A study on low-cycle fatigue of high chromium heat-resistant steel

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940034
Author(s):  
Il Heon Jeong ◽  
Yeong Min Park ◽  
Mun Ki Bae ◽  
Chi Hwan Kim ◽  
Tae Gyu Kim
Keyword(s):  
Plastic Deformation ◽  
High Temperature ◽  
Nuclear Power ◽  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Resistant Steel ◽  
Cycle Fatigue ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Treatment Conditions

The purpose of this study is to examine the low-cycle fatigue (LCF) characteristics of high-chrome heat-resistant steel, which is used in a high-temperature environment, at both ambient and high temperature. High-chrome heat-resistant steel, which is used for the turbine blades of a nuclear power plant, can be subject to plastic deformation due to overloading conditions at startup and shutdown. It is therefore very important to evaluate the damage caused by LCF, which is considered as fatigue damage due to plastic deformation. To examine the mechanical properties of high-chrome heat-resistant steel, the tensile strength was tested under different heat treatment conditions. In addition, the LCF characteristics were tested at ambient temperature and [Formula: see text].

scholarly journals Low cycle fatigue behavior and microstructure evolution of a novel Fe-22Cr-15Ni austenitic heat-resistant steel

2020 ◽  
Vol 9 (6) ◽  
pp. 14388-14400
Author(s):  
Lianyong Xu ◽  
Shangqing Yang ◽  
Lei Zhao ◽  
Yongdian Han ◽  
Hongyang Jing ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Resistant Steel ◽  
Cycle Fatigue ◽  
Heat Resistant Steel ◽  
Heat Resistant

High Temperature Fatigue Behavior of 23Cr26Ni Heat Resistant Steel

2010 ◽  
Vol 452-453 ◽  
pp. 433-436
Author(s):  
Hee Woong Lee ◽  
S.I. Kwun ◽  
Woo Sang Jung
Keyword(s):  
High Temperature ◽  
Dislocation Density ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Solution Treatment ◽  
Cyclic Hardening ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
High Temperature Fatigue ◽  
Heat Resistant

The influence of the cooling condition after solution treatment on the high temperature fatigue resistance of 23Cr-26Ni heat resistant steel was investigated. Two different cooling conditions were applied to the steel after solution treatment at 1230oC for 3 hours. One specimen was water quenched immediately after the solution treatment. The other one was furnace cooled at a rate of 0.5oC/min down to 750oC after the solution treatment. Then, both specimens were aged at 750oC for 5 hours. The low cycle fatigue (LCF) test was conducted to investigate the influence of high temperature on the LCF behaviors of the heat-resistant 23Cr26Ni alloy. Under two different heat treatment conditions, the LCF test was performed at total strain amplitudes ranging from ±0.4~0.9% at room temperature (RT) and 600°C. During the test, initial cyclic hardening occurred at both experimental temperatures. This phenomenon was attributed to the increase in the dislocation density due to cyclic deformation, which resulted in the interaction between the newly created dislocations and precipitates. Cyclic softening was observed in the later stages of the LCF test at RT. The formation of precipitates and increase in the dislocation density were observed using TEM. Also, the XRD and EDS techniques were used to verify the type and composition of the precipitates.

High-Temperature Ultrasonic Fatigue Testing at 1000°C

2014 ◽  
Vol 891-892 ◽  
pp. 1413-1418
Author(s):  
Yoshiyuki Furuya ◽  
Kazuo Kobayashi ◽  
Masao Hayakawa ◽  
Masao Sakamoto ◽  
Yutaka Koizumi ◽  
...  
Keyword(s):  
High Temperature ◽  
Fatigue Testing ◽  
Turbine Blades ◽  
Testing Machine ◽  
Fatigue Tests ◽  
Testing System ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Heat Resistant ◽  
Ultrasonic Fatigue

A high-temperature ultrasonic fatigue testing system was developed to evaluate the gigacycle fatigue properties of single-crystal superalloys used in aircraft engine turbine blades. In this development, a commercial ultrasonic fatigue testing machine was considerably modified to achieve high-temperature fatigue testing. The developed system took account of temperature dependency of Youngs modulus, and also had a function to evaluate the Youngs modulus. In order to protect the testing system from the heat of a specimen, straight and round rods were inserted between the testing system and the specimen. Other modifications achieved accurate control of temperature, edge displacement and resonance frequency, which were necessary for accurate control of stress amplitude. The testing system was first applied to a heat-resistant steel at 650 °C to check its accuracy, and next to SC superalloy samples at 1000 °C. In the conventional fatigue tests on the heat-resistant steel, the results were coincident in a frequency range from 1 Hz to 800 Hz, suggesting that comparable results would be obtained in ultrasonic fatigue testing at 20 kHz. In case of the SC superalloy samples, conventional fatigue tests were conducted at only 10 Hz, so the frequency effects were not clarified. In both cases, ultrasonic fatigue testing showed good agreement with conventional fatigue testing. The accuracy of the developed system is therefore high, even at 1000 °C. In these results, the SC superalloys showed no fatigue limit, indicating gigacycle fatigue tests to be necessary.

