KR20020076075A - Apparatus for indentation test, method for measuring data of indentation test and mechanical properties using it, and record medium saving method for measuring mechanical properties - Google Patents

Abstract

PURPOSE: An indentation testing apparatus, data measurement method, mechanical properties measurement method and record medium is provided to allow the indentation testing machine to be easily attached to a structure by minimizing volume of the indentation testing machine, while shortening testing time. CONSTITUTION: An indentation testing machine comprises a load generating unit(110) having a motor(111) for generating load to be applied to a material, and a decelerator(112); a load transmission unit for converting the rotating force generated from the load generating unit into a vertical load; a load sensor(123) mounted to the load transmission unit, and which continuously measures changes of load; a connection shaft and an indenter holder(125) connected to an end of the load transmission unit, and which move along the axis same with the load sensor; an indenter(127) exposed from an end of the indenter holder, and which substantially applies a contact load to the material; and a displacement sensor for continuously measuring changes of indentation depth.

Description

Apparatus for indentation test, method for measuring data of indentation test and mechanical properties using it, and record medium saving method for measuring mechanical properties}

The present invention relates to the indentation test data measuring method using the indentation tester and the indentation tester, a physical property measuring method, a recording medium storing the physical property measuring method, attached to the material to measure the physical properties and continuously performing the indentation test The obtained data can be used to calculate the properties of materials such as tensile properties in the field.

Structural steel used in modern structures and various industrial facilities has a big problem that the reliability of the material decreases over time due to the harsh environment of high pressure and temperature. Therefore, it has been recognized that the development of a non-destructive test method that can easily and easily measure the change in mechanical properties due to material deterioration, and can evaluate the properties of specific weak areas.

This necessity required a means for evaluating the tensile properties in the field or for evaluating the tensile properties of the localized regions without using a specimen of constant size. As a means of this, an indentation tester for predicting information on material properties from the indentation load-displacement curve obtained by measuring the change in indentation depth according to the indentation load using the indentation test was invented.

Such indentation tester was a conventional "Field indentation microprobe (FIM) for structural integrity evaluation (US Patent US4852397)". However, the FIM required a separate tensile test to calibrate the experimental constants in analyzing the measured data, which made it difficult to measure parts that were expensive and difficult to obtain.

In order to solve the above problems, it is an object of the present invention to provide an indentation tester which is easy to attach to a real structure by miniaturizing a volume.

In addition, an object of the present invention is to provide a press-fit tester that can be attached and tested by varying the attachment device irrespective of the type and size of the material to be evaluated.

In addition, an object of the present invention is to provide a indentation tester that does not need to move the body itself to test the various positions of the material to enable horizontal movement, a method of measuring the indentation test data using the same, a method of measuring physical properties, and a recording medium storing the same. It is done.

In addition, the present invention repeats the application and removal of the load, the indentation tester that enables the continuous indentation test to continuously measure the load and displacement generated at this time, the indentation test data measurement method using the same, the method of measuring the physical properties, storage thereof The purpose is to provide a record carrier.

In addition, an object of the present invention is to provide a method for measuring physical properties using an indentation tester that can reduce the test cost and do not require a separate tensile test for correction of the experimental constant, and also can measure the difficult part to obtain a tensile test piece.

1 is an overall configuration of the indentation tester according to an embodiment of the present invention.

Figure 2 is a front sectional view of the main body of Figure 1;

3 is a side cross-sectional view of the main body of FIG.

4 is a plan view of a main body including a partial cross section of the horizontal moving apparatus of FIG.

5 is a cross-sectional view of the lower part of the main body of FIG. 1, the attachment device, and the specimen table.

Figure 6 is a flow chart of the physical property measurement method using an indentation tester according to an embodiment of the present invention.

7 is a detailed flowchart of the indenter movement method selection step of FIG.

8 is a detailed flow diagram of the indenter access step of FIG.

9 is an initial screen when a computer executes a recording medium storing a property measurement method using an indentation tester according to an embodiment of the present invention.

10 is an experimental condition setting screen.

11A is a press-fit depth and indentation load curve screen measured by a recording medium storing a physical property measuring method using an indentation tester according to an embodiment of the present invention.

Fig. 11B shows the indentation depth and indentation load curve overlapping screens measured multiple for the same material or different materials.

12 is a flow curve analysis result screen derived using the indentation depth and indentation load curve of FIG.

* Explanation of symbols for main parts of the drawings

100: body 101: frame

110: load adding device 111: motor

112: reducer 113: coupling

114: connecting shaft 115: bearing

116 support shaft 117 ball screw

118: Ball screw nut

121: cylinder 123: load sensor

125: indenter holder 127: indenter

128: displacement sensor 130: attachment device

131: magnet 133: body base

140: horizontal moving unit 141: slider

143: clamp 151: indenter position control sensor

161, 161 ': Motor Connector

163, 163 ': Encoder connector 165, 165': Displacement connector

200: notebook computer 300: interface board

400: initial screen 430: manual drive of the motor

440: Engage button 450: Graph window

The present invention, in order to achieve the above object, in the indentation tester for measuring the load and the indentation depth of the material connected by a computer and an interface board equipped with a control program and a property analysis program, generating a load applied to the material A load adding device having a motor and a speed reducer; A load transmitting device for converting the rotational force produced by the load adding device into a vertical load; A load sensor mounted on the load transmitting device and continuously measuring a change in load; A connecting shaft and an indenter holder connected to one end of the load transmitting device and moving in the same axis as the load sensor; An indenter exposed at the end of the indenter holder and substantially applying a contact load to the material; An indentation tester having a displacement sensor for continuously measuring a change in indentation depth according to indentation of an indenter is provided.

