JP2013044042A - Heat treatment apparatus for metal wire rod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment apparatus for a metal wire rod, capable of preventing a surface flaw of the metal wire rod by suppressing direct contact between the metal wire rod and a pipe in less man-hour.SOLUTION: The heat treatment apparatus for the metal wire rod includes a heating furnace in which a plurality of pipes held in a non-oxidizing atmosphere are laid in parallel, and the metal wire rod is heat-treated in a state that the metal wire rod is inserted in the pipe. A tube made of carbon is provided along the inner surface of the pipe. Further, it is desirable that a plurality of pipes in which the metal wire rod is made to pass are laid in parallel on the downstream side in the passing direction of the heating furnace, and that a cooling device with the tube made of carbon along the inner surface of the pipe is provided.

Description

  The present invention relates to a heat treatment apparatus for a metal wire that runs a long metal wire and continuously heat-treats it.

Conventionally, heat treatment such as annealing, quenching, and tempering, which is performed to obtain a predetermined property on a long metal wire made of stainless steel, for example, has a pipe installed horizontally in a heat treatment furnace, and hydrogen gas or nitrogen is contained in the pipe A method in which a continuous heat treatment is performed by keeping a non-oxidizing atmosphere such as a gas and running a long metal wire in the longitudinal direction in a pipe is generally used.
In this continuous heat treatment method, a part of the wire drawing lubricant mainly composed of sodium stearate and the like applied to the surface of the metal wire in the drawing process of the previous step is brought into the pipe and melted and decomposed to react with the pipe. May form harmful hard carbides and adhere firmly to the inner surface of the pipe. In some cases, the hard deposits and the metal wire running in the pipe are in direct contact with each other, so that the surface of the metal wire may be cracked.

In order to prevent such surface flaws of the metal wire, a method has been proposed in which the metal wire is continuously heat-treated while being covered with a heat-resistant cloth over a predetermined circumference of the inner surface of the pipe in the heat treatment furnace (Patent Literature). 1). In Patent Document 1, the wire drawing lubricant is removed by using a cleaning device that cleans the surface of the metal wire in the previous stage of heat treatment, and the inner surface of the pipe in the heat treatment furnace is mainly composed of SiO ₂ ceramic fiber. Covering with a heat-resistant cloth for a predetermined circumference length is excellent in that the inner peripheral surface of the pipe and the metal wire are prevented from coming into direct contact and surface flaws on the metal wire are prevented.

JP 2008-50645 A

However, according to the study of the present inventor, in the method of installing a heat resistant cloth to heat-treat a long metal wire disclosed in Patent Document 1 in a pipe, if the heat resistant cloth is soft and the waist is weak, the heat resistant cloth alone Then, it was confirmed that it was not possible to decorate along the inner surface of the pipe.
In addition, as disclosed in Patent Document 1, as a method of installing the heat resistant cloth along the inner surface of the pipe, the take-up wire is wound around the end of the heat-resistant cloth, and the take-up wire is passed through the pipe. There is also a method of interior decoration while pulling in the axial direction, but it takes a lot of man-hours for the interior and impedes productivity.

  Moreover, since the heat resistant cloth may be broken due to its sliding by running a number of metal wires continuously, periodic replacement is required. The frequency with which the heat resistant cloth breaks depends on the shape and size of the metal wire or the strength of the wrinkles of the metal wire itself, so it is difficult to determine the replacement time. If the replacement time is incorrect, the heat-resistant cloth is torn and not only generates surface flaws on the metal wire, but the broken heat-resistant cloth may remain in the pipe and clog the pipe.

  The objective of this invention is providing the heat processing apparatus of the metal wire which can suppress the direct contact with a metal wire and a pipe with few man-hours, and can solve the problem of a surface flaw.

  The present inventor examined the problem of surface flaws of the metal wire due to the direct contact between the metal wire and the pipe, and adopted a configuration in which the tube made of carbon was installed in the pipe, thereby greatly increasing the man-hours for the protection tube It was found that the surface defects could be suppressed and the present invention was reached.

