CN113310437B - Method and device for automatically measuring wire rod area shrinkage - Google Patents
Method and device for automatically measuring wire rod area shrinkage Download PDFInfo
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Abstract
A method and a device for automatically measuring the reduction of area of a wire belong to the field of automatic detection, and comprise the following steps: s1, after a sample to be tested is broken, collecting a fracture image of the broken sample; s2, transmitting the fracture image to a processing system; s3, the processing system axially splices the fracture image along the stretch-broken sample, and fits according to the curvature radius of a contraction path at the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle; the vertical distance between the lowest point of the upper fitting circle and the top point of the lower fitting circle is used as the minimum diameter d after fracture; and S4, the processing system calculates the minimum cross-sectional area after fracture and the original cross-sectional area according to the minimum diameter D after fracture and the original diameter D of the sample to be detected, and the reduction of area is obtained. The method and the device can realize irregular fracture measurement, are simple and convenient and quick to operate, do not need manual intervention, and are high in detection efficiency and measurement accuracy.
Description
Technical Field
The application relates to the field of automatic detection, in particular to a method and a device for automatically measuring the reduction of area of a wire rod.
Background
Plastic deformation refers to deformation of a material under the action of external force, and after the external force is removed, an elastic deformation part disappears, the part which cannot be recovered and remains is deformed, and the area reduction rate is one of important performance indexes for measuring the plastic deformation capacity of the material. When the reduction of area is measured, the standard tensile sample is used for stretch breaking, and the percentage of the quotient of the difference of the cross section of the necked part of the sample and the original cross section is the reduction of area.
Most of the existing area shrinkage tests are manually measured, and have the defects of high strength, high repeatability, difficulty in ensuring accuracy and poor reproducibility. The minimum cross-sectional area after fracture is determined to be +/-2% accurately in the GB/T228.1 room temperature tensile test method, but the accuracy of measuring the cross-sectional area after fracture of a small-diameter wire rod round sample is difficult to achieve +/-2%.
In recent years, a lot of research has been conducted on measurement of shrinkage after breaking of a tensile sample.
The patent 'a metal reduction of area rate calculation device' proposes, including bottom plate, electronic slip table, camera and self-align mechanism, adopts the vision scanning mode in this patent, does not need to splice the sample after the fracture, even sample fracture is irregular, also can quick measurement. The patent 'a method for detecting the sample area shrinkage rate of a thermal tensile test' proposes to acquire a sample fracture in the thermal tensile test by a rubbing method, then a digital camera acquires a rubbing surface, and if the rubbing surface is a regular fracture, an area calculation formula is adopted; if the fracture is an irregular graph fracture, taking the average value of the cross section areas of the two sections of samples to calculate the shrinkage after fracture. The 2 patents respectively adopt visual scanning or rubbing methods, do not need to splice to acquire the appearance after fracture, and calculate the minimum cross-sectional area after fracture, but the shape of a sample after fracture can show different fracture after fracture according to parameters such as strength, and particularly, in the case of irregular fracture, the appearance of a complete fracture can be shown after the two ends are spliced.
The patent 'a method for measuring the elongation after fracture and the reduction of area of a tensile sample' proposes to completely splice two sections of sample fracture after tensile fracture, and the reduction of area is calculated by utilizing the relation between the length of a photo pixel calibrated before measurement and the actual size to obtain the minimum diameter after fracture. However, the difficulty of completely splicing the broken samples is high, and the identical positions of the two sections of the broken samples are not fixed, so that the broken samples are not twisted relatively, the broken samples are inevitably spliced at different positions during splicing, data are distorted, in addition, the broken lines are generally elliptical or irregularly circular, and the calculation by directly adopting a circular area formula is not accurate enough.
Therefore, the method for automatically measuring the reduction of area is urgently needed, can complete automatic measurement and calculation, automatically output calculation results, does not need manual intervention, can realize irregular fracture measurement, and is high in detection efficiency and accuracy.
Disclosure of Invention
In order to solve the problems of the prior art, one of the purposes of the application is to provide a method and a device for automatically measuring the reduction of area of a wire rod, which are simple and convenient to operate, quick, high in universality, quick in detection efficiency and capable of improving measurement accuracy, and a manual operation process is omitted.
