JPH0234684B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial field of application] The present invention is directed to cutting wire rods (cavities inside wire rods).
The present invention relates to a detection method and a detection device for detecting. [Problems to be solved by the prior art and the invention] Generally, in the wire drawing process of high-strength alloy wires, such as No. There may be a disconnection. Cutting is a destructive phenomenon inside the wire, and as schematically shown in Figure 8, it is an arrowhead-shaped cavity f that periodically occurs on the central axis of the wire a, and in rare cases, it is the effect of the drawing force during wire drawing. Even if the wire is broken, it may remain as a cavity inside the wire without breaking. If such a wire is used, for example, as an electric wire, the wire will break during the wire twisting process, and in the worst case, the wire will be shipped as an electric wire without any breakage. Wire breakage during the wire twisting process results in a loss in the cost of heat treatment and twisting of the strands, and if the wire is shipped as an electric wire, there is a possibility of wire breakage due to vibration fatigue during overhead wiring or during use as an electric wire. Yes, it is very dangerous. The eddy current flaw detection method is conventionally known as a method for detecting defects on the wire surface and is widely used in actual operations, but this flaw detection method cannot detect defects inside the wire such as cutting. X-ray transmission methods and ultrasonic flaw detection methods are known as methods for detecting defects inside metals, but the transmission distance is unstable for wires that have a thin, circular cross section and vibrate laterally. Furthermore, it cannot be applied to objects in which the transparent object (wire) moves at high speed. [Means and effects for solving the problem] In view of this, as a result of various studies, the present invention is capable of detecting cutting as a decrease in the drawing force by continuously measuring the drawing force when drawing the wire rod. Based on this knowledge, we have developed a wire rod cutting detection method and detection device.A cylindrical body is installed between the die for drawing the wire rod and the die receiver, and a bridge circuit is formed within the cylindrical body. A ring for detecting the pulling force with a strain-sensitive resistor pasted thereon is installed coaxially with the cylindrical body to support the die, and the wire is pulled through the die. It is characterized by detection. That is, the present invention provides a wire drawing machine, for example, a continuous wire drawing machine.
~ Install a cutting detection device between several dies and the die receiver, pull out the wire through the dies,
This detects the reduction in drawing force due to cutting of the wire rod. The cutting detection device includes a ring for tensile force detection in which a strain-sensitive resistor that forms a bridge circuit is pasted inside a cylindrical body for preventing lateral vibration of the die, which has a die mounting part at one end and a wire insertion hole at the other end. It is provided coaxially with the cylindrical body to form a die support surface, and detects a decrease in drawing force due to cutting of the wire as a decrease in the unbalanced current value of the bridge circuit. This will be explained in detail using the drawings. FIG. 1 shows an example of the method of the present invention, in which a wire rod a is drawn by a wire drawing machine 1 through a die 3 attached to a die receiver 2 in a conventional manner. Dice 3
A detection device 4 is installed between the die support 2 and the die receiver 2, and the pulling force detected by the device 4 is measured by a strain meter 5 and recorded in a recorder 6. The drawing force when drawing a homogeneous wire is constant, but the drawing force of a wire with internal cutting decreases and is detected as a cutting. FIG. 2 shows an example of the detection device 4.
