CN113049627A - Dynamic CCT test method - Google Patents
Dynamic CCT test method Download PDFInfo
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- CN113049627A CN113049627A CN202110322412.7A CN202110322412A CN113049627A CN 113049627 A CN113049627 A CN 113049627A CN 202110322412 A CN202110322412 A CN 202110322412A CN 113049627 A CN113049627 A CN 113049627A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/02—Investigating or analyzing materials by the use of thermal means by investigating changes of state or changes of phase; by investigating sintering
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/16—Investigating or analyzing materials by the use of thermal means by investigating thermal coefficient of expansion
Abstract
The invention discloses a dynamic CCT test method, and belongs to the field of metal material thermal simulation research. The dynamic CCT test method comprises the following steps: a. preparing a compressed sample; b. assembling a sample; c, test process: and (3) reducing the temperature to the deformation temperature after heating, then compressing, using an air cooling device for auxiliary contact conduction cooling after compression, continuously cooling at different cooling rates to obtain a temperature-expansion curve, and combining the temperature-expansion curve with the metallographic structure of the sample after deformation to obtain a dynamic CCT curve. According to the invention, by arranging the air cooling device, when the sample is cooled at different cooling rates after being deformed, argon or helium with different flow rates is blown into the sample box, and the introduced cooling gas can be uniformly sprayed on the sample, so that the test requirements of a large-range test on various cooling rates are met, a real and accurate temperature-expansion curve is obtained, a more accurate dynamic CCT curve is obtained, and the problem of lower accuracy of the existing dynamic CCT test result is effectively solved.
Description
Technical Field
The invention belongs to the field of metal material thermal simulation research, and particularly relates to a dynamic CCT test method.
Background
The thermodynamic simulation experiment is widely applied to the field of thermodynamic research of metal materials, wherein the dynamic CCT test is an important function in the thermodynamic simulation experiment, and a supercooled austenite continuous cooling transformation temperature curve, namely a dynamic CCT curve, of a deformed material can be obtained through the dynamic CCT test.
In the existing patents or documents, when a Gleeble device is used for testing a dynamic CCT curve, adopted samples are all cylinders with the diameter of phi 8 × 12 or phi 10 × 15, the cylinder samples are subjected to compression deformation, and then continuous cooling is performed at different cooling rates. When the Gleeble equipment is used for testing, 30-50Kg of acting force needs to be applied to the two ends of the sample, which is equivalent to the pre-acting force before the compression deformation test, and because the common sample is in a small cylindrical shape, the pre-acting force at the two ends becomes larger due to thermal expansion and cold contraction at a high temperature stage, thereby influencing the phase change tissue and the phase change transition temperature.
Meanwhile, the sample needs to be compressed during the test, the stress of the sample is large, and the tissue of the sample is not free to expand, so that the phase change distortion is caused; if the clamping force of the sample is reduced, the heating temperature and the cooling temperature are unstable and fluctuate greatly, and the measured phase change temperature is not very accurate. In the continuous cooling stage, a cooling system of the Gleeble device is a contact conduction and water spray quenching device for a test sample and a clamp, the contact conduction cooling is high in cooling rate in a high-temperature section, but is low in cooling rate in a low-temperature section, so that the maximum controllable cooling rate of the test sample is limited, a high-precision test result cannot be obtained, and the water spray quenching device has great damage to the test device and the test sample, and the test sample is easy to crack, age or break.
The dynamic CCT curve can provide technical parameters for the technological processes of rolling deformation, cooling and the like of the material, and the more accurate CCT curve can bring great benefits to the field process, so that the problems are solved, and the more accurate dynamic CCT curve is necessary.
Disclosure of Invention
The invention aims to solve the technical problem of lower accuracy of the existing dynamic CCT test result.
The technical scheme adopted by the invention for solving the technical problems is as follows: the dynamic CCT test method comprises the following steps:
a. preparation of a compressed sample: the compression sample is of a columnar structure, the middle section of the compression sample is a reducing part, the two ends of the compression sample are clamping parts, and an annular heat conducting plate is arranged on the clamping parts and close to the reducing part;
b. assembling a sample: welding a thermocouple wire in the middle of the reduced part of the compression sample by using an expander frame, and contacting the annular heat conducting plate with the clamp;
c. the test process comprises the following steps: and (3) reducing the temperature to the deformation temperature after heating, then compressing, using an air cooling device for auxiliary contact conduction cooling after compression, continuously cooling at different cooling rates to obtain a temperature-expansion curve, and combining the temperature-expansion curve with the metallographic structure of the sample after deformation to obtain a dynamic CCT curve.
In the step c, the air cooling device comprises a cooling copper pipe, one end of the copper pipe is connected with the air storage device, and the other end of the copper pipe enters the sample box and points to the compressed sample, so that the cooling gas is uniformly sprayed on the compressed sample.
