JP3487469B2 - Wire rod manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal wire rod, and more particularly to a method for manufacturing a thin wire having a wire diameter of 5.5 mm or less by rolling.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a metal wire rod, a wire drawing method and a rolling method, and a method in which both are combined are known. Among them, the wire drawing method is a method of obtaining a wire rod by sequentially passing the material to be rolled through a plurality of wire drawing dies whose pore diameters are gradually reduced, and is usually used for manufacturing a fine wire. On the other hand, in the rolling method, a pair of roll stands arranged adjacent to each other so that the rotation axis forms an angle of, for example, about 90 ° is provided in multiple stages, and the rolled material is sequentially rolled by the pair of rolls. It is a method of reducing the diameter. This rolling method has the advantage of higher productivity than the wire drawing method.

In the above rolling method, rolling is also performed by forming a groove portion that defines the cross-sectional shape of the material to be rolled on the rolling surface of the roll, and rolling is performed, for example, for a pair of rolls on the upstream side. , The cross-sectional shape of the groove portion (hereinafter, also referred to as roll hole type or simply hole type) when the rolled surfaces are combined with each other is set to be elliptical, and the hole type of the counter roll on the downstream side is set. If it is formed so as to have a circular shape, the area reduction rate of the wire material per pass can be increased, and the productivity can be further improved.

[0004]

However, in the rolling method described above, when the material to be rolled is transferred from the pair of rolls on the upstream side to the pair of rolls on the downstream side, the wire may be twisted. Such twisting of the wire easily occurs when the shape of the hole type of the pair of rolls is different between the upstream side and the downstream side, for example, when the elliptical-circular shape is set as described above, If the rolling is continued while the twisting occurs, the cross-sectional shape of the wire rod may be disturbed or the wire rod may be broken.

In this case, when the wire diameter of the wire is relatively large, for example, a roller guide constituted by an auxiliary roll or the like is provided at the entrance of the paired roll on the downstream side, and the wire guide is guided by the roller guide. It is also practiced to prevent the occurrence of twisting by supplying the roll. However, when the wire diameter becomes smaller, the roller guide must be made smaller accordingly. When the wire diameter becomes 5.5 mm or less, the roller guide cannot be installed substantially, and such a thin wire is manufactured by the rolling method. It was supposed to be impossible.

Under such circumstances, the thin line as described above is
It is manufactured by a method in which a wire diameter of up to about 5.5 mm is thinned by a rolling method, and then it is further thinned by a wire drawing method to a desired wire diameter. However, this method has a drawback that the high productivity of the rolling method is diminished because the wire drawing method is used together. In addition, the wire drawing method can only be used for cold working, so especially when making difficult-to-work materials such as high-speed tool steel and high-alloy steel into wire rods, it is necessary to remove strain every time the die passes through a certain pass. Since an annealing step must be added, the production efficiency will be further deteriorated.

An object of the present invention is to provide a method capable of producing a thin wire having a wire diameter of less than 5.5 mm with high efficiency and high quality only by the rolling method.

[0008]

Means for Solving the Problems and Actions / Effects The present invention is directed to a first pair of rolls and a second pair of rolls which are arranged in series in the rolling direction of a material to be rolled and which compress the material to be rolled from different directions. By the pair of rolls, the first pair of rolls as the introduction side, the second pair of rolls as the derivation side, which relates to a wire rod manufacturing method for sequentially rolling the material to be rolled, in order to solve the above-mentioned problems It has the following characteristics. That is, when the distance between the centers of the first pair of rolls and the second pair of rolls is L and the wire diameter of the wire rod derived from the second pair of rolls is D, the value of L / D is 30. The materials to be rolled are arranged so as to be as follows, and the material to be rolled is rolled so that the surface reduction rate is 5 to 35% in each of the first pair of rolls and the second pair of rolls, and finally the rolled material is obtained. The wire diameter of the wire to be used is less than 5.5 mm.