In order to achieve the above object, the present application provides a method for automatically measuring the reduction of area of a wire rod, which specifically includes the following steps:
s1, after a sample to be tested is broken, collecting a fracture image of the broken sample;
s2, transmitting the fracture image to a processing system;
s3, the processing system axially splices the fracture image along the stretch-broken sample, and fits according to the curvature radius of a contraction path at the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle; the vertical distance between the lowest point of the upper fitting circle and the top point of the lower fitting circle is used as the minimum diameter d after fracture;
and S4, the processing system calculates the minimum cross-sectional area after fracture and the original cross-sectional area according to the minimum diameter D after fracture and the original diameter D of the sample to be detected, and the reduction of area is obtained.
In the step S1, no relative rotation exists between the stretch-broken samples during the process of collecting the fracture image.
In a preferred embodiment, in the step S1, the fracture image is acquired by using a probe of an image acquisition module, and a distribution surface of the probe is perpendicular to a longitudinal direction of the stretch-broken sample.
In a preferred embodiment, the image acquisition module further comprises a light source, wherein the light source is located on an extension line of a connecting line of the probe and the broken sample straight line.
In a preferred embodiment, the image acquisition module further comprises an acquisition box, and a probe assembly disposed inside the acquisition box; the probe assembly comprises a probe and a light source arranged on an extension line of the probe and the stretch-break sample connecting line;
preferably, the image acquisition module is provided with at least two groups of probe assemblies;
preferably, the probe resolution is 10 μm or more.
In a preferred embodiment, the fracture image acquisition is performed by clamping the stretch broken specimen with a manipulator that is required to rotate longitudinally 180 ° after the clamping of the stretch broken specimen.
The accuracy of the measurement of the minimum cross-sectional area of the test sample after fracture is within +/-2%.
The application also provides a device for realizing automatic measurement of the reduction of area of a wire rod, which comprises: the device comprises a dimension measuring device, a fracture stretching device, a manipulator, an image acquisition module, a processing system and a transmission module.
A dimension measuring device for measuring an initial diameter of a sample to be measured;
the fracture stretching device is used for stretching the sample to be tested to fracture;
the manipulator is used for clamping the broken sample to be tested to the image acquisition module;
the image acquisition module is used for acquiring a fracture side view image of the fractured sample to be tested;
the processing system is used for processing the fracture side view image and the initial diameter to obtain the shrinkage rate;
the transmission module is used for collecting the data of the size measuring device and the data of the image acquisition module and transmitting the data to the processing system;
the manipulator comprises a clamping hand, a clamping arm, a clamping upright post, a base and a controller, and has the functions of positioning, integrally rotating, rotating a head and detecting and identifying whether the manipulator is in a clamping state or not;
the image acquisition module comprises an acquisition box body and a probe assembly arranged in the acquisition box body; the probe assembly comprises a probe and a light source arranged on an extension line of the probe and the stretch-break sample connecting line;
preferably, the image acquisition module is provided with at least two groups of probe assemblies.
The beneficial effects of the application include:
the image fitting technology is innovatively adopted, the arc fitting is utilized for direct measurement, and because the fracture is mostly an nonstandard circle, even the fracture position is sometimes an irregular shape, the fracture position is difficult to be in seamless joint together, so that through fitting, the influence points can be removed, the removed influence point part cannot influence the shrinkage trend, and the accuracy of the measurement result is ensured.
In the application, the manipulator clamps the stretch-break samples for image acquisition, the manipulator has the advantages of adjustability and strong adaptability, can adapt to samples with different diameters or weights, and keeps two stretch-break samples from relative rotation in the acquisition process, so that the accuracy of image splicing is ensured, and the accuracy of fitting data and measuring results is further ensured.
