JPH0422512A - Method and device for preventing surface flaw of hot rolling steel wire material - Google Patents

Abstract

PURPOSE:To prevent the generation of flaw on the surface of the steel wire material after passing the final path of the hot rolling or on every kind of guiding tools, etc., and the winding machine by feeding the steel wire material to the winding machine after forming the glass film of the specific thickness on the surface of the steel wire material exited from the finishing rolling machine till reaching to the winding machine. CONSTITUTION:After the final finishing stand of the hot rolling line for the steel wire material, the glass coating device 50 which can supply the glass powder continuously is set, and the steel wire material of hot temperature just after hot rolling is passed through it, the glass film of 3-50mu is formed on the surface of the steel sire material, the it is fed to the winding machine 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention forms a glass coating on the surface of a hot-rolled steel wire to prevent scratches caused by the steel wire, various guides, winders, etc. The present invention relates to a method and an apparatus for the same.

[Conventional technology]

Hot-rolled materials such as steel wire rods are generally processed after passing through a finishing mill.
Although hot-rolled materials have low deformation resistance, they often develop surface flaws such as scratches when they come into contact with various guiding device troughs, guides, etc. Scratches that occur before the final bath are rolled down by rolls, causing defects such as cracks and bald folds, and scratches that occur after the final bus are not rolled down by rolls, so they remain in that form and are rolled. It remains as a stripe-like flaw that is elongated in the direction and has a relatively open opening.

#4f has high deformation resistance in hot conditions like stainless steel!
Because of its strong stiffness when used as the right material, it comes into stronger contact with various guides compared to carbon steel, and often causes seizing on various guides. In addition, even under such conditions, with carbon steel, the scale removed during hot protection protects the steel material, and the occurrence of defects is relatively small, but in the case of stainless steel, the occurrence of scale is relatively small, and as defects, It often remains. For this reason, in hot rolling of stainless steel wire rods, scratches, seizure defects, etc. occur on both the wire rods, various guides, and winding machines. In particular, when stainless steel wire passes through a winding head type winding machine, the wire violently slides on the inner surface of the curved pipe, resulting in extremely large scratches, a large number of products with surface defects, and frequent winding of the curved pipe. Problems such as the need for replacement occurred.

[Problem to be solved by the invention]

An object of the present invention is to prevent the occurrence of flaws on the surface of a steel wire rod, various guides, and winding machines after passing through the final bath during hot rolling.

[Means to solve the problem]

In the hot rolling of steel wire, the present invention provides a surface thickness of 3 to 5 mm on the surface of the steel wire from the finishing mill to the winding machine.
A method for preventing surface flaws in a hot-rolled steel wire, which is characterized in that the steel wire is sent to a winding machine after forming a glass coating of 0 μm, and a passing line (L) of the hot-rolled wire is set at the axis. A powder flow nozzle (5) connected in front of the guide pipe (4), and a powder flow supply device (8) that supplies glass powder flow to the powder flow nozzle (5). ), which has a powder flow nozzle (5), a powder flow introduction port (17) communicating with the spring flow supply device (8), and a wire passageway (18) in the direction of the wire passage line (L), and a powder flow introduction Hot rolling characterized in that the opening (17) and the wire rod passage (18) are communicated with each other by a pre-drawn ring-shaped passage (19) with the wire rod passage (18) as the axis and in the wire advancing direction. This is a surface flaw prevention device for steel wire rods. In the surface flaw prevention device, it is preferable that a water cooling jacket (21) is provided around the outer periphery of the guide pipe (4).

[For production]

The method of the present invention uses a container (glass coating device) that can continuously supply glass powder with a melting temperature of 500 to 1000°C and a particle size of 50 mesh or less, for example, after the final finishing stand of a steel wire hot rolling line. A high-temperature steel wire immediately after hot rolling is passed through it, and the surface of the steel wire is coated with 3-50%
After forming a glass film of μ, it is sent to a winding machine.

Hereinafter, specific examples of the present invention will be explained with reference to the drawings.

In FIG. 1, S is a steel wire rod, and after being rolled in a final finishing mill 1, it passes through a pinch roll 7 for winding and then passes through a winding machine 3.
It is rolled up. During this time, a glass coating device 50 and, if necessary, a slip prevention device 60 are installed.

The glass coating device 50 is a glass box containing glass powder having a melting temperature of 500 to 1000° C. and a particle size of 50 mesh or less, and a steel wire S passes through the glass box. In addition, a rocking device is attached to the glass coating device 50 so that the glass powder adheres uniformly to the steel wire, and the glass melting temperature, m-wire temperature, wire speed, glass box length, and rocking period are optimized. It is possible to control the appropriate glass coating thickness by combining the following.