The inventor of the present invention arranges the first and second pair of rolls in close proximity to each other so that the L / D value is 30 or less, so that the material to be rolled can be treated as described above without using a roller guide. It has been found that it is possible to effectively prevent or suppress the occurrence of twisting, and it is possible to manufacture a fine wire having a wire diameter of 5.5 mm or less by a rolling method. As a result, the manufacturing efficiency of the thin wire having the wire diameter as described above can be dramatically increased as compared with the conventional wire drawing method and the like.

Here, if the wire diameter of the finally obtained wire rod is 5.40 to 1.30 mm, dimensional accuracy of the obtained wire rod is good and defects such as defects are less likely to occur. This is desirable because it has a particularly great advantage in manufacturing efficiency as compared with the conventional method. The method of the present invention is more preferably applied to the production of a wire having a wire diameter of 5.40 to 1.60 mm.

The material to be rolled is rolled such that the area reduction rate of each of the first pair of rolls and the second pair of rolls is 5 to 35%. When the area reduction rate is less than 5%, the manufacturing efficiency of the wire rod decreases. On the other hand, when the surface reduction rate exceeds 35%, the workability per pass becomes too large, which leads to defects in the work material or damage to the roll. Therefore, the surface reduction rate is set within the above range. The surface reduction rate is more preferably 10 to 30%.

The first and second pair of rolls can be arranged such that their axes of rotation form an angle of approximately 90 ° with each other. In this case, the material to be rolled is rolled by the first pair of rolls so that the cross-sectional dimension D1 in the compression direction is smaller than the cross-sectional dimension D2 in the direction orthogonal thereto, and the second pair of rolls rolls the material to be rolled. The material can be rolled such that the ratio D2 / D1 of their respective cross-sectional dimensions is reduced. By doing so, the area reduction rate per rolling pass can be increased, and the production efficiency can be further improved.

Next, at least one of the first and second counter rolls can be provided with a groove portion that defines the cross-sectional shape of the material to be rolled on the rolling surface of each roll constituting the counter roll. By doing so, a desired wire rod cross-sectional shape can be obtained with high accuracy. In addition, the cross-sectional shape of the groove portion (hereinafter, also referred to as roll hole type or simply hole type) when the rolling surfaces of the two rolls forming the pair of rolls are combined is referred to as the first and second pair rolls. On the other hand, by appropriately setting it, the area reduction rate can be increased and the manufacturing efficiency can be improved while maintaining the dimensional accuracy and the processing state of the wire in a good condition.

Various types of roll hole shapes can be adopted. For example, as the first pair of rolls, those having a roll pore type forming an elliptical cross section are used, and as the second pair of rolls, those having a roll pore type forming a circular cross section are used. A wire having a circular cross section can be manufactured with high accuracy and high efficiency.

Next, a plurality of sets of the above-mentioned first and second pairs of rolls can be arranged along the rolling direction of the material to be rolled, and the pair of pairs of rolls sequentially roll the material to be rolled. Can be given. In this way, the rolled material can be rolled in stages, and the thin wire can be efficiently manufactured even from the rolled material having a large cross-sectional dimension.

The material of the material to be rolled to which the above method can be applied is not particularly limited, but for example, high speed tool steel, stainless steel, and other high alloy steels, which have conventionally been difficult to perform fine wire processing efficiently, can be used. When applied to a hard-to-process iron-based material, it has a great ripple effect in increasing manufacturing efficiency. Other than the above, iron-based materials other than the above, such as mild steel, carbon tool steel and alloy tool steel that can be cold-worked, Ni alloys or Ti alloys (for example, Ni-Ti-based shape memory alloys), iron, etc. It can also be applied to a metal material containing an element other than the above as a main component.

In this case, depending on the material of the material to be rolled, the temperature of the material during rolling can be set appropriately. For example, for materials with high deformation resistance at room temperature, setting the rolling temperature higher than room temperature will reduce the deformation resistance and increase the area reduction rate, resulting in a significant increase in manufacturing efficiency. Can be increased. Also,
If the temperature of the material to be rolled is raised, it is less likely that processing strain will accumulate in the material to be rolled due to recovery or recrystallization of the material to be rolled that progresses with rolling processing, and strain removal and hardness reduction as in the wire drawing method. Since it is not necessary to carry out an intermediate heat treatment for, the production efficiency can be said to be even greater. .