The method is simple and convenient to operate, high in universality, free of manual intervention, capable of avoiding the problems of low measurement shrinkage precision, large deviation and high repeatability, capable of realizing automatic measurement of the broken face shrinkage rate, high in detection efficiency and high in measurement accuracy.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of automatic measurement of area reduction of a section according to the present application
FIG. 2 is a block diagram of an image acquisition module according to an embodiment of the present application
FIG. 3 is a test procedure of example 1 of the present application
FIG. 4 is a test procedure of example 2 of the present application
FIG. 5 is a test procedure of example 3 of the present application
FIG. 6 is a test procedure of example 4 of the present application
Detailed Description
Embodiments of the present application will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustration of the present application and should not be construed as limiting the scope of the present application. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention. The detection method used is not particularly specified, and is carried out according to national standards or conventional detection methods.
To achieve automatic measurement of the wire reduction, the present application exemplarily proposes an automatic measurement method to facilitate the implementation of the present application by those skilled in the art, and a flow chart is shown in fig. 1.
S1, after a sample to be tested is broken, collecting a fracture image of the broken sample;
the method comprises the following specific steps:
firstly, a sample to be tested is placed into a fracture stretching device, the fracture stretching device can adopt a conventional stretching machine, after the sample to be tested is fractured, an image acquisition module is used for acquiring fracture images of the fracture samples, and in the acquisition process, no relative rotation exists among the fracture samples.
In one possible embodiment, the image acquisition module comprises a probe with which the fracture image is acquired and the distribution face of which is perpendicular to the longitudinal direction of the stretch-broken specimen. The stretch-broken sample is generally a round wire rod, and the longitudinal direction of the wire rod is a longitudinal direction and the width direction of the wire rod is a transverse direction. Therefore, when acquiring fracture images, the distribution surface of the probe needs to be kept perpendicular to the longitudinal direction of the sample.
In one possible embodiment, the image acquisition module further comprises a light source located on an extension of the probe and the stretch-break specimen connection line, both the probe and the light source being maintained perpendicular to the longitudinal direction of the stretch-break specimen; the distribution surface of the light source is opposite to the distribution surface of the probe, and the light source provides a backlight light source for the probe, so that the fracture morphology of the breaking sample is clearer.
In one possible embodiment, the image acquisition module further comprises an acquisition box, and a probe assembly disposed inside the acquisition box; the probe assembly comprises a probe and a light source arranged on an extension line of the probe and the breaking sample connecting line, as shown in fig. 2; after the to-be-tested sample is broken, the mechanical arm clamps the broken sample to the collection box body, and places the fracture position of the to-be-tested sample between the probe and the light source for fracture image collection; the probe assembly at least comprises two groups, such as three groups of probe assemblies or four groups of probe assemblies, and the plurality of probe assemblies can acquire fracture images from each angle of the stretch-broken sample, so that the accuracy of subsequent measurement is improved; the resolution of the probe is more than 10 mu m.
The manipulator is positioned at the front end of the stretcher and comprises a clamping hand, a clamping arm, a clamping upright post and a base, wherein the clamping hand is axially and rotatably connected with the clamping arm, the clamping arm is axially and rotatably connected with the clamping upright post, and the bottom of the base is circular and can rotate along the circumferential direction; the inside has the controller, and after the sample that awaits measuring is broken, the manipulator passes through inside controller start-up.
The mechanical hand firstly finds out the breaking test sample through the locating function of the forefront end of the clamping hand, and the clamping hand starts to clamp the breaking test sample; when the manipulator detects that the manipulator is in the clamping state at present, the clamping hand, the clamping arm and the clamping upright post work, the base rotates to the front end of the image acquisition device, the clamped breaking sample is placed in the acquisition box body, the breaking position of the breaking sample is kept in the acquisition box body, the probe is arranged between the light source, and broken image acquisition is carried out.
Further, when the vertical stretcher is adopted by the fracture stretching device, the manipulator needs to longitudinally rotate 180 degrees when clamping and taking down the fracture sample and then clamps the fracture stretching device to the collection box body so as to ensure that the fracture position is arranged between the probe and the light source.
S2, transmitting the fracture image to a processing system;
the probes of the image acquisition module are connected with the transmission module, and the fracture image can be transmitted to the processing system through the transmission module.