In addition, the present invention has a space in which the connecting shaft and the indenter holder can move vertically, and is located below the components (hereinafter referred to as the "body") to support the fixed parts, and the base is fastened to press-in the material Further comprising an attachment device for fixing to the tester, the attachment device provides a press-fit tester, characterized in that any one of a magnet, chain, U-block.

In addition, the present invention further includes a horizontal moving device for horizontally moving only the main body to which the indenter is attached in a fixed state of the attachment device and the base, the horizontal moving device is fastened with the base on the upper surface of the base A slider base having a dovetail formed on an upper surface thereof, a dovetail groove formed between a slider base and a main body, and a dovetail groove that can be custom-fitted with the dovetail of the slider base formed thereon, and a thread formed on an outer circumferential surface in the same direction as the dovetail groove direction A slider having a groove, one end of which is formed with a thread of the groove of the slider and a threadable thread, is screwed with the thread of the groove of the slider, the other end of which has a handle, and between one end and the other end by a bracket between the base and the slider. Indentation tester characterized in that it has a movement handle screwed to the base Provided.

The present invention also provides an indentation tester further comprising an indenter movement control sensor attached to the limit position of the area set to allow the indenter and the displacement sensor to move safely.

In addition, the present invention provides a press-fit tester characterized in that the form of the indenter is one of spherical, conical, square pyramid type, the indenter holder and the indenter are integral.

In addition, the present invention provides a method for measuring the indentation test data of the material using the indenter installed in the indentation test apparatus, the indenter access step of moving the indenter to a position where the indentation test can be started to approach the material; A load adding step of setting a moving speed of the indenter and a moving depth of the indenter and applying a load to the material; A load removing step of moving the indenter upward by a predetermined load removal rate of the moving depth of the indenter after the indenter vertically moves by the moving depth of the indenter; A measurement step of measuring the indentation depth and the indentation load of the indenter according to the vertical movement of the indenter through a load addition step and a load removal step; A continuous test step of repeating the load adding step, the load removing step and the measuring step a plurality of times; It provides an indentation test data measurement method using an indentation tester comprising a; indentation removing step of removing the indenter from the material.

In addition, the present invention, the indenter approach step, the indenter downward movement step for moving the indenter down, if the indentation load is greater than the load set value, the indenter stops moving and moves the indenter upward by the distance set value, the indentation load Provided is a method of measuring indentation test data using an indentation tester having a determination step of continuing to carry out the indenter downward movement step if the load is less than the set value.

The present invention also provides a method for measuring indentation test data using an indentation tester, characterized in that the load setting value is 0.2 to 2 kgf and the distance setting value is 5 to 30 µm.

In addition, the present invention provides a method for measuring indentation test data using an indentation tester, characterized in that for each successive test step, one or more of the indenter movement speed, the indenter movement depth, and the load removal rate can be changed. to provide.

In addition, the present invention is a measuring method for measuring the physical properties of the material by using the indentation tester, by moving the indenter to the position where the indentation test can be started, if the indentation load is more than the load set value of the indenter An indenter approaching step of stopping the movement and raising the indenter by the distance setting value and continuously moving the indenter if the indentation load is less than the load setting value; A load adding step of setting a moving speed of the indenter and a moving depth of the indenter and applying a load to the material; A load removing step of moving the indenter upward by a predetermined load removal rate of the moving depth of the indenter after the indenter vertically moves by the moving depth of the indenter; A measurement step of measuring the indentation depth and the indentation load of the indenter according to the vertical movement of the indenter through a load addition step and a load removal step; A continuous test step of repeating the load adding step, the load removing step and the measuring step a plurality of times; The stress-strain curve of the material is calculated from the indentation load-strain curve, which consists of the indentation step of removing the indenter from the material and the indentation depth and the indentation load measured in the measurement step before and after the indenter removal step. It provides a physical property measurement method using an indentation tester comprising; calculating the physical properties of the material using a curve.

In addition, the present invention is to move only the frame containing the indentation in the indentation tester horizontally, without moving the base or the attachment device of the indentation tester by repeating the steps in a single position of the same material at various locations of the same material to average the physical properties of the material It provides a physical property measurement method using an indentation tester further comprising the step of calculating.

