CN110174309B - Sample design method for local melting of metal material fracture under fatigue load - Google Patents
Sample design method for local melting of metal material fracture under fatigue load Download PDFInfo
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- CN110174309B CN110174309B CN201910505764.9A CN201910505764A CN110174309B CN 110174309 B CN110174309 B CN 110174309B CN 201910505764 A CN201910505764 A CN 201910505764A CN 110174309 B CN110174309 B CN 110174309B
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- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The invention belongs to the technical field of design of a metal material fracture melting sample, and discloses a sample design method for local melting of a metal material fracture under a fatigue load, which comprises the steps of carrying out a heat treatment process on a material, wherein the heat treatment process comprises the steps of heating the material to 860 ℃, and preserving heat for 2 hours; then oil quenching is carried out to the room temperature, tempering is carried out for 1h at 180 ℃, and finally air cooling is carried out to the room temperature; after the heat treatment process is finished, the material is made into a shape with two sides opened with 45 degrees and inclined U-shaped grooves or other shapes. The test sample designed by the invention is subjected to a compression fatigue test, and the cycle number is controlled within 100 ten thousand cycles. After the specimen was fractured, a large amount of melt was observed on the fracture by observation under a scanning electron microscope.
Description
Technical Field
The invention belongs to the technical field of design of a metal material fracture fusion sample, and particularly relates to a sample design method for local fusion of a metal material fracture under a fatigue load, in particular to design of a sample for local fusion of the metal material fracture treated by a special heat treatment process under the fatigue load.
Background
Currently, the current state of the art commonly used in the industry is such that:
the fatigue fracture of a ductile material at normal temperature or a high-hardness low-ductility material at high temperature is considered. Also regardless of the fatigue loading mode, such as loading in combination of tension, compression, torsion, bending, or bending, ductile dimple fracture, brittle fracture, or a combination of both, is exhibited at the fatigue fracture. However, so far, no melting of the metal has been found on the fracture of the test piece under fatigue load. The onset of melting indicates that the temperature rises to the melting point of the material at the instant of fatigue fracture, reaching 1500 ℃.
In summary, the problems of the prior art are as follows:
when the sample is subjected to fatigue loading, the melting of the traditional-shape sample cannot be observed during test fracture, so that whether the fracture causes temperature rise cannot be judged, and the current method and theory for analyzing the fracture mechanism have certain limitations. However, by adopting the sample in the scheme, different from the traditional torsional shear fatigue sample, the mode of opening 45-degree oblique U-shaped grooves on two sides is adopted, the fracture position of the sample is positioned at the minimum section, and a complete shear surface is reserved, so that researchers can better research and analyze the shear fracture surface and the fracture mechanism of the metal material.
Two factors are needed for generating a molten state in a fatigue test, wherein one factor is the sample with two sides provided with 45-degree oblique U-shaped grooves; the second is a heat treatment process for manufacturing the sample material. To our knowledge, a large number of researchers have used the same test specimens to perform high speed impact tests, but never used the shaped specimens to perform fatigue tests. And whether the material is melted or not is greatly related to the heat treatment process of the material. Neither the high-speed impact test nor the fatigue test reported that a large amount of melting occurred in the fracture surface. In terms of the present, the sample with the U-shaped groove with the two sides opened by 45 degrees is matched with the heat treatment process of our material, and is the only fatigue test which can observe a large amount of molten metal on a fracture. The heat treatment process of the material comprises the steps of heating the material to 860 ℃, preserving heat for 2 hours, then carrying out oil quenching to room temperature, tempering the material at 180 ℃ for 1 hour, and finally air cooling to room temperature. The heat treatment process of the material and the shape of the fatigue test piece are the two conditions which are not necessary.
The difficulty of solving the technical problems is as follows:
by reviewing the data and our experiments with other materials, it was found that other materials which were subjected to other heat treatment processes, even when formed into a shape similar to the above-described test piece, did not receive a molten metal. Only our heat treatment process can achieve the molten state, the specific reasons for which are not currently clear, and is in continued research. This is a relatively large problem.
The significance of solving the technical problems is as follows: an intact fracture surface contains all the information of the material response to fatigue dynamic loading in fatigue tests, which is also a difficult problem for researchers. The sample used in the high-speed impact test is used as a shear fatigue sample, so that the position of the fracture is limited in a special area, complete information is reserved after the test is finished, and researchers can obtain the fracture mechanism of the material in the fatigue test by analyzing the fracture morphology and related information.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a sample design method for local melting of a metal material fracture under a fatigue load.
