CN106383171A - Transverse wave full-focus ultrasonic imaging detection method for crack defect of steel plate weld - Google Patents

Abstract

The embodiment of the present invention discloses a transverse wave full-focus ultrasonic imaging detection method for the crack defect of a steel plate weld. According to the invention, a probe with a transverse wave angle wedge block is placed on the parent metal of a to-be-detected steel plate butt weld workpiece. During the detection process of the probe, the direction of the probe is perpendicular to the direction of the weld. Without moving the probe, a phased array instrument acquires full-matrix echo signals inside the workpiece in real time. Meanwhile, the phased array instrument calculates the refraction propagation path of acoustic waves in real time according to a refraction point fast search algorithm for the propagation of acoustic waves in different workpieces and a reconstruction calculation model for crack defects. All the effective information of the crack defects is extracted out of an acquired information set in the distributed manner, and the extracted information is overlaid into the specific locations of real cracks in the workpiece. Therefore, the condition of crack defects in different directions inside the to-be-detected steel plate butt weld workpiece can be graphically and really reconstructed.

Description

A kind of shear wave total focus ultra sonic imaging detection method of steel plate bead crack defect

Technical field

The present invention relates to ultrasound detection field, more particularly, to a kind of ultrasonic one-tenth of shear wave total focus of steel plate bead crack defect As detection method.

Background technology

Steel plate butt weld common cracks mainly have stress corrosion cracking (SCC), hydrogen induced cracking and fatigue crack etc..These crackles Weld seam is in mainly genesis analysis, under the effect of various external force, crackle is easy to aggravation extension, causes Plate break.With common Pore, slag inclusion and do not merge defect and compare, the detection of crack defect is more complex, and dissimilar crackle needs different inspections Survey method, the scope of application of each detection method is again limited, and there is presently no one kind being capable of blanket crack detection side Method.Currently many companies and research institution have carried out numerous studies test around crack detection both at home and abroad, but still do not grind Study carefully and a kind of effective crack detecting method.Existing crack detecting method has ultrasound examination, electromagnetic acoustic detection, whirlpool Stream detection and Magnetic Flux Leakage Inspecting.Wherein, ultrasound examination is the most frequently used a kind of detection method in current crack detection.Ultrasound wave Crack detecting method mainly has traditional A type wave train column crack detection and conventional phased array crackle image checking.However, these inspections Survey that methods and techniques are still not ideal enough, the Detection results for defect are not directly perceived, and cannot real embodiment crack defect True shape, as shown in Figure 1.The operation of tandem crack detection is relatively complicated, and does not compare intuitively image checking work( Can be it is impossible to observation measurementss be carried out to crack defect；Conventional phased array crackle image checking, is capable of detecting when crack defect information, But the true shape of reduction crack defect cannot be imaged, and the accurate quantitative analysis measurement to crack defect, such as Fig. 2 can not be realized Shown.

Content of the invention

Embodiment of the present invention technical problem to be solved is, provides a kind of shear wave of steel plate bead crack defect entirely to gather Burnt ultra sonic imaging detection method.Crack defect in steel plate butt weld workpiece can be carried out with true reconstruction defect, reduce defect Original appearance.

In order to solve above-mentioned technical problem, embodiments provide a kind of shear wave of steel plate bead crack defect and entirely gather Burnt ultra sonic imaging detection method, the voussoir that will be equipped with phased array probe is placed on target mother metal, and is become by following steps As detection：

Determine that the sound wave of i-th array element transmitting of described phased array probe reaches impact point in described mother metal through described voussoir I_klThe shortest sound path D_ikl, and j-th array element receives the shortest sound path D of reflection echo_jkl；

To target mother metal with the array number n of described phased array probe_e*n_eAnd sampling number n_sConstitute three-dimensional matrice S_ij(t), Wherein 1≤i≤n_e, 1≤j≤n_e, 1≤t≤n_s；

Carry out the reconstruction of target defect pixel size by below equation：

$I_{kl}=\left|\underset{i=1}{\overset{n_e}{\Σ}}\underset{j=1}{\overset{n_e}{\Σ}}{s}_{ij}(D_{ikl}+D_{jkl})\right|.$

Wherein, described the shortest sound path D_iklAnd the shortest sound path D_jklDetermine by the following method：

Rectangular coordinate system is set up for initial point with the lower extreme point of the center graduation mark of described voussoir；

Calculate abscissa and the vertical coordinate E (ex of i-th array element_i,ey_i)；

Corresponding for described target mother metal image is separated into grid configuration, a pixel, I are represented with each cell_klGeneration Table any pixel point；

Determine described i-th array element sound wave to described impact point I_klThe shortest sound path.

