CN111122317A - Calibration method for r value test of metal material - Google Patents
Calibration method for r value test of metal material Download PDFInfo
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- CN111122317A CN111122317A CN201911291366.8A CN201911291366A CN111122317A CN 111122317 A CN111122317 A CN 111122317A CN 201911291366 A CN201911291366 A CN 201911291366A CN 111122317 A CN111122317 A CN 111122317A
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- 238000012360 testing method Methods 0.000 title claims abstract description 59
- 239000007769 metal material Substances 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 36
- 238000012795 verification Methods 0.000 claims abstract description 22
- 239000002699 waste material Substances 0.000 claims abstract description 10
- 238000012935 Averaging Methods 0.000 claims description 9
- 238000005259 measurement Methods 0.000 claims description 7
- 229910000831 Steel Inorganic materials 0.000 claims description 4
- 239000010959 steel Substances 0.000 claims description 4
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 238000009864 tensile test Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
- G01N2203/0075—Strain-stress relations or elastic constants
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0262—Shape of the specimen
- G01N2203/0278—Thin specimens
- G01N2203/0282—Two dimensional, e.g. tapes, webs, sheets, strips, disks or membranes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
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Abstract
The invention discloses a checking method for testing r value of a metal material, which utilizes waste materials of a target metal material to prepare a standard tensile sample; marking a straight line parallel to the parallel section on the parallel section of the standard tensile sample, and making a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a); measuring the original width b of the parallel segmento(ii) a Testing a strain point according to the r value of the target metal material, and stretching the marked standard tensile sample to obtain a stretched sample; measuring the gauge length L and the width b of the parallel section of the stretched sample; according to Lo，boL and b, obtaining a check r value of the target metal material; and comparing the verification r value with the test r value of the target metal material to obtain a verification result. Because the sample prepared by the waste is used for obtaining the check r value through marking, measuring and calculating, the sample can replace the certified standard sample with higher cost, the check cost can be obviously reduced, and the check result is accurate.
Description
Technical Field
The invention relates to the technical field of metal material performance testing, in particular to a verification method for r value testing of a metal material.
Background
In the field of steel and iron, performance testing of products is an important link for monitoring product quality. The r value test in the tensile property index of the metal material is mainly to directly test the r value of the metal material by using r value test equipment. However, the testing process has the highest technical requirements and strict requirements on the stability of equipment, and the testing process has more influence factors. Therefore, it is easy to cause the r-value test result to be inaccurate.
Therefore, the result of the r value test needs to be checked at regular time, and meanwhile, when detection abnormity occurs or equipment debugging occurs, the accuracy of the test also needs to be verified. In the prior art, for the calibration of the r value test accuracy, the certified standard sample is tested and calibrated, and the calibrated standard sample is used, so that the calibration cost is high.
Disclosure of Invention
The embodiment of the application provides a checking method for testing the r value of a metal material, and solves the technical problem that the existing checking method is high in cost.
On one hand, the present application provides the following technical solutions through an embodiment of the present application:
a method of verifying r-value testing of a metallic material, the method comprising:
preparing a standard tensile sample by using waste materials of a target metal material;
marking a straight line parallel to the parallel section on the parallel section of the standard tensile sample, and making a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a);
measuring the original width b of the parallel segmento；
Testing a strain point according to the r value of the target metal material, and stretching the marked standard tensile sample to obtain a stretched sample;
measuring the gauge length L and the width b of the parallel section of the stretched sample;
according to Lo，boL and b, obtaining a check r value of the target metal material;
and comparing the verification r value with the test r value of the target metal material to obtain a verification result.
Optionally, the measuring the width b of the parallel section of the sample after stretching specifically includes:
and measuring a plurality of width values of the parallel section of the sample after stretching, and averaging the plurality of width values to obtain b.
Optionally, the measuring a plurality of width values of the parallel section of the sample after stretching, and averaging the plurality of width values to obtain b specifically includes:
and measuring the width values of the two ends and the middle position of the stretched parallel section of the sample, and averaging the width values of the two ends and the middle position to obtain b.
