The Research Of Ferromagnetic Material Pipeline Pressure Testing Of Using Barkhausen Noise Method

It is a very important safety precaution to actualize stress testing for ferromagnetic material structural member in the practical application. In comparison with other common nondestructive stress testing methods, Barkhausen noise stress testing method, which was developed in the latest twenty years, is a new-style nondestructive detecting technology with enormous development potential, can carry out online, fast, portable, non-fixed stress testing and can evaluate fatigue damage, hardness, microstructure, surface state.In this paper, the production mechanism of Barkhausen noise, characteristic of the signal, relation between signal and material in different stress, hardness, microstructure or fatigue condition have been summarized. We also investigated the relation between signal and stress of various ferromagnetic materials under different magnetic density, and developed a stress testing system for ferromagnetic material structural element, and a special sensing head for pipeline circumferential stress testing. The system mainly includes signal detector, signal extraction processing circuit, analog-to-digital conversion circuit, single-chip processing and nixietube display circuit. Some circuit design, software programming were introduced in detail, and correspondent source program was given out in the paper.In this paper, Barkhausen noise stress testing system was applied in pipeline interior pressure testing based on the elastic mechanics relation between circumferential stress and pipeline internal pressure of high pressure transport pipeline. And detailed elastic mechanics derivation calculus has been given out. Consensus multisensor data fusion method was applied in data measured by sensors which been put along the pipeline separately and in multimetering data obtained by one sensor, in order to evaluate the running state of whole pipeline and eliminate interference caused by residual stress.