The diameter of the copper pipe is 13-17 mm.
In the step c, the cooling rate of the auxiliary water cooling continuous cooling by using the air cooling device is 0.1-100 ℃/s.
In the step c, the temperature is raised to 1000-1200 ℃ at the speed of 5-20 ℃/s, the temperature is kept for 2-10min, then the temperature is lowered to the deformation temperature at the speed of 10-15 ℃/s, and the compression is carried out after the temperature is kept for 0.5-2 min.
In the step c, the gas used by the gas cooling device is argon or helium.
In the step a, the diameter of the reduced part is 6-12mm, the length of the reduced part is 12-20mm, and the ratio of the length to the diameter is 0.4-0.66.
In the step a, the diameter of the clamping part is 8-20mm, and the length of the clamping part is 15-40 mm.
In the step a, the diameter of the periphery of the annular heat conducting plate is 22-40mm, and the thickness of the annular heat conducting plate is 2-5 mm.
The invention has the beneficial effects that: the common sample is easy to have poor contact in the experimental process, so that the temperature fluctuation is large, the obtained temperature point is inaccurate, the fluctuation of the temperature transition point on the corresponding CCT curve is large, and the accuracy of the CCT curve is reduced. When the test sample is assembled, the clamp is used for propping against the annular heat conducting plate arranged on the compression test sample, and the annular heat conducting plate are fully contacted, so that the precision of temperature and time curves can be improved; meanwhile, the compressed sample is provided with the clamping part, so that the clamping force at two ends of the sample can be avoided in the experiment, and the sample is not subjected to additional acting force before being compressed and deformed at a high-temperature stage, thereby reducing the influence of overlarge clamping force on the phase change of the material and improving the accuracy and the reliability of a CCT curve.
According to the invention, by arranging the air cooling device, argon or helium with different flow rates is blown into the sample chamber when the sample is cooled at different cooling rates after being deformed, the introduced cooling gas can be uniformly sprayed on the sample, the test requirements of a plurality of cooling rates in a wider test range are met, and a real and accurate temperature-expansion curve is obtained, so that a more accurate dynamic CCT curve is obtained, and the damage to equipment is reduced.
Drawings
FIG. 1 is a schematic view of a compressed sample according to the present invention.
Fig. 2 is a schematic view of an air cooling apparatus according to the present invention.
FIG. 3 is a time-expansion curve of the cooling rate of 1 deg.C/s for the examples.
FIG. 4 is a time-expansion curve of the cooling rate of 2 deg.C/s for the examples.
FIG. 5 is a time-expansion curve of the cooling rate of 3 deg.C/s for the examples.
FIG. 6 is a time-expansion curve of the cooling rate of 5 deg.C/s for the examples.
FIG. 7 is a metallographic structure graph showing the cooling rate of 1 ℃ per second in the examples.
FIG. 8 is a metallographic structure graph showing the cooling rate of 2 ℃/s for the examples.
FIG. 9 is a metallographic structure graph showing the cooling rate at 3 ℃/s for the examples.
FIG. 10 is a metallographic structure graph showing the cooling rate of 5 ℃/s for the examples.
Fig. 11 is a dynamic CCT curve plotted according to an example.
Labeled as: 1 is a sample box, 2 is a cooling copper pipe, 3 is a clamp, 4 is a compression sample, 4-1 is a clamping part, 4-2 is a reducing part, and 4-3 is an annular heat conducting plate.
Detailed Description
The technical solution of the present invention can be specifically implemented as follows.
The dynamic CCT test method comprises the following steps:
a. preparation of compressed sample 4: the compression sample 4 is of a columnar structure, the middle section of the compression sample is a reduced part 4-2, the two ends of the compression sample are clamping parts 4-1, and an annular heat conduction plate 4-3 is arranged on the clamping part 4-1 and close to the reduced part 4-2;
b. assembling the compression sample 4: the expansion instrument is arranged at the position of welding a thermocouple wire in the middle of the reduced part 4-2 of the compressed sample 4, and the annular heat conducting plate 4-3 is contacted with the clamp 3;
c. the test process comprises the following steps: and (3) reducing the temperature to the deformation temperature after heating, then compressing, using an air cooling device for auxiliary contact conduction cooling after compression, continuously cooling at different cooling rates to obtain a temperature-expansion curve, and combining the temperature-expansion curve with the metallographic structure of the sample after deformation to obtain a dynamic CCT curve.
Fig. 1 is a schematic view of a compressed sample 4 designed according to the present invention.