Optionally, said is according to Lo，boL and b, obtaining a verified r-value of the target metal material, comprising:
calculating and obtaining a check r value of the target metal material by using the following formula:
optionally, the marking, at the parallel section of the standard tensile specimen, a straight line parallel to the parallel section specifically includes:
and marking a straight line parallel to the parallel section in the middle of the parallel section of the standard tensile sample.
Optionally, the mark is marked on the straight line to obtain a length LoThe initial gauge length specifically comprises:
marking vertical lines perpendicular to the straight line at two ends of the straight line to obtain a length LoThe initial gauge length.
Optionally, L isoThe measurement accuracy of (1) and (b) is 0.01mm or more.
Optionally, b isoAnd b has a measurement accuracy of 0.005mm or more.
Optionally, the metal material is a steel plate.
One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:
the method of the invention utilizes the waste material of the target metal material to prepare a standard tensile sample; at the placeMarking a straight line parallel to the parallel section by the parallel section of the standard tensile sample, and marking a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a); measuring the original width b of the parallel segmento(ii) a Testing a strain point according to the r value of the target metal material, and stretching the marked standard tensile sample to obtain a stretched sample; measuring the gauge length L and the width b of the parallel section of the stretched sample; according to Lo，boL and b, obtaining a check r value of the target metal material; and comparing the verification r value with the test r value of the target metal material to obtain a verification result. Because the sample prepared by the waste is used for obtaining the check r value through marking, measuring and calculating, the sample can replace the certified standard sample with higher cost, the check cost can be obviously reduced, and the check result is accurate.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a flow chart of a verification method for r-value testing of a metallic material in one embodiment of the invention;
FIG. 2 is a schematic representation of a standard tensile specimen prior to stretching in one embodiment of the present invention;
FIG. 3 is a schematic representation of a standard tensile specimen after stretching in one embodiment of the present invention;
FIG. 4 is a pictorial representation of a standard tensile specimen before and after elongation in one embodiment of the present invention.
Detailed Description
The embodiment of the application provides a method for checking r value test of a metal material, and solves the technical problem that the existing method for checking r value test of a metal material is high in cost.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
a method of verifying r-value testing of a metallic material, the method comprising: preparing a standard tensile sample by using waste materials of a target metal material; marking a straight line parallel to the parallel section on the parallel section of the standard tensile sample, and making a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a); measuring the original width b of the parallel segmento(ii) a Testing a strain point according to the r value of the target metal material, stretching the marked standard tensile sample to obtain a tensile sample: measuring the gauge length L and the width b of the parallel section of the stretched sample; according to Lo，boL and b, obtaining a check r value of the target metal material; and comparing the verification r value with the test r value of the target metal material to obtain a verification result.
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
First, it is stated that the term "and/or" appearing herein is merely one type of associative relationship that describes an associated object, meaning that three types of relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
It should be noted that the performance test on the metal material includes various aspects, such as n value and r value. The r value test in the tensile property index mainly utilizes r value test equipment to directly test the r value of the metal material. However, the testing process has the highest technical requirements and strict requirements on the stability of equipment, and the testing process has more influence factors. Therefore, it is easy to cause the r-value test result to be inaccurate.
The r value is a plastic strain ratio, which is a ratio of the strain value of the material in width to the strain value in thickness during press forming.
Therefore, the result of the r value test needs to be checked at regular time, and meanwhile, when detection abnormity occurs or equipment debugging occurs, the accuracy of the test also needs to be verified.
To this end, the present embodiment provides a verification method for r value test of a metal material, and referring to fig. 1, the method includes:
s101, preparing a standard tensile sample by using waste materials of a target metal material;
s102, marking a straight line parallel to the parallel section on the parallel section of the standard tensile sample, and marking a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a);
s103, measuring the original width b of the parallel sectiono；
S104, testing a strain point according to the r value of the target metal material, and stretching the marked standard tensile sample to obtain a stretched sample;
s105, measuring the gauge length L and the width b of the parallel section of the stretched sample;
s106, according to Lo，boL and b, obtaining a check r value of the target metal material;
s107, comparing the checking r value with the testing r value of the target metal material to obtain a checking result.