In addition, the present invention is a recording medium in which the measuring method for measuring the physical properties of the material using the indentation tester is stored, the indenter is moved to a position to start the indentation test by moving the indenter down, the indentation load is set load value An indenter access means for stopping the movement of the indenter if it is abnormal and increasing the indenter by a distance setting value, and continuously moving the indenter if the indentation load is less than the load setting value; Load adding means for setting a moving speed of the indenter and a moving depth of the indenter and applying a load to the material; Load removing means for moving the indenter upward by a predetermined load removal rate of the moving depth of the indenter after the indenter vertically moves by the moving depth of the indenter; Measuring means for measuring the indentation depth and indentation load of the indenter according to the vertical movement of the indenter through a load adding step and a load removing step; Continuous test means for repeating the load adding means, the load removing means and the measuring means a plurality of times; The stress-strain curve of the material is obtained from the indentation removal means for removing the indenter from the material, and the indentation load-strain curve composed of the indentation depth and the indentation load measured by the measuring means before and after the indenter removal means. It provides a recording medium that stores a physical property measurement method using an indentation tester including a; physical property calculation means for calculating the physical properties of the material using a curve.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. These embodiments are merely one embodiment for describing the technical idea of the present invention, the present invention is not limited to these embodiments only.

1. Indentation tester

First, an embodiment of an indentation tester according to the present invention will be described with reference to FIGS. 1 to 5.

1 is an overall configuration diagram of the indentation tester according to an embodiment of the present invention, Figure 2 is a front cross-sectional view of the main body of Figure 1, Figure 3 is a side cross-sectional view of the main body of Figure 1, Figure 4 is a horizontal 5 is a plan view of the main body including the partial cross section of the moving device, and FIG. 5 is a cross-sectional view of the lower part of the main body of FIG.

Referring to Figure 1, the indentation tester according to the present invention basically an interface board for connecting the main body 100, the notebook computer 200 connected to the main body 100, the main body 100 and the notebook computer 200 ( 300).

The main body 100 is the main part of the device for performing the indentation test by attaching to the material to measure the physical properties. The notebook computer 200 is equipped with a program for controlling the operation of the main body 100 and analyzing the data measured by the measuring means of the main body 100. The interface board 300 is a device that connects the main body 100 and the notebook computer 200 to convert signal values, and the connectors included in the main body 100 and the notebook computer 200 are connectors of the interface board 300. Is connected to.

2 and 3, the main body 100 includes a frame 101, a load adding device 110, a cylinder 121, a load sensor 123, an indenter holder 125, an indenter 127, The displacement sensor 128, the horizontal moving device 140, the indenter movement control sensor 151, and the main body connectors 161, 163, and 165 are included.

The frame 101 is cylindrical and is a casing that protects internal components. The frame 101 includes a load adding device 110, a cylinder 121, a load sensor 123, a part of the indenter 127, etc., and is portable and transported by reducing the weight by using a high strength aluminum lightweight alloy. To facilitate.

The load adding device 110 is a place for generating a load applied to the material during the indentation test, and consists of a motor 111, a reducer 112, and a ball screw 117.

The motor 111 is stable to external loads and overloads, and uses an AC servomotor capable of precise control to remove the influence of dangerous factors such as external vibration in the field. The reducer 112 is located below the motor 111, and when the indenter 127 is moved by the power generated by the motor 111, the speed of movement of the indenter 127 is lowered as necessary for the test. Decrease. Below the reducer 112 is a coupling 113 connects the connecting shaft 114 to which the reducer 112 and the ball screw 117 are connected, and transmits the power of the motor 111 to the connecting shaft 114. . The bearing 115 is located at a predetermined position around the connecting shaft 114 to support the rotational movement of the connecting shaft 114. The support shaft 116 penetrates the cylinder 121 and guides the movement of the cylinder 121 when the cylinder 121 moves up and down, and prevents the cylinder 121 from impacting itself or shaking itself. The ball screw 117 is a portion that rotates due to the power generated from the motor 111 and applies a load to the load sensor 123 using the rotational force at this time. The ball screw nut 118 is threadedly coupled to the ball screw 117 so that when the ball screw 117 rotates, the ball screw nut 118 vertically moves in the vertical direction.

The cylinder 121 is press-bonded with the ball screw nut 118 to convert the rotational force produced by the load adding device 110 into a vertical load according to the vertical movement of the ball screw nut 118, so that the indenter 127 is loaded on the material. Allow to add The support shaft 116 penetrates the cylinder 121 as described above.

The load sensor 123 is positioned below the cylinder 121 and is continuously screwed by the cylinder 121 and the screw 123a to continuously measure a change in the load applied by the cylinder 121. When press-fitting the load sensor 123, a deformation proportional to the indentation load occurs, and according to this deformation, the electrical resistance of the strain gage built into the load sensor 123 changes, resulting in a change in the current because the current flowing therein changes. Detect and measure the load continuously. The maximum load of the load sensor 123 is 300 kgf, and the load resolution is 0.3 kgf. As the maximum load increases, the load resolution also increases, making precise analysis difficult. If the maximum load is low, sufficient data cannot be obtained. Therefore, the optimal load range is determined through various experiments.

Below the load sensor 123 is an extension shaft 124 connecting the ball screw 117 and the indenter 127 portion. Extension shaft 124 is a male screw is formed on the outer peripheral surface of the upper end is screwed with the female screw formed on the inner peripheral surface of the groove formed on the lower end of the load sensor 123.

