Thermal Aging of Cast Stainless Steel, and Its Impact on Piping Integrity

1985 ◽  
Vol 107 (1) ◽  
pp. 53-60 ◽  
Author(s):  
W. H. Bamford ◽  
E. I. Landerman ◽  
E. Diaz
Keyword(s):  
Stainless Steel ◽  
Failure Mode ◽  
Thermal Aging ◽  
Charpy Impact ◽  
J Integral ◽  
Duplex Structure ◽  
Test Program ◽  
Series Of Experiments ◽  
The Impact ◽  
Cast Stainless Steel

A series of experiments were conducted to characterize the effects of high temperature service (550–650°F or 288–343°C) on the mechanical properties of cast stainless steels. The material studied was Type 316 CF8M stainless steel, which has a duplex structure consisting of ferrite and austenite. Recent studies have shown that thermal aging can result in substantial changes in the Charpy impact energy of this material, and this study was designed to further investigate this finding, and to determine what the impact of this phenomenon might be on the failure mode of piping made of it. To do this one heat of material was furnace aged and tested to determine tensile, Charpy and J-integral R curve properties. To investigate the failure mode of thermally aged piping, entire sections of this heat of four inch (10.2 cm) schedule 80 cast piping were aged and tested to failure after the introduction of large flaws. The results of the test program showed excellent agreement with analytical predictions.

scholarly journals The Microstructure and Mechanical and Corrosion Behaviors of Thermally Aged Z3CN20-09M Cast Stainless Steel for Primary Coolant Pipes of Nuclear Power Plants

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 870
Author(s):  
Fei Xue ◽  
Fangjie Shi ◽  
Chuangju Zhang ◽  
Qiaoling Zheng ◽  
Dawei Yi ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Aging Time ◽  
Thermal Aging ◽  
Great Influence ◽  
Fracture Mechanisms ◽  
Rich Phase ◽  
Corrosion Behaviors ◽  
The Impact ◽  
Cast Stainless Steel

The effects of thermal aging time at 400 °C on the microstructure and mechanical and corrosion behaviors of Z3CN20.09M cast stainless steel were investigated; and the corresponding thermal aging mechanism was studied. It was revealed that the changes in mechanical properties after thermal aging were mainly caused by the iron-rich phase (α) and the chromium-rich phase (α’) produced by the amplitude-modulation decomposition of ferrite. A similar trend of thermoelectric potential during thermal aging was determined in relation to the Charpy impact energy. However, the corrosion resistance of Z3CN20.09M cast stainless steel deteriorates as thermal aging time increases. When the thermal aging is longer than 3000 h, the precipitation of G phase has a great influence on the corrosion resistance. The interfacial matching relationship between G phase and the surrounding ferrite was established by selected area electron diffraction of HRTEM. The relationship is of cube-on-cube phase boundary type. The impact fracture mechanisms in relation to thermal aging time were also studied and compared.

Investigation on Impact Energy of S30403 Austenitic Stainless Steel at Different Temperatures

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Zhiwei Chen ◽  
Caifu Qian ◽  
Guoyi Yang ◽  
Xiang Li
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cross Section ◽  
Test Temperature ◽  
Impact Energy ◽  
Welded Joint ◽  
Charpy Impact ◽  
Base Plate ◽  
Charpy Impact Energy ◽  
The Impact

In this paper, a series of impact tests on S30403 austenitic stainless steel at 20/−196/−269 °C were performed to determine the effects of cryogenic temperatures on the material properties. Both base plate and welded joint including weld and heat-affected zone were tested to obtain the Charpy impact energy KV2 and lateral expansion rate at the cross section. It was found that when the test temperature decreased from 20 °C to −196 °C or −269 °C, both the Charpy impact energy KV2 at the base plate and welded joint decreased drastically. Specifically, the impact energy KV2 decreased by 20% at the base plate and decreased by 54% at the welded joint from 20 °C to −196 °C, but the impact energy of base plate and welded joint did not decrease, even increased when test temperature decreased from −196 °C to −269 °C. Either at 20 °C or −196 °C, the impact energy KV2 with 5 × 10 × 55 mm3 specimens was about 0.53 times that of the 7.5 × 10 × 55 mm3 specimens, much lower than 2/3, the ratio of two specimens’ cross section areas.