The method is realized in such a way that the fracture of the metal material is locally molten under the compressive fatigue load through the special heat treatment process, and the fracture can be locally molten under the compressive fatigue load by the test sample designed by the method for designing the locally molten fracture of the metal material through the special heat treatment process under the fatigue load. In popular terms, a sample is taken to be subjected to a compression fatigue test, and after the sample is broken, a fracture can generate a large amount of melting phenomenon.
The method specifically comprises the following steps:
1) and (3) carrying out a heat treatment process on the material, wherein the heat treatment process comprises the steps of heating the material to 860 ℃, preserving heat for 2h, then carrying out oil quenching to room temperature, tempering the material at 180 ℃ for 1h, and finally carrying out air cooling to room temperature.
2) After the heat treatment process is completed, the material is made into the shape of the U-shaped groove with two sides opened in the figure 7, or other shapes, mainly the U-shaped groove with two sides opened. The groove depth and the groove width are determined according to the experimental requirements of the user. As shown in fig. 7.
The experimental method comprises the following steps: one end of the sample is fixed, and a fatigue load is applied to the other end of the sample, so that the sample can be sheared and brittle into two sections along the AB direction under the action of the load, as shown in figure 5. The melting phenomenon occurs on the cross-section C. As shown in fig. 5.
The embodiment of the invention provides a metal material manufactured by using a sample design method for local melting of a metal material fracture processed by a special heat treatment process under the fatigue load.
In summary, the advantages and positive effects of the invention are:
molten metal means a state in which a metal substance is at a temperature higher than the solidification temperature of the metal substance itself and is not broken to assume a liquid state. That is, the molten metal can appear at the fracture of the sample because the high temperature is generated due to the local shearing at the fracture in the sample, and the temperature change amplitude in the fatigue test can also be demonstrated. The melting refers to a process that when the temperature is increased, the thermal motion kinetic energy of molecules is increased to cause crystal destruction, and a substance has a crystal phase to be changed into a liquid phase, which indicates that the shear plane of the sample (material) has first-order phase change in a fatigue test.
Fig. 8 shows a comparison of XRD (X-ray diffraction) of the raw material and the fracture, from which it can also be seen that a phase transition has occurred at the fracture. It is clear from the figure that the residual austenite content of the raw material is only 5%, while the austenite content at the fracture reaches 20%. This is because the bcc martensite structure in the starting material is transformed into fcc austenite structure by austenitizing at a high temperature during the test, and after the sample is fractured, the temperature is rapidly lowered to rapidly cool the fracture surface, so that a part of the retained austenite is retained due to the incompleteness of the martensite transformation.
Drawings
Fig. 1 is a flow chart of a sample design method for local melting of a metal material fracture under a fatigue load according to an embodiment of the invention.
FIG. 2 is a scanning electron microscope of molten metal at the shear plane of a fracture according to an embodiment of the present invention.
FIG. 3 is a scanning electron microscope image II of molten metal at the shear plane of a fracture according to an embodiment of the present invention.
FIG. 4 is a scanning electron microscope image of molten metal at the shear plane of a fracture provided by an embodiment of the present invention.
FIG. 5 is a schematic diagram of fracture of a specimen under fatigue load in a scanning electron microscope for molten metal at a fracture shear surface according to an embodiment of the present invention.
FIG. 6 is a fracture morphology diagram of a sample in a scanning electron microscope of molten metal at a fracture shear plane according to an embodiment of the present invention.
Fig. 7 is a shape diagram of a U-shaped groove with two open sides and an oblique shape according to the material provided by the embodiment of the invention.
Fig. 8 is an XRD (X-ray diffraction) comparison of the raw material and fracture as provided in the examples of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The following detailed description of the principles of the invention is provided in connection with the accompanying drawings.
As shown in fig. 1, the sample design of local melting of a fracture of a metal material subjected to a special heat treatment process under a fatigue load provided by the embodiment of the invention comprises the following steps:
the designed test sample has the fracture which can be locally fused under the action of the compressive fatigue load. In popular terms, the sample is taken to be subjected to a compression fatigue test, and a fracture can be fused under the action of a fatigue load.
The method specifically comprises the following steps:
s101, performing a heat treatment process on the material, wherein the heat treatment process comprises the steps of heating the material to 860 ℃, preserving heat for 2 hours, performing oil quenching to room temperature, tempering at 180 ℃ for 1 hour, and finally air cooling to room temperature.
