Evaluation of Steam Turbine Blades Surface Cracks Detectability by Nondestructive Methods

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
J. Veselá ◽  
P. Mareš ◽  
P. Zahrádka ◽  
J. Patera
Keyword(s):  
Steam Turbine ◽  
Rayleigh Waves ◽  
Crack Detection ◽  
Turbine Blades ◽  
Surface Cracks ◽  
Advantages And Disadvantages ◽  
Array Probe ◽  
Steam Turbine Blade ◽  
Corrosion Pitting ◽  
Steam Turbine Blades

Abstract This article describes methods suitable for crack detection on low pressure steam turbine blades, not including the blade root. These cracks, which are initiated in the corrosion pitting, can cause serious damage to the steam turbine blade leading to its breakaway. Therefore, the detection of these cracks on the early stages of blade fracture is very important. Several methods for detecting of surface cracks (ultrasonic Rayleigh waves, eddy current with flexible array probe, etc.) has been tested on artificial flaws, which were manufactured into turbine blades. The comparison of all these methods is described as well as the evaluation of their advantages and disadvantages. Simulations of ultrasonic testing are also presented in this article.

scholarly journals Development of a new type of automatic magnetic particle inspection wall-climbing robot

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110473
Author(s):  
Jun Liu ◽  
Hanlin Yu ◽  
Linbo Mei ◽  
Bo Han
Keyword(s):  
Steam Turbine ◽  
Crack Detection ◽  
Magnetic Particle ◽  
Turbine Blades ◽  
Simulation Software ◽  
The Body ◽  
Working Environment ◽  
Climbing Robot ◽  
Magnetic Particle Inspection ◽  
Steam Turbine Blades

In the paper, a permanent magnet adsorption wall-climbing robot using magnetic particle detection technology for crack detection is introduced, which solves the problems of low efficiency of traditional manual detection and long detection time. According to the working environment of the detection system and the detection functions that need to be completed, the body structure of the robot is designed, the overall size of the robot is smaller than the distance between two steam turbine blades, so it can achieve the crack detection function of large steam turbine blades, and the stability and force analysis of the robot are carried out, and the adsorption conditions that meet the conditions of no sliding and overturning are obtained. In the paper, we use the magnetic circuit method to design a miniature excitation device for robotic applications and use the simulation software Ansoft-Maxwell to verify its feasibility. In the final experiment, it can be shown that the robot designed can achieve a series of functions such as magnetic particle inspection and image acquisition. There is a good prospect for the inspection of turbine blades.

Diagnostics and monitoring of the operating condition of steam-turbine blades

2007 ◽  
Vol 41 (5) ◽  
pp. 295-301
Author(s):  
A. I. Danilin ◽  
S. I. Adamov ◽  
A. Zh. Chernyavskii ◽  
M. I. Serpokrylov
Keyword(s):  
Steam Turbine ◽  
Turbine Blades ◽  
Operating Condition ◽  
Steam Turbine Blades

Studies on Determination of Natural Frequencies of Industrial Turbine Blades

1995 ◽  
Author(s):  
Mahesh M. Bhat ◽  
V. Ramamurti ◽  
C. Sujatha
Keyword(s):  
Steam Turbine ◽  
Dynamic Behavior ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Complex Structure ◽  
Turbine Blades ◽  
Blade Root ◽  
Steam Turbine Blade ◽  
Manufacturing Tolerances

Abstract Steam turbine blade is a very complex structure. It has geometric complexities like variation of twist, taper, width and thickness along its length. Most of the time these variations are not uniform. Apart from these geometric complexities, the blades are coupled by means of lacing wire, lacing rod or shroud. Blades are attached to a flexible disc which contributes to the dynamic behavior of the blade. Root fixity also plays an important role in this behavior. There is a considerable variation in the frequencies of blades of newly assembled turbine and frequencies after some hours of running. Again because of manufacturing tolerances there can be some variation in the blade to blade frequencies. Determination of natural frequencies of the blade is therefore a very critical job. Problems associated with typical industrial turbine bladed discs of a 235 MW steam turbine are highlighted in this paper.

