CN104123878A - Test method for welding CCT (continuous cooling transformation) diagram of resistance type thermal simulation test machine - Google Patents
Test method for welding CCT (continuous cooling transformation) diagram of resistance type thermal simulation test machine Download PDFInfo
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- CN104123878A CN104123878A CN201410344068.1A CN201410344068A CN104123878A CN 104123878 A CN104123878 A CN 104123878A CN 201410344068 A CN201410344068 A CN 201410344068A CN 104123878 A CN104123878 A CN 104123878A
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Abstract
Disclosed is a test method for a welding CCT diagram of a resistance type thermal simulation test machine. The test method includes the steps of heating a thermal simulation sample from the room temperature to the peak temperature Tp; staying for one second; subjecting the sample to linear cooling in three stages, wherein the first cooling stage is the cooling from the peak temperature Tp to 1000 DEG C, the second cooling stage is the cooling from 1000 DEG C to 800 DEG C, and the third cooling stage is the cooling from 800 DEG C to the room temperature; accurately identifying the start and end points of the phase transition on a thermal expansion curve according to a tangent method. The test method for the welding CCT diagram of the resistance type thermal simulation test machine takes the problems of heating rate, multi-stage linear cooling and temperature overshoot into overall consideration, so that the tested welding CCT diagram is close to the actual welding thermal cycle, and the measured phase transition points are accurate. The test method is applicable to the test of the welding of CCT on all resistance type thermal simulation test machines.
Description
Technical field
The present invention relates to a kind of physical simulation experiment method, belong to particularly the method for testing of a kind of resistance-type hot modeling test machine CCT of welding figure.
Background technology
CCT of welding figure is technical information important in welding field, and it can be used for indirectly evaluating the weldability of steel and reasonably determines weld procedure specification, in welding is produced and welded research, has important practical value and directive significance.
CCT of welding figure test is at present unified standard not.The Thermal Cycle model that equipment itself provides that directly utilizes that existing test technology has is tested, though this technique relatively approaches actual welding, but belongs to non-linear cooling when cooling, cannot accurately find out transformation temperature according to tangent method; Though adopting of having is linear cooling, mostly adopts one-part form cooling, can not reflect actual Thermal Cycle process; The impact of not considering firing rate having, during actual welding, heat input can descendingly be selected, and heat input is larger, and firing rate is slower, otherwise faster.Therefore, need to set up a kind of CCT of welding test technology, should approach with actual welding Thermal Cycling, according to tangent method, can accurately find out transformation temperature again.
Through retrieval, there is document to disclose a kind of " NM360 steel SH-CCT curve determination and fabric analysis ", its CCT of welding mensuration scheme is: sample is heated to peak temperature l350 ℃ with the speed of 200 ℃/s, sets the t in cooling procedure
8/5be respectively 6,10,15,20,30,60,150,300,600,1000 and 2000s.Its test technology is not considered variation, actual welding Thermal Cycling and the temperature overshot problem of firing rate, lower with the actual welding Thermal Cycling degree of approach, is difficult to accurately find out transformation temperature.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, provide a kind of CCT of welding figure of test more to approach actual welding Thermal Cycling, the transformation temperature of measuring is more accurate, and is suitable for carrying out the method for testing of CCT of welding figure on all resistance-type hot modeling test machines.
Realize the measure of above-mentioned purpose:
A method of testing of resistance-type hot modeling test machine CCT of welding figure, its step:
1) thermal simulation sample is heated to peak temperature Tp from room temperature, its firing rate foundation
t 8/5variation according to following situation, determine:
A, cool time
t 8/5be no more than 5s, firing rate is set as 700 ℃/s;
B, cool time 5s <
t 8/5≤ 25s, firing rate is set as 400 ℃/s;
C, cool time 25s <
t 8/5≤ 100s, firing rate is set as 200 ℃/s;
D, cool time 100s <
t 8/5≤ 500s, firing rate is set as 100 ℃/s
Wherein, when firing rate setting is greater than 200 ℃/s, according to following speed change degree heating, that is:
While being heated to 1000 ℃ from room temperature, according to the firing rate heating of setting, 1000 ℃～peak temperature Tp, heats according to 100 ℃/s;
2) after heating finishes, stopped for 1 second;
3) sample is carried out to linearity in three stages cooling:
The division in A, stage: being cooled to 1000 ℃ from peak temperature Tp is the first cooling stage; From 1000 ℃, being cooled to 800 ℃ is the second cooling stage; From 800 ℃, being cooled to room temperature is the 3rd cooling stage;
The cooling velocity of B, each cooling stage is according to determining following cool time: cooling velocity ν
1represent the first cooling velocity, ν
2represent the second cooling velocity, ν
3represent the 3rd cooling velocity;
When cool time, be 5s <
t 8/5during≤25s, ν
1according to 100 ℃/s, carry out cooling, ν
2according to 60 ℃/s, carry out cooling; ν
3according to ν
3=300 ℃/
t 8/5set cooling;
When cool time, be 25s <
t 8/5during≤100s, ν
1according to 40 ℃/s, carry out cooling, ν
2according to 20 ℃/s, carry out cooling; ν
3according to ν
3=300 ℃/
t 8/5set cooling;
When cool time, be 100s <
t 8/5during≤500s, ν
1according to 8 ℃/s, carry out cooling, ν
2according to 4 ℃/s, carry out cooling; ν
3according to ν
3=300 ℃/
t 8/5set cooling;
Work as cool time
t 8/5during≤5s directly from peak temperature T
pwith 300 ℃/
t 8/5cooling velocity be cooled to room temperature;
4), according to tangent method, on thermal expansion curve, accurately find out starting point and the end point of phase transformation.