In order to expand the cooling rate and temperature range and improve the accuracy, it is preferable that, in step c, the air cooling device includes a cooling copper tube 2, one end of the cooling copper tube 2 is connected to the air storage device, the other end of the cooling copper tube enters the sample box 1 and points to the compressed sample 4, so that the cooling gas is uniformly sprayed on the compressed sample 4, and the diameter of the cooling copper tube 2 is 13-17 mm.
Fig. 2 is a schematic view of an air cooling apparatus according to the present invention.
In order to obtain more accurate experimental results, it is preferable that in step c, the temperature is raised to 1000-1200 ℃ at the rate of 5-20 ℃/s, the temperature is maintained for 2-10min, then the temperature is lowered to the deformation temperature at the rate of 10-15 ℃/s, the compression is carried out after the temperature is maintained for 0.5-2min, and the cooling rate of the auxiliary water cooling continuous cooling by using an air cooling device is 0.1-100 ℃/s.
In order to obtain better experimental effects, it is more preferable that the gas introduced by the gas cooling device is argon or helium.
In order to obtain a compressed sample that is more compatible with the Gleeble device, it is therefore preferred that in step a, the reduced portion 4-2 has a diameter of 6-12mm, a length of 12-20mm, and a ratio of length to diameter of 0.4-0.66; the diameter of the clamping part 4-1 is 8-20mm, and the length is 15-40 mm; the diameter of the periphery of the annular heat conducting plate 4-3 is 22-40mm, and the thickness is 2-5 mm.
The technical solution and effects of the present invention will be further described below by way of practical examples.
Examples
The method comprises the following steps of (1) making a compression sample 4 designed by the invention from bainite steel, wherein the compression sample 4 is of a columnar structure; the middle section is a reduced part 4-2, the diameter is 6mm, and the length is 15 mm; the two ends are clamping parts 4-1, the diameter is 10mm, and the length is 33 mm; an annular heat conducting plate 4-3 is arranged on the clamping part 4-1 and close to the reducing part 4-2, the diameter of the periphery of the annular heat conducting plate 4-3 is 22mm, and the thickness of the annular heat conducting plate is 3 mm; the compressed sample 4 was mounted on a gleeble 3500 for a thermal simulated compression test.
Heating the sample to 1200 ℃ at the speed of 5 ℃/s, preserving heat for 2min, reducing the temperature to the deformation temperature T1 at the speed of 5 ℃/s, preserving heat for 30s, then compressing, starting an air cooling device after compression, uniformly spraying argon cooling gas on the compressed sample 4, and continuously cooling at different cooling rates to obtain a temperature expansion curve of the compressed sample as shown in figures 3, 4, 5 and 6, wherein figure 3 is a time-expansion curve of the cooling rate of 1 ℃/s, figure 4 is a time-expansion curve of the cooling rate of 2 ℃/s, figure 5 is a time-expansion curve of the cooling rate of 3 ℃/s, and figure 6 is a time-expansion curve of the cooling rate of 5 ℃/s.
And (2) preparing a metallographic sample from the sample after thermal simulation, and observing the change rule of the structure by using a Laica optical microscope, wherein the metallographic sample is shown in figures 7, 8, 9 and 10, the figure 7 is a metallographic structure diagram with a cooling rate of 1 ℃/s, the figure 8 is a metallographic structure diagram with a cooling rate of 2 ℃/s, the figure 9 is a metallographic structure diagram with a cooling rate of 3 ℃/s, and the figure 10 is a metallographic structure diagram with a cooling rate of 5 ℃/s.
Finally, the dynamic CCT curve of the bainite steel is drawn by combining the temperature expansion curve with the metallographic structure as shown in figure 11, and the result of the dynamic CCT curve drawn by the method is consistent with the structure change observed in the experimental process.
Claims (9)
1. The dynamic CCT test method is characterized by comprising the following steps:
a. preparation of compressed sample (4): the compression sample (4) is of a columnar structure, the middle section of the compression sample is a reducing part (4-2), the two ends of the compression sample are clamping parts (4-1), and an annular heat conduction plate (4-3) is arranged on the clamping part (4-1) and close to the reducing part (4-2);
b. assembling the compression sample (4): the expansion instrument is arranged at the position of welding a thermocouple wire in the middle of the reduced part (4-2) of the compression sample (4), and the annular heat-conducting plate (4-3) is contacted with the clamp (3);
c. the test process comprises the following steps: and (3) reducing the temperature to the deformation temperature after heating, then compressing, continuously cooling at different cooling rates by using an air cooling device for assisting water cooling after compression to obtain a temperature-expansion curve, and combining the temperature-expansion curve with the metallographic structure of the deformed sample to obtain a dynamic CCT curve.
