CN105203625B - The magnetic evaluation method of post weld heat treatment elimination residual stress effect - Google Patents
The magnetic evaluation method of post weld heat treatment elimination residual stress effect Download PDFInfo
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- CN105203625B CN105203625B CN201510580478.0A CN201510580478A CN105203625B CN 105203625 B CN105203625 B CN 105203625B CN 201510580478 A CN201510580478 A CN 201510580478A CN 105203625 B CN105203625 B CN 105203625B
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Abstract
The present invention relates to the magnetic evaluation methods that residual stress effect is eliminated in a kind of post weld heat treatment, it include: micro- magnetic signal in region to be evaluated before being heat-treated according to default acquisition path measurements, and acquired micro- magnetic signal and corresponding test point position are recorded, to obtain the first peak-to-peak value and the first greatest gradient value that acquire micro- magnetic signal；In the previous step at test point position after acquisition heat treatment region to be evaluated micro- magnetic signal, to obtain the second peak-to-peak value and the second greatest gradient value that acquire micro- magnetic signal；The peak-to-peak value reduction amount of the second peak-to-peak value and the first peak-to-peak value and the gradient value difference of the second greatest gradient value and the first greatest gradient value are calculated, to obtain the first ratio of peak-to-peak value reduction amount and the first peak-to-peak value and the second ratio of gradient value difference and the first greatest gradient value；The welding residual stress in region to be evaluated achieves the desired results after being heat-treated if the first ratio accords with preset condition with the second ratio.The present invention is implemented simply, and speed is fast, and evaluation result is accurate.
Description
Technical field
The present invention relates to the magnetic evaluations that detection technique field more particularly to a kind of post weld heat treatment eliminate residual stress effect
Method.
Background technique
Welding residual stress is interactive by many factors as a result, its generation process is as follows: heat input is not when welding
Uniformly generate non-uniform compressive plastic deformation；When cooling, the material the being plastically deformed restriction by adjacent material again,
Free shrink is unable to form tensile stress, " W " shape is substantially presented in the welding residual stress distribution perpendicular to bead direction.
Welding residual stress is the major reason for causing welding structure to fail, it is therefore desirable to eliminate welding residual stress.It is existing
Post weld heat treatment is carried out to eliminate welding residual stress to welding structure in the art, so that the residual stress of material is super when heating
Yield stress at this temperature is crossed, plastic deformation is released.Since heat treatment on spot is affected by external environment, hold
Easily phenomena such as target and soaking time are insufficient is not achieved in appearance heating unevenness, heating temperature, remaining so as to cause eliminating
The effect of stress cannot be met the requirements, and cause security risk.Therefore, it is necessary to carry out residual stress measurement to weld seam.
Currently, the residual stress measuring method of quantitative detection has electrical measuring method, flash spotting, x-ray method etc., but these are surveyed
Amount method needs region surface to be evaluated finish with higher, generates to measured region due to using contact type measurement
Slight constructural destroys, and detection cycle is long and operating process is complicated.Therefore it needs at a kind of lossless, quick, qualitative evaluation postwelding heat
The method that reason eliminates residual stress.
Summary of the invention
One of the objects of the present invention is to provide a kind of post weld heat treatment eliminate residual stress effect magnetic evaluation method, with
It is long complicated for operation and treat the technology that evaluation region has higher requirements and ask to solve the Measuring Welding Residual Stresses period in the prior art
Topic.
For achieving the above object, the embodiment of the invention provides a kind of post weld heat treatment to eliminate residual stress effect
Magnetic evaluation method, comprising:
Micro- magnetic signal in region to be evaluated before being heat-treated according to default acquisition path measurements, and record acquired micro- magnetic signal
And corresponding test point position, to obtain the first peak-to-peak value and the first greatest gradient value that acquire micro- magnetic signal；
According to region to be evaluated after acquisition heat treatment at identical default acquisition path in the previous step test point position
Micro- magnetic signal, acquire the second peak-to-peak value and the second greatest gradient value of micro- magnetic signal to obtain；
Calculate second peak-to-peak value and first peak-to-peak value peak-to-peak value reduction amount and second greatest gradient
Value and the gradient value difference of the first greatest gradient value, to obtain the of the peak-to-peak value reduction amount and first peak-to-peak value
Second ratio of one ratio and the gradient value difference and the first greatest gradient value；
Judge whether first ratio and second ratio accord with preset condition, if meeting preset condition at heat
The welding residual stress in region to be evaluated has reached desired effect after reason.
Optionally, the default acquisition path orthogonal is in weld seam, and extends to the weld seam two sides pre-determined distance respectively.
Optionally, the pre-determined distance is the sum of weld width, weld seam influence sector width and redundant wide.
