AT and AE monitoring for a pressure equipment (cowper) for steel production

摘要

The cowper is an key tool in process line for steel production. In case of an unforeseen problem the complete process line will be stooped. Therefore a pre-warning against failures is important and pre-warning methodologies have to be evaluated. It is obvious, that AT and much more AE monitoring are excellent for this purpose, especially if all necessary preparations are done properly. According AE standardisation (EN 13455 "General information") the pre-information's have to be evaluated on-time and must influence the design and later on also production of the cowpers. During the design stage one of the most critical part is the selection of the "right" sensors, their application methodology and especially also their position. One of the first steps of measurement is to gather the information about the acoustic behaviour of the material and the cowpers at all. The complete test was performed according EN 14584 with Δ-t location. During the acceptance tests the maximum pressure were applied twice, because on one hand the residual stress from the welding process shall be eliminated but much more on the other hand the influence of the inside insulation have to be taken into account. This insulation may be also one of the most critical parts during the life-time of the cowper. Both pressure tests were monitored with AE and the acquired data were evaluated according known and pre-defined evaluation criteria. The aim of these tests was to proof the quality of the production but also give the AE a basic signature of the acoustic behaviour of all sources, which were detected in the structure. The tests gave also an opportunity to improve and verify the evaluation and rejection criteria. The influence of all detected source has to be considered according their present and future influence of the different stages of the service life. The results of the basic pressure test of a new cowper will used for a comparisons for the later AT and planed discontinuous and/or continuous AE monitoring as a pre-warning tool against a failure and for on-time detection of possible defects. The presented works will be checked against the on-going works for the standardisation of AE monitoring of metallic pressure equipment's in the sense of pre-warning methodology against failure and for detection of imperfections (defects).