And S102, after the heat treatment process is finished, manufacturing the material into the shape of the U-shaped groove with the two sides provided with the oblique grooves in the figure 7, or into other shapes, wherein the two sides are mainly required to be provided with the oblique U-shaped grooves. The groove depth and the groove width are determined according to the experimental requirements of the user.
The invention is further described with reference to specific examples.
Fig. 5 is a schematic diagram of a fatigue test principle of the sample. The sample is subjected to shear brittle fracture along the AB direction under the action of fatigue load, and the two sections of the left graph A, B are shown (FIG. 6 is a fracture morphology graph of an example of the sample in the case). The C-plane is the shear plane and the molten state is present at the shear plane C. Example pictures are shown in the end pages of fig. 2-6. The appearance of the molten state proves that high temperature is generated at the local shearing of the fracture of the sample, and the sample is the first sample which can generate high temperature at the shearing part of the fatigue test. The example of the fracture of the sample in the scheme is shown in figure 6.
In the embodiment of the invention, fig. 2 is a scanning electron microscope image i of molten metal at a fracture shear plane according to the embodiment of the invention.
FIG. 3 is a scanning electron microscope image II of molten metal at the shear plane of a fracture according to an embodiment of the present invention.
FIG. 4 is a scanning electron microscope image of molten metal at the shear plane of a fracture provided by an embodiment of the present invention.
FIG. 5 is a schematic diagram of fracture of a specimen under fatigue load in a scanning electron microscope for molten metal at a fracture shear surface according to an embodiment of the present invention.
The 3 examples are given as samples with different numbers, so that the samples can generate molten metal at the fracture. That is, the creation of molten metal is a common but not specific example of the present case.
The invention is further described with reference to specific examples.
Examples
The method for designing the sample with the local melting of the metal material fracture under the fatigue load comprises the following steps:
1) and (3) carrying out a heat treatment process on the material, wherein the heat treatment process comprises the steps of heating the material to 860 ℃, preserving heat for 2h, then carrying out oil quenching to room temperature, tempering the material at 180 ℃ for 1h, and finally carrying out air cooling to room temperature.
2) After the heat treatment process is completed, the material is made into the shape of the U-shaped groove with two sides opened in the figure 7, or other shapes, mainly the U-shaped groove with two sides opened. The groove depth and the groove width are determined according to the experimental requirements of the user. As shown in fig. 7.
The experimental method comprises the following steps: one end of the sample is fixed, and a fatigue load is applied to the other end of the sample, so that the sample can be sheared and brittle into two sections along the AB direction under the action of the load, as shown in figure 5. The melting phenomenon occurs on the cross-section C. As shown in fig. 5.
Fig. 8 shows a comparison of XRD (X-ray diffraction) of the raw material and the fracture, from which it can also be seen that a phase transition has occurred at the fracture. It is clear from the figure that the residual austenite content of the raw material is only 5%, while the austenite content at the fracture reaches 20%. This is because the bcc martensite structure in the starting material is transformed into fcc austenite structure by austenitizing at a high temperature during the test, and after the sample is fractured, the temperature is rapidly lowered to rapidly cool the fracture surface, so that a part of the retained austenite is retained due to the incompleteness of the martensite transformation.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (2)
1. A sample design method for local melting of a metal material fracture processed by a special heat treatment process under a fatigue load is characterized by comprising the following steps:
1) carrying out heat treatment on the material, heating the material to 860 ℃, and preserving heat for 2 h;
2) then oil quenching is carried out to the room temperature, tempering is carried out for 1h at 180 ℃, and air cooling is carried out to the room temperature;
3) after the heat treatment process is finished, the material is made into a shape with two sides opened with 45 degrees and inclined U-shaped grooves or other shapes; realizing a compressive fatigue test with dominant shearing stress;
the test sample designed by the sample design method is characterized in that the local melting of the compressive fatigue fracture is dominated by the shear stress, and the fracture is locally melted under the action of the fatigue load of the sample.
