Improving the dimensional precision and surface quality of cold-rolled pipe

摘要

The surface state and dimensional precision of pipe have a significant influence on the performance of heat-liberating casings in atomic reactors, heat-exchangers, and other equipment operating at elevated load, pressure, and temperature. In particular, low surface quality may result in the formation of pitting corrosion, which later becomes local cracks and induces premature pipe failure. Accordingly, reliable evaluation of the state of pipe is of great importance. At the State Pipe Institute (SPI, Ukraine), an algorithm for processing measurement results has been developed (Fig. 1), on the basis of analysis of information from instruments for nondestructive dimensional monitoring, measuring microscopes, and instruments for circle measurement, fitted with sensors of increased resolving power. This method permits the collection and analysis of copious measurement data, including scanning of the sample surface in combination with the cross sections, at a rate of up to 3500 measurements per rotation (Figs. 2 and 3); the analysis of up to 500,000 readings is possible.