A strain-sensitive resistor that forms a bridge circuit is attached to the inside of a cylindrical body 7 for preventing lateral vibration of the die, which has a mounting port 8 for attaching the die 3 at one end and an insertion hole 9 for inserting the wire a at the other end. A pull-out force detection ring 10 is provided coaxially with the cylindrical body 7, and a die support surface 11 is formed at the tip thereof. FIG. 3 shows another example of the above-mentioned detection device 4, in which a die mounting port 8 of a cylindrical body 7 for preventing lateral vibration of dice is provided with a die mounting port 8 at one end and a wire insertion hole 9 at the other end. A drawing force detection ring 10 is provided inside the body 7 coaxially with the cylindrical body 7, and a die support surface 11 is formed at the lower end thereof. As shown in FIG. 1, the detection device 4 is attached to the die receiver 2, the die 3 is attached to the die mounting port 8 of the device 4, and the die 3 is supported on the die support surface of the drawing force detection ring 10, and the wire material a is drawn. Then, the drawing force detection ring 10 is compressed and deformed due to the deformation resistance of the wire material a and the frictional resistance with the die surface. As shown in FIG. 4, this pull-out force detection ring 10 is in the form of a thin ring, with a pair of vertical strain-sensitive resistors b facing the surface and a pair of horizontal strain-sensitive resistors b facing the surface. A resistor c is attached to form a bridge circuit shown in FIG. When a pull-out force p acts on such a detection ring 10 and the ring 10 is compressively deformed, the pressure-sensitive resistor c changes its resistance due to tensile strain, and the strain-sensitive resistor b changes its resistance due to compressive strain, respectively. As a result, an unbalanced current is generated in the bridge circuit. That is, the pulling force p is converted into an unbalanced current value generated in the bridge circuit and recorded. The cylindrical body for preventing lateral vibration of the die prevents lateral vibration of the wire drawing die, prevents the detection ring from being deformed to one side, and prevents the strain-sensitive resistor and bridge circuit attached to the detection ring from being damaged. It is something that plays a role. Also, in Figure 5, 12
1 shows a constant voltage power supply 13 and an ammeter. [Example] Next, an example of the present invention will be described. The detection device shown in FIG. 2 was installed between the die shown in FIG. 1 and the die receiver, and cutting was detected at the same time as the No. 1 aluminum wire was drawn. It should be noted that it is difficult to intentionally introduce foreign matter large enough to cause cutting into the wire, or to create casting defects such as cavities or blowholes, so the strength characteristics of the wire are reduced to less ductile. As two types, small and large,
Detection experiments were conducted with the wire drawing area reduction rate smaller than usual. This is based on the conventionally well-known knowledge that wire rods have low ductility, foreign objects and defects are present, and cutting is likely to occur when wire drawing with a reduced area ratio is performed. The wire used is Cu0.02
%, Fe 0.17%, Si 0.58%, Mg 0.64%, and the balance Al (wire diameter 12 mm) was further drawn to a wire diameter of 9.5 mm, and this was heated to 550℃. There are two types: one is solution treated by heating for 2 hours and then water quenched, and the other is solution treated and then aged at 180°C for 6 hours. The latter is a wire rod manufactured with low ductility and a tendency to cause cutting, and Table 1 shows its tensile properties.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to easily detect cutting, which has been difficult to detect in the past, and it is possible to prevent a wire rod in which cutting has occurred from being sent to a subsequent process, which brings about remarkable industrial effects.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the cutting detection method of the present invention, FIG. 2 is a sectional side view showing an example of the detecting device of the present invention, and FIG. 3 is a side sectional view showing another example of the same device. Figure 4 is an explanatory diagram of the pull-out force detection ring.
Figure 5 is an explanatory diagram of the bridge circuit of the same ring, Figure 6
The figure shows a drawing force variation diagram of a wire rod that does not cause cutting.
FIG. 7 is a drawing force variation diagram of a wire rod in which cutting has occurred, and FIG. 8 is a schematic diagram of an X-ray photograph of the wire rod in which cutting has occurred. a... Wire rod, b... Vertical strain sensitive resistor, c... Horizontal strain sensitive resistor, p... Pulling force, f... Cutting defect, 1... Wire drawing machine, 2... Dice receiver, 3... Dice,
4...Detection device, 5...Strain meter, 6...Recorder, 7...Cylindrical body for preventing side vibration of dice, 8...Dice mounting port, 9...Wire insertion hole, 10...Detection ring, 1
1...Dice support surface.

Claims (1)

[Scope of Claims] 1. A ring for detecting drawing force, in which a cylindrical body for preventing lateral vibration of the die is attached between a die for drawing a wire rod and a die receiver, and a strain-sensitive resistor forming a bridge circuit is pasted inside the cylindrical body. A method for detecting cutting of a wire rod, characterized in that a wire rod is provided coaxially with a cylindrical body to support a die, the wire rod is pulled out through the die, and a reduction in drawing force due to cutting of the wire rod is detected as a reduction in an unbalanced current value of a bridge circuit. 2. A pullout force detection ring with a strain-sensitive resistor that forms a bridge circuit pasted is placed coaxially with the cylindrical body, inside a cylindrical body for preventing lateral vibration of the die, which has a die attachment part formed at one end and a wire insertion hole at the other end. A cutting detection device for a wire rod formed in a shape to form a die support surface.