Interactive Mechanisms of Sulfide Inclusions and Environmental Factors in Low Cycle Fatigue Process of Pressure Vessel Steels in High Temperature Water

2005 ◽  
Vol 475-479 ◽  
pp. 253-256
Author(s):  
Xin Qiang Wu
Keyword(s):  
High Temperature ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
Fatigue Cracking ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
High Temperature Water ◽  
Pressure Vessel Steels ◽  
Temperature Water

Low cycle fatigue tests were conducted in high temperature water for A533B pressure vessel steels with sulfur contents of 0.013, 0.025 and 0.038 wt.% respectively. Cyclic stress amplitude response and fatigue resistance as well as influence of strain rate, temperature and dissolved oxygen concentration in water were investigated. Fatigue cracking/fractograhpic features were examined. Sulfide-related environmentally assisted cracking mechanism is discussed.

Effect of Strain Rate on Low Cycle Fatigue Behavior of Thermally Aged A533B Pressure Vessel Steels in High Temperature Water

2003 ◽  
Author(s):  
Xinqiang Wu ◽  
Yasuyuki Katada
Keyword(s):  
Strain Rate ◽  
Pressure Vessel ◽  
Environmental Effect ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Aging Treatment ◽  
Cycle Fatigue ◽  
High Temperature Water ◽  
Pressure Vessel Steels ◽  
Temperature Water

Safe and reliable management of light water reactors demand a full understanding on their component materials properties throughout their service lives. In present work the effects of strain rate on low cycle fatigue behavior of ASTM A533B pressure vessel steels after long-term thermal aging at 673 K in air have been investigated in simulated BWR environments. It was found that the aging treatment led to a certain decrease in fatigue life. Environmental effect on the fatigue life of aged materials closely depended on strain rate. More strongly environmental effect appeared at low strain rate. The aging treatment enhanced the stain-rate dependence of the fatigue resistance of A533B steels. Comparison between ASME design fatigue curves and present results as well as some literatures’ data suggested that safety margins of the standard design curves tended to decrease with decrease in strain rate. Based on the above results, possible corrosion fatigue mechanisms of pressure vessel steels in high temperature water were discussed by taking into account the effects of inclusions, hydrogen embrittlement, dynamic strain aging and aging-induced material degradation as well as their combined actions.

Corrosion Fatigue Behavior of Low-Alloy Pressure Vessel Steels in High Temperature Water Under Multi-Factor Conditions

2004 ◽  
Vol 126 (4) ◽  
pp. 466-472 ◽  
Author(s):  
Xinqiang Wu ◽  
Yasuyuki Katada
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Sulfur Content ◽  
Fatigue Resistance ◽  
Corrosion Fatigue ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
High Temperature Water ◽  
Pressure Vessel Steels ◽  
Temperature Water

The corrosion fatigue resistance of pressure vessel steels in simulated light water reactor coolant water is greatly influenced by the mechanical factor such as strain rate, environmental factor such as temperature and dissolved oxygen (DO) concentration in water, and material factor such as sulfur content in steels. In most of previous work, the mechanical or environmental conditions were usually fixed as a constant throughout an individual test. However, these factors may change frequently during actual operations in power plants. So, it is of great interest to investigate the effects of change of the above factors on fatigue resistance of components materials in service environments and to develop appropriate methods for evaluating the environmental effects on fatigue damage. The present work was to investigate the low cycle fatigue (LCF) behavior of low-alloy pressure vessel steels in high temperature water. Special attention was paid on the influence of strain rate change in an individual LCF test on fatigue resistance of the steels. The alternate sequence of strain rate in a test was also considered. Moreover, the influence of DO, temperature and sulfur content in the steels was investigated. The detailed cracking and fractographic features were examined to assist the understanding of underlying corrosion fatigue mechanisms.

Corrosion Fatigue Behavior of Low-Alloy Pressure Vessel Steels in High Temperature Water Under Multi-Factor Conditions

2004 ◽  
Author(s):  
Xinqiang Wu ◽  
Yasuyuki Katada
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Sulfur Content ◽  
Fatigue Resistance ◽  
Corrosion Fatigue ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
High Temperature Water ◽  
Pressure Vessel Steels ◽  
Temperature Water

The corrosion fatigue resistance of pressure vessel steels in simulated light water reactor coolant water is greatly influenced by the mechanical factor such as strain rate, environmental factor such as temperature and dissolved oxygen (DO) concentration in water, and material factor such as sulfur content in steels. In most of previous work, the mechanical or environmental conditions were usually fixed as a constant throughout an individual test. However, these factors may change frequently during actual operations in power plants. So, it is of great interest to investigate the effects of change of the above factors on fatigue resistance of components materials in service environments and to develop appropriate methods for evaluating the environmental effects on fatigue damage. The present work was to investigate the low cycle fatigue (LCF) behavior of low-alloy pressure vessel steels in high temperature water. Special attention was paid on the influence of strain rate change in an individual LCF test on fatigue resistance of the steels. The alternate sequence of strain rate in a test was also considered. Moreover, the influence of DO, temperature and sulfur content in the steels was investigated. The detailed cracking and fractographic features were examined to assist the understanding of underlying corrosion fatigue mechanisms.

Comparative Study of Microstructure and High Temperature Low Cycle Fatigue Behaviour of Nickel Base Superalloys Inconel 713LC and MAR-M247

2016 ◽  
Vol 713 ◽  
pp. 86-89 ◽  
Author(s):  
Ivo Šulák ◽  
Karel Obrtlík ◽  
Ladislav Čelko
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Casting Defects ◽  
Cycle Fatigue ◽  
Stress Strain Curve ◽  
Nickel Base

The present work is focused on the study of microstructure and low cycle fatigue behavior of the first generation nickel-base superalloy IN 713LC (low carbon) and its promising second generation successor MAR-M247 HIP (hot isostatic pressing) at 900 °C. Microstructure of both alloys was studied by means of scanning electron microscopy (SEM). The microstructure of both materials is characterized by dendritic grains, carbides and casting defects. Size and morphology of precipitates and casting defects were evaluated. Fractographic observations have been made with the aim to reveal the fatigue crack initiation place and relation to the casting defects and material microstructure. Low cycle fatigue tests were conducted on cylindrical specimens in symmetrical push-pull cycle under strain control with constant total strain amplitude and strain rate at 900 °C in air. Hardening/softening curves, cyclic stress-strain curve and fatigue life data of both materials were obtained. Cyclic stress-strain curve of MAR M247 is shifted approximately to 120 MPa higher stress amplitudes in comparison with IN 713LC. Significantly higher fatigue life of MAR-M247 has been observed in Basquin representation. On the other hand IN 713LC shows prolonged lifetime compared with MAR-M247 in the Coffin-Manson representation. Results obtained from high temperature low cycle fatigue tests are discussed.

Sign in / Sign up

Export Citation Format

Share Document