KR20200137646A - Apparatus and method for torsion test of wire rod - Google Patents

Abstract

Disclosed are a device and a method for testing torsion of a wire rod. According to an embodiment of the present invention, the device for testing torsion of a wire rod comprises: a fixing chuck fastening one side end of a wire rod; a rotary chuck fastening the other side end of the wire rod and applying torsional force to the wire rod by rotation thereof; a hydrogen injection chamber storing and sealing a portion of the wire rod between the fixing chuck and the rotary chuck and filled with hydrogen injection solution impregnating the inner wire rod; and a potentiostat applying current to the wire rod and the hydrogen injection solution; and a control unit controlling operation of the potentiostat and the rotary chuck in accordance with a setting.

Description

Wire torsion test device and test method {APPARATUS AND METHOD FOR TORSION TEST OF WIRE ROD}

The present invention relates to a wire rod torsion test apparatus and test method capable of testing whether a wire rod is torsional fracture after hydrogen is injected into the wire rod.

PC-stranded wires and wire ropes go through a wire-drawing process of thinly drawing a wire rod, a heat treatment process of heat-treating the wire rod, and a twisting process of twisting wires and heat-treated multiple strands into one wire. Is manufactured.

However, these products are difficult to manufacture because the wires are broken due to the torsional force generated in the twisting process, resulting in product defects.

In the related field, it is assumed that the cause of the wire breakage in the stranding process is the hydrogen penetrating into the wire during the heat treatment of the wire, and a study on the effect of the penetration of hydrogen on the disconnection of the wire through a twist test of the wire. In progress.

The torsion test of the wire rod can be conducted by applying a torsional force to the wire rod to determine whether the wire rod is broken according to the degree of twist. However, it is difficult to test the breakage of the wire rod due to hydrogen permeation because the conventional wire rod torsion test apparatus is a method that only applies a torsional force to the wire rod.

An aspect of the present invention is to provide a wire rod torsion test apparatus and test method capable of testing whether a wire rod is torsional fracture after hydrogen is injected under a set condition.

Another aspect of the present invention is to provide a wire rod torsion test apparatus and test method capable of continuously performing a process of injecting hydrogen into a wire rod and a process of testing torsional fracture after hydrogen injection.

According to an aspect of the present invention, a fixed chuck for binding one end of the wire rod; A rotating chuck that binds the other end of the wire rod and applies a torsional force to the wire rod by rotation; A hydrogen injection chamber to receive and seal a portion of the wire rod between the fixed chuck and the rotating chuck, and filled with a hydrogen injection solution for immersing the wire rod therein; A constant potential for applying a current to the wire rod and the hydrogen injection solution; And a control unit for controlling the operation of the constant electric potential and the rotating chuck according to the setting.

The hydrogen injection chamber includes a lower case with an open top; An upper case covering and sealing the upper part of the lower case while the wire is interposed therebetween; A sealing member for sealing the coupling portion of the lower case and the upper case to be coupled to each other; And a plurality of binding devices for maintaining the coupling between the lower case and the upper case.

The wire torsion test apparatus may further include a cylindrical electrode member that surrounds the wire rod in the hydrogen injection chamber in a state immersed in the hydrogen injection solution and to which (-) power is applied from the predetermined electric potential.

The cylindrical electrode member is mounted inside the upper case by an insulating member, and may include a longitudinal cutout through which the wire rod passes.

The wire rod torsion test apparatus may further include a vacuum pump controlled by the controller to maintain the inside of the water tank injection chamber in a vacuum.

The wire rod twist test apparatus includes a supply port and a discharge port respectively connected to the water tank injection chamber for supply and discharge of the hydrogen injection solution; A supply valve for opening and closing the flow path of the supply pipe; And a discharge valve for opening and closing the flow path of the discharge pipe.

According to another aspect of the present invention, the process of binding both ends of the wire rod to a fixed chuck and a rotating chuck, respectively; Installing a hydrogen injection chamber to receive a portion of the wire rod between the fixed chuck and the rotating chuck in a sealed state; Supplying a hydrogen injection solution to the water tank import chamber so that the wire rod inside the water tank import chamber is immersed; A step of maintaining the inside of the hydrogen injection chamber in a vacuum using a vacuum pump after supplying the hydrogen injection solution; A water tank injection step of forcibly injecting hydrogen generated by applying a set current to the wire rod and the hydrogen injection solution for a set time into the wire rod; A fracture test step of testing whether the wire rod is broken by rotating the rotating chuck according to a setting after the hydrogen injection step to apply a twist to the wire rod; And a process of recording test data and results of the hydrogen injection process and the breaking test process.