At the end of the extension shaft 124 is an indenter holder 125 and an indenter 127. The indenter 127 is a portion that substantially applies a contact load to the material, the shape of which is spherical. The indenter holder 125 and the indenter 127 are integrally formed with the indenter 127 at the end of the indenter holder 125. Since the indenter holder 125 and the indenter 127 are integrally formed as described above, the indenter holder 125 is broken to eliminate the risk of the indenter 127 escaping from the indenter holder 125 and thus the indenter holder 125. ) And the experimental error occurring between the indenter 127. In the present embodiment, the shape of the indenter 127 is spherical, but a conical shape or a square pyramid type may be used depending on the application. In addition, the indenter holder 125 and the indenter 127 may be separate types instead of integral types.

The displacement sensor 128 is located under the connector 128a in parallel contact with the indenter 127. The displacement sensor 128 may be inserted when a force is applied into the groove formed at the lower end of the connector 128a, but when the force is removed, the displacement sensor 128 is extended to its original length by an elastic member installed inside the groove. The sensor bracket 129 fastens the connecting shaft 124 connected to the indenter 127 and the connector 128a connected to the displacement sensor 128. When the indenter 127 is pressed into the specimen, the displacement sensor 128 is inserted into the groove of the connector 128a to measure the insertion depth, thereby measuring the indentation length of the indenter. The maximum measurement range of the displacement sensor 128 is 2 mm, but LVDT (Linear Variable Displacement Transducer) is used to measure the precise indentation depth, but the present invention is not limited thereto.

There is a horizontal moving device 140 between the load adding device 110 and the load sensor 123 and the base 133. The horizontal moving device 140 is a device for performing the next indentation test by horizontally moving only the frame 101 without moving the entire indentation tester when the next indentation test is performed at a different position on the same material after the indentation test. to be.

2, 3, and 4, but mainly referring to FIG. 4, the horizontal moving device 140 located below the frame 101 of the main body 100 includes a slider 141, a slider base 142, and a clamp ( 143) and the clamping bolt (143a) and the movement handle 145. The slider 141 is located under the frame 101 of the main body 100, and the slider base 142 is located under the slider 141. Concave dovetail grooves 142a are formed in the slider base 142, and convex dovetails 141b and dovetail are formed in the slider 141, and they are fitted to each other. Accordingly, the slider 141 may slide in the dovetail direction 141b or the dovetail groove 142a in the slider base 142 to horizontally move the main body 100. The clamping bolt 143a is in cross-sectional contact with the slider base 142 through a groove formed in the slider 141. The fastener 143 is fastened to the fastener bolt 143a to rotate the fastener 143, the fastener bolt 143a moves up and down. When the clamp 143 is rotated to extend the clamp bolt 143a, the clamp bolt 143a presses the slider base 142 to fix the slider 141. In this state, when the clamping bolt 143 is rotated to shorten the clamping bolt 143a, the clamping bolt 143a releases the pressure of the slider base 142, and when the force is applied to the slider 141, horizontal movement is possible. The horizontally movable force of the slider 141 is obtained by rotating the movement knob 145. The movement handle 145 has a bolt 145b screwed with the nut 145c formed on the slider 141 through the bracket 145a. Rotating the movement knob 145 also rotates the movement knob bolt (145b). By the rotation of the movement knob bolt 145b, the movement knob nut 145c, the slider 141, and the frame 101 can move in the direction of the movement knob 145 or the opposite direction according to the direction of the thread. The movement handle 145 is formed with a scale to know the moving distance.

The indenter movement control sensor 151 is attached to prevent damage to the device due to excessive movement of the indenter 127 and the displacement sensor 128. Set the area where the indenter 127 and the displacement sensor 128 can safely move, and attach the indenter movement control sensor 151 to the limit position of each area. When this area is exceeded, the rotation of the motor 111 is stopped and the movement of the indenter 127 and the displacement sensor 128 is stopped.

At the end of the body 100 is a body base 133. The body base 133 connects the attachment device 130 to the main body 100, and supports the main body 100 when the attachment device 130 is not fastened.

Referring to Figure 5, the indentation tester according to the present invention has an attachment device 130 separately from the main body 100. The attachment device 130 has a magnet 131, a magnet bracket 131a, and two bolts 133b and 133b '. The magnet 131 and the main body base 133 are screwed together by the magnet bracket 131a and two bolts 133b and 133b '. The magnet 131 is used when the portion to be attached is made of a steel material, and in the case of a material having curvature, the bottom of the magnet 131 is processed to be used according to the curvature. In the present embodiment, the attachment device 130 is described as being a magnet 131, but a U-block having a chain or curvature may be used according to the type of material to be attached. If the magnet cannot be used, the chain is wound around the material and attached to the body. Four-row chain is used to support the high load of 300kg, and the body base 133 and the chain is fastened by mixing the bolt fastening method and the fastening screw fastening method. The U-block is used for the tube and fastens the main body 100 by fastening the brackets and the U-blocks that support the main body 100 with bolts.