t 8/5-the time used while referring to that sample is down to 500 ℃ from 800 ℃ is first setting value.
Why the present invention takes firing rate and cool time
t 8/5coupling combination, be that weld heat input can be selected within the specific limits because during actual welding, weld heating speed is not unalterable, heat input is larger, firing rate is slower, otherwise less.Therefore, in the present invention firing rate with cool time
t 8/5variation set different.
Why take the linear type of cooling of syllogic, on the one hand, because want accurately to measure the starting point and the end point that change mutually, must take the linear type of cooling, on the other hand, the cooling procedure of actual welding thermal cycle is an alternating temperature process, only has through test and finds, adopting that syllogic is cooling can be the most approaching with actual welding Thermal Cycling.
Why when firing rate is set while being greater than 200 ℃/s, according to speed change degree, heat, while being greater than 200 ℃/s because of firing rate, peak temperature overshoot phenomenon is comparatively serious, directly cause temperature control precision to decline, in the case, adopt the heating of speed change degree, effectively solved the generation of temperature overshot phenomenon in heating process, test temperature control accuracy is improved greatly.
In this process,
t 8/5the longlyest be chosen as 500 seconds, contained from little heat input to the needed whole heat input scopes of the Large Heat Input Weldings such as electro-gas (enclosed) welding, therefore, be applicable to the test all about arc welding CCT figure.
The present invention compared with prior art, owing to having considered the linear cooling and temperature overshot problem of firing rate and multistage, therefore the CCT of welding figure of test more approaches actual welding Thermal Cycling, the transformation temperature of measuring is more accurate, and it is suitable for carrying out the test of CCT of welding on all resistance-type hot modeling test machines.
Accompanying drawing explanation
Fig. 1 is t cool time
8/5the present invention under=3s condition and actual welding thermal cycle process curve figure;
Fig. 2 is t cool time
8/5the present invention under=15s condition and actual welding thermal cycle process curve figure;
Fig. 3 is t cool time
8/5the present invention under=45s condition and actual welding thermal cycle process curve figure;
Fig. 4 is t cool time
8/5the present invention under=200s condition and actual welding thermal cycle process curve figure.
Embodiment
Below the present invention is described in detail:
Embodiment 1
A method of testing of resistance-type hot modeling test machine CCT of welding figure, its step:
1) thermal simulation sample is heated to 1300 ℃ of peak temperature Tp, cool time from room temperature
t 8/5be made as 3s, firing rate is set as 700 ℃/s;
Because firing rate setting is greater than 200 ℃/s, therefore:
While being heated to 1000 ℃ from room temperature, according to the 700 ℃/s of firing rate setting, heat, according to 100 ℃/s of firing rate, be heated to peak temperature Tp1300 ℃ afterwards;
2) after heating finishes, stopped for 1 second;
3) because setting cool time, be
t 8/5=3s, therefore be directly cooled to room temperature from 1300 ℃ of speed with 100 ℃/s;
4), according to tangent method, it is 310 ℃ with end point that the phase transition temperature starting point of accurately finding out on thermal expansion curve is 460 ℃.
Above-mentioned simulation process and actual welding thermal cycle contrast are found: adopt test technology and the actual welding Thermal Cycling of the method simulation CCT of welding figure more approaching, owing to adopting the heating of speed change degree, solved temperature overshot problem in heating process, guaranteed test temperature control accuracy, the phase transformation temperature points of measuring is more accurate, has effectively disclosed the structural transformation feature of welding under these process conditions.