Optionally, the pre-determined distance is 100mm
Optionally, the acquisition step-length of micro- magnetic signal in the region to be evaluated of acquisition heat treatment front and back is 0.5mm~1mm.
Optionally, described to judge whether first ratio and second ratio accord with preset condition, if meeting pre-
If in condition the step of residual stress has been eliminated in region to be evaluated after being then heat-treated, the preset condition are as follows:
The curve of micro- magnetic signal in the region to be evaluated after heat treatment tends to horizontal, the first ratio >=50% and the second ratio
Value >=50%.
Optionally, it is following to tend to horizontal needs satisfaction for the curve of micro- magnetic signal in the region to be evaluated after the heat treatment
Formula:
dH2/dx≤3(A/m)/mm。
Evaluation method provided in an embodiment of the present invention may determine that residual stress of the weldment after heat treatment around weld seam is
It is no to reach expected elimination of level, do not reach the requirement for eliminating residual stress after heat treatment so as to avoid weldment due to makes
With there is security risk in the process.The present invention is implemented simply, and speed is fast, and evaluation result is accurate.
Detailed description of the invention
The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, and attached drawing is schematically without that should manage
Solution is carries out any restrictions to the present invention, in the accompanying drawings:
Fig. 1 is the process for the magnetic evaluation method that residual stress effect is eliminated in the post weld heat treatment that one embodiment of the invention provides
Schematic diagram；
Fig. 2 is the default detection path profile of welded plate employed in one embodiment of the invention；
Fig. 3 is the default detection path profile of welded tube part employed in further embodiment of this invention.
Specific embodiment
With reference to the accompanying drawings and examples, specific embodiments of the present invention will be described in further detail.Implement below
Example is not intended to limit the scope of the invention for illustrating the present invention.
The embodiment of the invention provides the magnetic evaluation methods that residual stress effect is eliminated in a kind of post weld heat treatment, such as Fig. 1 institute
Show, comprising:
Micro- magnetic signal in region to be evaluated before being heat-treated according to default acquisition path measurements, and record acquired micro- magnetic signal
HpAnd corresponding test point position X, to obtain the first peak-to-peak value H for acquiring micro- magnetic signalp-p1With the first greatest gradient value
In the previous step at the X of test point position after acquisition heat treatment region to be evaluated micro- magnetic signal Hp, to obtain
Acquire the second peak-to-peak value H of micro- magnetic signalp-p2With the second greatest gradient value
Calculate the second peak-to-peak value Hp-p2With the first peak-to-peak value Hp-p1Peak-to-peak value reduction amount Δ Hp-p=Hp-p1-Hp-p2And the
The gradient value difference of two greatest gradient values and the first greatest gradient value is to obtain peak peak
It is worth reduction amount Δ Hp-p=Hp-p1-Hp-p2With the first peak-to-peak value Hp-p1The first ratio and gradient value difference
Second ratio of value and the first greatest gradient value
Judge the first ratio λ1With the second ratio λ2Whether preset condition is accorded with, after being heat-treated if meeting preset condition
The residual stress elimination in region to be evaluated has reached desired effect.
The magnetic evaluation method of residual stress effect is eliminated in post weld heat treatment provided in an embodiment of the present invention, respectively at acquisition heat
The peak-to-peak value and greatest gradient value for managing the residual stress of front and back, may determine that weldment after heat treatment around weld seam after being handled
Residual stress whether effectively eliminated, thus avoid weldment because after heat treatment the elimination of residual stress do not reach requirement
And there is security risk in use, there is realistic meaning and industry meaning.Evaluation method result of the invention is accurate, inspection
Survey process is fast and effective, easy to operate.
By the accuracy for guaranteeing institute's micro- magnetic signal of acquisition, optionally, in the embodiment of the present invention it is default acquire path orthogonal in
Weld seam, and the weld seam two sides pre-determined distance is extended to respectively.I.e. signal acquisition path is set at a certain distance along bead direction
One is set, and every default acquisition path extends pre-determined distance to the two sides of weld seam respectively.Optionally, which is
100mm.Micro- magnetic signal can be quickly detected in this way, it can be to avoid emergency situations in the detection process to the shadow of testing result
It rings, to improve the accuracy of testing result.
The accuracy of the micro- magnetic signal of acquisition to further increase, the embodiment of the present invention are to be evaluated before and after acquisition heat treatment
The acquisition step-length of micro- magnetic signal in valence region is 0.5mm~1mm.It can lead to institute by reducing acquisition step-length to avoid step-length is excessive
Micro- magnetic signal inaccuracy of acquisition or the consequence that does not acquire, make the first peak-to-peak value H of detectionp-p1With the second peak-to-peak value Hp-p2
It is more accurate.
