Effect of Creep Load on Oxidation Behavior of Main Steam Pipes

2015 ◽  
Author(s):  
Bo Yang ◽  
Yi-chang Huang ◽  
Xiao-ying Tang ◽  
Yu-hui Huang
Keyword(s):  
High Temperature ◽  
Growth Characteristic ◽  
P92 Steel ◽  
Applied Loading ◽  
Long Time ◽  
Temperature And Pressure ◽  
High Temperature Steam ◽  
Main Steam ◽  
Creep Loading ◽  
Steam Pipes

Main steam pipelines work in the environment of high temperature and pressure steam and withstand double damage between oxidation and creep load for a long time. Creep-oxidation interrupt tests were used in high temperature steam conditions at different stress load to get P92 steel mechanochemical behavior date in the present study. Weight gain method was used to get the oxidation kinetics under different applied loading. Scanning electron microscopy (SEM) micro observation techniques was applied to obtain growth characteristic in the interaction between steam oxidation and creep loading.

Corrosion of an Austenitic Heat-Resistant Steel HR3C in High-Temperature Steam and Supercritical Water

2014 ◽  
Vol 908 ◽  
pp. 67-71 ◽  
Author(s):  
Yan Hui Li ◽  
Shu Zhong Wang ◽  
Xue Dong Li ◽  
Jia Ming Lu
Keyword(s):  
High Temperature ◽  
Supercritical Water ◽  
Ph Value ◽  
Steel Matrix ◽  
X Ray Diffraction ◽  
Spinel Layer ◽  
Working Medium ◽  
Long Time ◽  
Corrosion Behaviors ◽  
High Temperature Steam

By Scanning Electronic Microscope (SEM), X-ray diffraction analyzer (XRD) and Cross hatch scanning analysis method, the corrosion behaviors of the HR3C steel in high temperature steam and supercritical water was investigated. The results indicates that within the scope of these tests, the corrosion rate of HR3C steel increases with an increase in temperature, which negatively correlates with the pH value of working medium, while the pressure has fewer effects on it. For specimens with the exposure time of 100h under various corrosion conditions, the oxide films almost cant be detected on all specimen surfaces, indicating the high corrosion resistance of HR3C steel. After long time oxidation corrosion in high temperature or supercritical water, the common oxide film of HR3C steel is always composed of four layers, from the oxide layer to the steel matrix, which are Fe3O4, pyknotic Cr2O3, partial oxidation layer with rich Cr element, and (Fe, Cr) 3O4 spinel layer in turn.

The Steam Pipe Network Mathematical Modeling and Flow Field Analysis of Zibo Power Plant

2014 ◽  
Vol 960-961 ◽  
pp. 1081-1085
Author(s):  
Dong Yang ◽  
Xiao Lu
Keyword(s):  
Power Plant ◽  
Velocity Vector ◽  
Field Analysis ◽  
Pipe Network ◽  
Before And After ◽  
Long Time ◽  
Flow Field Analysis ◽  
Steam Pipe ◽  
Main Steam ◽  
Steam Pipes

As Zibo power plant original steam pipes for a long time to run, the strength decreased and resistance was large, transformation was proposed to optimize. A mathematical model of the main steam pipe network was established to analysis changes of temperature, pressure and velocity vector before and after transformation. After transformation, the loss was significantly reduced,so transformation successfully achieve the optimization, adjustment and analysis functions of the main steam pipe network.

Microstructure Evolution of the as Tempered P92 Steel at High Temperature Exposure

2020 ◽  
Vol 998 ◽  
pp. 21-29
Author(s):  
Yang Xu ◽  
Tao Lei ◽  
Xi Sheng Yang ◽  
Che Chang ◽  
Lin Feng Qian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
High Temperatures ◽  
Microstructure Evolution ◽  
Thermal Exposure ◽  
Lath Boundary ◽  
P92 Steel ◽  
Subgrain Growth ◽  
Long Time ◽  
Dislocation Annihilation

The microstructure evolution during aging at high temperatures is usually used to thermodynamically simulate those cases of aging at low temperatures but for a very long time for P92 steel, because high temperature can accelerate the microstructure process. Therefore, in the present research, in order to comprehensively understand the microstructure evolution mechanisms during aging at especially high temperatures, the as-tempered P92 steel was exposed at 790 °C. Optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the microstructures. The dominant mechanisms at the four stages in microstructure evolution process during thermal exposure are (I) dislocation annihilation, (II) lath broadening and equiaxed subgrain nucleation, (III) equiaxed subgrain growth, (IV) recrystallization nucleation and growth. The martensitic lath broadening is dominated by both the motion of “Y”-type lath boundary and the combination of parallel lath boundary. The subgrain growth is by virtue of both the combination of the equiaxed subgrain and the bowing out of subgrain boundary.

