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| Research Interests |
| Residual Stress Ultrasonic Critical Refraction Longitudinal Wave Testing System |
| Function Summary |
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| Welding residual stress testing system is based on acoustic elasticity theory and can realize rapid nondestructive testing of residual stress for the surface and subsurface of weld heat-affected zone by using the ultrasonic longitudinal wave. The testing system includes a high frequency data acquisition card that can real-time analysis data and display A scan image, test results can show the residual stress value and the state of tension and compression. All test results will be automatically saved and output an inspection report in a Word document which provides reference for the detection of post-processing. The magnetic suction sensor can be without magnetic manually that adapts to the testing for a variety of types of welding residual stress. A temperature sensor real time monitoring the change of temperature during testing is integrated in detection sensors, the influence of temperature on the test results can be eliminated through temperature compensation. The software interface is simple, easy to operate. The testing system has a big rang of testing for stress, good repeatability, high precision, high integration, small shape size and is easy to carry. This system can be equipped with multiple batteries, has a small power consumption and a long working time that can adapt to all kinds of field testing. |
| Technical Features |
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| Ultrasonic method for residual stress measurement has many advantages such as rapid detection, no radiation harm to human body, low cost, better spatial resolution and large range of detection depth, easy to carry, detection in site by hand, able to complete the detection for the macroscopic residual stress in surface and subsurface and the state of tension and compression. |
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| Residual Stress Ultrasonic Critical Refraction Longitudinal Wave Testing System |
Specifications |
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Detecting Depth: 2mm
Detection Range: -1800MPa~＋1800MPa
Detection Error: ±20MPa
Ultrasonic Sensor Center Frequency: 5MHz
Temperature Sensor Working Range: -50℃~100℃
The Highest Sampling Frequency: 100MHz
Credibility: 95% when within 5000 times
System Working Voltage: AC 220V, or power supply by battery
Working Temperature: -20℃~＋50℃
Service Life: 5 years in laboratory environment, 2 years in bad environment |
| Technical principle |
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| Critical refraction longitudinal wave is the most sensitive to stress, according to Snell’s law, refraction phenomenon occurs when ultrasonic longitudinal wave oblique incident from a medium with slower wave velocity into another medium with faster wave velocity. If the longitudinal wave refraction angle is 90°, the longitudinal refracted wave will propagate along the surface of the second medium. This longitudinal refracted wave is named Lcr wave. By accurately measuring the velocity of Lcr wave, which can effectively obtain the residual stress value of the material. |
| Applications |
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| This system has been widely applied for more than 30 enterprises and research units, such as State-run 447th Factory Measurement And Inspection Institute, AVIC GuiZhou LiYang Aircraft Engine (group) co., LTD, Lanzhou Institute Of Petrochemical Equipment, The Seventh Institute of China Aerospace Science and Industry Corporation, Shijiazhuang Tiedao University, Welding Factory of Long March Machinery Factory, The 5th Institute of China Aerospace Science and Industry Corporation, etc. |
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