Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines
The influence of electrode material on the state of build-up layer of steam turbine rotor blades is investigated. The strengthening layer is formed by means of the electrospark alloying with use of alloy Т15К6 and steel 15Х11МФШ. Microstructure, microhardness, and thickness of build-up layer are inv...
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Інститут металофізики ім. Г.В. Курдюмова НАН України
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| Cite this: | Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines / D.B. Glushkova, E.D. Grinchenko, L.L. Kostina, S.V. Demchenko, Yu.V. Ryzhkov // Металлофизика и новейшие технологии. — 2017. — Т. 39, № 12. — С. 1647-1654. — Бібліогр.: 5 назв. — англ. |
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Glushkova, D.B. Grinchenko, E.D. Kostina, L.L. Demchenko, S.V. Ryzhkov, Yu.V. 2018-02-13T20:14:40Z 2018-02-13T20:14:40Z 2017 Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines / D.B. Glushkova, E.D. Grinchenko, L.L. Kostina, S.V. Demchenko, Yu.V. Ryzhkov // Металлофизика и новейшие технологии. — 2017. — Т. 39, № 12. — С. 1647-1654. — Бібліогр.: 5 назв. — англ. 1024-1809 PACS: 62.20.Qp, 68.35.Gy, 68.55.J-, 68.55.Ln, 68.60.Bs, 81.15.Cd, 81.65.Lp DOI: doi.org/10.15407/mfint.39.12.1647 https://nasplib.isofts.kiev.ua/handle/123456789/130470 The influence of electrode material on the state of build-up layer of steam turbine rotor blades is investigated. The strengthening layer is formed by means of the electrospark alloying with use of alloy Т15К6 and steel 15Х11МФШ. Microstructure, microhardness, and thickness of build-up layer are investigated. The advantages of steel 15Х11МФШ for the strengthening of leading edges of steam turbine rotor blades are substantiated. Исследовано влияние материала электрода на состояние наплавленного слоя рабочих лопаток паровых турбин. Упрочнённый слой формировался электроискровым легированием сплавом Т15К6 и сталью 15X11МФШ. Исследовались микроструктура, микротвёрдость и толщина наплавленного слоя. Обоснованы преимущества стали 15X11МФШ для упрочнения входных кромок рабочих лопаток паровых турбин. Досліджено вплив матеріялу електроди на стан натопленого шару робочих лопаток парових турбін. Зміцнений шар формувався електроіскровим леґуванням стопом Т15К6 і крицею 15Х11МФШ. Досліджувалися мікроструктура, мікротвердість і товщина натопленого шару. Обґрунтовано переваги криці 15Х11МФШ для зміцнення вхідних крайок робочих лопаток парових турбін. en Інститут металофізики ім. Г.В. Курдюмова НАН України Металлофизика и новейшие технологии Физика прочности и пластичности Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines Материал для упрочнения входных кромок рабочих лопаток паровых турбин Матеріял для зміцнення вхідних крайок робочих лопаток парових турбін Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines |
| spellingShingle |
Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines Glushkova, D.B. Grinchenko, E.D. Kostina, L.L. Demchenko, S.V. Ryzhkov, Yu.V. Физика прочности и пластичности |
| title_short |
Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines |
| title_full |
Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines |
| title_fullStr |
Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines |
| title_full_unstemmed |
Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines |
| title_sort |
material for strengthening of entrance edges of work blades of stream turbines |
| author |
Glushkova, D.B. Grinchenko, E.D. Kostina, L.L. Demchenko, S.V. Ryzhkov, Yu.V. |
| author_facet |
Glushkova, D.B. Grinchenko, E.D. Kostina, L.L. Demchenko, S.V. Ryzhkov, Yu.V. |
| topic |
Физика прочности и пластичности |
| topic_facet |
Физика прочности и пластичности |
| publishDate |
2017 |
| language |
English |
| container_title |
Металлофизика и новейшие технологии |
| publisher |
Інститут металофізики ім. Г.В. Курдюмова НАН України |
| format |
Article |
| title_alt |
Материал для упрочнения входных кромок рабочих лопаток паровых турбин Матеріял для зміцнення вхідних крайок робочих лопаток парових турбін |
| description |
The influence of electrode material on the state of build-up layer of steam turbine rotor blades is investigated. The strengthening layer is formed by means of the electrospark alloying with use of alloy Т15К6 and steel 15Х11МФШ. Microstructure, microhardness, and thickness of build-up layer are investigated. The advantages of steel 15Х11МФШ for the strengthening of leading edges of steam turbine rotor blades are substantiated.