Embodiment 2
1) thermal simulation sample is heated to peak temperature Tp1300 ℃, cool time from room temperature
t 8/5while electing 15s as, firing rate is set as 400 ℃/s;
Because firing rate is set as being greater than 200 ℃/s, therefore:
While being heated to 1000 ℃ from room temperature, according to the 400 ℃/s of firing rate setting, heat, according to 100 ℃/s of firing rate, be heated to peak temperature Tp1300 ℃ afterwards;
2) after heating finishes, stopped for 1 second;
3) sample is carried out to linearity in three stages cooling:
The division in A, stage: being cooled to 1000 ℃ from peak temperature Tp1300 ℃ is the first cooling stage; From 1000 ℃, being cooled to 800 ℃ is the second cooling stage; From 800 ℃, being cooled to room temperature is the 3rd cooling stage;
The cooling velocity of B, each cooling stage is according to determining following cool time: cooling velocity ν
1represent the first cooling velocity, ν
2represent the second cooling velocity, ν
3represent the 3rd cooling velocity;
Because of cool time
t 8/5be set as 15s, ν
1according to 100 ℃/s, carry out cooling, ν
2according to 60 ℃/s, carry out cooling; ν
3according to: 300 ℃/15s=20 ℃/s is cooled to room temperature;
4), according to tangent method, it is 329 ℃ with end point that the starting point of the phase transition temperature of accurately finding out on thermal expansion curve is 520 ℃.
Above-mentioned simulation process and actual welding thermal cycle contrast are found: adopt test technology and the actual welding Thermal Cycling of the method simulation CCT of welding figure to approach very much (see figure 1), owing to adopting the heating of speed change degree, solved temperature overshot problem in heating process, guaranteed test temperature control accuracy, the phase transformation temperature points of measuring is more accurate, has effectively disclosed the structural transformation feature of welding under these process conditions.
Embodiment 3
1) thermal simulation sample is heated to peak temperature Tp1300 ℃, cool time from room temperature
t 8/5be made as 45s, firing rate is set as 200 ℃/s, and sample is directly heated to peak temperature Tp1300 ℃ with the firing rate of 200 ℃/s;
2) after heating finishes, stopped for 1 second;
3) sample is carried out to linearity in three stages cooling:
The division in A, stage: being cooled to 1000 ℃ from peak temperature Tp1300 ℃ is the first cooling stage; From 1000 ℃, being cooled to 800 ℃ is the second cooling stage; From 800 ℃, being cooled to room temperature is the 3rd cooling stage;
The cooling velocity of B, each cooling stage is according to determining following cool time: cooling velocity ν
1represent the first cooling velocity, ν
2represent the second cooling velocity, ν
3represent the 3rd cooling velocity;
Because of cool time
t 8/5be set as 45s, ν
1according to 40 ℃/s, carry out cooling, ν
2according to 20 ℃/s, carry out cooling; ν
3according to: 300 ℃/45s=6.67 ℃/s is cooled to room temperature;
4), according to tangent method, it is 427 ℃ with end point that the starting point of the phase transition temperature of accurately finding out on thermal expansion curve is 564 ℃.
Above-mentioned simulation process and actual welding thermal cycle contrast are found, adopt the test of the method simulation CCT of welding not only to approach (see figure 2) with actual welding Thermal Cycling, and the phase transformation temperature points of measuring is more accurate, effectively disclosed the structural transformation feature of welding under these process conditions.
Embodiment 4
A method of testing of resistance-type hot modeling test machine CCT of welding figure, its step:
1) thermal simulation sample is heated to peak temperature Tp1300 ℃, cool time from room temperature
t 8/5while electing 200s as, firing rate is set as 100 ℃/s, and sample is directly heated to peak temperature Tp1300 ℃ with the firing rate of 100 ℃/s;
2) after heating finishes, stopped for 1 second;
3) sample is carried out to linearity in three stages cooling:
The division in A, stage: being cooled to 1000 ℃ from peak temperature Tp1300 ℃ is the first cooling stage; From 1000 ℃, being cooled to 800 ℃ is the second cooling stage; From 800 ℃, being cooled to room temperature is the 3rd cooling stage;
The cooling velocity of B, each cooling stage is according to determining following cool time: cooling velocity ν
1represent the first cooling velocity, ν
2represent the second cooling velocity, ν
3represent the 3rd cooling velocity;
Because of cool time
t 8/5be set as 200s; ν
1according to 8 ℃/s, carry out cooling, ν
2according to 4 ℃/s, carry out cooling; ν
3according to: 300 ℃/200s=1.5 ℃/s is cooled to room temperature;
4), according to tangent method, it is 447 ℃ with end point that the starting point of the phase transition temperature of accurately finding out on thermal expansion curve is 616 ℃.