That is, the present invention has a heating furnace in which a plurality of pipes maintained in a non-oxidizing atmosphere are arranged in parallel, and heat treatment of the metal wire by passing the metal wire through the pipe and heat-treating the metal wire. The apparatus is a heat treatment apparatus for a metal wire in which a cylinder made of carbon is provided along the inner surface of the pipe.
In the heat treatment apparatus of the present invention, a plurality of pipes through which the metal wire passes are arranged in parallel on the downstream side in the wire passage direction of the heating furnace, and a cylinder made of carbon is provided along the inner surface of the pipe. It is preferable to provide a cooling device.
Moreover, it is preferable that the cylinder which consists of the said carbon applied by this invention forms a slit over the full length of the side surface of this cylinder.

  According to the present invention, the problem of surface flaws of a metal wire can be solved with a small number of man-hours, and the production efficiency can be improved. Therefore, this technology is indispensable for mass production of metal wires.

It is a schematic diagram which shows an example of the heat processing apparatus of this invention. It is a schematic diagram which shows another example of the heat processing apparatus of this invention. It is a schematic diagram which shows an example of the cylinder with which the heat processing apparatus of this invention is equipped.

An important feature of the present invention is that a continuous heat treatment apparatus for a metal wire adopts a configuration in which a cylinder made of carbon is provided along the inner surfaces of pipes of a heating furnace and a cooling furnace. As described above, if a soft cloth-like material such as a heat-resistant cloth is used to prevent direct contact between the metal wire and the pipe, the heat-resistant cloth alone cannot be well decorated along the inner surface of the pipe. Therefore, there is a method of winding a take-up wire or the like around a heat-resistant cloth and passing it through a pipe and pulling it in the axial direction, but it takes a lot of man-hours for the interior and hinders productivity.
The metal wire heat treatment apparatus of the present invention will be described in detail below with reference to the drawings.

An example of the metal wire rod heat treatment apparatus of the present invention is schematically shown in FIG.
In FIG. 1, a metal wire 1 wound around a plurality of coils (not shown) is continuously drawn from each coil, and a plurality of pipes are arranged in parallel (not shown). After being cooled through the furnace 2 and subjected to heat treatment for obtaining predetermined characteristics, it is wound around the coil again. The metal wire heat treatment apparatus of the present invention can greatly improve productivity by simultaneously heat-treating a plurality of metal wires in parallel.
In addition, as shown in FIG. 1, the metal wire heat treatment apparatus according to the present invention has a plurality of pipes 4 (not shown) arranged in parallel on the downstream side of the heating furnace 2 in the direction of passage of the metal wire. The cooling device 3 is preferably provided with a cylinder 5 made of carbon along the inner surface of the pipe 4. Thereby, the heated metal wire 1 can be cooled in a short time, and the heat treatment apparatus full length can be shortened. Moreover, it can be used as a quenching device when performing quenching treatment, and can impart desired characteristics to the metal wire 1. Here, as the cooling device 3, for example, a device that cools the outer periphery of the pipe 4 with a refrigerant and indirectly cools the metal wire 1 through the cylinder 5 made of carbon can be applied.

  The metal wire heat treatment apparatus of the present invention includes a cylinder 5 made of carbon along the inner surface of the pipe 4 inside the pipe 4 in which the metal wire 1 in the heating furnace 2 and the cooling apparatus 3 travels. 5 is maintained in a non-oxidizing atmosphere. Thereby, this invention suppresses that the pipe 4 inner peripheral surface and the metal wire 1 contact directly, and can prevent the surface flaw to the metal wire 1. In particular, when the metal wire 1 that has been processed in the previous process such as wire drawing has a curl or bend, the metal wire 1 may come into contact with the inner peripheral upper surface of the pipe 4. Even in such a case, according to the present invention, by covering the inner peripheral surface of the pipe 4 with the cylinder 5, it is possible to suppress the direct contact between the inner peripheral surface of the pipe 4 and the metal wire 1. Can be reliably prevented.

