JP3319067B2 - Manufacturing method of steel wire rod - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to terminate a predetermined rolling line while easily removing the scale of a steel wire rod having a scale formed on its surface after heating such as hot rolling and heat treatment by a simple and short process. The present invention relates to a method of manufacturing a steel wire rod suitable for performing the method.

[0002]

2. Description of the Related Art Conventionally, when removing the scale of a steel wire having a scale formed on its surface after heating such as hot rolling or heat treatment, particularly, the scale of a stainless steel wire is removed as shown in FIG.
This was implemented as a steel wire pickling line as shown in FIG.

[0003] In a pickling line for a steel wire, particularly a stainless steel wire shown in FIG. 3, a wire coil 31 is made of a large amount of pickling salt or the like in order to remove the scale of the surface generated after heating such as hot rolling and heat treatment. Was used for descaling.

[0004] In this pickling treatment step, N
In the i-SUS stainless steel wire rod, the Fe-rich layer in the surface layer is dissolved in the acid bath 32, and after washing and drying, heating of the steel wire rod with the salt in the salt bath 33 and oxidation and dissolution of the scale (however, The amount is small)
After rapid cooling to form cracks on the scale, dissolve the water-soluble scale, neutralize the salt with an acid, remove most of the scale with nitric acid (HF / HNO ₃ ) in a nitric acid tank. (Acid penetrates from the cracks previously formed by quenching to dissolve the base iron, thereby releasing the scale from the base iron and removing most, for example, about 70%.) Removal of smut and discoloration by acid Alternatively, passivation treatment with nitric acid (such as in the case of Ni-SUS) is performed as appropriate.

After this pickling, the wire coil 31 is immersed in a resin tank 35 and dried to form a resin film on the surface of the steel wire. The wire drawing by cold drawing is performed on the steel wire rod 1a by a dry wire drawing machine 37 having a 37a.
Next, after passing through a degreasing tank 38 to perform degreasing to remove the resin, the material is collected by a collecting device 39, further installed in another feeding device 40, and brightly annealed in a bright annealing furnace 41. They were collected and shipped by the device 42.

[0006]

However, in such a conventional wire pickling line, in order to remove the scale formed on the surface after heating such as hot rolling and heat treatment, the acid bath 32 is used. Dissolution of the surface layer Fe-rich layer, dissolution and heating in the salt tank 33, generation of cracks by rapid cooling after salt heating and dissolution of the water-soluble scale, neutralization of the salt, and nitrification in the hydrofluoric / nitric acid tank (HF / HNO ₃ ) 34 The removal of scale, that is, the need for batch-type scale removal, required the maintenance of pickling equipment and waste liquid treatment to be troublesome, and repeated immersion and pulling over several tanks. Therefore, a long time is required for the pickling process, and there is a problem that it takes time to produce the steel wire rod.

[0007] Therefore, there is a problem that a manufacturing process involving the removal of scale generated on the surface of such a steel wire is performed simply and in a short time.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is intended to remove scale when producing a steel wire rod having a scale formed on a surface after heating such as hot rolling and heat treatment. It is an object of the present invention to enable the steel wire rod to be rolled in a short time while performing the process quickly.

[0009]

SUMMARY OF THE INVENTION A method for producing a steel wire according to the present invention is characterized in that, when a steel wire having a scale formed on its surface after heating such as hot rolling or heat treatment, the steel wire is heated by hot rolling or heat treatment. Later, the steel wire rod with the scale formed on the surface is subjected to wire drawing by cold rolling using a rolling roll such as cold rolling or cold drawing or a roller die, and fine cracks are formed on the surface scale. And then heat treatment such as solution treatment and annealing is performed in a loop state, and then pickling is performed in the loop state. In the embodiment, the pickling is performed using nitric hydrofluoric acid. In the embodiment, fine cracks are generated on the scale of the surface of the steel wire rod, and then a solution treatment, a heat treatment such as annealing is performed, and then the pickling is performed. crack Directly erosion of the base steel by acid infiltrated through so as to remove the scale, in same embodiments, the steel wire is characterized in that as a stainless steel wire.

[0010]

According to the method for rolling a steel wire according to the present invention, since the above-described configuration is employed, in the rolling step of the steel wire, the steel wire having the scale formed on its surface is subjected to cold rolling and cold rolling. By performing wire drawing by cold rolling using a rolling roll or roller die such as stretching, fine cracks will be generated on the surface scale, so most of the scale is The small scale that was peeled off and dropped off due to rough descaling, and the acid that infiltrated into the base iron side through cracks in the subsequent pickling was in direct contact with the base iron and eroded the base iron. Therefore, the steel wire rod with the scale is removed in a very short time.