The method is realized by the following basic principle: the material is subjected to uniform plastic deformation after the elastic stage and before the uniform elongation Ag, the r value of the material is calculated by utilizing the actual measurement size of the sample before and after stretching, and the r value is compared with the equipment test data, so that the accuracy of the equipment test result is directly evaluated.
The steps are explained in detail below with reference to the drawings.
Referring to fig. 1, S101 is first executed to prepare a standard tensile sample by using scrap of a target metal material;
it should be noted that the standard tensile specimen is a specimen conforming to the tensile test standard, and referring to fig. 2, the standard tensile specimen includes a holding portion at both ends, and a parallel section in the middle. Wherein, the parallel section is used for observing the change condition before and after stretching.
The metal material is exemplified by a steel plate.
Next, S102 is executed atMarking a straight line parallel to the parallel section by the parallel section of the standard tensile sample, and marking a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a);
in a specific implementation, the straight line can be marked at any position parallel to the parallel section, but for the convenience of observation, as an alternative implementation, the marking of the straight line parallel to the parallel section on the parallel section of the standard tensile test sample specifically comprises:
referring to fig. 2, a straight line parallel to the parallel section is marked in the middle of the parallel section of the standard tensile specimen.
Similarly, the distance mark may be in various forms as long as the initial distance is marked, and as an alternative embodiment, the distance mark is made on the straight line to obtain the length LoThe initial gauge length specifically comprises:
marking vertical lines perpendicular to the straight line at two ends of the straight line to obtain a length LoThe initial gauge length.
Furthermore, the initial gauge length LoThe length of the check mark can be set arbitrarily, and the final check effect is not influenced.
In fig. 2, points a and B are two marked points of the initial gauge length.
Next, S103 is executed to measure the original width b of the parallel segmento。
As an optional implementation manner, in order to reduce errors and improve the accuracy of the verification, the measuring the width b of the parallel section of the specimen after stretching specifically includes:
and measuring a plurality of width values of the parallel section of the sample after stretching, and averaging the plurality of width values to obtain b.
Specifically, the measuring a plurality of width values of the parallel section of the sample after stretching, and averaging the plurality of width values to obtain b specifically includes:
and measuring the width values of the two ends and the middle position of the stretched parallel section of the sample, and averaging the width values of the two ends and the middle position to obtain b.
Next, S104 is executed, the strain point is tested according to the r value of the target metal material, and the marked standard tensile sample is stretched to obtain a post-stretching sample.
In the specific implementation process, a testing machine is used for stretching, and the stretching amount is based on the r value testing strain point of the target metal material, namely the testing strain point corresponding to the r value performance test of the target metal, such as 15%.
Next, S105 is performed, and the gauge length L and the width b of the parallel section of the sample after stretching are measured.
Referring to fig. 3, the stretched sample is lengthened, and the gauge length L and the width b of the parallel section of the stretched sample are measured.
As an alternative embodiment, to ensure the accuracy of the verification, L isoAnd L has a measurement accuracy of 0.01mm or more.
As an alternative embodiment, in order to ensure the accuracy of the verification, b isoAnd b has a measurement accuracy of 0.005mm or more.
Next, S106 is executed according to Lo，boL and b, obtaining a check r value of the target metal material;
specifically, the check r value of the target metal material is calculated and obtained by using the following formula:
next, S107 is executed, and the verification r value is compared with the test r value of the target metal material, so as to obtain a verification result.
Specifically, if the test r value is the same as the check r value, or the error is within an acceptable range, the test r value is accurate, otherwise, the test r value is inaccurate, and the test equipment needs to be adjusted.
After the overall implementation of the method is clarified, the implementation of the invention is further illustrated below in a specific experimental example.