The test data may include current value, hydrogen injection time, and torsion information applied to the wire rod.

The hydrogen injection solution may contain an aqueous NH4SCN solution.

The wire rod twist test apparatus according to an embodiment of the present invention can easily derive various test results because hydrogen is injected into the wire rod under the conditions set in the hydrogen injection process, and then the twist test can be performed under the conditions set in the breaking test process. In addition, it can be used as data to investigate the cause of torsional disconnection of wire rods, to prevent the inflow of hydrogen and to develop new steel types with high torsional rigidity.

The wire rod torsion test apparatus according to an embodiment of the present invention can easily perform a twist test of a wire rod for evaluating torsional failure due to penetration of hydrogen because the hydrogen injection process and the torsional failure test process can be successively performed.

1 shows a wire rod twist test apparatus according to an embodiment of the present invention.
2 is a perspective view of a state in which the hydrogen injection chamber of the wire rod torsion test apparatus according to an embodiment of the present invention is assembled.
3 is a perspective view of a state in which the hydrogen injection chamber of the wire rod twist test apparatus according to an embodiment of the present invention is separated.
4 is a cross-sectional view taken along line IV-IV' of FIG. 2.
5 is a cross-sectional view taken along line V-V' of FIG. 2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented in order to sufficiently convey the spirit of the present invention to those of ordinary skill in the art to which the present invention pertains, and may be embodied in other forms without being limited thereto. In the drawings, in order to clarify the present invention, portions not related to the description may be omitted, and the size of components may be slightly exaggerated to help understanding.

1, the wire rod twist test apparatus according to an embodiment of the present invention includes a fixed chuck 20, a rotating chuck 30, a hydrogen injection chamber 40, a constant potentiometer 60, and a vacuum pump 70. ), a control unit 80, an input unit 82, and a data storage unit 85.

The fixed chuck 20 is installed on the moving frame 21 on the base portion 10, and may be configured as an interlocking chuck capable of binding one end of the test target wire 1 or releasing the binding. The moving frame 21 supporting the fixed chuck 20 may move in the axial direction along the rail 23 provided on the base portion 10. Accordingly, the fixed chuck 20 may be changed in position by moving the moving frame 21 when the wire rod 1 under test is bound or separated, and the length of the wire rod 1 is changed. The moving frame 21 may be fixed so as not to move after a position change.

The rotating chuck 30 is installed on the fixed frame 31 on the base 10 so as to face the fixed chuck 20. Like the fixed chuck 20, the rotating chuck 30 may be configured as an interlocking chuck capable of binding or releasing the other end of the wire rod 1 to be tested. A driving motor 33 for rotating the rotating chuck 30 is installed inside the fixed frame 31 supporting the rotating chuck 30.

The rotating chuck 30 rotates by the operation of the driving motor 33 in a state in which the test target wire 1 is coupled to the fixed chuck 20 and the rotating chuck 30, so that the torsion force for the test is applied to the wire 1 Can be added. The rotational speed, torque, and rotational speed of the rotating chuck 30 may be controlled by the controller 80.

The water tank injection chamber 40 is installed between the fixed chuck 20 and the rotating chuck 30 so as to receive a part of the test target wire 1 in a sealed state, as shown in FIG. 1. A hydrogen injection solution (S) for immersing the wire rod 1 is filled inside the hydrogen injection chamber 40.

2 and 3, the hydrogen injection chamber 40 is coupled to each other at the upper and lower sides of the wire 1 to receive and seal the intermediate portion between both ends of the wire 1 and the upper case 42 and the lower case. (41), maintaining the coupling of the upper sealing member 44 and the lower sealing member 43, the lower case 41 and the upper case 42 that seals the coupling portion between the upper case 42 and the lower case 41 It may include a plurality of binding devices 45 to let.

The lower case 41 may be provided in the form of a rectangular container with an open upper surface, and the upper case 42 may be provided in the form of a rectangular container with an open lower surface. The upper opening of the lower case 41 and the lower opening of the upper case 42 are provided with corresponding sizes so that they can be coupled to each other and sealed.

The lower sealing member 43 is installed along the upper circumference of the lower case 41, and the upper sealing member 44 is along the lower circumference of the upper case 42 so that it can be coupled to correspond to the lower sealing member 43. Installed. The lower sealing member 43 and the upper sealing member 44 may be made of an elastic material such as rubber or silicone. The lower sealing member 43 and the upper sealing member 44 are in close contact with each other when the upper case 42 and the lower case 41 are coupled to each other, thereby sealing the coupling portion, through which the hydrogen injection chamber 40 It is possible to prevent leakage of the filled hydrogen injection solution (S).