Исследовано влияние материала электрода на состояние наплавленного слоя рабочих лопаток паровых турбин. Упрочнённый слой формировался электроискровым легированием сплавом Т15К6 и сталью 15X11МФШ. Исследовались микроструктура, микротвёрдость и толщина наплавленного слоя. Обоснованы преимущества стали 15X11МФШ для упрочнения входных кромок рабочих лопаток паровых турбин.
Досліджено вплив матеріялу електроди на стан натопленого шару робочих лопаток парових турбін. Зміцнений шар формувався електроіскровим леґуванням стопом Т15К6 і крицею 15Х11МФШ. Досліджувалися мікроструктура, мікротвердість і товщина натопленого шару. Обґрунтовано переваги криці 15Х11МФШ для зміцнення вхідних крайок робочих лопаток парових турбін.
|
| issn |
1024-1809 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/130470 |
| citation_txt |
Material for Strengthening of Entrance Edges of Work Blades of Stream Turbines / D.B. Glushkova, E.D. Grinchenko, L.L. Kostina, S.V. Demchenko, Yu.V. Ryzhkov // Металлофизика и новейшие технологии. — 2017. — Т. 39, № 12. — С. 1647-1654. — Бібліогр.: 5 назв. — англ. |
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1647
PACS numbers: 62.20.Qp, 68.35.Gy, 68.55.J-, 68.55.Ln, 68.60.Bs, 81.15.Cd, 81.65.Lp
Material for Strengthening of Entrance Edges of Work Blades
of Stream Turbines
D. B. Glushkova, E. D. Grinchenko, L. L. Kostina, S. V. Demchenko,
and Yu. V. Ryzhkov
Kharkiv National Automobile and Highway University,
25 Yaroslava Mudrogo Str.,
61002 Kharkiv, Ukraine
The influence of electrode material on the state of build-up layer of steam
turbine rotor blades is investigated. The strengthening layer is formed by
means of the electrospark alloying with use of alloy Т15К6 and steel
15Х11МФШ. Microstructure, microhardness, and thickness of build-up lay-
er are investigated. The advantages of steel 15Х11МФШ for the strengthen-
ing of leading edges of steam turbine rotor blades are substantiated.
Key words: electrospark alloying, electrode, surfacing layers, microstruc-
ture, microhardness, strengthening.
Досліджено вплив матеріялу електроди на стан натопленого шару робо-
чих лопаток парових турбін. Зміцнений шар формувався електроіскро-
вим леґуванням стопом Т15К6 і крицею 15Х11МФШ. Досліджувалися
мікроструктура, мікротвердість і товщина натопленого шару. Обґрунто-
вано переваги криці 15Х11МФШ для зміцнення вхідних крайок робочих
лопаток парових турбін.
Ключові слова: електроіскрове леґування, електрода, натоплений шар,
мікроструктура, мікротвердість, зміцнення.
Исследовано влияние материала электрода на состояние наплавленного
слоя рабочих лопаток паровых турбин. Упрочнённый слой формировался
электроискровым легированием сплавом Т15К6 и сталью 15X11МФШ.
Corresponding author: Diana Borysivna Glushkova
E-mail: diana@khadi.kharkov.ua
Please cite this article as: D. B. Glushkova, E. D. Grinchenko, L. L. Kostina,
S. V. Demchenko, and Yu. V. Ryzhkov, Material for Strengthening of Entrance Edges
of Work Blades of Stream Turbines, Metallofiz. Noveishie Tekhnol., 39, No. 12: 1647–
1654 (2017), DOI: 10.15407/mfint.39.12.1647.
Ìåòàëëîôèç. íîâåéøèå òåõíîë. / Metallofiz. Noveishie Tekhnol.