[0011]

FIG. 1 shows a production line for a stainless steel wire rod according to an embodiment of the method for producing a steel wire rod according to the present invention. The wire coil 1 wound with a steel wire having a scale formed on the surface later is appropriately stored in the material supply device 2.

Next, the steel wire 1a supplied from the material supply device 2 is sent to the cold rolling mill 3 and cold drawn.

In the cold drawing by the cold rolling mill 3, when the steel wire 1a is rolled by the roll 3a, as shown in the column of "rough descaling" on the left side of FIG.
a is drawn relatively easily, while scale 1b
Since is not stretched so easily, cracks 1c are generated in the scale 1b, whereby most (for example, 90 to 95% or more) of the scale 1b is peeled or dropped, and rough descaling is performed.

The steel wire rod 1a exiting the cold rolling mill 3 is sent to a bright annealing furnace (or a solution treatment furnace or the like) 6 in a loop state by passing through a tuning mechanism (dancer stand) 4 and a looper 5, and brightly. Annealing (or solution treatment, etc.)
Is performed, and then the steel wire 1a enters a pickling process in a loop state.

In this pickling step, light pickling is performed in a hydrofluoric acid tank 7, a water washing tank 8, and a neutralization tank 9.

In this light pickling, the steel wire rod 1a is light pickled together with the remaining scale 1b that has not been removed by cold rolling, as shown in the column of "Finish descaling" on the right side of FIG. The remaining scale 1b has fine cracks 1c due to the cold rolling.

When such a steel wire rod 1a enters the fluorinated nitric acid tank 7, the solution 7a of fluorinated nitric acid enters from between the cracks 1c and directly oxidizes the ground iron, so that the scale 1b falls off. It easily occurs, and effective descaling is performed only by such light pickling.
And in an example of implementation for Ni-SUS based wire rod,
Compared with the conventional descaling treatment using acid-salt-fluoric-nitric acid, it was possible to remove a small amount of remaining scale by light acid pickling in a very short time of about 1/10.

After the light pickling, after passing through a coating / drying device 10 if necessary, the material is collected in a collecting device 11 and shipped as a coil or sent to the next step.

Therefore, in the steel wire rod manufacturing line shown in the embodiment, the cold rolling mill 3 using the roll 3a is used.
Because of the cold drawing, the formation of the resin film before cold rolling and the removal (degreasing) of the resin film after cold rolling are omitted, and bright annealing (or solution treatment, etc.) is performed in-line.
And the descaling is performed in a short time with high efficiency by rough descaling by the cold rolling mill 3 in-line and finish descaling by light pickling, which involves scale removal of the steel wire rod 1a. Even in this case, the production of the steel wire can be performed in a short time.

[0020]

According to the method for producing a steel wire according to the present invention, since the above-described structure is employed, the steel wire having a scale formed on its surface is subjected to cold rolling such as cold rolling or cold drawing. Since fine cracks can be generated on the surface scale by performing wire drawing by dynamics, most of the scale is peeled off and dropped off by such rough descaling, and the small scale remaining is In the pickling process, the acid that penetrates into the iron base via cracks comes in direct contact with the iron base and erodes the iron base, which is efficiently removed. This has the significant advantage that it can be done in time.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a production line for a stainless steel wire, showing one embodiment of a method for producing a steel wire according to the present invention.

FIG. 2 is an explanatory view showing a descaling mechanism by cold drawing and light pickling of a steel wire.

FIG. 3 is an explanatory view showing a conventional steel wire rod production line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire coil 1a Steel wire 1b Scale of steel wire surface 1c Scale crack 3 Cold rolling mill (cold wire drawing) 3a Roll of cold rolling mill 4 Back tensioner 5 Looper 6 Bright annealing furnace 7 Fluorinated nitric acid tank 8 Rinse Tank 9 Neutralization tank

Claims (4)

(57) [Claims] When a steel wire having a scale formed on its surface after heating such as hot rolling or heat treatment is rolled, hot rolling,
Cold rolling such as cold rolling, cold drawing, etc. is performed on the steel wire rod with a scale formed on the surface after heating such as heat treatment to generate fine cracks on the scale of the surface. A method for producing a steel wire, comprising performing heat treatment such as solution treatment and annealing in a loop state, and then pickling in a loop state. 2. The method according to claim 1, wherein the pickling is a light pickling using hydrofluoric acid. 3. A fine crack is generated on the scale of the surface of the steel wire rod, and then heat treatment such as solution treatment and annealing is performed. The method for producing a steel wire according to claim 1 or 2, wherein the scale is removed by acid erosion. 4. The method for producing a steel wire according to claim 1, wherein the steel wire is a stainless steel wire.