Above-mentioned simulation process and actual welding thermal cycle contrast are found, adopt the test of the method simulation CCT of welding not only to approach with actual welding Thermal Cycling, and the phase transformation temperature points of measuring is more accurate, effectively disclosed the structural transformation feature of welding under these process conditions.
Above-described embodiment only exemplifies for the best, and is not the restriction to embodiments of the present invention.
Claims (1)
1. a method of testing of resistance-type hot modeling test machine CCT of welding figure, its step:
1) thermal simulation sample is heated to peak temperature Tp from room temperature, its firing rate foundation
t 8/5variation according to following situation, determine:
A, cool time
t 8/5be no more than 5s, firing rate is set as 700 ℃/s;
B, cool time 5s <
t 8/5≤ 25s, firing rate is set as 400 ℃/s;
C, cool time 25s <
t 8/5≤ 100s, firing rate is set as 200 ℃/s;
D, cool time 100s <
t 8/5≤ 500s, firing rate is set as 100 ℃/s
Wherein, when firing rate setting is greater than 200 ℃/s, according to following speed change degree heating, that is:
While being heated to 1000 ℃ from room temperature, according to the firing rate heating of setting, 1000 ℃～peak temperature Tp, heats according to 100 ℃/s;
2) after heating finishes, stopped for 1 second;
3) sample is carried out to linearity in three stages cooling:
The division in A, stage: being cooled to 1000 ℃ from peak temperature Tp is the first cooling stage; From 1000 ℃, being cooled to 800 ℃ is the second cooling stage; From 800 ℃, being cooled to room temperature is the 3rd cooling stage;
The cooling velocity of B, each cooling stage is according to determining following cool time: cooling velocity ν
1represent the first cooling velocity, ν
2represent the second cooling velocity, ν
3represent the 3rd cooling velocity;
When cool time, be 5s <
t 8/5during≤25s, ν
1according to 100 ℃/s, carry out cooling, ν
2according to 60 ℃/s, carry out cooling; ν
3according to ν
3=300 ℃/
t 8/5set cooling;
When cool time, be 25s <
t 8/5during≤100s, ν
1according to 40 ℃/s, carry out cooling, ν
2according to 20 ℃/s, carry out cooling; ν
3according to ν
3=300 ℃/
t 8/5set cooling;
When cool time, be 100s <
t 8/5during≤500s, ν
1according to 8 ℃/s, carry out cooling, ν
2according to 4 ℃/s, carry out cooling; ν
3according to ν
3=300 ℃/
t 8/5set cooling;
Work as cool time
t 8/5during≤5s directly from peak temperature T
pwith 300 ℃/
t 8/5cooling velocity be cooled to room temperature;
4), according to tangent method, on thermal expansion curve, accurately find out starting point and the end point of phase transformation.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105116003A (en) * | 2015-07-28 | 2015-12-02 | 南京钢铁股份有限公司 | Measurement method for calculating two-phase transition ratio by thermal expansion curve |
| CN107356625A (en) * | 2017-06-19 | 2017-11-17 | 江阴兴澄特种钢铁有限公司 | A kind of method for measuring large-deformation-resistance pipeline steel SH CCT curves |
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| CN101788509A (en) * | 2010-02-09 | 2010-07-28 | 中南大学 | Measuring method of aluminum alloy CCT (Continuous Cooling Transformation) diagram |
| CN101871899A (en) * | 2010-06-22 | 2010-10-27 | 天津钢铁集团有限公司 | Cooling-control CCT (Continuous Cooling Transformation) curve determination method for iron and steel materials |
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2014
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Patent Citations (4)
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| CN101038235A (en) * | 2007-03-27 | 2007-09-19 | 顾韻 | High acceleration temperature changing test chamber |
| CN101788509A (en) * | 2010-02-09 | 2010-07-28 | 中南大学 | Measuring method of aluminum alloy CCT (Continuous Cooling Transformation) diagram |
| CN102275042A (en) * | 2010-06-08 | 2011-12-14 | 上海振华重工(集团)股份有限公司 | Process for welding high-strength steel |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105116003A (en) * | 2015-07-28 | 2015-12-02 | 南京钢铁股份有限公司 | Measurement method for calculating two-phase transition ratio by thermal expansion curve |
| CN107356625A (en) * | 2017-06-19 | 2017-11-17 | 江阴兴澄特种钢铁有限公司 | A kind of method for measuring large-deformation-resistance pipeline steel SH CCT curves |
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Application publication date: 20141029 |