The lower sealing member 43 and the upper sealing member 44 each include wire recombination portions 43a and 44a on both sides in contact with the wire 1, and each wire recombination unit 43a and 44a has a semicircular cross section. It is formed and includes a wire passing groove (43b, 44b) that is closely coupled to the outer surface of the wire (1). Each wire passing groove (43b, 44b) may be provided with a size slightly smaller than the radius of the wire rod (1). When the lower case 41 and the upper case 44 are coupled to each other, the wire joining portions 43a and 44a may stably seal a portion through which the wire rod 1 passes.

In the present embodiment, the lower case 41 and the upper case 42 in the form of a rectangular container are presented, but the lower case 41 and the upper case 42 may be changed into various shapes such as a semi-cylindrical shape.

The plurality of binding devices 45 for binding the lower case 41 and the upper case 42 may be provided in the form of a conventional cicada clamp, as shown in FIGS. 2 and 3. Each binding device 45 is provided on the side of the locking hook (45a) provided on the side of the upper case (42), the lower case (41), a locking hook (45b), a locking hook (45b) that is caught in the locking hook (45a) It may include a binding lever (45c) for binding by pulling. The binding lever (45c) is rotatably coupled to the side of the lower case (41), and the locking ring (45b) is rotatably coupled to the binding lever (45c). Here, as an example, the fastening device 45 in the form of a cicada clamp is presented, but the fastening device may be changed in various forms such as a screw fastening method.

3 and 4, a supply pipe 51 for supplying a hydrogen injection solution S is connected to the upper case 42, and a supply pipe 51 for discharging the hydrogen injection solution S is connected to the lower case 41 The discharge pipe 52 may be connected. The supply pipe 51 may be provided with a supply valve 53 for opening and closing the flow path, and the discharge pipe 52 may be provided with a discharge valve 54 for opening and closing the flow path. Although not shown in the drawing, the supply pipe 51 is connected to a tank storing the hydrogen injection solution (S).

The operation of the supply valve 53 and the discharge valve 54 is controlled by the control unit 80. When supplying the hydrogen injection solution (S) into the water tank injection chamber (40), the supply valve (53) is opened while the discharge valve (54) is closed, and the hydrogen injection solution (S) inside the hydrogen injection chamber (40) When discharging, the discharge valve 54 may be opened while the supply valve 53 is closed.

The vacuum pump 70 may be connected to the upper case 42 by a connection pipe 71. The operation of the vacuum pump 70 is controlled by the control unit 80. The vacuum pump 70 may maintain the inside of the hydrogen injection chamber 40 in a vacuum after supplying the hydrogen injection solution (S).

Referring to FIGS. 1 and 3, the constant potentiometer 60 can supply a constant current to the wire rod 1 and the hydrogen injection solution S in the hydrogen injection process. The positive power of the constant potential 60 is connected to the wire 1 outside the hydrogen injection chamber 40 through the clamp 62, and the negative power of the constant potential 60 is the hydrogen injection chamber ( 40) It can be connected to the cylindrical electrode member 64 immersed in the hydrogen injection solution (S) inside.

The cylindrical electrode member 64 may be installed to surround the wire 1 in the hydrogen injection chamber 40 in a state immersed in the water tank injection solution S, as shown in FIGS. 3 to 5. The cylindrical electrode member 64 may be mounted inside the upper case 42 by the insulating member 65, and includes a cut groove 64a cut in the longitudinal direction at the lower side so that the wire 1 can pass. . The electrode member 64 may be made of a platinum plate or a platinum mesh in a cylindrical shape.

Referring to FIG. 1, the control unit 80 includes a supply valve 53, a discharge valve 54, a vacuum pump 70, and a single electric potential according to a setting for a hydrogen injection process of injecting hydrogen into the wire 1 60) can be controlled. In addition, it is possible to control the operation of the rotating chuck 30 for the torsional fracture test of the wire rod 1.

The input unit 82 may input information for setting hydrogen injection conditions and torsional fracture test conditions. The data storage unit 85 may store test data and results of the hydrogen injection process and the fracture test process. The test data may include a current value of a constant electric potential, a time to perform the hydrogen injection process, the number of rotations of the rotating chuck 30 for applying a twist to the wire 1, a torque, whether or not torsion breakage, etc.

