PJSC Severstal, one of the world's largest vertically integrated steel and mining companies, has successfully completed full-scale pneumatic testing of a new generation of large diameter pipes (LDP) of K65 strength class with high deformation capacity, confirming their readiness for use in the construction of gas pipelines.

A new type of pipe products was developed within the framework of the Program of Scientific and Technical Cooperation between Severstal and Gazprom for 2019-2022. The final stage of the complex of research and testing of pipe products was organized by Severstal. The tests were carried out at a special experimental testing ground of Gazprom in the Chelyabinsk Region under the direction of the permanent commission of PJSC Gazprom for the acceptance of new types of pipe products and with the participation of specialists from Gazprom VNIIGAZ and Gazprom Gaznadzor.

The tests were performed on LDP manufactured at the Izhora Pipe Plant (ITZ, part of the Severstal Russian Steel division of PAO Severstal) located at a production site in the Kolpinsky District of St. Petersburg. For the manufacture of pipes, rolled metal products of our own production were used, which produces a mill 5000 of the company's sheet-rolling shop.

LDPs were pre-welded into a 200-meter "lash" simulating a real gas pipeline, on which a set of measuring equipment was installed to control pressure, temperature and a number of other parameters ... The preparatory work took several months. During the tests - especially for the experimental destruction of the initiator pipe - a training shaped charge was detonated.

For the first time in the history of field tests, a standard mass charge failed the task the first time. The pipe with an artificially applied surface notch with a depth of about 25% of the wall thickness and up to 6 mm wide withstood the action of the charge - the "whip" was not destroyed, the pressure in the "whip" remained at 15 MPa. It was decided to re-test the "string" of pipes, installing a new charge in the same position, more than 50% higher than its original mass. In this case, the residual wall thickness of the initiator tube after the first blast was already only 16.9 mm. After the repeated explosion, it was found that the main crack on both sides stopped with looping within the first test pipe at a distance of 4.4 m from the annular joint with the initiator pipe. This is the best result since 2008, when the first such full-scale tests in the field took place in the Russian Federation.

Also for the first time, one of the two sections of the tested pipes was welded from three pipes, originally manufactured at the factory with a length of 18.3 m and then cut to length 11.8 m. The obtained identical result of resistance to the propagation of extended fractures testifies to the stability of the level of mechanical properties and the quality of sheet metal regardless of the length.

and pipes. We have confirmed the highest resistance to the spread of extended fracture and the operational reliability of the new generation of pipe products, the tests were recognized as successful ", - comments Anton Smelov, senior manager of the Directorate for work with energy companies of Severstal.

advantages over pipe generations. The complex of mechanical properties of LDP of strength class K65 with high deformation capacity allows ensuring the safety and integrity of the pipeline in the event of exposure to loads significantly exceeding the design ones. At the same time, the minimum pipe wall temperature during operation is minus 40 ° C, and the reduced pipe wall thickness is 27.6 mm.

Severstal has once again confirmed its readiness to develop innovative products for the energy industry in a short time. The new generation of tubular products is the result of joint work with Gazprom to improve technologies and develop new types of products. The benefits of the new product open up additional opportunities for the customer to reduce capital costs and improve the operational reliability of facilities. Severstal is open to cooperation with knowledgeable pipe manufacturers and is ready to supply strip rolled products to replicate the new generation pipe production technology. We are confident that the use of LDP of strength class K65 with high deformation capacity can become a big step in the development of the gas transmission system of the Russian Federation, ”commented Vitaly Lipin, Severstal Technical Sales Director. On this day, 15 years ago, the grand opening of the Izhora Pipe Plant took place.

Link to the test video: https://youtu.be/IIRigapp4aA

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