2. The dynamic CCT test method according to claim 1, wherein: in the step c, the air cooling device comprises a cooling copper pipe (2), one end of the cooling copper pipe (2) is connected with the air storage device, the other end of the cooling copper pipe enters the sample box (1) and points to the compressed sample (4), and cooling gas is uniformly sprayed on the compressed sample (4).
3. The dynamic CCT test method according to claim 2, wherein: the diameter of the cooling copper pipe (2) is 13-17 mm.
4. The dynamic CCT test method according to claim 1, wherein: in the step c, the cooling rate of the auxiliary water cooling continuous cooling of the air cooling device is 0.1-100 ℃/s.
5. The dynamic CCT test method according to claim 1, wherein: in the step c, the temperature is raised to 1000-1200 ℃ at the speed of 5-20 ℃/s, the temperature is kept for 2-10min, then the temperature is lowered to the deformation temperature at the speed of 10-15 ℃/s, and the compression is carried out after the temperature is kept for 0.5-2 min.
6. The dynamic CCT test method according to claim 1, wherein: in the step c, the gas used by the gas cooling device is argon or nitrogen.
7. The dynamic CCT test method according to claim 1, wherein: in the step a, the diameter of the reduced part (4-2) is 6-12mm, the length is 12-20mm, and the ratio of the length to the diameter is 0.4-0.66.
8. The dynamic CCT test method according to claim 1, wherein: in the step a, the diameter of the clamping part (4-1) is 8-20mm, and the length is 15-40 mm.
9. The dynamic CCT test method according to claim 1, wherein: in the step a, the diameter of the periphery of the annular heat conducting plate (4-3) is 22-40mm, and the thickness is 2-5 mm.
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| CN202110322412.7A CN113049627A (en) | 2021-03-25 | 2021-03-25 | Dynamic CCT test method |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1409360A (en) * | 2001-09-26 | 2003-04-09 | 奥斯兰姆施尔凡尼亚公司 | Quartz electric arc tube for metal halogen lamp and tis producing method |
| CN103033430A (en) * | 2012-10-23 | 2013-04-10 | 鞍钢股份有限公司 | Simulation ultrafast cold test device and test method |
| CN103048141A (en) * | 2012-12-31 | 2013-04-17 | 武汉理工大学 | Test system for heat exchange of internal cooling oil duct of internal-combustion engine piston |
| CN103604713A (en) * | 2013-11-21 | 2014-02-26 | 西南交通大学 | Multidirectional fretting wear device and testing method for heat transmission pipe of steam generator |
| CN104390867A (en) * | 2014-12-12 | 2015-03-04 | 中国石油天然气集团公司 | Testing device and method for predicting thermal creep performance of metal material for thick oil thermal recovery sleeve |
| CN106568657A (en) * | 2016-11-14 | 2017-04-19 | 山西太钢不锈钢股份有限公司 | Thermal simulated test machine dynamic CCT compression test sample, and installation method thereof |
| CN107941845A (en) * | 2017-11-23 | 2018-04-20 | 攀钢集团攀枝花钢铁研究院有限公司 | The test method of dynamic CCT |
| CN111687732A (en) * | 2020-06-05 | 2020-09-22 | 成都先进金属材料产业技术研究院有限公司 | Surface treatment device and method for titanium alloy wire |
-
2021
- 2021-03-25 CN CN202110322412.7A patent/CN113049627A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1409360A (en) * | 2001-09-26 | 2003-04-09 | 奥斯兰姆施尔凡尼亚公司 | Quartz electric arc tube for metal halogen lamp and tis producing method |
| CN103033430A (en) * | 2012-10-23 | 2013-04-10 | 鞍钢股份有限公司 | Simulation ultrafast cold test device and test method |
| CN103048141A (en) * | 2012-12-31 | 2013-04-17 | 武汉理工大学 | Test system for heat exchange of internal cooling oil duct of internal-combustion engine piston |
| CN103604713A (en) * | 2013-11-21 | 2014-02-26 | 西南交通大学 | Multidirectional fretting wear device and testing method for heat transmission pipe of steam generator |
| CN104390867A (en) * | 2014-12-12 | 2015-03-04 | 中国石油天然气集团公司 | Testing device and method for predicting thermal creep performance of metal material for thick oil thermal recovery sleeve |
| CN106568657A (en) * | 2016-11-14 | 2017-04-19 | 山西太钢不锈钢股份有限公司 | Thermal simulated test machine dynamic CCT compression test sample, and installation method thereof |
| CN107941845A (en) * | 2017-11-23 | 2018-04-20 | 攀钢集团攀枝花钢铁研究院有限公司 | The test method of dynamic CCT |
| CN111687732A (en) * | 2020-06-05 | 2020-09-22 | 成都先进金属材料产业技术研究院有限公司 | Surface treatment device and method for titanium alloy wire |
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Application publication date: 20210629 |