2 certified standard samples with the gauge length of 80mm are adopted, 15% of standard samples are extended to be r value taking points, the relative deviation between the method and the equipment measured value and the standard value of the standard samples is controlled within 5%, the accuracy is high, and the method is feasible. The photographs of the test specimens before and after stretching are shown in FIG. 4, and the results of the verification are shown in Table 1 below:
table 1:
the error between the test r value and the check r value is clearly shown in table 1, so that it can be determined whether the test r value is relatively accurate. Therefore, when the r value of the tensile test is abnormal or the accuracy of the r value needs to be verified after equipment is debugged, the r value monitoring method can be used for verifying whether the test data of the equipment is accurate or not under the condition of not consuming any cost, and the r value monitoring method is convenient, fast and cost-free.
The technical scheme in the embodiment of the application at least has the following technical effects or advantages:
in the implementation, a standard tensile sample is prepared by utilizing the waste material of the target metal material; marking a straight line parallel to the parallel section on the parallel section of the standard tensile sample, and making a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a); measuring the original width b of the parallel segmento(ii) a Testing a strain point according to the r value of the target metal material, and stretching the marked standard tensile sample to obtain a stretched sample; measuring the gauge length L and the width b of the parallel section of the stretched sample; according to Lo，boL and b, obtaining a check r value of the target metal material; and comparing the verification r value with the test r value of the target metal material to obtain a verification result. Because the sample prepared by the waste is used for obtaining the check r value through marking, measuring and calculating, the sample can replace the certified standard sample with higher cost, the check cost can be obviously reduced, and the check result is accurate.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (9)
1. A verification method for r value test of a metal material is characterized by comprising the following steps:
preparing a standard tensile sample by using waste materials of a target metal material;
marking a straight line parallel to the parallel section on the parallel section of the standard tensile sample, and making a gauge length mark on the straight line to obtain a length LoThe initial gauge length of (a);
measuring the original width b of the parallel segmento；
Testing a strain point according to the r value of the target metal material, and stretching the marked standard tensile sample to obtain a stretched sample;
measuring the gauge length L and the width b of the parallel section of the stretched sample;
according to Lo，boL and b, obtaining a check r value of the target metal material;
and comparing the verification r value with the test r value of the target metal material to obtain a verification result.
2. The method according to claim 1, wherein said measuring the width b of the parallel section of the specimen after stretching comprises:
and measuring a plurality of width values of the parallel section of the sample after stretching, and averaging the plurality of width values to obtain b.
3. The method of claim 2, wherein measuring a plurality of width values of parallel segments of the sample after stretching and averaging the plurality of width values to obtain b comprises:
and measuring the width values of the two ends and the middle position of the stretched parallel section of the sample, and averaging the width values of the two ends and the middle position to obtain b.
4. The method of claim 1, wherein the function is according to Lo，boL and b, obtaining a verified r-value of the target metal material, comprising:
calculating and obtaining a check r value of the target metal material by using the following formula:
5. the method according to claim 1, wherein marking the parallel segments of the standard tensile specimen with straight lines parallel to the parallel segments comprises:
and marking a straight line parallel to the parallel section in the middle of the parallel section of the standard tensile sample.
6. The method of claim 1, wherein said making a gauge mark on said line results in a length LoThe initial gauge length specifically comprises:
marking vertical lines perpendicular to the straight line at two ends of the straight line to obtain a length LoThe initial gauge length.
7. The method of claim 1, wherein said L isoAnd L has a measurement accuracy of 0.01mm or more.
8. The method of claim 1, wherein b isoAnd b has a measurement accuracy of 0.005mm or more.
9. The method according to any one of claims 1 to 8, wherein the metallic material is a steel plate.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110411836A (en) * | 2019-08-28 | 2019-11-05 | 武汉上善仿真科技有限责任公司 | A kind of test and calculation method measuring metal material plastic strain ratio |
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| A. CHAMANFAR等: "Effect of specimen geometry, gage length, and width measurement locations on plastic strain ratio (R-value) in sheet metals", 《METALLURGICAL AND MATERIALS TRANSACTIONS A》 * |
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| CN113376013A (en) * | 2021-05-12 | 2021-09-10 | 首钢京唐钢铁联合有限责任公司 | Strip steel sample for forming limit test and limit test method |
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Application publication date: 20200508 |