Testing Technology Of Titanium-Steel Composite Sheets With Ultrasonic Creeping Waves

Titanium materials have good corrosion resistance in special environments and are often used in the production of highly corrosive products.Affected by processing technology,internal fluid corrosion and thermal stress,titanium steel clad plate is prone to delamination,corrosion pit and crack,which seriously affects the operation safety of titanium steel clad plate related equipment.According to the structural characteristics of titanium steel composite plate,a nondestructive testing method based on ultrasonic creep wave detection technology is proposed in this paper,which can effectively detect the interface defects of titanium steel composite plate.The application technology advantages of bimetal composite plate are analyzed comprehensively,and a variety of nondestructive testing methods are compared.There is a great difference in the acoustic impedance between titanium and steel in titanium steel composite plate,and the ultrasonic wave will produce obvious echo on the joint surface of titanium steel.Conventional ultrasonic testing is difficult to identify the bonding defects of titanium steel.Ultrasonic creeping wave can effectively detect delamination,corrosion pit and crack of titanium steel clad plate because of its detection advantage under this condition.In this paper,the ultrasonic creeping wave technology is applied to the defect detection of titanium steel composite plate.The basic theoretical research,sound field test,numerical simulation and experimental verification of the detection technology are carried out respectively.Theoretical study of ultrasonic creeping wave.The technical principle is described,the artificial test block is designed,and the sound field characteristics of creeping wave are studied by experimental test method.The results show that the creeping wave is a special form of wave formed by refraction after ultrasonic wave propagates from the first medium to the second medium at the first critical angle.Its sound field has a variety of vibration modes,including creeping wave,shear wave and head wave.This feature is used to detect common defects at the boundary of titanium steel clad plate.Research on ultrasonic testing scheme of titanium steel clad plate based on the analysis of ultrasonic testing model and conventional ultrasonic testing scheme,the ultrasonic creep wave testing scheme of titanium steel clad plate is determined.Numerical study on ultrasonic creep wave detection of titanium steel composite plate the propagation law of ultrasonic creep wave in titanium steel composite plate was studied by using COMSOL multi physical field finite element software.The interface of titanium steel is designed with three kinds of defects:porosity,crack and debonding.The propagation of creep wave under the condition of interface defects is studied,and the displacement comparison curves of observation points with and without defects are obtained.The results show that the scattering signals caused by the.three defects are obvious,which indicates that the ultrasonic creeping wave technology is feasible to detect the interface defects of titanium steel composite plate.Experimental verification of ultrasonic creep wave detection for titanium steel clad plate,Design and manufacture artificial prefabricated defect samples to simulate air holes,internal cracks,slag inclusions,incomplete fusion and other defects.The creeping wave probe assembly is designed and manufactured,and the ultrasonic creeping wave detection system is constructed.The test block was tested by bow scanning,and the ultrasonic A-scan and C-scan imaging results were obtained.The experimental results show that the detection system can detect the Φ Air hole defect,crack defect of 0.1mm wide and 2mm deep groove,and debonding defect of 3mm wide and 0.3mm deep.Finally,the relationship between the creeping wave detection signal and the detection thickness is tested by using the detection device.The experimental results are consistent with the simulation results.Finally,the relationship between the creeping wave detection signal and the detection thickness is tested by using the detection device.Comparing the experimental results with the numerical simulation results,the relationship curve between the detection signal and the detection thickness is consistent.