Furthermore, slips are likely to occur in the pinch rolls 7 and the winding machine 3 due to molten glass adhering to the steel wire, but slipping can be prevented by blowing glass powder into the pinch rolls 7. Note that the injection of glass powder onto the pinch roll 7 does not necessarily have to be performed to a size that can be stably wound depending on the wire diameter of the steel wire.

The composition and melting temperature of the glass powder used (viscosity is 100
Examples are shown in Table 1 regarding the temperature at which 0 noise is achieved.

The lower the melting temperature of the glass, the greater the amount of adhesion, but choose the optimal glass according to the temperature of the steel wire, speed 1 length of the glass box, oscillation period, and cooling curve after winding the steel wire. I can do things. If the thickness of the attached glass film is less than 3 μm, there will be areas where no glass is attached, and the effect on preventing scratches will be small. Also, if it exceeds 50 μm, the material will not pass through the material.
This is also unfavorable from the viewpoint of descaling in post-processes and cost. Therefore, the thickness of the glass coating attached to the steel wire is 3
It is necessary to set the thickness to ~50μ.

As described above, low melting point glass tends to have a thicker deposited film, and high melting point glass has a thinner deposited film thickness, and tends to have areas where it does not adhere.

Generally, the finishing temperature of wl wire is 850~1150℃,
In such a temperature range, the melting temperature is 500 to 1000℃
glass is suitable.

Next, the apparatus of the present invention will be explained with reference to the embodiments shown in FIGS. 2-5.

As shown in FIG. 2, in the hot-rolled steel wire passing line L, the steel wire exiting the final finishing mill 1 passes through a powder depositing device 2, and then is placed in a cooling device (see FIG. (not shown), and is formed into a continuous ring shape by a winding head type winding machine 3. A wire guide tube 4, a powder flow nozzle 5 for supplying glass powder from a glass powder flow supply device (not shown) into the guide tube 4, a seal nozzle 6 for sealing the glass powder in the guide tube 4, It has a pinch roll 7.

FIG. 3 shows the main parts of the apparatus of the present invention, showing the powder flow supply device 8.
Powder flow nozzle5. and a guide pipe 4. In this example, as shown in FIG. 4, the powder flow nozzle 5 and the seal nozzle 6 are provided in two stages.

As shown in FIG. 3, there is provided a tank 9 containing glass powder G therein, a pressure gas outlet 10 at the lower end, and a powder outlet 11 at the upper end.

Note that the particle size of the glass powder is preferably 100 mesh or less.

Dehumidified high-pressure air is supplied to the high-pressure air conduit 12 from the direction of the arrow. A powder flow supply device 8 is constituted by a switching valve 13, a check valve 14, a flexible hose 15, and a swing motor 16 for preventing tunneling of glass powder in the tank.

The powder flow nozzle 5 has a powder flow inlet 17 connected to the powder flow supply device 8 via a flexible hose 15, and
), the wire rod passage 18 is provided in the direction of the wire passage line L, and the powder flow inlet 17 and the wire rod passage 18 are communicated with each other, and the wire rod passage 18 is formed as an axis in a pre-drawn shape in the direction of wire movement. It is constituted by a ring-shaped flow path 19. The fitting ring 20, which is made of a cushioning material such as rubber, prevents the nozzle from being worn out due to collisions of powder streams.

A powder flow nozzle 5 is connected in front of the guide tube 4, and the ratio of the diameter of the wire of the guide tube 4/the diameter of the guide tube is preferably 0.3 to 0.8.

The guide tube 4 is heated and deformed by the high temperature wire. To prevent this, cooling water is usually sprayed on the outer surface of the guide tube 4, but in this case, the sprayed cooling water enters the inner surface of the guide tube 4, causing glass powder to adhere to the inner surface of the tube and causing the steel wire to become stained. This will impede passage. In this embodiment, as shown in FIGS. 343 and 4, by providing a water cooling jacket 21 around the outer periphery of the guide tube 4, thermal deformation of the guide tube 4 and adhesion of glass powder can be prevented.

FIG. 5 shows another example of the powder flow supply device 8, in which a predetermined amount of powder is dropped into an ejector 23 from a known powder quantitative cut-out device 22 per unit time only when the wire passes. The glass powder flow can be sent to the powder flow nozzle 5 by sending high pressure air from the high pressure gas pipe 24 to the ejector 23 only when the wire passes through.

Further, when the wire does not pass through, the glass powder remaining in the guide tube 4 can be discharged by high pressure air from the ejector 23.

By installing this device closer to the finishing rolling mill 1, it is possible to expand the temperature range for heat treatment of the wire rod by water cooling. Note that the number of installed devices may be determined as necessary, and in this case, one powder flow supply device 8 and a plurality of powder flow nozzles 5 may be connected.

