Experience in Selection of Cavitation-Resistant Steels for Inducers of Centrifugal Pumps of JSC "VNIIAEN" Specialization

Abstract

To formulate the problems of increasing the resistance to cavitation erosion of the hydraulic parts of centrifugal pumps by selecting the most suitable steel grades and to review the experience of using cavitation-resistant steels for inducers of centrifugal pumps of JSC “VNIIAEN” specialization. Analytical and statistical analyses were carried out using research and experimental development data of cavitation-resistant steels for inducers of centrifugal pumps at JSC "VNIIAEN", as well as using data from open access publications. The article deals with the problem of centrifugal pump hydraulic part failure caused by cavitation. It has been actually demonstrated that the most effective way to improve the cavitation performance of centrifugal pumps is to use an inducer upstream of the first stage impeller. Therefore, the study of cavitation-resistant steels was carried out on inducers which are most exposed to cavitation when operating under condition of developed cavitation. The results of tests carried out on experimental model test rig and full – scale pumps are presented. The selection of steels resistant to cavitation has been optimized. The relationship between the chemical and mechanical properties of steels and resistance to cavitation is shown. In addition, the essential role of structural properties of steel is shown in terms of heat of steel 08Х15Н4ДМЛ. The article provides a rationale for the fact that the potential for improving the cavitation-erosion properties of the hydraulic parts of centrifugal pumps solely by improving their hydrodynamic characteristics is practically exhausted; therefore, more attention should be paid to the search for cavitation-resistant steels used for the manufacture of hydraulic parts. It is shown that in order to achieve the best cavitation-erosion properties, it is necessary to provide a certain interaction of the selected chemical and mechanical properties of materials. The possibility of achieving better resistance to cavitation erosion by modifying the melting process is shown in terms of steel 08Х15Н4ДМЛ.