S3, the processing system axially splices the fracture image along the stretch-broken sample, and fits according to the curvature radius of a contraction path at the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle; the vertical distance between the lowest point of the upper fitting circle and the top point of the lower fitting circle is used as the minimum diameter d after fracture;
after the processing system receives the fracture image acquired by the probe, the fracture photographs of the stretch-broken samples acquired by the same probe can be spliced axially. Because the fracture morphology often presents a section in a cup shape and a section in a projection shape after stretch breaking, two sections are needed to be spliced to complete a complete contraction. According to the method, when the image is spliced, only the simple splicing is needed, each group of fracture images are not required to be spliced together, the curvature of the other end of the fracture images is required to be matched and butted, the splicing process is simplified, the requirements of spliced images are reduced, the influence on a measuring result caused by poor splicing in the prior art is avoided, and the success rate and the accuracy are high.
When the curvature radius of the contracted path at the minimum contracted position of the image is matched after the splicing is completed, burrs, foreign matters and the like on the surface of the spliced image are removed, so that the curvature radius of a fitting circle is prevented from being influenced by the burrs, the foreign matters and the like.
A minimum contraction position exists on the spliced image, and fitting is carried out on the upper side and the lower side of the minimum contraction position along the curvature radius of the contraction path respectively to obtain an upper fitting circle and a lower fitting circle; because the fracture is mostly in an irregular circle, even the fracture position is sometimes in an irregular shape, the fracture is difficult to be connected together in a seamless way, the influence points can be removed by fitting, and the removed influence point part does not influence the shrinkage trend. The minimum shrinkage diameter of the irregular fracture can be calculated in a fitting mode, and the accuracy of a measurement result is ensured.
The vertical distance between the lowest point of the upper fitted circle and the vertex of the lower fitted circle is taken as the minimum diameter d of shrinkage after breaking.
In one possible embodiment, when the probe assembly is two groups, the stretch broken sample can obtain 2 groups of spliced images, and according to the vertical distance between the two groups of spliced images, taking the average value of the two groups of vertical distances as the minimum diameter d of the broken sample to be tested.
Illustratively, when the probe assembly is three sets, an average value of vertical distances according to the three sets of stitched images is taken as the post-fracture minimum shrinkage diameter d of the test sample.
Illustratively, when the probe assembly is four sets, an average value of vertical distances from the four sets of stitched images is taken as the post-fracture minimum shrinkage diameter d of the test sample.
Fracture images of the stretch-break samples are collected at multiple angles, fracture shrinkage of the stretch-break samples is monitored in an omnibearing manner, fracture shrinkage of the irregular fracture is monitored in different directions through multiple groups of probes, multiple groups of vertical distances are obtained through fitting, average numerical values of the vertical distances are used as the minimum shrinkage diameter after fracture, and the result is more accurate.
And S4, the processing system calculates the minimum cross-sectional area after fracture and the original cross-sectional area according to the minimum diameter D after fracture and the original diameter D of the sample to be detected, and the reduction of area is obtained.
The diameter of the original sample to be measured can be measured through laser surrounding of the size measuring device, measured data are uploaded to the processing system, and the processing system directly calculates the shrinkage rate Z after fracture according to the diameter D of the original sample to be measured and the minimum shrinkage diameter D after fracture.
Specifically, the post-break shrinkage Z can be calculated using the following formula:
wherein Z is the reduction of area, S 0 S is the original cross-sectional area U The diameter of the original sample to be measured is D, and D is the minimum shrinkage diameter after fracture.
The application also provides a device for realizing automatic measurement of the reduction of area of a wire rod, which comprises: the device comprises a dimension measuring device, a fracture stretching device, a manipulator, an image acquisition module, a processing system and a transmission module.
A dimension measuring device for measuring an initial diameter of a sample to be measured;
the fracture stretching device is used for stretching the sample to be tested to fracture;
the manipulator is used for clamping the broken sample to be tested to the image acquisition module;
the image acquisition module is used for acquiring a fracture side view image of the fractured sample to be tested;
the processing system is used for processing the fracture side view image and the initial diameter to obtain the shrinkage rate;
the transmission module is used for collecting the data of the size measuring device and the data of the image acquisition module and transmitting the data to the processing system;
the manipulator comprises a clamping hand, a clamping arm, a clamping upright post, a base and a controller; the device has the functions of positioning, integrally rotating, rotating the head and detecting and identifying whether the device is in a clamping state or not;
the image acquisition module comprises an acquisition box body and a probe assembly arranged in the acquisition box body; the probe assembly comprises a probe and a light source arranged on an extension line of the probe and the stretch-break sample connecting line;
preferably, the image acquisition module is provided with at least two groups of probe assemblies.