Optionally, judge whether the first ratio and the second ratio accord with preset condition, if meeting preset condition at heat
In the step of residual stress has been eliminated in region to be evaluated after reason, preset condition are as follows:
The curve of micro- magnetic signal in the region to be evaluated after heat treatment tends to horizontal, the first ratio >=50% and second
Ratio >=50%.
Optionally, it is following public to tend to horizontal needs satisfaction for the curve of micro- magnetic signal in the region to be evaluated after heat treatment
Formula:
dH2/dx≤3(A/m)/mm。
To fully demonstrate the superiority that residual stress appraisal procedure is eliminated in post weld heat treatment provided in an embodiment of the present invention, such as
Shown in table 1, present invention combination welded plate and welded tube part, Fig. 2~Fig. 3 and 1~table of table 3 make further the appraisal procedure
It is bright.
1 running parameter table of table
| Welded plate 1# | Welded tube part 2# | |
| Material | Q235B | 20# |
| Specification (mm) | 280×260×14 | Φ195×8 |
| Detect path | 2-1、2-2、2-3 | 3-1、3-2、3-3 |
Fig. 2 is the default detection path profile of welded plate employed in one embodiment of the invention.Referring to Fig. 2, the present invention one is real
Apply in example and the welded plate 20 of Q235B type heat treatment front and back residual stress detected, along weld seam 21 take three perpendicular to weldering
The default detection path in direction is stitched, i.e., default detection path 2-1, default detection path 2-2 and default detection path 2-3.Respectively
Micro- magnetic signal H is measured along three default detection pathsp, acquisition step-length is 1mm, and records micro- magnetic signal H collectedp
With micro- magnetic signal HpCorresponding test point position X (X1 that is found out in such as Fig. 2 ..., Xm).
Micro- magnetic signal according to micro- magnetic signal of every default acquisition path acquisition welded plate heat treatment front and back, before heat treatment
It is denoted as H1、H2, and calculate the first peak-to-peak value H of micro- magnetic signal of the distortion of every default acquisition passage zonep-p1With the first maximum
Gradient valueSecond peak-to-peak value Hp-p2With the second greatest gradient value
Calculate the second peak-to-peak value Hp-p2With the first peak-to-peak value Hp-p1Peak-to-peak value reduction amount Δ Hp-p=Hp-p1-Hp-p2And the
The gradient value difference of two greatest gradient values and the first greatest gradient value is to obtain peak peak
It is worth reduction amount Δ Hp-p=Hp-p1-Hp-p2With the first peak-to-peak value Hp-p1The first ratio and gradient value difference
Second ratio of value and the first greatest gradient value
It is as shown in table 2 to the detection data of welded plate heat treatment front and back.
The testing result of 2 welded plate of table
| Path | Hp-p1 | Hp-p2 | dH1/dx | dH2/dx | ΔHp-p1 | ΔdH1/dx | λ1 | λ2 |
| 2-1 | 75 | 16 | 6 | 2 | 59 | 4 | 78.7% | 66.7% |
| 2-2 | 152 | 12 | 10 | 2 | 140 | 8 | 92.1% | 80.0% |
| 2-3 | 210 | 26 | 15 | 3 | 184 | 12 | 87.6% | 80.0% |
Note: Hp-p1With Hp-p2, unit A/m；dH1/ dx and dH2/ dx, unit: (A/m)/mm.
In the embodiment of the present invention, dH after three default detection path heat treatments2/ dx is respectively 2,2 and 3, the first ratio λ1
Respectively 78.7%, 92.1%, 87.6%, the second ratio λ2Respectively 66.7%, 80.0%, 80.0%, meet preset condition
Requirement, illustrate that region to be evaluated after this heat treatment has reached the requirement of residual stress elimination.
In another embodiment of the present invention, as shown in table 1 and Fig. 3, use diameter for the welded tube part 30 of Φ 195mm, along
The direction of weld seam 31 takes three default acquisition paths perpendicular to weld seam 31 respectively, as shown in Figure 3 default acquisition path 3-
1, acquisition path 3-2 and default acquisition path 3-3 are preset.Remnants are eliminated using post weld heat treatment provided in an embodiment of the present invention to answer
The magnetic evaluation method of power effect is detected, and dH/dx is respectively 2,2,2, λ after three detection path heat treatments1Respectively
65.8%, 50.0%, 81.8%, λ2Respectively 50.0%, 66.7,60.0%, meet the requirement of preset condition, illustrate this heat
Region to be evaluated has reached the requirement of residual stress elimination after processing.
The testing result of 3 welded tube part of table
Note: Hp-p1With Hp-p2, unit A/m；dH1/ dx and dH2/ dx, unit: (A/m)/mm.
