The invention discloses an array ultrasonic focusing imaging correction method for a metal additive manufacturing heterogeneous structure. The method comprises the steps: constructing a space structure model of a heterogeneous medium; measuring elastic constants of a transverse isotropic structure; measuring five transverse isotropic elastic constants of the sample by using an X-ray diffraction calibration method to form an elastic matrix C; setting an initial angle of ultrasonic incidence at a first array element position of the array ultrasound; calculating a sound ray termination point F' of a focal plane in a forward direction; reversely calculating a sound ray termination point P' of an excitation position plane; circularly calculating acoustic propagation time between the excitationpoint and the focus point; calculating an array ultrasonic time delay matrix; and superposing the ultrasonic signals according to the delay matrix to obtain a corrected focusing image. Therefore, a problem that a traditional array ultrasonic focusing method fails due to signal phase distortion generated by an additive heterogeneous structure can be solved, and high-resolution imaging detection ofinternal defects of an additive workpiece is achieved.

Array ultrasonic focusing imaging correction method for metal additive manufacturing heterogeneous structure

The invention discloses a molten bath morphology obtaining and dynamic analysis device based on a pulse ultrasonic sensor. The molten bath morphology obtaining and dynamic analysis device based on thepulse ultrasonic sensor mainly aims at molten bath morphology obtaining and dynamic analysis. The device is technically characterized by being composed of a pulse ultrasonic transmitting set, a pulseultrasonic receiver array set, a data processing module, a molten bath morphology reduction module and a dynamic control module. Ultrasonic transmitters at the two sides of a molten bath scan the twosides of the molten bath according to the set trajectory, the ultrasonic receiver array set receives pulse signals reflected on the surface of the molten bath, after operation of the data processingmodule, the molten bath surface morphology is extracted, and therefore the molten bath morphology is dynamically analyzed; the device has the advantages of resisting arc light interference, saving thecircuit design and optimizing the structure, and meanwhile, being high in molten bath morphology obtaining precision and capable of performing dynamic analysis on the molten bath morphology.

Molten bath morphology obtaining and dynamic analysis device based on pulse ultrasonic sensor

The invention discloses a method for accurately measuring the defect size of a rough component based on laser ultrasonic imaging. The method comprises the following steps: scanning to obtain a surfacewave time domain signal group; extracting a defect-free area surface wave signal as a reference signal; drawing a two-dimensional color map by taking the moment of the maximum amplitude position of the reference signal as a reference; preliminarily identifying a defect image, and setting a defect evaluation box; performing cross-correlation operation and amplitude difference operation on all thesignals in the evaluation frame and the reference signal to obtain a two-dimensional matrix of a cross-correlation maximum value X, a time shift value tau and an amplitude difference value delta respectively; setting thresholds of the cross-correlation maximum value X, the time shift value tau and the amplitude difference value delta, and constructing a defect binary matrix by taking any one condition of X(Xdec, [tau])[tau]dec and [delta])[delta)dec as a criterion; and removing binary matrix abnormal points, counting zero element regions, and respectively obtaining the area, length and width of a defect region. According to the invention, the problems of defect amplitude jump and non-uniform signal-to-noise ratio distribution caused by the rough surface of the part can be avoided, and theaccurate quantitative measurement of the defect size is realized.

Rough component defect size accurate measurement method based on laser ultrasonic imaging

The invention discloses a laser ultrasonic imaging detection system and a detection method for a self-adaptive irregular surface. The detection system comprises a surface contour measurement module, alaser scanning control module, an ultrasonic data collection module and a lamination imaging and evaluation module, and the surface contour measurement module is connected with the laser scanning control module and the lamination imaging and evaluation module and used for workpiece contour shape and size measurement and data transmission; wherein the laser scanning control module and the ultrasonic data collection module are two independent modules and work synchronously and cooperatively to realize excitation and reception of laser ultrasonic signals respectively; and the overlapping imagingand evaluation module performs virtual focusing processing on the laser ultrasonic signal and overlapping imaging display of the surface contour of the workpiece, and identifies and positions defectsand structural echoes. According to the invention, non-contact laser ultrasonic scanning detection can be carried out on an irregular surface with an unknown geometrical shape, a defect signal can bequickly identified, and the relative position of a defect in an irregular workpiece can be visually displayed.

Laser ultrasonic imaging detection system and detection method for self-adaptive irregular surface

The invention provides a laser cladding layer and molten pool morphology presentation method, belongs to the technical field of laser cladding remanufacture, and relates to the laser cladding layer and molten pool morphology presentation method. According to the method, firstly the cladding substrate sample is cut by a wire cutting machine along the direction perpendicular to the scanning path ofthe cladding layer; then the cut substrate sample is polished on sandpaper with different particle size according to the ascending order of the particle size based on the metallographic sample preparation method; then the polished substrate sample is photographed at the depth of field; then the morphology and the profile of the cladding layer and the molten pool in the ultra-depth-of-field photograph are drawn by arc extension with different curvature radii and the curvature radii of each arc are recorded; and finally the width and the height of the whole morphology and the profile and the inclined angle between the cladding layer and the molten pool are measured. The method can quickly and accurately present the morphology and the profile of the cladding layer and the molten pool.

Laser cladding layer and molten pool morphology presentation method

The invention discloses a metallic molten pool internal contour online measurement device and method. The device comprises an excitation assembly, a receiving assembly and a computer for data analysisand control; the excitation assembly comprises a laser, a beam splitter for dividing a beam emitted by the laser into a plurality of beams, and a plurality of sets of array optical fibers for receiving the plurality of beams respectively; and the computer is provided with a dynamic modulation module for dynamically modulating the beam. With the metallic molten pool internal contour online measurement device and method of the invention adopted, metallic molten pool internal contour online measurement can be realized based on a laser ultrasonic phased array detection technology; and a printingprocess can be adjusted according to a detection result, so that high manufacturing quality of parts can be realized.

Metallic molten pool internal contour online measurement device and method

The invention discloses a high-frequency ultrasonic online monitoring method for internal defects of a metal movable molten pool. The high-frequency ultrasonic online monitoring method comprises the following steps: providing N focusing points of different depths along the center line of the molten pool, obtaining the emission angle thetas of an ultrasonic beam according to the relationship between the focusing points and an incident point in order to obtain N groups of fiber array delay rules corresponding to the focusing points of all angles; exciting a laser according to a delay rule corresponding a first focusing point F1 to realize the incidence of the ultrasonic beam focused at a point N1, and sampling; replacing the delay rule, and exciting the laser according to a delay rule corresponding to a next focusing point F2; repeating the previous steps to finally obtain signals of all focusing points Fi; when a spray nozzle moves to a next position, repeating the previous data acquisition and storage step; starting to analyze data of M positions collected on a straight line; performing drawing analysis on a two-dimension matrix, wherein one or more crescentic ultrasonic signals, namely, diffraction signals of slag inclusion or pores are found in an image rating range.

Dai Ting

Papers

Metallic molten pool internal contour online measurement device and method

High-frequency ultrasonic online monitoring method for internal defects of metal movable molten pool