2. A metal material manufactured by using a sample design method of local melting of a fracture of the metal material subjected to special heat treatment process under fatigue load as described in claim 1.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103217346A (en) * | 2013-04-01 | 2013-07-24 | 北京航空航天大学 | Method for measuring high-temperature creep crack growth threshold value of material |
| CN105067791A (en) * | 2015-08-06 | 2015-11-18 | 中国航空工业集团公司北京航空材料研究院 | Method for simulating high temperature alloy ultra-high cycle fatigue damage |
| CN204789086U (en) * | 2015-07-20 | 2015-11-18 | 西安科技大学 | Take sharp stress corrosion cracking state verification sample of splitting of permanent displacement load loading device |
| CN205138865U (en) * | 2015-11-28 | 2016-04-06 | 西安科技大学 | Sample of test stress corrosion cracking speed |
| CN105651617A (en) * | 2015-12-31 | 2016-06-08 | 内蒙古科技大学 | Treatment method for preventing fracture melting of tensile sample |
| CN107796874A (en) * | 2017-11-15 | 2018-03-13 | 宁波大学 | A kind of online defect detecting device of shaft forgings |
| CN108398336A (en) * | 2017-02-05 | 2018-08-14 | 鞍钢股份有限公司 | A method of obtaining drawing by high temperature fracture surface of sample |
| CN208239224U (en) * | 2018-04-18 | 2018-12-14 | 宁波大学 | A kind of corrosion device matched with rotary bending tester |
| CN208366809U (en) * | 2018-06-21 | 2019-01-11 | 宁波大学 | A kind of salt air corrosion device on rolling contact fatigue-testing machine |
| CN109632428A (en) * | 2019-01-29 | 2019-04-16 | 青海大学 | A kind of metal material cracking performance evaluation method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070099245A1 (en) * | 2005-09-29 | 2007-05-03 | Boris Gorovits | Assays for neutralizing antibodies |
| FR2904577B1 (en) * | 2006-08-03 | 2009-06-05 | Snecma Sa | METHOD FOR EVALUATING FATIGUE RESISTANCE OF WELDED JOINTS |
| CN102620990B (en) * | 2012-03-30 | 2014-01-29 | 中国科学院合肥物质科学研究院 | Device and method for testing material embrittlement under liquid metal condition |
| US20130319131A1 (en) * | 2012-05-31 | 2013-12-05 | Chevron Phillips Chemical Company Lp | Controlling Melt Fracture in Bimodal Resin Pipe |
| CN107356479B (en) * | 2017-07-12 | 2020-03-17 | 南方科技大学 | Metal material tensile property evaluation method based on selective laser melting technology |
| CN109338093A (en) * | 2018-11-16 | 2019-02-15 | 中国科学院金属研究所 | A kind of electric pulse treating method reducing steel material fatigue crack growth rate |
-
2019
- 2019-06-12 CN CN201910505764.9A patent/CN110174309B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103217346A (en) * | 2013-04-01 | 2013-07-24 | 北京航空航天大学 | Method for measuring high-temperature creep crack growth threshold value of material |
| CN204789086U (en) * | 2015-07-20 | 2015-11-18 | 西安科技大学 | Take sharp stress corrosion cracking state verification sample of splitting of permanent displacement load loading device |
| CN105067791A (en) * | 2015-08-06 | 2015-11-18 | 中国航空工业集团公司北京航空材料研究院 | Method for simulating high temperature alloy ultra-high cycle fatigue damage |
| CN205138865U (en) * | 2015-11-28 | 2016-04-06 | 西安科技大学 | Sample of test stress corrosion cracking speed |
| CN105651617A (en) * | 2015-12-31 | 2016-06-08 | 内蒙古科技大学 | Treatment method for preventing fracture melting of tensile sample |
| CN108398336A (en) * | 2017-02-05 | 2018-08-14 | 鞍钢股份有限公司 | A method of obtaining drawing by high temperature fracture surface of sample |
| CN107796874A (en) * | 2017-11-15 | 2018-03-13 | 宁波大学 | A kind of online defect detecting device of shaft forgings |
| CN208239224U (en) * | 2018-04-18 | 2018-12-14 | 宁波大学 | A kind of corrosion device matched with rotary bending tester |
| CN208366809U (en) * | 2018-06-21 | 2019-01-11 | 宁波大学 | A kind of salt air corrosion device on rolling contact fatigue-testing machine |
| CN109632428A (en) * | 2019-01-29 | 2019-04-16 | 青海大学 | A kind of metal material cracking performance evaluation method |
Non-Patent Citations (1)
| Title |
|---|
| 激光熔化沉积与锻造AerMet100钢的疲劳断口形貌;刘天琦;《金属热处理》;20170831;第42卷(第8期);205-209 * |
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