Referring back to FIG. 1, the main body connector located at the upper end of the main body 100 frame 101 is a part for signal connecting the main body 100 and the interface board 300. The main body connector includes a motor connector 161, an encoder connector 163, and a displacement connector 165, respectively, and the motor connector 161 ', the encoder connector 163' and the displacement connector 165 'of the interface board 300, respectively. Connected.

The notebook computer 200 may be equipped with a program for analyzing the indentation load and displacement data of the measured material to calculate a variety of physical properties in the field. Convertible property values include hardness, flow curve, yield strength, work hardening index, tensile strength, non-uniform elongation, etc. The applicant filed a patent on January 12, 2001, but the unpublished work hard work index and stress Determination method of coefficient "(Application No. 10-2001-1770)," Determination of yield strength using continuous indentation test "(Application No. 10-2001-1771)," Determination method of tensile strength using continuous indentation test "(Application No. 10 -2001-1772).

In addition, the program loaded in the notebook computer 200 includes a manual driving function of a motor for approaching the indenter 127 to the material before the test or removing the indenter 127 from the material after the test, and automatically starting the test. There is an engagement function that moves the material to the position where the test can be started. This will be described later in detail.

Referring back to FIG. 1, the interface board 300 includes a motor connector 161 ′, an encoder connector 163 connected to a motor connector 161, an encoder connector 163, and a displacement connector 165 of the main body 100, respectively. ') And displacement connector 165'. In addition, there is a computer connector 167 connected to the communication port of the notebook computer (200). In addition, the interface board 300 has an UP / DOWN button 301 for moving the indenter 127 up and down when the indenter 127 is manually driven. In addition, there is an initialization button 303, emergency button 305, power button 307.

Hereinafter, the operation of the indentation tester according to the present invention will be described in detail with reference to FIGS. 1 to 5.

First, the attachment device 130 is screwed onto the body base 133 of the body 100, and then the attachment device 130 is attached to the material to be tested. The clamp 143 is locked and the clamp bolt 143 is rotated so that the clamp bolt 143a moves downward, and the clamp bolt 143a presses the slider base 142 to fix the slider 141 and the main body 100. Let's do it. Press the power button 307 of the interface board 300 to turn on the power and rotate the motor 111 with the program mounted on the notebook computer, at a low speed as necessary for the moving speed of the indenter 127 in the reducer 112 Slow down. The rotational force of the motor 111 rotates the connecting shaft 114 and the ball screw 117 to vertically move the ball screw nut 118 downward. Vertical movement of the ball screw nut 118 causes the cylinder 121, the load sensor 123, the extension shaft 124, the indenter holder 125, and the indenter 127 to move downward at the same time. At this time, the load sensor 123 continuously measures the change in the load. The vertical load presses the indenter 127 into the material. The displacement sensor 128 is inserted into the groove of the connector 128a when the indenter 127 is press-fitted to extend the indentation depth, and continuously measures the indentation depth of the indenter 127 by the insertion length. The load and indentation depth are measured to a certain depth by the load sensor 123 and the displacement sensor 128, and the motor 111 is rotated in the opposite direction to remove the load of the indenter 127 to a certain degree. The process of calculating the stress and strain by measuring the results is carried out continuously at one location. Again, by applying a load to the indenter 127 in this manner to further extend the indentation depth to measure the load and the indentation depth, and remove the load to some extent to continuously measure the load and the indentation depth to obtain the stress and strain. This process is repeated to complete the stress and strain curves at one location.

When the indentation test is completed in one position, the lock 143 of the horizontal moving device 140 is released and the slider 141 is horizontally moved by rotating the movement knob 145, and then the same indentation test is performed at the next position.

In order to perform the indentation test on other materials, the magnet 131 of the attachment device 130 is removed, the entire indentation tester is moved to another material, and the magnet 131 is again attached to the other material to perform the indentation test. In addition, the magnet can be used to bend the curvature to attach to the object having a curvature. On the other hand, when the measurement material is not a magnetic material, by rotating the bolt 133b for screwing the magnet bracket 133a and the body base 133 of the attachment device 130 of FIG. After detaching from the other attachment device, for example a chain or a U-block is fastened to the body base 133, and then subjected to a press-fit test.

2. Method of measuring indentation test data and physical property calculation using indentation tester

With reference to FIGS. 6 to 8 mainly, and with reference to Figures 1 to 5 additionally will be described an embodiment of the indentation test data measurement method using the indentation tester according to the present invention and a physical property calculation method.

Figure 6 is a flow chart of a physical property measurement method using an indentation tester according to an embodiment of the present invention, Figure 7 is a detailed flow chart of the indenter moving method selection step of Figure 6, Figure 8 is a indenter access step of FIG. Show detailed flow chart.

Referring to Figure 6, the physical property measurement method using the indentation tester according to the present invention, the indenter movement method selection step (S10), the indenter access step (S20), the load addition step (S30), the load removal step ( S40), the measuring step (S50), the continuous test step (S60), the physical property calculation step (S70), and the indenter removal step (S80). The indentation test data measuring method according to the present invention is a method of measuring the basic data for the physical property calculation, except the physical property calculation step (S70) of the above step. Indentation test data measurement method is explained while explaining the property measurement method to avoid repeated explanation.