Open the switching valves 13a and 13b shown in FIG.
When high-pressure air is ejected from the pressure gas outlet 10 at the bottom of the tank, the glass powder G in the tank floats up and the powder flow outlet 11.
Check valve 14. Flexible hose 15, powder flow inlet 17
After that, it is fed into the guide tube 4 from the ring-shaped channel 19 shown in FIG. 4(B) and floats therein. On the other hand, the wire rod is introduced into the powder flow nozzle 5 and further into the guide tube 4 at high speed, and comes into contact with the glass powder floating in the guide tube 4, so that the glass powder adheres uniformly to the entire surface of the wire rod and is heated due to the high heat of the wire rod. to weld. The wire rod with the glass powder welded to its surface in this manner comes into contact with various guides and the curved tube of the laying head through the glass coating, so both surfaces are protected and the occurrence of scratches can be prevented. Note that the glass coating attached to the surface of the wire may react with surface scale, but it will not react with the wire itself, so it should be removed at the same time as scale removal (chemical or mechanical methods are also acceptable). be done.

When using the powder flow supply device 8, which is a combination of the powder quantitative cut-out device 22 and the esector 23 shown in FIG. It is most suitable for uniformly attaching glass powder to the surface.

Since the device of the present invention has a structure in which the powder stream is ejected from the ring-shaped channel 19, the powder stream can be sent to the gap between the inner wall of the guide pipe 4 and the steel wire without clogging the nozzle.

In this gap, the glass powder is suspended by the drawing action of the steel wire passing at high speed, so that the glass powder can be uniformly adhered to the entire surface of the steel wire without causing a tunneling phenomenon. Note that changes in rolling speed can be dealt with by changing the number of powder flow nozzles 5 used.

[Example] Table 2 shows that during hot rolling of S[15304 stainless steel wire rod, glass powder was attached to the wire rod between the finishing mill and the winding machine, and a glass coating was applied to the wire rod to a predetermined thickness. An example of the present invention in which the glass coating was formed, a comparative example in which the glass coating was formed only on a part of the wire surface, and a conventional example in which no glass powder was attached are shown.

〔Effect of the invention〕

According to the present invention, when hot rolling a wl wire rod, sliding friction when the steel wire rod passes through various guides and a laying head can be significantly reduced. This can prevent damage to the steel wire as well as the various guides and winding machines that come into sliding contact with the steel wire, and has a significant effect on improving the surface quality of the steel wire and extending the life of the various guides and winding machines. can get.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing an apparatus for carrying out the method of the present invention, FIG. 2 is a diagram showing the installation position of the apparatus of the present invention, and FIG. 3 is a diagram showing the apparatus of the present invention installed in a wire rod rolling line. 4 is a partially enlarged sectional view of FIG. 3, and FIG. 5 is a sectional view showing another embodiment of the device of the present invention. 1...Final finishing rolling machine, 2...Powder deposition device, 3.
... Winding machine, 4... Guide pipe, 5... Powder flow nozzle, 6
...Seal nozzle, 7...Pinch roll, 8...
Powder flow supply device, 9...Tank, 10...Pressure gas outlet, 11...Powder flow outlet, 12...High pressure air conduit, 13...Switching valve, 14...Return check Valve, 15... Flexible hose, 16... Rocking motor, 17...
Powder flow inlet, 18... Wire passageway, 19... Ring-shaped channel, 20... Fitting ring, 21... Water cooling jacket, 22... Powder quantitative cutting device, 23...・Ejector 24...High pressure gas pipe, 50...Glass coating device,
60...Slip prevention device, S...steel wire rod, L...
- Passing line. Agent: Patent attorney Masamitsu Akizawa and 1 other person

Claims (3)

[Claims] (1) In hot rolling of steel wire, the surface of the steel wire from the finishing mill to the winding machine has a thickness of 3 to 50 μm.
1. A method for preventing surface flaws on a hot-rolled steel wire, which comprises sending the steel wire to a winding machine after forming a glass coating of m. (2) A wire guide pipe (4) whose axis is the hot-rolled wire passing line (L), a powder flow nozzle (5) connected in front of the guide pipe (4), and a powder flow nozzle. (5) and a powder flow supply device (8) that supplies a glass powder flow to the powder flow nozzle (
5) is a powder flow inlet (17) that communicates with the powder flow supply device (8).
) and the wire passage (18) in the direction of the wire passage line (L).
The powder flow inlet (17) and the wire passageway (18) are communicated with each other by a pre-drawn ring-shaped passageway (19) with the wire passageway (18) as the axis and in the wire advancing direction. Surface flaw prevention device for hot rolled steel wire. (3) A surface flaw prevention device for hot rolled steel wire according to claim 2, characterized in that a water cooling jacket (21) is provided on the outer periphery of the guide pipe (4).