For example, when the material to be rolled is an iron-based material, the temperature of the material to be rolled when it is introduced into the first pair of rolls is 400.
It is desirable to set the temperature to ˜1300 ° C. Temperature is 400
If the temperature is lower than ° C, the effect of improving the processing efficiency due to the reduction of the deformation resistance cannot be sufficiently obtained. On the other hand, if the temperature exceeds 1300 ° C, the deformation resistance becomes too small, and the wire rod is likely to be buckled or twisted, which makes it difficult to carry out normal rolling. Here, when performing rolling in multiple stages using a plurality of pairs of rolls, the work material, for example, at the time of being introduced into at least the first one of the pair of pairs of rolls, the temperature is as described above. It may be set to fall within the range. The temperature of the material to be rolled during rolling may have a more desirable temperature range depending on the material. For example, in the case of high speed tool steel, its temperature is preferably set in the range of 800 ° C to 1150 ° C. If the temperature is lower than 800 ° C., sufficient workability cannot be obtained, and carbides in the structure of the material to be rolled are cracked to generate microvoids, which leads to a decrease in ductility and quenching hardness. On the other hand, when the temperature is higher than 1150 ° C., the carbides present in the structure of the material to be rolled become coarse and the strength of the obtained wire rod is lowered. The temperature range is more preferably 950 to 1150 ° C.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a main part of a rolling mill for carrying out the wire rod manufacturing method of the present invention. This rolling mill 1 is provided with a first pair of rolls 1a and 1b arranged on the introduction side of the material A1 to be rolled so that the rotation axis is oriented substantially perpendicular to the installation surface (not shown). One stand 1H (horizontal stand), and a second stand 2V (vertical stand) provided with second pair of rolls 2a and 2b arranged so that the rotation axes thereof are oriented substantially in the horizontal direction, respectively. The stands 1H and 2V form a stand S1. The rotation axes of the pair of rolls 1a and 1b and 2a and 2b form an angle of approximately 90 ° with each other.

As shown in FIGS. 2A and 2B, the outer surfaces of the first pair of rolls 1a and 1b and the second pair of rolls 2a and 2b are rolling surfaces 51a and 51, respectively.
b and 52a and 52b, and groove portions 61a that define the cross-sectional shape and dimensions of the material A1 to be rolled are formed on the rolling surfaces.
And 61b and 62a and 62b are formed. Here, as shown in FIG. 2A, the first stand 1
Rolls 1a and 1b of H are rolling surfaces 51a and 5 of each other.
When 1b are combined, a roll hole die 61c having an elliptical cross section is formed. Also,
The paired rolls 2a and 2b of the second stand 2V are configured to form a roll hole die 62c having a circular cross-sectional shape when the rolling surfaces 52a and 52b are combined with each other.

When a material A1 to be rolled having a circular cross section and an outer diameter dimension D0 is introduced from the first stand 1H side to the stand S1 shown in FIG. 1, as shown in FIG. The rolled material A1 is rolled by the hole die 61c of the first stand 1H so as to have an elliptical cross section, and then, as shown in FIG. 7 (b), the hole die 62c of the second stand 2V has a circular cross section. Rolled to obtain the final wire diameter D as shown in FIG.
The wire rod A2 of (<D0) is led out. That is, the cross-sectional shape of the material to be rolled changes from circular to elliptical to circular as shown in FIG. Here, as shown in FIG. 2A, in the first stand 1H, the material to be rolled A1 has a sectional dimension D1 in the compression direction (that is, equivalent to the minor axis of the ellipse), and a sectional dimension D2 in the direction orthogonal thereto. (I.e., corresponding to the major axis of the ellipse). Next, in the second stand 2V, since the compression direction with respect to the material A1 to be rolled changes by about 90 °, rolling is performed so that the ratio D2 / D1 of the cross-sectional dimensions is reduced. That is, assuming that the above dimensions after rolling are D1 'and D2', (D2 / D1)> (D2 '/ D
1 '). Here, the area reduction rate of the rolled material in each of the stands 1H and 2V is adjusted to be 5 to 35%.