The indenter movement method selection step (S10) is a step of manually or automatically selecting the movement of the indenter 127 of the indentation tester. Referring to FIG. 7, first, the method of moving the indenter 127 is selected in order to approach the indenter 127 to the material before starting the indentation test (S100). When asked if the indenter 127 is to be moved manually (S110), if it is done manually, the movement speed of the indenter 127 is set (S120). After setting the moving speed of the indenter 127 and selecting Up (S130), the indenter 127 is moved upward (S150). On the other hand, if Down is selected (S135), the indenter 127 is moved down (S155).

Even if the indenter 127 is automatically moved without being manually moved (S115), the moving speed of the indenter 127 should be set once (S120 '). Then, enter the moving distance (S140), and determine whether the moving distance is negative (S145), if the moving distance is negative to move the indenter 127 up (S150), if the moving distance is positive, the indenter down It moves (S155).

Indenter access step (S20) is to move the indenter 127 to a position to start the indentation test to approach the material. Referring to FIG. 8, while moving the indenter 127 down (S210), the moving distance and the load are displayed in real time (S220). Next, it is determined whether the load received by the indenter 127 is 1 kgf or more (S230), and when the load is 1 kgf or more (Yes), the downward movement of the indenter 127 is stopped (S240) and then moved upwards 10 μm (S240). S250) Stop (S260). This sets the distance between the indenter 127 and the material to an appropriate level to begin the test. If the load is not greater than 1 kgf (No), the indenter 127 continues to move down until the load of the indenter 127 reaches 1 kgf and repeats the indenter approach step. At this time, the values of 1 kgf and 10 μm represent the load set value and the length set value, respectively. The values obtained from the repeated test results do not affect the measurement of physical properties since the data measurement start range is 1 kgf or more. In addition, in the present embodiment, the load set value and the length set value are 1 kgf and 10 μm, respectively. Engagement setting within the range will be within the scope of the present invention.

The loading step S30 is a step of vertically lowering the indenter 127 by applying a load to the material. At this time, the vertical descent speed (moving speed) and the vertical descent length (moving distance) are set in advance. The moving speed and the moving distance of the indenter 127 can be obtained by controlling the motor 111 and the reducer 112 of the indentation tester. For example, when the maximum moving depth is 300 µm and the repetition frequency is 10, the moving speed can be 0.1 mm / min and the one-time moving depth can be 30 µm.

The load removing step S40 is a step in which the indenter 127 moves downward by a moving length, and then removes a load by a predetermined load removal rate to move the indenter upward by a predetermined distance. This can also be obtained by controlling the motor 111 and the reducer 112 of the indentation tester. In the above example, when the load removal rate is 30%, the indenter is moved upwards to a load corresponding to 70% of the added load to obtain a one-time moving depth.

The measuring step S50 is a step of measuring the indentation depth and the indentation load of the indenter 127 according to the vertical movement of the indenter 127 through the load adding step S30 and the load removing step S40. This step (S50) is made by the displacement sensor 128 and the load sensor 123 of the indentation tester.

Continuous test step (S60) is a step of repeating the load addition step (S30), the load removal step (S40) and the measurement step (S50) a predetermined number of times. On the other hand, the moving speed, the indenter moving depth, and the load removal rate can be varied for each order. For example, when the order is low and the additional load is low (1 to 3 times), the load removal rate may be increased, and as the order increases, the load removal rate may be reduced. When the degree is low, the load removal rate is increased to accurately reflect the plastic deformation pattern.

Physical property calculation step (S70) is a step of calculating the stress-strain curve using the indentation load curve for the indentation depth measured in the measurement step (S60), and calculates the physical properties of the material using the stress-strain curve. Here, the physical properties are the flow curve, yield strength, work hardening index, tensile strength, non-uniform elongation, etc. Method "(Application No. 10-2001-1770)," Determination of Yield Strength Using Continuous Indentation Test "(Application No. 10-2001-1771)," Determination of Tensile Strength Using Continuous Indentation Test "(Application No. 10-2001 -1772).

The indenter removal step S80 is a step of removing the indenter 127 from the material. Of course, the physical property calculation step (S70) may be located before and after the indenter removal step (S80).

As mentioned above, although the indentation test data measuring method and the physical property measuring method using the indentation tester were demonstrated with reference to drawings, this invention is not limited to this.

The property measurement method is repeated while the indenter 127 is horizontally moved in the uniaxial direction with respect to the same material by using the horizontal moving device 140 of the indentation tester. Therefore, a large number of property values may be calculated for the same material. The data indicating too small or too large of the measured physical properties are discarded and the remaining properties are averaged to obtain more accurate physical properties of the material.

3. Recording medium storing property measurement method using indentation tester

Referring to Figs. 9 to 12 and incidentally with reference to Figs. 1 to 8, a recording medium (hereinafter referred to as " this recording medium ") storing a physical property measuring method using an indentation tester according to the present invention will be described. The recording medium can be executed in a computing device such as a computer. For example, the recording medium may be executed in the notebook computer 200 shown in FIG. 1 to control the indentation tester through the interface board 300, receive measurement data of the indentation tester, and measure and output material properties. Can be.

