Use of wear-resistant coatings for strengthening pipe tools for the production of pipes by pressing from high alloy steel
Authors:   Kharkiv Institute of Physics and Technology of the National Academy of Sciences of Ukraine, Stolbovy V. O. , Deineko L. M. ,   Ukrainian State University of Science and Technology, Pinchuk V. L. ,   Nikopol Vocational College of Ukrainian State University of Science and Technology, Kryvchyk L. S. ,   Nikopol Vocational College of Ukrainian State University of Science and Technology, Khokhlova T. S. ,   Ukrainian State University of Science and Technology
Published: February 2024

In Ukraine, the production of pipes is one of the most important branches of industry. These are the oil, gas, food, chemical, machine-building, aviation, and construction materials industries. Pipes made of highly alloyed, corrosion-resistant steels are especially widely used. The process of producing steel pipes by pressing on hydraulic presses has become widespread. When pressed, the metal undergoes three-way compression, so it exhibits high plasticity, which is especially important for highly alloyed steels that are difficult to deform. In contrast to pipe rolling plants, it is possible to obtain pipes with a thinner wall and smaller diameter on presses, especially when reducing and calibrating mills are used on pipe pressing plants. The tube press tool is subject to intensive wear. According to the conditions of operation, press needles and matrices belong to a heavily loaded tool, since they are in contact with the metal being pressed. The possibility of obtaining a high coefficient of extraction during pressing is due to a favorable scheme of the stressed state of the metal in the process of deformation, as a result of which the metal undergoes large degrees of deformation without destruction. However, to implement the pressing process with a large amount of extraction, it is necessary to add a large pressure, regulated by the resistance of the metal to plastic deformation and the amount of friction force at the contact boundary of the deformed metal with the tool. Production of steel pipes by pressing is carried out on pipe press units with a vertical mechanical press (VMP) or with a hydraulic horizontal press (HGP). The working tool of pipe-profile presses works in conditions of high temperatures, impact and sign-changing loads, significant specific pressure, therefore the material for making the tool must have increased strength, viscosity, and heat resistance. When pressing pipes made of highly alloyed, corrosion-resistant steels, there is a low stability of the pipe tool, which requires frequent adjustments of the equipment and stops of the press. Conventional thermosetting technologies (hardening with tempering) do not provide sufficient properties of the pipe press tool. Therefore, the search for rational technologies of thermal strengthening and application of wear-resistant microstructural coatings significantly increases the operational properties and service life of the pipe press tool, which is confirmed by the results of industrial tests at the operating enterprises of Ukraine. The purpose of the work is to improve the strengthening technologies of the pipe tool for pressing pipes made of high-alloy steels, which are difficult to deform, and to study the patterns of structure formation in the metal of the main pipe press tool - matrix rings for pressing pipes on pipe press installations and their effect on the mechanical properties to improve the quality and performance of the tool.