Here, as shown in FIG. 3, the counter stand S1
In the above, when the distance between the centers of the first stand 1H and the second stand 2V is L and the wire diameter of the wire A2 is D, the value of the relationship L / D is 30 or less. By bringing 1H and the second stand 2V close to each other, the rolled material A1 is less likely to be twisted, and it is not necessary to provide a roller guide or the like between these stands. When the outer diameter of the roll is d, if the relationship L <1.2d is established with the center-to-center distance L, twisting of the material A1 to be rolled is less likely to occur. Become. It is more desirable that L <1.0d. When rolling is finished at this point, the wire diameter D of the wire A2 is set to 5.5 mm or less.

Next, when the wire A2 obtained by rolling on the stand S1 is processed into a wire A3 having a smaller diameter, as shown by a chain double-dashed line in FIG.
If a pair of stands S2 having the same structure as the pair of stands S1 and having a diameter of each hole smaller than that of the pair of stands S1 is installed in the subsequent stage, the material A1 to be rolled can be rolled in multiple stages. In this case, the wire diameter of the finally obtained wire rod is 5.5 mm
Rolling will be carried out so that the number becomes less. In addition,
The pair of stands can be installed in three or more stages in the rolling direction. Further, in the above-mentioned example, the introduction side of the material to be rolled is the horizontal stand and the delivery side is the vertical stand in the pair of stands, but this positional relationship can be reversed.

Next, the first and second pair of rolls 1a and 1
b and roll hole mold 61c formed on 2a and 2b
The shapes of 62c and 62c are not limited to the elliptic-circular combination, and various shapes can be used. An example is shown below. Figure 4
In the above, the roll hole dies 61c and 62c are formed in a vertically long rhombus shape and a square shape, respectively, and the wire A2 is led out in a square cross section. In addition to this, by selecting the shape of each of the roll die 61c and 62c, the change in the cross-sectional shape from the material A1 to be rolled to the wire A2 is
For example, as shown in FIG. 5, various shapes such as a square shape, an elliptical shape, and a circular shape can be adopted.

Furthermore, it is also possible to use, for at least one of the first and second pair of rolls 1a and 1b and 2a and 2b, those which do not form a roll hole type. In the example shown in FIG. 6, the material A1 to be rolled has a square cross section, and as shown in FIG. 6A, the rolling surfaces 51a and 51b of the first pair of rolls 1a and 1b are flat. Roll roll type is not formed. By such pair of rolls 1a and 1b, the material A1 to be rolled is deformed so as to be crushed in the compression direction by the rolls as shown in (a) to have a rectangular cross section, and then as shown in (b). By passing the second pair of rolls 2a and 2b having, for example, a square-shaped roll hole die 62c, a wire A2 having a cross section of a corresponding shape is obtained. Also, FIG.
Shows an example using both the first and second pair of rolls having a flat rolling surface on which a roll die is not formed. The material A1 to be rolled is compression-deformed into a rectangular cross section by the first pair of rolls 1a and 1b as shown in FIG. 4A, and then the second pair of rolls 2a as shown in FIG. And 2b compressively deforms in the opposite direction to form a wire A2 having, for example, a square cross section.

When a plurality of paired stands as described above are used for rolling in stages, the roll-hole shape (or flat rolling surface) in each paired stand is rolled using only the same combination. Alternatively, the rolling may be performed by combining a combination of two or more kinds. Figure 9
An example of rolling using two pairs of stands S1 and S2 is shown, and FIGS. 7A and 7B show the same roll hole such as an elliptical-circular shape or a vertically elongated rhombus-diamond shape. In the case of rolling using only the combination of dies, (c) shows an example in which different combinations are combined. That is,
In (c), the combination of the flat rolling surface and the flat rolling surface on the stand S1 on the front side is the stand S2 on the rear side.
In, an elliptical-circular roll hole type combination is adopted.

