Strengthening of the Working Edges of the Blades of Steam Turbines

Abstract

The working conditions of the blades of steam turbines require increased hardness of the input edges and resistance to impact erosion, high corrosion resistance. In order to increase the service life of the blades, the inlet edges are quenched by high-frequency currents. The hardened layer was formed by electrospark alloying with T15K6 alloy and 15X11MFSh steel. The use of the widely used T15K6 alloy as a hardened electrode is limited due to the presence of cobalt, as an element forming, as a result of activation, long-lived isotopes that reduce the erosion resistance of the blades. Ultra high speed heating and cooling, pulsed effects of temperatures and pressures result lead to the fact that the composition of the alloyed layer can significantly differ from the composition of the starting materials. The microstructure, microhardness, and thickness of the deposited layer were investigated. The hardened surface was monitored by external inspection, bending tests, microhardness measurements, and microstructure studies. The advantages of 15X11MFSh steel for hardening the input edges of the working blades of steam turbines are substantiated.

Study of the influence of the structure of rolled iron on its hardness

“…Therefore, in materials science, various types of modeling are widely used to control and predict the quality criteria materials [8][9][10]. Models based on the analysis of the influence of the chemical composition are especially common (see, for example, [11][12][13][14]). There are also many models based on the influence of structure on properties, for example [15][16][17].…”

“…Based on the analysis of the data obtained, the relationship between the structure and hardness of roll cast irons of СПХН-43 and СШХНФ-47 was established. Regression equations (2)(3)(4)(5)(6)(7)(8)(9)(10)(11) were obtained that describe the dependence of hardness on structure parameters: the percentage of its elements, the area of the largest cementite inclusions, and the linear dimensions of graphite inclusions. The analysis of the obtained equations shows that a relatively high correlation R 2 = = 0.73...0.87 for linear models is observed between the percentage of pearlite, cementite, and flake graphite [3][4][5][6].…”

“…The values of the pairwise correlation coefficients R 2 = 0.78...0.88 (13)(14)(15)(16) in determining the hardness of cast iron rolls of СПХН-43 design indicate a higher degree of prediction compared to traditional methods of quantitative metallography [5][6][7][8][9][10][11] and the expediency of using multifractal theory to assess the quality of long-range cast iron rolls. We recorded a decrease in hardness indicators with an increase in the information (Fig.…”

Study of the structure and phase composition of ion-plasma coatings

“…Особливістю структурного стану ренгенографічно досліджених покриттів є наявність значних стискаючих напружень і текстури, закономірно пов'язаних з режимами осадження. Подібні результати, які спостерігались раніше при дослідженні плівок, осаджених з потоків енергетичних часток, широко описувалися різними авторами [3][4][5]. При цьому аналізувався вплив окремих факторів організації структури покриттів, таких як «атомная поковка» (пінінг) [3,4], «ущільнення» [12], «зіткнення кристалітів» [13].…”