Wherein, described the shortest sound path is carried out by following steps：

S1：Determine the hunting zone of the refraction point of shortest path：With described any array element E (ex_i,ey_i) arrive refracting interface Vertical mapping point is as starting point S₁(ss, 0), with described any array element E (ex_i,ey_i) and described any pixel point I_klLine and x The coordinate of the intersection point of axle is as terminal S₂(se,0)；

S2：Sliding-model control is carried out to described hunting zone：Mark off possible refraction point to set step-length；

S3：Calculate the acoustical paths time corresponding to propagation path that sound wave passes through each refraction point respectively；

S4：The sound path time finding out minimum is as the shortest sound path.

Further, described step-length is 0.2mm.

Further, described wedge angle is 36 degree.

Implement the embodiment of the present invention, have the advantages that：The phased array shear wave total focus technology of the present invention is passed through to adopt The complete information set of collection crack defect, and according to the actual physical propagation characteristic of sound wave and refraction path, by special weight Structure algorithm computation model, the distributed extraction all of effective information of crack defect be added to true from the information aggregate collecting Real crackle particular location residing within the workpiece, truly reconstructs crack defect, restores the original appearance of defect, and the image reconstructing Result is fitted like a glove with the true shape of crack defect, basically identical with the size of actual crack, can be to crack defect Carry out qualitative and quantitative analysis exactly.

Brief description

Fig. 1 is existing shear wave total focus inclination angle crack detection imaging schematic diagram；

Fig. 2 is existing shear wave total focus vertical crack detection imaging schematic diagram；

Fig. 3 is the structural representation of phased array probe rectangular coordinate system；

Fig. 4 is the structural representation of refraction path discrete search method；

Fig. 5 is crack detection reconstruction model；

Fig. 6 is the schematic diagram that the present invention is imaged to inclination angle crack detection；

Fig. 7 is the schematic diagram to vertical crack detection imaging for the present invention.

Specific embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, the present invention is made into one Step ground describes in detail.

With reference to the structural representation shown in Fig. 3, Fig. 4, Fig. 5.

A kind of shear wave total focus ultra sonic imaging detection method of steel plate bead crack defect of the present invention, will be equipped with phased array Probe is placed on the mother metal of tested steel plate butt weld workpiece, and probe orientation is detected perpendicular to bead direction, without movement Probe, phased array instrument gathers the complete matrix echo-signal of inside workpiece in real time, and according to the sound wave proposing in different workpieces Refraction point fast search algorithm during interior propagation and the reconstruction calculations model of crack defect, the refraction calculating sound wave in real time passes Broadcast path, from the information aggregate collecting distributed extraction all of effective information of crack defect and the real crack that is added to exist Residing particular location in workpiece, truly reconstructs in tested steel plate butt weld workpiece image conversion and has splitting of different directions Stricture of vagina defect.

The method of the present invention specifically includes following steps.

Determine the shortest sound path of the array element of phased array probe to impact point.

With the center graduation mark instruction array center of shear wave angle voussoir, with the lower extreme point of center graduation mark for initial point O (0, 0), and using voussoir and workpiece interface as x-axis, set up rectangular coordinate system, as shown in figure 3, center graduation mark upper extreme point corresponds to Height h1 be known parameters, wedge angle be α, array element number be N, array element distance be d.Wedge angle direction extending line intersection point It is labeled as O ', then the distance of array center to O is

L1=h1/sin (α).

'

The distance of O to coordinate origin is

L2=l1/cos (α).

The distance of the first array element to O ' is

Ep (1)=l1- (N-1) * d/2.

The distance of the i-th array element to O ' is

Ep (i)=ep (1)+(i-1) * d.

The abscissa of the i-th array element is

ex_i=ep (i) * cos (α)-l2.

The vertical coordinate of the i-th array element is

ey_i=ep (i) * sin (α).

