JPH03130B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a composite metal wire, particularly a method for manufacturing a composite metal wire such as an aluminum coated steel wire (AS wire). Generally, the following methods are known or practiced when manufacturing composite metal wires such as AS steeled wires. (1) Co-pulling method A method of creating a composite base material by covering the core wire with a coated metal tube, etc., and then drawing this with a die. (2) Clad method A method in which a coated metal tape is supplied (wound) around the core wire and pressure-bonded. (3) Hot-dip galvanizing method A method in which a core wire is passed through a molten aluminum bath and aluminum is coated on its surface. (4) Powder sintering method (Almoweld method) A method in which aluminum powder is heated and sintered around a core wire and then rolled. (5) Extrusion method with forward tension applied A method of extruding coating metal from a billet-shaped material around the core wire under forward tension. (6) Powder drawing method A method in which the coated metal powder present around the core wire is brought under high pressure, similar to the lubricant in fluid lubrication drawing, and drawn into a die together with the core wire, and the powder is pressed around the core wire. (Unexamined Japanese Patent Publication No. 1983-
Publication No. 82610). Among these methods, the most advantageous method in terms of production efficiency is the hot-melting method (3), but since this method melts the aluminum and handles it as a plating bath, the hot-melting bath is not used. There are many problems in terms of management and equipment, and when aluminum-coated steel wire is used, there are also quality problems such as the formation of a layer of hard and brittle intermetallic compounds between the steel and aluminum. be. For these reasons, the powder sintering method (4) and (6) are methods that have manufacturing efficiency equivalent to or second to the melt plating method and can solve the above-mentioned problems specific to the melt plating method. ) powder extraction method has been investigated. However, the powder sintering method (4) has the drawback of requiring expensive equipment and complicated technology from the viewpoint of quality control. In addition, in method (6), when the coated metal powder enters the die hole, high internal pressure is generated and adhesion occurs between the coated metal powder and the core wire, resulting in a composite coating, but due to the relative slippage between the powder and the core wire. Frictional force alone does not have the ability to forcefully draw the powder into the die entrance, and even if the powder is drawn into the die hole and becomes composite within the die hole, the continuity is poor, causing defects such as pinholes, and the adhesion is poor. Has enough drawbacks. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a method for manufacturing a composite metal wire in which a core wire is continuously coated with metal powder without defects. The present invention includes a step of heating a core wire whose surface has been cleaned in an oxidizing atmosphere to form an oxide film on the surface, and placing the heated core wire as it is in powder of a coating metal that is more easily oxidized than the metal of the core wire. Alternatively, the step of introducing the powder after further heating and heating if necessary to cause a reaction to reduce the oxide on the surface of the core wire with the coated metal powder to facilitate adhesion of the powder to the surface of the core wire, and the step of bonding the powder to the core wire. A method for manufacturing a composite metal wire, which comprises the steps of drawing powder into a processing tool inlet using frictional adhesive force and at the same time performing processing in a cold or heated state to coat and composite the powder on the surface of the core wire. be. Generally, metals are bonded together after the surfaces to be bonded are cleaned and activated. Therefore, even in the conventional powder sintering method and powder drawing method, the core wire is cleaned before bonding with the coated metal, and if necessary, the core wire is heated in an inert atmosphere. This improves adhesion while preventing the formation of an oxide film on the surface. In the present invention, of course, the surface of the core wire is cleaned, but it is completely different from these conventional adhesives. Rather, the core wire is actively oxidized, and the surface has several tens to several
