Experimental Researcj And Development Of Pipe Residual Stress Electromagnetic Detection

In the machinery field, there are large variety of component produces such as pressure vessel, spherical tank and pipe, etc, usually have the welding residual stress. Residual stress has great effect on structure fatigue strength, the strength of stress corrosion, especially in low temperature condition. Problems are highly concerned at home and abroad, for many years a variety of means have be taken to eliminate the welding stress, such as heat treatment, vibration, explosion, etc. So it seems much more important to measure the welding residual stress in a fast and accurate way. With the development of science and technology, magnetic anisotropy detection means for detecting has been highly concerned because it does not cause damage. But until now, the detection principle and the method still needs further research, therefore, only a few of testing instrument based on this method have been applied to practical engineering cases. Through exploring previous research results, this article study and promote the microscopic mechanism of magnetic-stress effect, and try to combine the micro theory and macro performance. Through software simulation and laboratory experiment research, author have developed the TMT-150welding residual stress detector, and did several experiments on it. The main research content is as follows:1. By studying the magnetic-stress relationship of ferromagnetic materials, try to find out the mathematical model of magnetic-stress. Then set up circuit to converts magnetic permeability into current or voltage signal.2. Put forward a new standard to evaluate the effect of welding residual stress, and by using the observed data analysis of a steam drum boiler to verify this kind of evaluation method is scientific and useful.3. By using the Ansoft Maxwell software, author did several simulated research to provide technical support for the further research and development of sensors and instruments.4. Developed the three electrode sensor which is appropriated for hook surface.5. Chose different materials and then calibrate their sensitivity coefficients, after that, give out the VC(R)-R calibration curves according to different pipelines.6. With the help of shearing stress difference method and the boundary conditions that we have known, author did several experiment, and make contrastive analysis of different measuring methods.