As the cylinder 5 made of carbon in the present invention, for example, a carbon powder formed into a cylinder by pressure sintering or extrusion, or a carbon fiber twisted into a cylinder can be used. From the standpoint of properties, ease of regeneration, and cost, it is preferable to use a powder sintered product or an extruded product.
Further, in the present invention, by using the cylinder 5 made of carbon having high thermal conductivity, the pipe 4 can be covered with a cylinder even when the entire circumference in the pipe 4 is covered with a cylinder, for example, compared with the case where the entire circumference is covered with a heat resistant cloth. Therefore, the metal wire 1 can be heated uniformly without hindering radiant heat transfer from the metal wire 1 to the metal wire 1, and desired properties can be imparted to the metal wire 1.
Further, by using the cylinder 5 made of carbon, a part of the wire drawing lubricant mainly composed of sodium stearate applied to the surface of the metal wire 1 in the drawing process or the like is brought into the pipe and part thereof. Even if melted and decomposed, only the reaction between the carbon of the wire drawing lubricant and the carbon of the cylinder 5 occurs, and the formation of harmful hard carbides that cause surface defects on the metal wire 1 is suppressed.

As shown in FIG. 1, the cylinder 5 made of carbon applied in the present invention is formed as one continuous long cylinder 5 from the heating furnace 2 to the cooling device 3, so that a take-up wire or the like is placed in the pipe 4. Without passing through, the cylinder 5 made of carbon can be smoothly inserted along the inner surface of the pipe 4 with less man-hours. Moreover, since the cylinder 5 made of carbon can be manufactured at a relatively low cost, maintenance such as periodic cleaning in the pipe 4 which is troublesome can be omitted if they are replaced together.
Further, as shown in FIG. 2, it is more preferable to divide the cylinder 5 made of carbon into a predetermined length and insert it into the pipe 4, thereby improving handling without causing damage to the cylinder 5 made of carbon. Workability such as easy insertion into the pipe 4 is greatly improved.
In addition, when a cylinder 5 made of carbon having a predetermined length is pushed from the inlet side or the outlet side of the heating furnace 2 so that the used carbon cylinder 5 comes out from the opposite side, The cylinder 5 made of can be easily replaced.

  An example of the shape of the cylinder 5 made of carbon applicable in the present invention is shown in FIG. FIG. 3A is a front view of the cylinder 5 made of carbon, and FIG. 3B is a side view thereof. As shown in FIG. 3, it is preferable to form the slit 6 over the entire length in the axial direction of the circumferential surface of the cylinder 5 made of carbon. Thereby, even in a state where the metal wire is passed through the pipe, the metal wire can be passed through the slit 6 and the tube 5 can be passed through the pipe. It can improve productivity significantly. The slit 6 formed in the cylinder 5 is preferably formed with a width of about +1 mm in diameter of the metal wire so that the metal wire does not directly contact the pipe.

  1. 1. metal wire, 2. heating furnace; 3. cooling device; Pipe, 5. Cylinder, 6; slit

Claims (3)

  In a heat treatment apparatus for a metal wire having a heating furnace in which a plurality of pipes held in a non-oxidizing atmosphere are arranged in parallel, and heat-treating the metal wire through the metal wire, the pipe A metal wire heat treatment apparatus, wherein a cylinder made of carbon is provided along the inner surface of the metal wire.   A cooling device comprising a plurality of pipes through which the metal wire passes in parallel on the downstream side in the wire passage direction of the heating furnace, and a cylinder made of carbon along the inner surface of the pipe is provided. The heat treatment apparatus for metal wire according to claim 1.   The metal wire heat treatment apparatus according to claim 1 or 2, wherein the cylinder made of carbon has a slit formed over the entire length of a side surface of the cylinder.