Next, a twist test method of a wire rod using the wire rod twist test apparatus of the present embodiment will be described. The torsion test method of the wire 1 includes a preparation process for the test, a hydrogen injection process in which hydrogen is injected into the wire 1, and a fracture test process in which a torsional force is applied to the wire 1 after hydrogen injection.

The preparation process is a process of binding both ends of the test target wire 1 to the fixed chuck 20 and rotating chuck 30, respectively, a process of installing a hydrogen injection chamber 40, a process of supplying a hydrogen injection solution (S). , Including a process of maintaining a vacuum.

When installing the hydrogen injection chamber 40, the wire 1 is bound to the fixed chuck 20 and the rotating chuck 30, and then the upper case 42 and the lower case 41 are respectively located at the upper and lower sides of the wire 1 Combined so that the middle part of the wire 1 is sealed by the hydrogen injection chamber 40. When the hydrogen injection chamber 40 is installed in this way, as shown in FIG. 5, the electrode member 64 inside the hydrogen injection chamber 40 is in a state surrounding the outside of the wire 1.

After installing the hydrogen injection chamber 40, connect the (+) power of the constant potentiometer 60 to the wire rod 1 using the clamp 62, open the supply valve 53, and open the hydrogen injection solution (S ) Is supplied into the hydrogen injection chamber 40. The hydrogen injection solution (S) is filled to a height in which the electrode member 64 as well as the wire 1 in the hydrogen injection chamber 40 are completely immersed. The hydrogen injection solution (S) may be an aqueous solution of NH4SCN having a concentration of 0.1 to 1.0%. After filling the hydrogen injection chamber 40 with the hydrogen injection solution S, the vacuum pump 70 is operated to maintain the inside of the hydrogen injection chamber 40 in a vacuum.

In the hydrogen injection process, after completing the preparation process, the current is applied for a time set at the current value set by the constant potential 60. In this way, hydrogen generated in the hydrogen injection solution (S) is injected into the wire 1 immersed in the hydrogen injection solution (S) by an electrochemical method. The current value and the hydrogen injection time for the water tank injection can be set in advance through the input unit 82, and the control unit 80 controls the constant potentiometer 60 according to the set condition to control the wire rod 1 in the hydrogen injection chamber 40. ) To be forced into hydrogen.

When the hydrogen injection process is completed, the control unit 80 stops the operation of the constant potentiometer 60, closes the supply valve 53, and opens the discharge valve 54 to provide the hydrogen injection solution in the hydrogen injection chamber 40. (S) can be discharged. After the hydrogen injection solution (S) is discharged, the control unit 80 can operate the rotating chuck 30 to perform a fracture test process.

In the breaking test process, after the hydrogen injection process, the control unit 80 rotates the rotating chuck 30 according to the setting to apply a twist to the wire 1 to test whether the wire 1 is broken. The breaking test process may be set in advance by the input unit 82 to automatically proceed after the hydrogen injection process. In this case, the fracture test process can be carried out even if the manager does not specifically command the operation. The conditions under which the rotating chuck 30 is driven for the breaking test, that is, the torque (kgf) and the number of revolutions can be set in advance through the input unit 82, and the control unit 80 operates the rotating chuck 30 according to the set conditions. So that the torsional force can be applied to the wire rod 1.

Specifically, as in the test examples shown in Table 1 below, the twisting test of the wire rod can be performed by changing the twisting condition of the wire rod 1 each time while the hydrogen injection condition is fixed.

Test round Current value Hydrogen injection time Torque(kgf) Number of revolutions Disconnection One 1mA 5Hr 0.01 10 X 2 1mA 5Hr 0.03 14 X 3 1mA 5Hr 0.05 17 X 4 1mA 5Hr 0.07 19 X 5 1mA 5Hr 0.09 22 X 6 1mA 5Hr 0.12 25 X 7 1mA 5Hr 0.15 27 0

In the test examples in Table 1, the test target wire 1 was a PC stranded wire having a length of 300 mm and a diameter of 2 mm. And the hydrogen injection conditions of the hydrogen injection process were all the same with a current value of 1mA and a hydrogen injection time of 5Hr. The torsion conditions (torque (kgf), rotational speed) of the fracture test step that proceeds following the hydrogen injection step were changed each time.

In addition, the twist test of the wire rod can be performed by changing the injection conditions of hydrogen each time while the twisting condition of the wire rod 1 is fixed as in the test examples shown in Table 2 below.