Example 1
The method for automatically measuring the reduction of area of the wire rod is provided, the specific mark of the material of the sample to be measured is 10B21, and the sample to be measured is pulled off by adopting a ZWICK 600kN electronic stretcher in the embodiment.
The first step: after a sample to be tested is broken, firstly clamping the upper breaking sample by a mechanical arm, placing the broken position of the clamped upper breaking sample between two groups of probe assemblies in a collecting box body, keeping the longitudinal direction of the breaking sample vertical to the distribution surfaces of the probe and the light source, emitting compensation light by the light source, starting the collection of a broken image by the probe, and transmitting the collected image to a processing system;
and a second step of: the mechanical arm continuously clamps and takes down the breaking sample, the mechanical arm longitudinally rotates by 180 degrees by utilizing the head rotation function of the mechanical arm, the breaking position of the breaking sample is ensured to be downward, the breaking position of the breaking sample is placed between probe assemblies in the collecting box body according to the same moving path as the breaking sample, no relative torsion exists between the breaking sample and the breaking sample, the longitudinal direction of the breaking sample is kept vertical to the distributing surfaces of the two groups of probes, and the breaking image of the breaking sample is collected and transmitted;
and a third step of: the processing system axially splices fracture images of the upper and lower stretch-break samples acquired by the same probe to obtain two groups of spliced images, as shown in fig. 3; removing burrs on the surface of an image, and then fitting according to the curvature radius of a contraction path of the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle, wherein the vertical distance is formed between the lowest point of the upper fitting circular arc and the vertex of the lower fitting circular arc;
fourth step: the processing system respectively obtains d according to the vertical distance between the two groups of spliced images 1 ＝3.53mm，d 2 =3.88 mm, taking the average of two sets of vertical distances as the minimum shrinkage diameter d after fracture of the test sample, d being 3.71mm, thereby calculating the shrinkage rate Z after fracture 1 。
Example 2
The method for automatically measuring the reduction of area of the wire rod is provided, the specific mark of the material to be measured is ML08AL steel, and a ZWICK 300kN electronic stretcher is adopted.
The first step: after a sample to be tested is broken, firstly clamping the upper breaking sample by a mechanical arm, placing the broken position of the clamped upper breaking sample between two groups of probe assemblies in a collecting box body, keeping the longitudinal direction of the breaking sample vertical to the distribution surfaces of the probe and the light source, emitting compensation light by the light source, starting the collection of a broken image by the probe, and transmitting the collected image to a processing system;
and a second step of: the mechanical arm continuously clamps and takes down the breaking sample, the mechanical arm longitudinally rotates by 180 degrees by utilizing the head rotation function of the mechanical arm, the breaking position of the breaking sample is ensured to be downward, the breaking position of the breaking sample is placed between probe assemblies in the collecting box body according to the same moving path as the breaking sample, no relative torsion exists between the breaking sample and the breaking sample, the longitudinal direction of the breaking sample is kept vertical to the distributing surfaces of the two groups of probes, and the breaking image of the breaking sample is collected and transmitted;
and a third step of: the processing system axially splices fracture images of the upper and lower stretch-break samples acquired by the same probe to obtain two groups of spliced images, as shown in fig. 4; removing burrs on the surface of an image, and then fitting according to the curvature radius of a contraction path of the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle, wherein the vertical distance is formed between the lowest point of the upper fitting circular arc and the vertex of the lower fitting circular arc;
fourth step: the processing system respectively obtains d according to the vertical distance between the two groups of spliced images 3 ＝3.77mm，d 4 =3.91 mm, taking the average value of two groups of vertical distances as the minimum shrinkage diameter d after fracture of the test sample, d being 3.71mm, thereby calculating the shrinkage rate Z after fracture 2 。
Example 3
The method for automatically measuring the reduction of area of the wire rod is provided, the material mark of the sample to be measured is SWRCH8A, and a ZWICK 600kN electronic stretcher is adopted.