As described in Figure 4, corresponding for workpiece mother metal target image is separated into grid configuration, each grid represents a picture Vegetarian refreshments, pixel precision is customized for 0.2mm/pixel.I_klRepresent wherein any point, k, l represent that the horizontal, vertical of this point sits respectively Mark, wherein 1≤k≤W, 1≤l≤H, W and H are respectively self-defining target image width, highly.

Arbitrarily array element E (ex_i, ey_i) sound field launched propagated in shear wave angle voussoir with longitudinal waves first, reach To reflect when voussoir and workpiece interface, and enter inside workpiece in the form of refracted shear and continue to propagate, and arrive Reach any point I in workpiece_kl, according to sound wave between the two media of Fermat along refraction path propagation time the shortest principle meter Calculate refraction path.

The method searching for the shortest sound path：

1) determine refraction point hunting zone.The coordinate system set up according to Fig. 5, because voussoir and workpiece interface correspond to x Axle, is equivalent in boundary faceted search refraction point and scans in x-axis.

Starting point S of hunting zone₁(ss, 0) is any array element E (ex_i, ey_i) to refracting interface vertical mapping, search for model Enclose terminal S₂(se, 0) is array element E (ex_i,ey_i) any point I in workpiece_klLine and x-axis intersecting point coordinate.Wherein, search The starting point abscissa ss=ex of rope scope_i, the terminal abscissa se of hunting zone calculates according to the meter seeking two straight-line intersections Calculate formula to be solved.

Se=(ex_i×l-k×ey_i)/(l-ey_i)

2) birefringence point search scope carries out sliding-model control.Starting point S in hunting zone₁(ss, 0) and hunting zone are eventually Point S₂Between (se, 0), a series of possible refraction point R (rx are marked off with certain step delta x_i,ry_i), wherein ss≤rx_i≤ Se, ry_i=0.

Step-length is less, and the refraction point calculating is more accurate, and the time simultaneously scanning for required for computing is longer, can be comprehensive Close and choose a suitable step-length.Because target image definition of accuracy is 0.2mm/pixel, then choose step delta x=here 0.2mm can meet requirement.

3) calculate the propagation time that sound wave passes through the sound path corresponding to propagation path of each refraction point respectively.

Assume that longitudinal wave velocity in voussoir for the sound wave is known as c₁, sound wave transverse wave velocity within the workpiece is known as c₂.So From array element E, through refraction point R, the sound path time needed for M point reaching in workpiece is sound wave：

$t({\mathrm{rx}}_i,{\mathrm{ry}}_i)=\sqrt{{({\mathrm{ex}}_i-{\mathrm{rx}}_i)}^2+{({\mathrm{ey}}_i-{\mathrm{ry}}_i)}^2}/c_1+\sqrt{{(l-{\mathrm{rx}}_i)}^2+{(k-{\mathrm{ry}}_i)}^2}/c_2$

4) in the sound path time calculated at these, find out the sound path time of minimum, that is, sound wave reflects along real Sound path time T required for propagated.

T=min (t)

The extraction reconstruction model of crack defect：

Assume that a phased array probe has n_eArray element, adds that angle voussoir carries out shear wave total focus crack detection.System is real When ground carry out complete matrix data acquisition it is assumed that the i-th array element transmitting, jth array element receives, and every waveform collecting has n_sSampling Point, then the complete matrix data of final collection is a size is n_e×n_e×n_sThree-dimensional matrice, this matrix S_ijT () carrys out table Show, wherein 1≤i≤n_e, 1≤j≤n_e, 1≤t≤n_s.

As shown in figure 5, target image matrix is represented with I, with complete matrix information reconstruction impact point I_klCarry out total focus imaging As a example.Transmitting sound wave I in workpiece from array element i_klPoint, reflection echo is received by array element j again, the whole communication process of sound wave Have passed through transmitting AB+BC+CO and receive this two refraction paths of OD+DE+EF.D_iklRepresent that the sound wave of the i-th array element transmitting reaches work I in part_klThe refraction path AB+BC+CO corresponding sound path time of point, D_jklRepresent that jth array element receives I_klThe folding of point reflection echo The rays footpath OD+DE+EF corresponding sound path time, this two parts sound path time is respectively calculated according to the T in (8), (9) formula, Pixel size I after so (k, l) point is rebuild_klFor：