2017, т. 39, № 12, сс. 1647–1654 / DOI: 10.15407/mfint.39.12.1647
Îòòèñêè äîñòóïíû íåïîñðåäñòâåííî îò èçäàòåëÿ
Ôîòîêîïèðîâàíèå ðàçðåøåíî òîëüêî
â ñîîòâåòñòâèè ñ ëèöåíçèåé
2017 ÈÌÔ (Èíñòèòóò ìåòàëëîôèçèêè
èì. Ã. Â. Êóðäþìîâà ÍÀÍ Óêðàèíû)
Íàïå÷àòàíî â Óêðàèíå.
https://doi.org/10.15407/mfint.39.12.1647
https://doi.org/10.15407/mfint.39.12.1647
1648 D. B. GLUSHKOVA, E. D. GRINCHENKO, L. L. KOSTINA et al.
Исследовались микроструктура, микротвёрдость и толщина наплавлен-
ного слоя. Обоснованы преимущества стали 15X11МФШ для упрочнения
входных кромок рабочих лопаток паровых турбин.
Ключевые слова: электроискровое легирование, электрод, наплавленный
слой, микроструктура, микротвёрдость, упрочнение.
(Received September 7, 2017; in final version, November 24, 2017)
1. INTRODUCTION
Rotor blades of steam turbines determine the serviceability of the tur-
bine. Their working conditions require high hardness of leading edges.
Further, erosion damage reduces their resistance.
To increase the service life of blades, the leading edges are exposed
to such processing methods like hardening by high-frequency currents
and application of the widely used alloy Т15К6 based on carbides Ti
and W as in forcing electrode. The binder for this alloy is Co.
However, the mode of operation of blades is such that requires in-
creased resistance to shock erosion, lack of adverse influence of coat-
ing formation parameters on mechanical properties, high corrosion
properties.
2. ANALYSIS OF PUBLICATIONS
Application of the above methods has limitations. Thus, using the
high-frequency current makes it difficult to technically temper the ra-
dius blend from the blade air foil portion to the bookshelf bandage, and
use of the widely applied alloy Т15К6 as a reinforcing electrode is lim-
ited due to the presence of cobalt—an element that, as a result of acti-
vation, forms long-lived isotopes, which reduce the erosion resistance
of blades [1, 2].
In connection with the above, the objective of the present work was
to develop a method that would enable to simultaneously reinforce the
leading edges of blades and reduce their erosion resistance [3, 5].
3. PURPOSE AND TASK
In the given paper, there were tested two materials to be used as an
electrode—alloy Т5К16 and steel 15Х11МФШ.
The electric spark method is based on the phenomenon of electric
erosion of materials under spark discharge in a gaseous medium, the
polar erosion product transport on the layer of modified structure and
alloy. Because of electrical breakdown of the interelectrode gap, there
occurs a spark, in which the flow of electrons leads to local heating of
MATERIAL FOR STRENGTHENING OF ENTRANCE EDGES OF WORK BLADES 1649
the electrode (anode) [1, 4]. On the surface of the cathode under the in-
fluence of high thermal loads, there is carried out a mixing of both the
cathode and anode materials that promotes the formation of proper
adhesion between the substrate and the formed layer. Figure 1 shows
the general scheme of the electrospark alloying (ESA).
The composition of the doped layer may differ significantly from the
composition of the raw materials. It is caused by the specifics of the
ESA impact, which consists in the ultra-high heating and cooling
rates, the contact of surfaces to each other and with the surrounding
elements of the environment under pulse exposure to high tempera-
tures and pressures.
The study was conducted, using samples of steel 15Х11МФШ that
was thermally treated to obtain the hardness of 285 HV with removing
the decarburized layer to the depth of 1 mm along the hardening plane.
Works on the strengthening of samples were carried out using elec-
trospark equipment EIL 8A.
4. PRIMARY PARTITION
The microstructure of the base metal of specimens presents sorbitol
with retaining orientation along martensitic planes. The structure of
the samples is of different uniformity, the structure contains grains of
different etch ability, and the size of needles corresponds to 7–8 points
Fig. 1. General scheme of the electrospark alloying.
1650 D. B. GLUSHKOVA, E. D. GRINCHENKO, L. L. KOSTINA et al.
(Fig. 2).
Control of the hardened surface is carried out by visual inspection
with a magnifying glass with 3, 10 power.
On the surface of the samples after hardening by both alloys Т15К6
and steel 15Х11МФШ, defects such as cracks were not revealed. Fig-
ure 3 shows the appearance of the surface hardened by alloy Т15К6.