9 is an initial screen when a recording medium storing a physical property measuring method using an indentation tester according to an embodiment of the present invention is executed by a computer, FIG. 10 is an experimental condition setting screen, and FIG. 11A is an embodiment of the present invention. Indentation depth and indentation load curve screen measured by the recording medium storing the physical property measurement method using the indentation tester according to an embodiment, Figure 11b is a superimposed screen of the indentation depth and indentation load curve multiple measured for the same or different materials 12 shows a flow curve analysis result screen derived using the indentation depth and indentation load curve of FIG. 11A.

Referring to FIG. 9, the initial screen 400 when the recording medium is executed by a computer includes an upper menu 410, an apparatus current state display unit 420, a manual drive unit 430 of the motor, and an engagement button. , 440, a graph window 450, a flow curve button 460, and a hardness analysis button 470. Components of the initial screen may be clicked using a mouse or a keyboard or manually operated using a keyboard.

The upper menu 410 has basic menus such as experiment condition setting 410a, device setting 410b, and graph 410c. When the experiment condition setting menu 410a is selected, the experiment condition setting screen shown in FIG. 10 is output. Experimental conditions include indenter type, indenter radius, multiple experiments, maximum displacement, load removal rate and load holding time. The lower passive part can adjust final displacement and test speed. The experimental condition schematic diagram according to the experimental condition is output and the experimental result is predicted and output according to the experimental condition.

The current instrument status display unit 420 displays the load and displacement of the indenter 127 of the current indentation tester.

Manual drive button 430 of the motor is a menu used to remove the indenter 127 from the material in order to approach the indenter 127 to the material before the test, or to move to the next indentation test position after the end of the indentation test. . Referring to FIG. 7, after setting the moving speed of the indenter 127 (S120), pressing the Up button of the manual driving button (S130) moves the indenter up (S150). On the other hand, if the down button (button) is pressed (S135), the indenter 127 is moved downward (S155).

Engage button 440 automatically initiates testing of the material to eliminate the inconvenience of having the indenter approach the material while the tester observes the indenter and the material directly when the material is moved to a starting point. It is a menu to move to a location. Referring to FIG. 8, first, when the gauge button 440 is pressed, the indenter approaching step S20 of FIG. 6 is executed to move to the position where the indenter 127 can be pressed.

If the start button is not shown on the initial screen 400, the measurement method stored in the recording medium may be executed to measure the physical property value of the material. First, the load and displacement of the current indenter is output to the current state portion 420 of the device described above. The indentation load curve according to the cumulative indentation depth (displacement) thus far is shown in the graph window 450 as shown in Fig. 11A. When a plurality of indentation load curves according to the indentation depth are obtained by moving horizontally with respect to the same material or when tensile properties change according to the test site and a comparison is necessary, the curves may be overlapped as shown in FIG. 11B. .

The initial screen 400 has a flow curve button 460 and a hardness analysis button 470, when the flow curve button 460 is clicked, a flow curve analysis window appears on the screen. Press the Start Analysis button in the flow curve analysis window to induce the flow curve. In addition, when the hardness analysis button 470 is clicked, the hardness curve analysis window is displayed on the screen, and when the analysis start button is pressed, the hardness value is displayed. For example, when the flow curve button 460 is clicked on, a flow curve appears with a horizontal axis as strain and a vertical axis as stress as shown in FIG. In the lower part of the flow curve of Fig. 12, the Hollomon equation for optimizing the work hardening behavior is shown, and the yield strength, tensile strength and work hardening index are shown on the right side. You can also save this content in a variety of file formats, for example BMP.

The present invention provides a press-fit tester that is easy to attach to the actual structure by miniaturizing the volume.

In addition, the present invention has an effect that can be attached to a variety of materials and tested by varying the attachment device regardless of the size and type of the target material.

In addition, the present invention has the effect that it is possible to move horizontally so that the body itself does not need to be moved to test different positions of the material.

In addition, the present invention has the effect of saving the test time by enabling one continuous indentation test.

In addition, the present invention does not require a separate tensile test for the correction of the experimental constant in analyzing the measured data, reducing the test cost, there is an effect that can be measured for the difficult to obtain a tensile test piece.

Claims (12)