The first step: after a sample to be tested is broken, firstly clamping the upper breaking sample by a mechanical arm, placing the broken position of the clamped upper breaking sample between two groups of probe assemblies in a collecting box body, keeping the longitudinal direction of the breaking sample vertical to the distribution surfaces of the probe and the light source, emitting compensation light by the light source, starting the collection of a broken image by the probe, and transmitting the collected image to a processing system;
and a second step of: the mechanical arm continuously clamps and takes down the breaking sample, the mechanical arm longitudinally rotates by 180 degrees by utilizing the head rotation function of the mechanical arm, the breaking position of the breaking sample is ensured to be downward, the breaking position of the breaking sample is placed between two groups of probe assemblies in the collecting box body according to the same moving path as the breaking sample, no relative torsion exists between the breaking sample and the breaking sample, the longitudinal direction of the breaking sample is kept vertical to the distributing surfaces of the two groups of probes, and the breaking image of the breaking sample is collected and transmitted;
and a third step of: the processing system axially splices fracture images of the upper and lower stretch-break samples acquired by the same probe to obtain two groups of spliced images, as shown in fig. 5; removing burrs on the surface of an image, and then fitting according to the curvature radius of a contraction path of the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle, wherein the vertical distance is formed between the lowest point of the upper fitting circular arc and the vertex of the lower fitting circular arc;
fourth step: the processing system respectively obtains d according to the vertical distance between the two groups of spliced images 5 ＝6.82mm，d 6 =6.77 mm, taking the average of two sets of vertical distances as the minimum shrinkage diameter d after fracture of the test sample, d being 6.80mm, thereby calculating the shrinkage rate Z after fracture 3 。
Example 4
The method for automatically measuring the reduction of area of the wire rod is provided, the specific mark of the material to be measured is SWRCH10A, and a ZWICK 600kN electronic stretcher is adopted.
The first step: after a sample to be tested is broken, firstly clamping the upper breaking sample by a mechanical arm, placing the broken position of the clamped upper breaking sample between two groups of probe assemblies in a collecting box body, keeping the longitudinal direction of the breaking sample vertical to the distribution surfaces of the probe and the light source, emitting compensation light by the light source, starting the collection of a broken image by the probe, and transmitting the collected image to a processing system;
and a second step of: the mechanical arm continuously clamps and takes down the breaking sample, the mechanical arm longitudinally rotates by 180 degrees by utilizing the head rotation function of the mechanical arm, the breaking position of the breaking sample is ensured to be downward, the breaking position of the breaking sample is placed between two groups of probes and two groups of light sources in the collecting box body according to the same moving path as the breaking sample, no relative torsion exists between the breaking sample and the breaking sample, the longitudinal direction of the breaking sample is kept vertical to the distributing surfaces of the two groups of probes, and the breaking image of the breaking sample is collected and transmitted;
and a third step of: the processing system axially splices fracture images of the upper and lower stretch-break samples acquired by the same probe to obtain two groups of spliced images, as shown in fig. 6; removing burrs on the surface of an image, and then fitting according to the curvature radius of a contraction path of the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle, wherein the vertical distance is formed between the lowest point of the upper fitting circular arc and the vertex of the lower fitting circular arc;
fourth step: the processing system respectively obtains d according to the vertical distance between the two groups of spliced images 7 ＝6.79mm，d 8 =7.14 mm, taking the average of two sets of vertical distances as the minimum shrinkage diameter d after fracture of the test sample, d being 6.97mm, thereby calculating the shrinkage rate Z after fracture 4 。
Table 1 measurement results and accuracy of the examples of the present application
| Examples | Shrinkage after break | Accuracy of |
| Example 1 | Z 1 ＝38％ | 2％ |
| Example 2 | Z 2 ＝77％ | 1％ |
| Example 3 | Z 3 ＝74％ | 1％ |
| Example 4 | Z 4 ＝70％ | 1％ |
The foregoing is merely a specific embodiment of the present application and is not intended to limit the application, and various modifications and variations may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims (7)
1. A method for automatically measuring the reduction of area of a wire, comprising the steps of:
s1, after a sample to be tested is broken, collecting a fracture image of the broken sample;
s2, transmitting the fracture image to a processing system;
s3, the processing system axially splices the fracture image along the stretch-broken sample, and fits according to the curvature radius of a contraction path at the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle; taking the vertical distance between the lowest point of the upper fitting circle and the top point of the lower fitting circle as the minimum diameter d after fracture;
s4, the processing system calculates the minimum cross-sectional area and the original cross-sectional area of the fracture according to the minimum diameter D after fracture and the diameter D of the original sample to be detected, so as to obtain the reduction of area;
in the process of collecting the fracture image in the step S1, no relative rotation exists between the stretch-broken samples, the fracture image is collected by using a probe of an image collecting module, and the distribution surface of the probe is vertical to the longitudinal direction of the stretch-broken samples;
in the step S3, the fracture images of each group do not need to be completely spliced during the axial splicing.