A chemical reaction that forms a uniform oxide film of about 1000 Å and reduces the oxide on the surface of the core wire with powder of the coating metal, which is easier to oxidize (lower oxide formation energy) (in the case of iron and aluminum, it is called "thermite"). This is a method of making bonding chemically easier than before using a reaction known as ``reaction'', and at the same time press-bonding them by drawing, rolling, swaging, etc. (without unnecessary heating). Therefore, according to the method of the present invention, adhesion between the core wire and the covering metal becomes easy and reliable. As for the oxide film formed on the surface of the core wire, it is desirable to make the thickness and quality as uniform as possible from the viewpoint of uniformity of adhesion and uniformity of product quality. For this purpose, it is very effective not only to simply heat-treat the core wire in an oxidizing atmosphere, but also to perform a cleaning treatment before that. In the method of the present invention, wires made of iron-based metals and copper-based metals, for example, are used as the core wires. Also,
A composite wire whose surface is made of these metals can also be used as a core wire. The reducible coating metal used in the present invention includes:
For example, powders of Al, Mg, Zn, Sn, Ti, Zr, Be, etc. are used. The oxidation treatment may be wet anodic oxidation treatment or chemical oxidation treatment using chemicals, but it is desirable that the oxide film formed be less than 10,000 Å. As for oxidation treatment, in the case of steel wire, 150 to 500
It is preferable to heat the wire at a constant temperature of 150 to 350°C in the air in the case of copper wire. When introducing and running an oxidized core wire into coated metal powder, the powder generally moves with the core wire due to the frictional adhesive force between the core wire and the powder, and is drawn toward the next processing tool. , its pulling amount,
Continuity is not always satisfactory. At this time, as a result of various experiments, it was found that the drawing effect is better if the core wire is heated and oxidized. Heating temperature is 300-400
℃ is optimal, good results can be obtained even at 200-500℃,
The effect can be obtained if the temperature is 150℃ or higher. When steel wire is heated to these temperatures, it oxidizes from pale yellow to yellowish brown, purple-blue, and dark-purple depending on the temperature. When the steel wire is passed through the aluminum powder in this state, the entire surface of the steel wire is coated with a thin layer of adhesive, and a sufficient amount of aluminum is drawn into the entrance of a tool such as a die. This adhesion is thought to be due to the fact that the oxide film on the steel wire is reduced to the aluminum powder by a thermite reaction, and the chemical reaction causes temporary adhesion, and the surface becomes rough with the aluminum powder, increasing the frictional force with other aluminum powders. It will be done. At this time, if the temperature of the steel wire and aluminum is high, the thermite reaction is likely to occur, so it is most effective to carry out the process at a high temperature. By using the temperature of the steel wire during the oxidation treatment, the operation becomes simple and economical and sufficient effects can be obtained. Further, sufficient effects can be obtained by heating only the steel wire. Although it is of course possible to heat only the aluminum powder, it is more effective and economical to heat only the steel wire. When a steel wire with aluminum powder adhered to it is drawn into a processing tool such as a die, a hydrodynamic wedge effect occurs at the wedge-shaped angle between the entrance angle of the tool and the steel wire, causing the wire to be strongly drawn in and the pressure inside the tool to increase. This results in deformation of the aluminum powder and adhesive coating. In this case as well, when the temperature reaches a high temperature of 150° C. or higher, the deformation resistance of the aluminum powder decreases and the reaction at the interface is promoted, resulting in better adhesive coating and better surface condition. The optimal heating temperature is 200 to 500°C, but higher temperatures are acceptable. However, if the temperature is too high, intermetallic compounds of Al and Fe will occur, so it is desirable to keep the temperature up to about 550°C. The dies used as processing tools in the present invention include conical, trumpet (convex), arc-shaped, and
Concave type, sigmoidal type, etc. dies are used. Furthermore, a die for fluid lubrication wire drawing can also be used. Further, as processing tools, roller dies, turquoise heads, driven rolling rolls, swagers, etc. are also used. As a heat source for this step, the temperature during heating and oxidation can be used together with the step of temporarily adhering the aluminum powder and the core wire. It is possible and preferred to contact the aluminum powder and the steel wire and draw them into the die at the same time. As the heating source, direct energization, high-frequency or low-frequency induction heating, electric furnace heating, heating using a gas combustion furnace, etc. can be used. Oxidative heating is performed in an oxidizing atmosphere such as oxygen, a mixed gas of oxygen and a neutral gas, a mixed gas of oxygen and combustion gas, or air. Next, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing one embodiment of the present invention, in which 1 is a core wire such as a steel wire, and in this embodiment, the diameter