$I_{kl}=\left|\underset{i=1}{\overset{n_e}{\Σ}}\underset{j=1}{\overset{n_e}{\Σ}}{s}_{ij}(D_{ikl}+D_{jkl})\right|$

Under the detection such as of the present invention：

To inclination angle crackle steel plate butt weld test block, steel plate thickness is 19mm, and ARTIFICIAL CRACK development length is 6mm, workpiece In transverse wave velocity be 3200m/s.Complete matrix real time data acquisition imaging system uses Shantou ultrasonic instrument company and produces PA22X ultrasound phased array devices and phased array probe.From phased array probe model：4L16-1.0×10；Probe angle Spending voussoir parameter is：Wedge angle 36., center array element height 12mm, voussoir velocity of sound 2700m/s；Make couplant using machine oil, this The algorithm that invention proposes carries out image checking to inclination angle crackle, is arranged to as area size：From the beginning of voussoir zero point, long 50mm, High 19mm, imaging arrangement as shown in fig. 6, the present invention is detected and reconstructs to this inclination angle crackle, tie by the detection image reconstructing In fruit, the position of inclination angle crackle, size and bearing of trend are all very accurate, and image rate is ideal respectively.

To vertical crack steel plate butt weld test block, bottom there is is the cutting vertical crack that a length is 6mm examine Survey, as shown in fig. 7, the present invention is detected to vertical crack defect and reconstructs, reconstruction result crackle reduces its imaging results Very true to nature, its positions and dimensions information is basically identical with the vertical crack defect in practical work piece.

Above disclosed be only a kind of preferred embodiment of the present invention, certainly the power of the present invention can not be limited with this Sharp scope, the equivalent variations therefore made according to the claims in the present invention, still belong to the scope that the present invention is covered.

Claims (5)

1. a kind of shear wave total focus ultra sonic imaging detection method of steel plate bead crack defect is it is characterised in that will be equipped with phased The voussoir of battle array probe is placed on target mother metal, and carries out image checking by following steps：

Determine that the sound wave of i-th array element transmitting of described phased array probe reaches impact point I in described mother metal through described voussoir_kl's The shortest sound path D_ikl, and j-th array element receives the shortest sound path D of reflection echo_jkl；

To target mother metal with the array number n of described phased array probe_e*n_eAnd sampling number n_sConstitute three-dimensional matrice S_ij(t), wherein 1 ≤i≤n_e, 1≤j≤n_e, 1≤t≤n_s；

Carry out the reconstruction of target defect pixel size by below equation：

$I_{kl}=\left|\underset{i=1}{\overset{n_e}{\mathrm{\Σ}}}\underset{j=1}{\overset{n_e}{\mathrm{\Σ}}}{S}_{ij}\left(D_{ikl}+D_{jkl}\right)\right|.$

2. method according to claim 1 is it is characterised in that described the shortest sound path D_iklAnd the shortest sound path D_jklBy following Method determines：

Rectangular coordinate system is set up for initial point with the lower extreme point of the center graduation mark of described voussoir；

Calculate abscissa and the vertical coordinate E (ex of i-th array element_i,ey_i)；

Corresponding for described target mother metal image is separated into grid configuration, a pixel, I are represented with each cell_klRepresent and appoint One pixel；

Determine described i-th array element sound wave to described impact point I_klThe shortest sound path.

3. method according to claim 2 is it is characterised in that described the shortest sound path is carried out by following steps：

S1：Determine the hunting zone of the refraction point of shortest path：With described any array element E (ex_i,ey_i) vertical to refracting interface Mapping point is as starting point S₁(ss, 0), with described any array element E (ex_i,ey_i) and described any pixel point I_klLine and x-axis The coordinate of intersection point is as terminal S₂(se,0)；

S2：Sliding-model control is carried out to described hunting zone：Mark off possible refraction point to set step-length；

S3：Calculate the acoustical paths time corresponding to propagation path that sound wave passes through each refraction point respectively；

S4：The sound path time finding out minimum is as the shortest sound path.

4. method according to claim 3 is it is characterised in that described step-length is 0.2mm.

5. method according to claim 4 is it is characterised in that described wedge angle is 36 degree.