Next, when using a non-workable iron-based material such as high speed tool steel, stainless steel or other high alloy steel, or a Ni-Ti based shape memory alloy, etc. Further, it is advantageous to heat the material to be rolled to reduce the deformation resistance in terms of the rolling efficiency and hence the manufacturing efficiency of the wire rod. The heat treatment at this time is performed immediately before the material to be rolled is introduced into the first stand. As a method for heating the material to be rolled, an electric heating method by directly energizing the material to be rolled can be preferably adopted. That is, as shown in FIG. 3, the rolled material A1 is provided with electrodes 71a and 71b which are in contact with the rolled material A1, and the power source 72 supplies the rolled material A1 through the electrodes 71a and 71b.
By energizing, it can be heated based on its resistance heating. The heating method is not particularly limited as long as the material to be rolled can be heated substantially uniformly before rolling, and for example, a heating furnace such as an induction heating furnace may be provided in a portion immediately before the first stand 1H. It may be installed and the rolled material may be introduced into the first stand 1H after passing through the furnace.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a rolling mill.

FIG. 2 is a schematic diagram showing an example of a cross-sectional shape of a roll hole type of first and second counter rolls.

FIG. 3 is a plan view conceptually showing a rolling mill provided with a plurality of pairs of rolls.

FIG. 4 is a schematic view showing a first modified example of a roll hole type cross-sectional shape.

FIG. 5 is a schematic cross-sectional view showing still another example of changes in the cross-sectional shape of the wire rod due to rolling.

FIG. 6 is a schematic view showing an example in which one of the first and second counter rolls has a flat rolling surface.

FIG. 7 is a schematic view showing an example in which the rolling surfaces of the first and second pair of rolls are flat.

FIG. 8 is a schematic cross-sectional view showing an example of a change in the cross-sectional shape of a wire rod when rolling is performed stepwise by a set of a plurality of pairs of rolls.

[Explanation of symbols]

1a, 1b First pair of rolls 2a, 2b Second pair of rolls A1 Rolled material A2, A3 wire rod 51a, 51b, 52a, 52b Rolled surface 61a, 61b, 62a, 62b Groove part 61c, 62c Roll hole type

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B21B 1/00-1/46 B21B 27/02 B21B 45/00 C21D 8/06

Claims (6)

(57) [Claims] 1. A first pair of rolls and a second pair of rolls, which are arranged in series in the rolling direction of a material to be rolled and which compress the material to be rolled from different directions, introduce the first pair of rolls. In the wire rod manufacturing method of sequentially rolling the material to be rolled with the side and the second pair of rolls as the lead-out sides, the first pair of rolls and the second pair of rolls have a center-to-center distance between them of L and the second pair of rolls. When the wire diameter of the wire rod derived from the pair of rolls is D, it is arranged so that the value of L / D is 30 or less, and the material to be rolled is the first pair of rolls and the second roll. The surface reduction rate is 5 to 35% for each roll
And the wire diameter of the finally obtained wire rod is less than 5.5 mm. 2. The first pair of rolls and the second pair of rolls are arranged such that their rotation axes form an angle of about 90 ° with each other, and the first pair of rolls form the material to be rolled. The cross-sectional dimension D1 in the compression direction is rolled so as to be smaller than the cross-sectional dimension D2 in the direction orthogonal thereto, and the material to be rolled is reduced in the ratio D2 / D1 of each cross-sectional dimension by the second pair of rolls. The method for manufacturing a wire rod according to claim 1, wherein the wire rod is rolled so as to be rolled. 3. At least one of the first pair of rolls and the second pair of rolls, on the rolling surface of each roll constituting the pair of rolls,
The wire rod manufacturing method according to claim 1, wherein a material having a groove portion that defines a cross-sectional shape of the rolled material is used. 4. Each of the rolls forming the first pair of rolls has an elliptical cross-sectional shape (hereinafter referred to as a roll hole type) when the rolling surfaces are combined with each other. 4. The wire rod manufacturing method according to claim 3, wherein each of the rolls forming the second pair of rolls has a roll hole shape of a circular shape. 5. A plurality of sets of the first and second pair of rolls are arranged along the rolling direction of the material to be rolled, and the pair of rolls are sequentially rolled to the material to be rolled. The wire rod manufacturing method according to any one of claims 1 to 4. 6. The wire rod manufacturing method according to claim 1, wherein the temperature of the material to be rolled when it is introduced into the first pair of rolls is set to 400 to 1300 ° C.