A 3.8mm steel wire was used. In No. 2, aluminum powder was used as a powder material. 3 is a very commonly used ordinary die with a full approach angle of 16 degrees and a bearing inner diameter of 3.8 mm. 4 is a heating furnace. The steel wire 1 is degreased with perchlorethylene, polished with a wire foil made of stainless steel wire with a diameter of 0.5 mm, and then heated to 400° C. in an oxidizing atmosphere in a heating furnace 4. Next, the steel wire 1 is introduced into an aluminum powder tank 5, and in this tank, the aluminum powder 2 reduces iron oxide on the surface of the steel wire 1 and chemically reacts on the surface of the steel wire, so that the aluminum powder turns into steel. Weakly adheres to the wire surface. A die 3 is provided at the other end of the powder tank 5 in the direction in which the steel wire advances, and the aluminum powder 2 has a frictional adhesive force with the steel wire 1, an adhesive action due to the oxide reduction reaction, and a hydrodynamic flow action. Therefore, it is drawn into the bearing of the die 3, where the aluminum powder is pressure-coated onto the circumference of the steel wire, and it emerges from the die 3 as an aluminum-coated steel wire 6. There was no work interruption line, and the outer diameter of the aluminum-coated steel wire produced was 3.8 mm. FIG. 2 is an explanatory diagram showing another embodiment of the present invention, in which the entire system is vertical. Note that the symbol is the first
It is similar to the figure. In this example, the amount of aluminum powder 2 drawn into the die 3 increases due to the action of gravity and the drawing action of the steel wire 1, resulting in the effect that the coating becomes complete and thick. In this case, a more favorable effect can be obtained by applying vibration (preferably ultrasonic vibration) to the aluminum powder 2 and/or the hopper (tank) 5. Next, 5 mm diameter tubes were prepared by the conventional forward tension extrusion method and the method according to the present invention as shown in FIG.
A crush test was conducted to evaluate the adhesion of aluminum to mm aluminum coated steel wire, and the load required to peel aluminum from the steel wire was compared, and the results are shown in the table below.

[Table] As is clear from this result, the aluminum steel wire produced by the method of the present invention has the same or better adhesion between steel wire and aluminum than that produced by the conventional forward tension extrusion method. ing. Although the case where the method of the present invention is applied to a core wire has been described above, the present invention can also be applied to other pipes, rods, etc. Furthermore, it is also possible to obtain a composite wire with few defects and a thick coating by repeating the subsequent methods, excluding the surface oxidation treatment, twice or more on the composite wire obtained by the above method. In this case, a multilayer composite wire can also be obtained by using different metal powders in the second pass.
Further, as the outermost coating layer, a plastic powder such as polyvinyl chloride can be coated by the method described above to obtain an insulating or corrosion-resistant composite wire. As described above, the present invention eliminates the drawbacks of the conventional methods and makes it possible to continuously produce a composite metal wire without defects and having a coating layer with good adhesive properties, and also has the following effects. . (1) According to the present invention, the coated metal powder lightly adheres to the steel wire by an oxidation-reduction reaction on the surface of the core wire, and the amount of the coated metal powder drawn into the die is increased (increasing the coating thickness). Adhesive coating can be easily applied using pressure applied by dies, rolls, etc. Therefore, a composite wire can be obtained using an ordinary die without using a drawing method using a fluid-lubricated die. (2) When a normal die is used, the drawing force is small, so it is possible to coat soft steel wire with aluminum, and the range of production can be expanded. (3) The configuration of the device can be simplified.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing another embodiment. 1... Core wire, 2... Aluminum powder, 3...
Dice, 4...Heating furnace, 5...Aluminum powder tank, 6...Aluminum steel wire.

Claims (1)

[Claims] 1. A step of heating a core wire whose surface has been cleaned in an oxidizing atmosphere to form a uniform oxide film on its surface,
A step of introducing the core wire into powder of a coating metal that is more easily oxidized than the core wire metal and causing a reaction to reduce oxides on the surface of the core wire with the coating metal powder to facilitate adhesion of the powder to the surface of the core wire; Manufacture of a composite metal wire characterized by a process of drawing the powder into the inlet of a processing tool by frictional adhesive force with the coated metal powder and simultaneously processing it in a cold or heated state to coat and composite the powder on the surface of the core wire. Method.