A Research on Laser Cladding Co-Based Alloy to Repair Heat Resistant Steel of the Valves Used in Ultra-Super Critical Nuclear Power Plants

2021 ◽  
Vol 58 (5) ◽  
pp. 0514007-514007220
Author(s):  
刘福广 Liu Fuguang ◽  
李勇 Li Yong ◽  
杨二娟 Yang Erjuan ◽  
米紫昊 Mi Zihao ◽  
王博 Wang Bo ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Heat Resistant

Study on the High Temperature Creep Behavior of 30Cr25Ni20 Heat-Resistant Steel

2019 ◽  
Vol 814 ◽  
pp. 157-162
Author(s):  
You Yang ◽  
Xiao Dong Wang ◽  
Wei Feng Tang
Keyword(s):  
High Temperature ◽  
Internal Structure ◽  
Creep Strain ◽  
High Temperature Creep ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Creep Fracture ◽  
Heat Resistant ◽  
Temperature Creep ◽  
Before And After

The high temperature creep test of heat-resisting steel 30Cr25Ni20 for automobile exhaust manifolds was carried out, and the creep strain-time curves at 650°C and 700°C in the different loads were obtained. The effects of different creep temperature and stress on creep life of materials were studied. The microstructure of the fracture after creep was observed by scanning electron microscopy. Microstructures before and after creep at different temperatures were compared by optical microscopy. The results show that the creep fracture life of heat-resistant steel decreases with the increase of stress at the same temperature. The creep fracture life decreases with the increase of temperature at the same stress, too. The fracture of heat-resistant steel shows good high temperature plasticity and a ductile fracture after creep. The fracture dimples become deeper with the increase of stress. At 650°Cand 700°C, the stress exponent is 8.6 and 6, respectively. When the sample was subjected to high temperature creep at 700°C, the precipitates increase obviously and the reticular structure became very large. At this point, the internal structure of the material is destroyed, and the matrix structure becomes unevenly distributed. The failure of the internal structure leads to the dramatic increase of the creep strain, and the failure of the internal structure will be more serious with the deformation of the sample.

High-Temperature Oxidation Behaviors of 30Cr25Ni20Si Heat-Resistant Steel in Air

2020 ◽  
Vol 861 ◽  
pp. 83-88
Author(s):  
You Yang ◽  
Xiao Dong Wang
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
High Temperature Oxidation ◽  
Film Growth ◽  
Surface Oxidation ◽  
Mass Gain ◽  
Resistant Steel ◽  
Temperature Oxidation ◽  
Heat Resistant Steel ◽  
Heat Resistant

High temperature oxidation dynamic behaviors and mechanisms for 30Cr25Ni20Si heat-resistant steel were investigated at 800, 900 and 1000°C. The oxide layers were characterized by scanning electron microscopy (SEM-EDS), X-ray diffractometer (XRD). The results showed that the oxidation rate of test alloys is increased with increasing the oxidation time. The oxidation dynamic curves at 800 and 900°C follow from liner to parabolic oxidation law. The transition point is 10 h. At 1000°C, the steel exhibits a catastrophic oxidation, and the oxidation mass gain value at 50 h is 0.77 mg/cm2. This suggests that the steel at 900°C has formed a dense protective surface oxidation film, effectively preventing the diffusion of the oxygen atoms and other corrosive gas into the alloy. Therefore, at the first stage of oxidation, chemical adsorption and reaction determine the oxide film composition and formation process. At the oxide film growth stage, oxidation is controlled by migration of ions or electrons across the oxide film. When the spinel scale forms, it acts as a compact barrier for O element and improving the oxidation resistance.

scholarly journals Properties of High Temperature Oxidation of Heat-resistant Steel with Aluminium and Copper

2019 ◽  
Vol 25 (4) ◽  
pp. 394-400
Author(s):  
Hong LI ◽  
Chengzhi ZHAO ◽  
Tao YAN ◽  
Chao DING ◽  
Hexin ZHANG ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Oxide Films ◽  
Main Element ◽  
Resistant Steel ◽  
Temperature Oxidation ◽  
Heat Resistant Steel ◽  
X Ray ◽  
Heat Resistant ◽  
Test Steel

The research is focused on a novel aluminum and copper-containing heat-resistant steel. The steel was designed by the material performance simulation software JmatPro, performed high-temperature oxidation tests at 650 °C and 700 °C atmospheric conditions, and analyzed the high-temperature oxidation processes and its mechanisms.The phase transtions and surface morphology of the oxide films were studied using X-ray diffraction (XRD), electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the equilibrium phase of the test steel is composed of γ phase and δ phase at 1050 °C and tranforms to tempered martensite and δ-Fe mixed structure after heat treatment. The preferential oxidation of Fe and Cr and the internal oxidation of Al occurred during the high temperature oxidation of the test steel. The oxide films were formed with various shape and weak bonding properties after high-temperature oxidation at 650℃. To the contrary, the oxide films more regular and evenly distributed, and has a certain protective effect after high-temperature oxidation at 700 ℃. The oxide films were divided into two layers, Fe2O3 is main element in the outer layer, the inner layer is mainly consisting the oxide of Cr. However, the addition of Cu element can promote the diffusion of Al and Si elements, which is beneficial to the formation of Al2O3 and SiO2 protective oxide films and excellent in high temperature oxidation resistance.

Sign in / Sign up

Export Citation Format

Share Document