2. The method of claim 1, wherein the image acquisition module comprises a light source positioned on an extension of an extension line of the probe and the line of the stretch-break specimen.
3. The method of claim 2, wherein the image acquisition module further comprises an acquisition box and a probe assembly disposed inside the acquisition box;
the probe assembly comprises a probe and a light source arranged on an extension line of the probe and the stretch-break sample connecting line;
the image acquisition module is provided with at least two groups of probe assemblies;
the probe resolution is more than 10 mu m.
4. A method according to claim 3, wherein the fracture image acquisition is performed by clamping the stretch broken specimen with a manipulator which is required to rotate longitudinally 180 ° after clamping the stretch broken specimen.
5. The method according to claim 1, wherein in the step S2, the stitched images are at least two groups, and the at least two groups of upper fitted circles and lower fitted circles are obtained by fitting, and an average value of a vertical distance between a lowest point of the at least two groups of upper fitted circles and a vertex of the lower fitted circles is taken as the post-fracture minimum shrinkage diameter d.
6. The method of claim 1, wherein the fracture minimum cross-sectional area measurement accuracy is within ± 2%.
7. An apparatus for automatically measuring the reduction of area of a wire, comprising
A dimension measuring device for measuring an initial diameter of a sample to be measured;
the fracture stretching device is used for stretching the sample to be tested to fracture;
the image acquisition module is used for acquiring a fracture side view image of the fractured sample to be tested;
the image acquisition module comprises an acquisition box body and a probe assembly arranged in the acquisition box body; the probe assembly comprises a probe and a light source arranged on an extension line of the probe and a breaking sample connecting line; the image acquisition module is provided with at least two groups of probe assemblies;
the mechanical arm is used for clamping a broken sample to be tested to the image acquisition module and comprises a clamping hand, a clamping arm, a clamping upright post and a base, wherein the clamping hand is axially and rotationally connected with the clamping arm, the clamping arm is axially and rotationally connected with the clamping upright post, and the clamping upright post is circularly arranged at the bottom of the base and can rotate along the circumferential direction; the inside is provided with a controller, and after the sample to be tested is broken, the manipulator is started through the internal controller; the mechanical hand firstly finds out the breaking test sample through the locating function of the forefront end of the clamping hand, and the clamping hand starts to clamp the breaking test sample; when the manipulator detects that the current clamping state is achieved, the clamping hand, the clamping arm and the clamping upright post work, the base rotates to the front end of the image acquisition module, the clamped breaking sample is placed in the acquisition box body, and the breaking position of the breaking sample is kept to be placed between the probe and the light source in the acquisition box body, so that broken image acquisition is carried out;
the processing system is used for processing the fracture side view image and the initial diameter to obtain the shrinkage rate; the processing system axially splices the fracture side view image along the stretch broken sample, and fits according to the curvature radius of the contraction path at the minimum contraction position of the spliced image to obtain an upper fitting circle and a lower fitting circle; the vertical distance between the lowest point of the upper fitting circle and the top point of the lower fitting circle is used as the minimum diameter d after fracture;
and the transmission module is used for collecting the data of the size measuring device and the data of the image acquisition module and transmitting the data to the processing system.
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