' ≧} 1.0 wherein the front tension ratio _{σ f '= σ f / σ} y2, rear pressure ratio sigma
_b ′ = σ _b / σ _y1 , σ _f is the forward tension, σ _y2 is the yield stress after processing the material, σ _b is the rear pressure, and σ _y1 is the yield stress before processing the material.

[0013]

[Action] Figure 1 is a track 4,4 'by grasping the material 1 before the process gives push the rear pressure sigma _b the material behind the working die, like endless track 5,5', the post-processing shows an example of a continuous processing apparatus of profiled metal bar having a complicated shape which imparts the pulling forward tension sigma _f in die forward of grip the workpiece 2.

In this figure, a pair of connecting shoes 4,
An endless track type extrusion device formed by continuously arranging and connecting 4 ′ is installed behind the processing die 3 to apply a rearward pressure σ _b for pushing the material 1. On the other hand, a forward tension σ _f is similarly provided in front of the processing die 3 by an endless track type drawing device in which a pair of connecting shoes 5, 5 ′ are continuously arranged and connected.
At the same time as the rear pressure σ _b .

At this time, a load control method in which the rear pressure σ _b is constant is employed, and the forward tension σ _f is a method of sharing a part required for machining, and conversely, the forward tension σ _f is constant. In the load control method, the rear pressure σ _b uses one of the methods of sharing a part required for processing. This device is used to continuously process coiled or linear materials. The processed product can be arbitrarily worked, for example, when it is wound around a coil again, or when it is cut to a fixed length with a straight line.

In the present invention, applying a backward pressure to the material behind the processing die has a higher compressive stress as compared with the case of processing by pulling-out front tension, and has a very effective effect on filling the mold in the die. I do. Here, the reason why the rear pressure is set to be 1.0 times or less of the yield stress before processing of the material is to set the range in which buckling does not occur in the material metal rod, and to be 0.2 times or more. , Below which the rear pressure has less effect on mold filling,
This is because it is difficult to obtain a large area reduction rate.

Further, if the front tension is appropriately combined in front of the die, a large reduction in area can be easily applied to the processed metal rod by combination with the rear pressure, so that the desired mold filling can be achieved. Instead, the bending of the material after processing can be extremely reduced by the action of tension. The reason that the forward tension is set to 1.0 times or less of the yield stress after the work is applied to the material to prevent breakage, and the value of 0.1 times or more is set to be less than this value if the product is bent. Is to be large. The yield stress referred to here is JIS Z22.
It refers to the yield point or 0.2% proof stress described in 41.

As described above, the combination of the die front tension and the rear pressure makes it possible to fill the die of a complicated-shaped die and prevent the die from breaking.
Many of the problems of the prior art, such as curving, are eliminated. In addition, by having a mechanism that controls either the rear pressure or the front tension to a constant value, the rear pressure,
Even when operating with the forward tension close to the limit, by suppressing both fluctuations, breakage and buckling can be prevented, and the cross-sectional shape of the metal rod can be processed uniformly and precisely in the longitudinal direction. it can. Further, when the product is straight and has a specified length, such as a steel wire having an irregular cross section, it is desirable to arrange a cutting machine.

As described above, the present invention is a high-area-reduction machining method that does not cause buckling or breakage of a metal rod, and also enables effective forming of an irregular-shaped metal rod having a complicated shape. In particular, the present invention provides an effective technique for cold continuous processing of a metal bar having a deformed cross section of a high-strength material such as steel or a high-strength alloy or a difficult-to-work metal material having low ductility.

[0020]

FIG. 2 is a perspective view of a round metal bar with fins, in which four fins are provided continuously in the longitudinal direction. Since this shape makes it difficult to form the fin, and the fin height is a very good measure as a measure of mold filling, the effectiveness of the present invention was evaluated centering 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 phosphate for lubrication. The drawing speed of the machined metal rod was controlled to 30 m / min during initial machining and to 70 m / min during steady machining.

