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

Ferritic heat-resistant steel comprises basic alloys of Fe-10mass%Cr-W. This study investigates how stress, the addition of Co, and tempering before aging affect the precipitation of the Laves phase of Fe-10Cr-6W ferritic heat-resistant steel, which is used in ultra-supercritical power plants and nuclear reactor materials. The study also investigates the mechanical properties of the steel. Precipitation of the Laves phase by aging increases the tensile strength, but decreases the elongation and impact strength of the alloys. Toughness of the alloys decreases greatly as very fine disk-like Laves phases appear in early aging stage. The strength and impact value of the steel decrease when the steel is tempered before aging. This is mainly due to decrease of density and increase of the particle size in the Laves phase. Since precipitation of the Laves phase increases by addition of Co; the strength increases and the elongation and impact value decrease.

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A Modified HR3C Austenitic Heat-Resistant Steel for Ultra-supercritical Power Plants Applications Beyond 650 °C

Metallurgical and Materials Transactions A ◽

10.1007/s11661-017-4424-z ◽

2017 ◽

Vol 49 (2) ◽

pp. 434-438 ◽

Cited By ~ 11

Author(s):

C. Z. Zhu ◽

Y. Yuan ◽

P. Zhang ◽

Z. Yang ◽

Y. L. Zhou ◽

...

Keyword(s):

Power Plants ◽

Resistant Steel ◽

Heat Resistant Steel ◽

Heat Resistant

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

Modern Physics Letters B ◽

10.1142/s0217984919400347 ◽

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].

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An Investigation on Precipitation Behaviour of Cu-Rich Phase in Super304H Heat-Resistant Steel by Three Dimensional Atom Probe

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.110 ◽

2010 ◽

Vol 654-656 ◽

pp. 110-113

Author(s):

Cheng Yu Chi ◽

Jian Xin Dong ◽

Wen Qing Liu ◽

Xi Shan Xie

Keyword(s):

Aging Time ◽

Power Plants ◽

Three Dimensional ◽

Atom Probe ◽

Strengthening Effect ◽

Resistant Steel ◽

Heat Resistant Steel ◽

Rich Phase ◽

Heat Resistant ◽

Precipitation Behaviour

Super304H, a Cu-containing 18Cr-9Ni-3CuNbN heat-resisting steel is wildly used as an superheater/reheater tube material for ultra-super-critical (USC) power plants all over the world. It is recognized that the Cu-rich phase is an important strengthening phase for Super304H. However, the detail precipitation behaviour and its strengthening effect are still not very clear. Investigated material was taken from routine production and was aged at 650°C for different times. The precipitation of Cu-rich phase in Super304H was studied by three dimensional atom probe (3DAP) and TEM. Experimental results show that Cu-rich clusters have been formed at very early stage of 650°C aging. The Cu-rich particle images have been clearly caught just after 650°C aging for 5h. The Cu atoms gradually concentrate to Cu-rich particles and the other elements (such as Cr, Ni etc) diffuse away from Cu-rich particles to γ-matrix with the increasing of aging time. The Cu-rich particle size and its density have been determined as a function of aging time. Cu-rich particles still keep nano-size and distribute homogenously in grains even after long time (1,000h) aging, which is one of the most important reasons for keeping good strength of Super304H heat-resistant steel at high temperatures.

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Strengthening mechanisms and creep rupture behavior of advanced austenitic heat resistant steel SA-213 S31035 for A-USC power plants

Materials Science and Engineering A ◽

10.1016/j.msea.2020.138991 ◽

2020 ◽

Vol 775 ◽

pp. 138991 ◽

Cited By ~ 1

Author(s):

You Li ◽

Xue Wang

Keyword(s):

Power Plants ◽

Creep Rupture ◽

Resistant Steel ◽

Strengthening Mechanisms ◽

Heat Resistant Steel ◽

Heat Resistant ◽

Rupture Behavior

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650°C Long-Term Structure Stability Study on 18Cr10NiNb Heat-Resistant Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.180 ◽

2011 ◽

Vol 399-401 ◽

pp. 180-184 ◽

Cited By ~ 2

Author(s):

Hong Yao Yu ◽

Cheng Yu Chi ◽

Jian Xin Dong ◽

Xi Shan Xie

Keyword(s):

Aging Time ◽

Power Plants ◽

Stability Study ◽

Structure Stability ◽

Temperature Structure ◽

Strengthening Effect ◽

Resistant Steel ◽

Heat Resistant Steel ◽

Heat Resistant

The Nb-contained austenitic heat-resistant steel 18Cr10NiNb(TP347H) has been widely used as super-heater and re-heater tube material for modern ultra-super-critical (USC) power plants in the world. High temperature structure stability is considered to be one of the most important factors for long-term service. Long-term aging at 650 °C for this steel was conducted till 10,000 hours. Effect of aging time on microstructure was studied by means of SEM and TEM. Tensile tests were carried out after aging at 650 °C for different times. Experimental results show that MX phase and M23C6 carbides are major strengthening precipitates in this steel. With increasing of aging time, fine nano-size MX particles precipitate in grains and its size keeps about 50 nm till 10,000 h at 650 °C. Carbide M23C6 mainly precipitates at grain boundaries but coarsens quickly. Investigation results show that MX phase plays the most important strengthening effect in grains. The amount of MX phase increases with increasing of Nb and C contents. The effects of Nb and C contents on mole fractions of MX phase in 18Cr10NiNb steel have been calculated by using Thermo-Calc software.

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