Test round Current value Hydrogen injection time Torque(kgf) Number of revolutions Disconnection One 1mA 5Hr 0.07 19 X 2 2mA 5Hr 0.07 19 X 3 3mA 5Hr 0.07 19 X 4 4mA 5Hr 0.07 19 X 5 5mA 5Hr 0.07 19 X 6 6mA 5Hr 0.07 19 X 7 7mA 5Hr 0.07 19 0

In the test examples in Table 2, the wire to be tested was a PC steel wire having a length of 300 mm and a diameter of 2 mm. And the hydrogen injection conditions of the hydrogen injection process were changed every time while maintaining the same hydrogen injection time. The torsional conditions of the fracture test process were all kept the same at 0.07 torque (kgf) and 19 rotation speed.

Test data and test results of the hydrogen injection process and the fracture test process as shown in Tables 1 and 2 are recorded in the data storage unit 85. Such information can be used as data to determine the cause of torsional disconnection of the wire rod (1), to prevent the inflow of hydrogen and to develop new steel types with high torsional rigidity.

In addition, since the wire rod torsion test apparatus according to the present embodiment can perform a hydrogen injection process and a torsional failure test process in succession, it is possible to easily perform a torsion test of a wire rod to evaluate torsional failure due to penetration of hydrogen.

1: wire rod, 10: base portion,
20: fixed chuck, 30: rotating chuck,
33: drive motor, 40: water tank injection chamber,
41: lower case, 42: upper case,
43: lower sealing member, 44: upper sealing member,
45: binding device, 53: supply valve,
54: discharge valve, 60: constant potential,
62: clamp, 64: electrode member,
70: vacuum pump, 80: control unit,
82: input unit, 85: data storage unit.

Claims (9)

A fixed chuck that binds one end of the wire rod;
A rotating chuck that binds the other end of the wire rod and applies a torsional force to the wire rod by rotation;
A hydrogen injection chamber containing and sealing a portion of the wire rod between the fixed chuck and the rotating chuck, and filled with a hydrogen injection solution for immersing the wire rod therein;
A constant potential for applying a current to the wire rod and the hydrogen injection solution; And
Wire rod torsion test apparatus comprising; a control unit for controlling the operation of the constant electric potential and the rotating chuck according to the setting. The method of claim 1,
The hydrogen injection chamber,
A lower case with an open top;
An upper case covering and sealing the upper part of the lower case while the wire is interposed therebetween;
A sealing member for sealing the coupling portion of the lower case and the upper case to be coupled to each other; And
Wire rod twist test apparatus comprising a; a plurality of binding devices for maintaining the coupling of the lower case and the upper case. The method of claim 2,
The wire rod twist test apparatus further comprising a; cylindrical electrode member surrounding the wire rod inside the hydrogen injection chamber while immersed in the hydrogen injection solution and applied with (-) power from the constant potential. The method of claim 3,
The cylindrical electrode member is mounted inside the upper case by an insulating member, and the wire rod torsion test apparatus including a longitudinal cutout through which the wire rod passes. The method of claim 1,
A wire rod twist test apparatus further comprising a vacuum pump that maintains the inside of the water tank injection chamber in a vacuum and is controlled by the control unit. The method of claim 1,
A supply pipe and a discharge pipe respectively connected to the water tank injection chamber for supply and discharge of the hydrogen injection solution;
A supply valve for opening and closing the flow path of the supply pipe; And
Wire rod torsion test apparatus further comprising a; discharge valve for opening and closing the flow path of the discharge pipe. A step of binding both ends of the wire rod to a fixed chuck and a rotating chuck, respectively;
Installing a hydrogen injection chamber to receive a portion of the wire rod between the fixed chuck and the rotating chuck in a sealed state;
Supplying a hydrogen injection solution to the water tank import chamber so that the wire rod inside the water tank import chamber is immersed;
A step of maintaining the inside of the hydrogen injection chamber in a vacuum using a vacuum pump after supplying the hydrogen injection solution;
A water tank injection step of forcibly injecting hydrogen generated by applying a set current to the wire rod and the hydrogen injection solution for a set time into the wire rod;
A breaking test step of testing whether the wire rod is broken by rotating the rotating chuck according to a setting after the hydrogen injection step to test whether the wire rod is broken; And
A wire rod twist test method comprising a step of recording test data and results of the hydrogen injection step and the break test step. The method of claim 7,
The test data includes a current value, hydrogen injection time, and twist information applied to the wire rod. The method of claim 7,
The hydrogen injection solution is a wire rod twist test method containing an aqueous NH4SCN solution.

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