It should be noted that eliminate the effect assessment of welding residual stress to the post weld heat treatment of whole weld seam, should to
At least three different evaluation regions of selection are evaluated according to the above process on evaluation fusion length direction, only all to be evaluated
The post weld heat treatment in the valence region residual effect fruit evaluation result that disappears is qualification, could assert that weldering is eliminated in the post weld heat treatment of whole weld seam
The effect for connecing residual stress reaches target.
In conclusion the magnetic evaluation method of residual stress effect is eliminated in post weld heat treatment provided in an embodiment of the present invention, point
It Cai Ji be heat-treated the peak-to-peak value and greatest gradient value of the residual stress of front and back, may determine that weldment is being heat-treated after being handled
Whether the residual stress around weld seam is effectively eliminated afterwards, to avoid weldment remaining because not reaching elimination after heat treatment
The requirement of stress and there is security risk in use, have realistic meaning and industry meaning.Evaluation method of the invention
As a result accurate, detection process is fast and effective, easy to operate.
In the present invention, term " first ", " second ", " third " are used for description purposes only, and should not be understood as instruction or
Imply relative importance.Term " multiple " refers to two or more, unless otherwise restricted clearly.
Although the embodiments of the invention are described in conjunction with the attached drawings, but those skilled in the art can not depart from this hair
Various modifications and variations are made in the case where bright spirit and scope, such modifications and variations are each fallen within by appended claims
Within limited range.
Claims (7)
1. the magnetic evaluation method that residual stress effect is eliminated in a kind of post weld heat treatment characterized by comprising
Micro- magnetic signal in region to be evaluated before being heat-treated according to default acquisition path measurements, and record acquired micro- magnetic signal and phase
Corresponding test point position, to obtain the first peak-to-peak value and the first greatest gradient value that acquire micro- magnetic signal；
According to the micro- of region to be evaluated after acquisition heat treatment at identical default acquisition path in the previous step test point position
Magnetic signal, to obtain the second peak-to-peak value and the second greatest gradient value that acquire micro- magnetic signal；
Calculate second peak-to-peak value and first peak-to-peak value peak-to-peak value reduction amount and the second greatest gradient value with
The gradient value difference of the first greatest gradient value, to obtain the first ratio of the peak-to-peak value reduction amount and first peak-to-peak value
Second ratio of value and the gradient value difference and the first greatest gradient value；
Judge whether first ratio and second ratio accord with preset condition, after being heat-treated if meeting preset condition
The welding residual stress in region to be evaluated has reached desired effect.
2. the magnetic evaluation method that residual stress effect is eliminated in post weld heat treatment according to claim 1, which is characterized in that institute
Default acquisition path orthogonal is stated in weld seam, and extends to the weld seam two sides pre-determined distance respectively.
3. the magnetic evaluation method that residual stress effect is eliminated in post weld heat treatment according to claim 2, which is characterized in that institute
State the sum that pre-determined distance is weld width, weld seam influences sector width and redundant wide.
4. the magnetic evaluation method that residual stress effect is eliminated in post weld heat treatment according to claim 3, which is characterized in that institute
Stating pre-determined distance is 100mm.
5. the magnetic evaluation method that residual stress effect is eliminated in post weld heat treatment according to claim 1, which is characterized in that adopt
The acquisition step-length of micro- magnetic signal in the region to be evaluated of thermal-arrest before and after the processing is 0.5mm~1mm.
6. the magnetic evaluation method that residual stress effect is eliminated in post weld heat treatment according to claim 1, which is characterized in that institute
State and judge first ratio and whether second ratio accords with preset condition, after being heat-treated if meeting preset condition to
Evaluation region was eliminated in the step of residual stress, the preset condition are as follows:
The curve of micro- magnetic signal in the region to be evaluated after heat treatment tend to horizontal, the first ratio >=50% and the second ratio >=
50%.
7. the magnetic evaluation method that residual stress effect is eliminated in post weld heat treatment according to claim 6, which is characterized in that institute
The curve of micro- magnetic signal in the region to be evaluated after stating heat treatment tends to level and needs to meet following formula:
dH2/dx≤3(A/m)/mm；
Wherein, dH2/ dx is the second greatest gradient value.
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| JP3408687B2 (en) * | 1996-02-29 | 2003-05-19 | 三菱重工業株式会社 | Welding equipment with welding residual stress reduction device |
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| CN1374508A (en) * | 2002-04-05 | 2002-10-16 | 西安交通大学 | Evaluation system of visible deformation as residual welding stress eliminating effect |
| CN101210904A (en) * | 2006-12-28 | 2008-07-02 | 上海宝钢工业检测公司 | Metal magnetic memory rapid previewing method |
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