Here, the force applied to the material metal rod includes a die back pressure of 0.0 to 1.14 times the yield stress σ _y1 before processing and a yield stress σ _y2 after processing the material metal rod. A forward tension of 0.0 to 1.11 times or less was applied in various combinations. The die used was the shape shown in FIG.
= 3 mm, the fin width was 2 mm, and the height H was 0.9 mm, and it was determined that if the fins were filled with the material, the mold filling was sufficient.

Table 1 shows the results.

[0024]

[Table 1]

Although the molds A to J were full, the molds K to M buckled behind the die and became unworkable, and N and O broke at the front of the die and became unworkable. In P to X, the fin height was less than 0.9 mm, and the dies were not filled.
The results as shown in FIG. 3, the front tension ratio on the horizontal axis sigma _f '
= Σ _f / σ _y2 , and the vertical axis shows the rear pressure ratio σ _b ′ = σ _b / σ _y1 .

In this figure, when the mold is normally filled, ○,
The symbol "x" indicates that the die was broken in front of the die, the symbol "+" indicates that the die buckled, and the symbol "●" indicates that the mold was not sufficiently filled. It can be seen that a mold-filled product is obtained when the following equations are simultaneously satisfied. σ _f ′ ≦ 1.0, σ _b ′ ≦ 1.0 Further, above the straight line d, that is, 0.95 σ _f ′ +1.7 σ _b ′ ≧ 1.0 Further, as described above, the pushing force is σ _b ′ ≧ 0.
2. If the drawing force is limited by σ _f ′ ≧ 0.1,
The hatched area is an area where predetermined molding is possible, which shows the effectiveness of the present invention.

[0027]

According to the present invention, there are problems such as disconnection caused when a deformed metal rod is processed by simply applying a pulling force by a conventional winder to a material in front of a die, and a steel rod having a straight rod shape. By overcoming the drawbacks of continuous processing of wire, it is possible to efficiently and continuously process deformed metal bars having complex shapes, especially difficult-to-machine materials and high-strength materials. Moreover, according to the present invention, since bending can be greatly suppressed, precision machine parts can be subjected to optimal processing. The material to be processed is not limited to a solid material, but may be a hollow material, or a material in which a pipe is filled with a non-metallic substance or a dissimilar metal.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a continuous processing apparatus for deformed metal bars for applying a rear pressure and a front tension of a processing die constituting the present invention.

FIG. 2 is an explanatory view of a perspective view of a deformed metal bar with fins that can be implemented in the present invention.

FIG. 3 is a table of a front tension ratio and a rear pressure ratio.

FIGS. 4A and 4B are explanatory views of the shape of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Material 2 Work material 3 Die 4,4 ', 5,5' Endless track connection shoe

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takanari Miyagi 12 Nakamachi, Muroran Nippon Steel Corporation Muroran Works (56) References JP-A-3-254311 (JP, A) JP-A-2-2 224813 (JP, A) JP-A-6-277743 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21C 1/00

Claims (1)

(57) [Claims] In a cold continuous working method of a deformed metal rod having a complicated shape in one pass by combining indentation and drawing of a workpiece into a die by two pairs of connecting shoes, a material behind the die is The indentation rear pressure of 0.2 to 1.0 times the yield stress of the material before processing, and the work material in front of the die having a yield stress of 0.1 to
1.0 times withdrawal forward tension, while appropriately adding in combination within the range of the following formula, and controlling either one of the rear pressure or the front tension to a constant value,
Cold continuous processing of deformed metal bars with complex shapes. To _{0.95σ f '+ 1.7σ b' ≧} 1.0 wherein the front tension ratio _{σ f '= σ f / σ} y2, rear pressure ratio sigma
_b ′ = σ _b / σ _y1 , σ _f is the forward tension, σ _y2 is the yield stress after processing the material, σ _b is the rear pressure, and σ _y1 is the yield stress before processing the material.