The layer is homogeneous, fine-grained, and, in some places, there can
be found small size craters.
Figure 4 shows the appearance of the surface hardened by steel
15Х11МФШ. The layer is homogeneous, fine-grained, and it has small
Fig. 2. Microstructure of the main sample metal.
Fig. 3. The appearance of the sample surface strengthened by alloy Т15К6.
MATERIAL FOR STRENGTHENING OF ENTRANCE EDGES OF WORK BLADES 1651
craters in small quantities.
To assess the quality of adhesion of doped layers with the substrate,
the samples after hardening were tested according to the following
scheme: samples Nos. 1 and 2 were tested for bending at an angle of 90
using a mandrel with R 20 mm; samples Nos. 3 and 4 were tested for
bending at an angle of 70 using a mandrel with R 40 mm.
The test results are shown in Table 1.
When viewing the bends, the peel of the hardened layer from the
base metal was not detected.
Measurement of the thickness of the hardened layer was carried out
in sections manufactured according to the cross-sectional plane of the
sample.
The surface hardened layer is characterized by heterogeneity of the
layer thickness, but the average value of the thickness in case of hard-
ening by alloy Т15К6 and steel 15Х11МФШ is virtually identical
(Fig. 5).
Study of the microstructure of the deposited layer showed that the
structure is homogeneous and almost no etch ability. In some places,
there were detected individual pores.
Fig. 4. The appearance of the sample surface hardened by steel 15Х11MФШ.
TABLE 1. Bending test results.
Sample
brand
Material Test result Notes
1
2
3
4
Т15К6
15Х11МФШ
15Х11МФШ
15Х11МФШ
No ruination
No ruination
No ruination
No ruination
In the place of bending, detected tears
In the place of bending, detected tears
In the place of bending, no detected tears
In the place of bending, no detected tears
1652 D. B. GLUSHKOVA, E. D. GRINCHENKO, L. L. KOSTINA et al.
Fig. 5. Histograms of the mean values of thickness of layers hardened by alloy
Т15К6 (1) and steel 15Х11MФШ (2).
Fig. 6. Histograms of microhardness measurement in samples hardened by
alloy Т15К6 (1) and steel 15Х11MФШ (2): a—deposited layer; b—transition
(diffusion) zone; c—HAZ ( 0.05 mm from the border); d—HAZ ( 0.1 mm
from the border).
MATERIAL FOR STRENGTHENING OF ENTRANCE EDGES OF WORK BLADES 1653
When surfacing by steel 15Х11МФШ, the layer structure is of
mainly dendritic structure. In the surface layer of the base metal under
high temperatures, there was observed the formation of the light etch
ability zone formed by diffusion of the electrode material into the sam-
ple depth and the dark-etch ability zone of under alloying. In some
places, there were detected pores.
Figure 6 shows histograms of microhardness measurement in the
zone ‘hardened layer–base metal’ of the samples under study.
As it follows from the above histograms, in all areas, the micro-
hardness at hardening by alloy Т15К6 and steel 15Х11МФШ is practi-
cally identical.
5. CONCLUSIONS
1. When there was performed visual inspection and carried out metal-
lographic analysis of samples reinforced by the electrospark method
using the equipment EIL 8A with electrodes made of steel 15Х11МФШ
and hard alloy Т15К6, cracks were not revealed.
2. The bending tests of the samples hardened by both the solid alloy
Т15К6 and steel 15Х11МФШ are not failed.
3. In examination of the bends, the peel of the hardened layer from the
base metal was not detected.
4. The average thickness of the surface layer hardened by both alloy
Т15К6 and steel 15Х11МФШ was virtually identical.
5. The microhardness of the deposited layer, the transition zone, and
HAZ at different distances from the boundary, when using both the
hardened alloy Т15К6 and steel 15Х11МФШ, is not practically differ-
ent.
6. Based on these studies, it is recommended to replace the applied re-
inforcing electrode with one made of alloy Т15К6 and steel
15Х11МФШ to increase the hardness of the leading edges of steam en-
gine rotor blades.
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Poverkhnostey Instrumentov i Detaley Mashin Elektrodnymi Materialami,
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and Machine Components with Electrode Materials Obtained from Mineral Raw
Materials] (Vladivostok: Dal’nauka: 1999) (in Russian).
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(in Russian).
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