Water-droplet erosion behavior of high-velocity oxygen-fuel-sprayed coatings for steam turbine blades

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dingjun Li ◽  
Peng Jiang ◽  
Fan Sun ◽  
Xiaohu Yuan ◽  
Jianpu Zhang ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Water Droplet ◽  
Erosion Resistance ◽  
Turbine Blades ◽  
Impingement Angle ◽  
Erosion Behavior ◽  
Water Droplet Erosion ◽  
Steam Turbine Blades ◽  
Oxygen Fuel ◽  
Sprayed Coatings

Abstract The water-droplet erosion of low-pressure steam turbine blades under wet steam environments can alter the vibration characteristics of the blade, and lead to its premature failure. Using high-velocity oxygen-fuel (HVOF) sprayed water-droplet erosion resistant coating is beneficial in preventing the erosion failure, while the erosion behavior of such coatings is still not revealed so far. Here, we examined the water-droplet erosion resistance of Cr3C2–25NiCr and WC–10Co–4Cr HVOF sprayed coatings using a pulsed water jet device with different impingement angles. Combined with microscopic characterization, indentation, and adhesion tests, we found that: (1) both of the coatings exhibited a similar three-stage erosion behavior, from the formation of discrete erosion surface cavities and continuous grooves to the broadening and deepening of the groove, (2) the erosion rate accelerates with the increasing impingement angle of the water jet; besides, the impingement angle had a nonlinear effect on the cumulative mass loss, and 30° sample exhibited the smallest mass loss per unit area (3) an improvement in the interfacial adhesion strength, fracture toughness, and hardness of the coating enhanced the water-droplet erosion resistance. These results provide guidance pertaining to the engineering application of water erosion protective coatings on steam turbine blades.

Titanium steam turbine blades

JOM ◽  
1989 ◽  
Vol 41 (3) ◽  
pp. 31-35
Author(s):  
R.R. Jaffee
Keyword(s):  
Steam Turbine ◽  
Turbine Blades ◽  
Steam Turbine Blades

Corrosive resistance of nitride coatings of steam turbine blades

2009 ◽  
Vol 56 (2) ◽  
pp. 91-96 ◽  
Author(s):  
V. I. Nikitin ◽  
A. M. Smyslov ◽  
A. S. Lisyanskii ◽  
M. K. Smyslova ◽  
O. N. Simin ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Turbine Blades ◽  
Nitride Coatings ◽  
Steam Turbine Blades ◽  
Corrosive Resistance

Brazed coatings for steam turbine blades: impact of the tape architecture and composition on mechanical properties

2020 ◽  
Vol 111 (11) ◽  
pp. 916-922
Author(s):  
K. Bobzin ◽  
W. Wietheger ◽  
J. Hebing ◽  
L. Gerdt ◽  
H. Krappitz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Steam Turbine ◽  
Volume Fraction ◽  
Steel Substrate ◽  
Turbine Blades ◽  
Surface Hardness ◽  
Three Point Bending ◽  
Wear And Corrosion ◽  
Steam Turbine Blades ◽  
Positive Effect

Abstract Ni-based brazing coatings with tungsten or chromium carbides are used for wear and corrosion protection in various applications. Steam turbine blades especially present a highly stressed application in which in particular the resistance to erosion and corrosion is essential. Therefore, novel tape architectures of brazed coatings have been developed and investigated within this study. In contrast to the use of powders, the application by means of tapes offers a high potential with regard to later use in industry due to the reproducible handling and automation. In this work, different coating systems were successfully deposited by means of vacuum brazing on X12CrNiMo-12 steel substrate. In order to achieve a sufficient fracture toughness of the coatings, pure nickel powder was added to the tapes. The influence of this additive on the mechanical properties was analyzed by means of three-point bending tests. A positive effect has been observed when adding a volume fraction of φ(Ni) = 25% of nickel, increasing the flexural strength up to σf = 580 MPa. Furthermore, the surface hardness of the coating has been analyzed depending on coating architecture and post-deposition treatment by grinding.

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