Electron-Microprobe Study of Scale Formations on Cr-Mo Superheater Tubing After Long-Time Exposure to 2000 Psi Steam of 1100 F and 1200 F

1965 ◽  
Vol 87 (2) ◽  
pp. 205-209 ◽  
Author(s):  
F. Eberle ◽  
J. L. McCall
Keyword(s):  
High Temperature ◽  
Base Metal ◽  
Electron Microprobe ◽  
Scale Thickness ◽  
Metal Composition ◽  
Long Time ◽  
High Temperature Steam ◽  
Iron Manganese ◽  
Scale Composition ◽  
Tube Metal

Metallographically polished sections through the steam-scaled inside surface of 2-in-od × 0.50-in-wall superheater tubing used in ASME High Temperature Steam Research Tests were subjected to electron-microprobe analyses and the concentrations of iron, manganese, silicon, chromium, and molybdenum determined at intervals of 8 to 15 microns (0.3 to 0.6 mil) across the scale thicknesses and in the adjacent tube metal. The relationships between base-metal composition, scale composition, and scale thickness were examined as a function of temperature and time of exposure. The suitability and value of the electron-microprobe as a research tool for studying mechanisms of scaling behavior and scale formations are outlined.

Creep Characteristics and Micro-Defects of Main Steam Pipe Steel at High Temperature

2006 ◽  
Vol 326-328 ◽  
pp. 1129-1132
Author(s):  
C.S. Jeong ◽  
Bum Joon Kim ◽  
Byeong Soo Lim
Keyword(s):  
High Temperature ◽  
Void Nucleation ◽  
Early Stage ◽  
Pipe Material ◽  
P92 Steel ◽  
Micro Cracks ◽  
Creep Characteristics ◽  
Martensite Packet ◽  
Steam Pipe ◽  
Main Steam

The initiation and growth of micro-defects such as micro cracks and voids usually causes the failure of long term operated structural components at high temperature. In this study, the creep characteristics and void nucleation and growth characteristics of P92 steel which is used as main steam pipe material in power plant were investigated at several temperatures and loading conditions. The area fraction of void increased with increase of test temperature, stress, and load holding time. In case of internal defect presence, micro-voids initiated in the early stage of loading period and resulted in the increased load line displacement and crack growth rate. The microvoids were found to form along the prior austenite grain boundaries and at the martensite packet boundaries.

scholarly journals Health-Monitoring Methodology for High-Temperature Steam Pipes of Power Plants Using Real-Time Displacement Data

2021 ◽  
Vol 11 (5) ◽  
pp. 2256
Author(s):  
Woosung Choi ◽  
Jihoon Han
Keyword(s):  
High Temperature ◽  
Real Time ◽  
Health Monitoring ◽  
Surrogate Model ◽  
Power Plants ◽  
Creep Life ◽  
Operating Stress ◽  
High Temperature Steam ◽  
Steam Pipes ◽  
Design Stress

We developed a health-monitoring methodology for high-temperature steam pipes that estimated the life prediction of creep–fatigue interaction by directly measuring the displacement of hot parts. Three different methods (boiler code, design stress, and operating stress) were used to estimate the stress of the high-temperature pipe system. As a theoretical approach, the German boiler standard code calculates the stress according to the pipe shape, while design stress, which is also called allowable stress, was determined by a function of the operating temperature. The operating stress was immediately calculated using the surrogate model, with maximum displacement measured using the 3D displacement measurement system. To achieve the surrogate model, the stress was estimated by the pipe-stress analysis under the given displacements, and the surface-response model was developed to relate the stress and displacement. We showed that those methods are efficient methods to predict the stress and are applicable in health-monitoring methodology. Finally, the creep life and the low-cycle fatigue life were investigated using the Larson–Miller parameter equation, as well as the Smith, Hirschberg, and Manson equations. Our proposed monitoring system can be used to predict the fatigue and creep life of high-temperature steam pipes in real time, and we believe that the system can be applied to actual maintenance in thermal power plants.

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