Development of profile pipes production technology, providing higher accuracy of geometric parameters compared to foreign manufactures

The method of profiling circular pipes is used in the lines of pipe-electric welding and profiling units in order to master the production of pipe products of non-circular cross-section from corrosion-resistant steel grades. Tubular products used in nuclear power generation facilities have higher requirements to mechanical properties and geometrical parameters. In particular, the most difficult aspect of manufacturing profile pipes-windings for turbo-generator stators with a rectangular cross-section is ensuring the flatness of flanges and achieving the radius of the outer corner rounding within a tolerance of ±0.10 mm relative to the nominal value. In order to successfully master the production of this type of product, a synthesis of the circular pipe profiling scheme was carried out. The authors developed the technology of profiling in drive rolls forming box gauges and in non-driven four-roll stands. Computer modeling of the profiling process was carried out in the Marc Mentat 2021 program. After experimental rolling, the profiles’ geometric parameters were analyzed using an optical microscope and special software. Acceptance tests were performed in accordance with the requirements to profile pipes for windings of turbogenerator stators.