In the indentation tester for measuring the load and indentation depth of the material connected by a computer and interface board equipped with a control program and a property analysis program, A load adding device having a motor and a speed reducer for generating a load applied to the material; A load transmitting device for converting the rotational force produced by the load adding device into a vertical load; A load sensor mounted on the load transmitting device and continuously measuring a change in load; A connecting shaft and an indenter holder connected to one end of the load transmitting device and moving in the same axis as the load sensor; An indenter exposed at the end of the indenter holder and substantially applying a contact load to the material; Indentation tester having a displacement sensor for continuously measuring the change in the indentation depth according to the indentation of the indenter. The method of claim 1, A base having a space in which the connecting shaft and the indenter holder can move vertically and positioned below the parts (hereinafter referred to as the “body”) to hold and support the parts; Further comprising an attachment device for fixing to the indentation test, The attachment device is any one of a magnet, a chain, U-block indentation tester. The method of claim 2, In addition, the attachment device and the base in the fixed state further comprises a horizontal moving device for horizontally moving only the main body to which the indenter is attached to one axis, The horizontal moving device, A slider base fastened to the upper surface of the base and having a dovetail formed on the upper surface thereof; A slider which is positioned between the slider base and the main body, and has a dovetail groove formed at a lower surface thereof, the dovetail groove being customizable to be coupled with the dovetail of the slider base, and having a groove having a thread formed on an outer circumferential surface in the same direction as the dovetail groove direction; One end is formed with a screw thread of the groove of the slider and a screw rotatable thread is screwed with the screw thread of the groove of the slider, the other end is formed with a handle, between the one end and the other end by the bracket to the base or the slider base Indentation tester characterized in that it has a movement handle screwed to. The method according to any one of claims 1 to 3, Indentation tester further comprises an indenter movement control sensor attached to the limit position of the area set to allow the indenter and the displacement sensor to move safely. The method according to any one of claims 1 to 3, The shape of the indenter is one of spherical, conical, square pyramid type, indentation holder, characterized in that the indenter holder and the indenter is integral. In the method of measuring the indentation test data of the material using the indenter installed in the indentation tester, An indenter access step of moving the indenter to a position where the indentation test can be started to access the material; A load adding step of setting a moving speed of the indenter and a moving depth of the indenter and applying a load to the material; A load removing step of moving the indenter upward by a predetermined load removal rate of the moving depth of the indenter after the indenter vertically moves by the depth of movement of the indenter; A measurement step of measuring the indentation depth and the indentation load of the indenter according to the vertical movement of the indenter simultaneously with each step in the load adding step and the load removing step; A continuous test step of repeating the load adding step, the load removing step and the measuring step a plurality of times; Indentation test data measurement method using an indentation tester including the indenter removing step of removing the indenter from the material. The method of claim 6, The indenter approach step, An indenter downward movement step of moving the indenter downward; If the indentation load is equal to or greater than the load setting value, the indenter is stopped and the indenter is moved by the distance setting value. Indentation test data measurement method. The method of claim 7, wherein The load setting value is 0.2 to 2kgf, and the length setting value is 5 to 30㎛ Indentation test data measuring method using the indentation tester. The method according to claim 7 or 8, For each continuous test step, the indentation test data measuring method using the indentation tester, characterized in that any one or more of the indenter moving speed, the indenter moving depth and the load removal rate can be changed. In the measuring method for measuring the physical properties of the material using an indentation tester, The indenter is moved downward to move the indenter to a position where the indentation test can be started, and if the indentation load is greater than the load setting value, the movement of the indenter is stopped and the indenter is raised by the distance setting value, and the indentation load is set by the load. An indenter accessing step of continuously moving the indenter if it is less than the value; A load adding step of setting a moving speed of the indenter and a moving depth of the indenter and applying a load to the material; A load removing step of moving the indenter upward by a predetermined load removal rate of the moving depth of the indenter after the indenter vertically moves by the depth of movement of the indenter; Measuring step of measuring the indentation depth and indentation load of the indenter in accordance with the vertical movement of the indenter through the load addition step and the load removal step: A continuous test step of repeating the load adding step, the load removing step and the measuring step a plurality of times; An indenter removal step of removing the indenter from a material; The stress-strain curve of the material is obtained from the indentation load-strain curve, which is composed of the indentation depth and the indentation load measured in the measurement step before and after the indenter removal step, and the physical properties of the material using the stress-strain curve. Physical property measurement method comprising a; indentation tester comprising; The method of claim 10, In the indentation tester, only the frame including the indenter is horizontally moved, and the base material of the indentation tester is not moved, and the physical properties of the material are obtained by averaging the property values calculated by repeating the steps at various positions on the same axis of the material. Physical property measurement method using an indentation tester further comprising the step of calculating. In a recording medium storing a measuring method for measuring the physical properties of the material using an indentation tester, The indenter is moved downward to move the indenter to a position where the indentation test can be started, and if the indentation load is greater than the load setting value, the movement of the indenter is stopped and the indenter is raised by the distance setting value, and the indentation load is set by the load. Indenter access means for continuing to move the indenter below a value; Load adding means for setting a moving speed of the indenter and a moving depth of the indenter and applying a load to the material; Load removing means for moving the indenter upward by a predetermined load removal rate of the moving depth of the indenter after the indenter vertically moves by the depth of movement of the indenter; Measuring step of measuring the indentation depth and indentation load of the indenter in accordance with the vertical movement of the indenter through the load addition step and the load removal step: Continuous test means for repeating the load adding means, the load removing means and the measuring means a plurality of times; Indenter removal means for removing the indenter from a material; The stress-strain curve of the material is obtained from the indentation load-strain curve, which is composed of the indentation depth and the indentation load measured by the measuring means before and after the indenter removing means, and the physical properties of the material are obtained using the stress-strain curve. Recording medium storing the physical property measurement method using an indentation tester comprising;