Fracture Toughness of Z3CN20.09M Cast Stainless Steel with Long-Term Thermal Aging

2017 ◽  
Vol 26 (9) ◽  
pp. 4442-4449 ◽  
Author(s):  
Weiwei Yu ◽  
Dunji Yu ◽  
Hongbo Gao ◽  
Fei Xue ◽  
Xu Chen
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Thermal Aging ◽  
Cast Stainless Steel

Effects of thermal aging on the fracture toughness of cast stainless steel CF8

2019 ◽  
Vol 173 ◽  
pp. 45-54 ◽  
Author(s):  
David A. Collins ◽  
Emily L. Barkley ◽  
Timothy G. Lach ◽  
Thak Sang Byun
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Thermal Aging ◽  
Cast Stainless Steel

scholarly journals Non-hardening embrittlement mechanism of pressure vessel steel Ni-Cr-Mo-V welds during thermal aging

2020 ◽  
Vol 12 (2) ◽  
pp. 168781402090456
Author(s):  
Guojun Wei ◽  
Chenglong Wang ◽  
Xingwang Yang ◽  
Zhenfeng Tong ◽  
Wenwang Wu
Keyword(s):  
Weld Metal ◽  
Thermal Aging ◽  
Pressure Vessel ◽  
Impact Test ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Reactor Pressure Vessel ◽  
Impact Fracture ◽  
The Impact ◽  
Reactor Pressure

The mechanical performance of reactor pressure vessel materials is an important factor in the safety and economics of the operation of a nuclear power plant. The ductile-to-brittle transition temperature tested by Charpy impact test is the key parameter for evaluating the reactor pressure vessel embrittlement. In this article, the study of thermal aging embrittlement of temperature sets of reactor pressure vessel surveillance Ni-Cr-Mo-V steel weld metal was conducted by Charpy impact test. The thermal aging effect on the impact fracture behavior was analyzed. The impact test of the three batches of weld surveillance sample indicated that the weld metal embrittled during thermal aging. The study of impact fracture and Auger electron spectroscopy indicated that the element P segregated to the grain boundaries and lowered their cohesion strength during the long-term thermal aging. Therefore, the non-hardening embrittlement of Ni-Cr-Mo-V steel welds in a reactor pressure vessel caused by segregation of impurity elements P occurs during thermal aging.

The Charpy Impact Behavior of Fe3Al and Fe3Al-20 at % Mn Alloys

1996 ◽  
Vol 460 ◽  
Author(s):  
J. N. Liu ◽  
W. Yan ◽  
J. L. Ma ◽  
K. H. Wu
Keyword(s):  
Impact Energy ◽  
Charpy Impact ◽  
Testing Temperature ◽  
Impact Behavior ◽  
Al Alloy ◽  
Impact Fracture Behavior ◽  
Series Of Experiments ◽  
Growth Energy ◽  
The Impact ◽  
Total Impact

ABSTRACTA series of experiments were conducted to investigate the impact fracture behavior of Fe3Al and Fe3Al-20 Mn alloys. The results of this study indicated that: (i) The addition of Mn introduces an ordered Ll2-type phase in the Fe3Al-based alloys. On the other hand, the addition of Mn decreases the order parameter of the DO3 a phase, (ii) The total- impact energy of an Fe3Al alloy increases with the temperature at the low-temperature range (<600°C), then drops around 700°C, and finally increases again as the temperature further elevates, (iii) The trend of the variation of the impact energy of Fe3Al-20 at % Mn alloy with temperature is the same as that of the Fe3Al alloy, (iv) And the addition of Mn significantly improves the impact energy of the Fe3Al-based alloy, and changes the variation of the crack-growth energy with the testing temperature when the temperature is above 700°C.

Methodology for Estimating Thermal and Neutron Embrittlement of Austenitic Stainless Steel Welds During Service in Light Water Reactors

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
O. K. Chopra ◽  
A. S. Rao
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Lower Bound ◽  
Thermal Aging ◽  
Welding Process ◽  
Charpy Impact ◽  
Inert Gas ◽  
Gas Tungsten Arc ◽  
Water Reactors

The effect of thermal aging on the degradation of fracture toughness and Charpy-impact properties of austenitic stainless steel (SS) welds has been characterized at reactor temperatures. The solidification behavior and the distribution and morphology of the ferrite phase in SS welds are described. Thermal aging of the welds results in moderate decreases in Charpy-impact strength and fracture toughness. The upper-shelf Charpy-impact energy of aged welds decreases by 50–80 J/cm2. The decrease in fracture-toughness J integral-resistance (J-R) curve or JIc is relatively small. Thermal aging has minimal effect and the welding process has a significant effect on the tensile strength. However, the existing data are inadequate to accurately establish the effect of the welding process on fracture properties of SS welds. Consequently, the approach used for evaluating thermal and neutron embrittlement of austenitic SS welds relies on establishing a lower-bound fracture-toughness J-R curve for unaged and aged and nonirradiated and irradiated SS welds. The existing fracture-toughness J-R curve data for SS welds have been reviewed and evaluated to define lower-bound J-R curves for submerged arc (SA)/shielded metal arc (SMA)/manual metal arc (MMA) welds and gas tungsten arc (GTA)/metal inert gas (MIG)/tungsten inert gas (TIG) welds in the unaged and aged conditions. At reactor temperatures, the fracture toughness of GTA/MIG/TIG welds is a factor of about 2.3 higher than that of SA/SMA/MMA welds. Thermal aging decreases the fracture toughness of all welds by about 20%. The potential combined effects of thermal and neutron embrittlement of austenitic SS welds are also described. Lower-bound curves are presented, which define the change in coefficient C and exponent n of the power-law J-R curve and the JIc value for SS welds as a function of neutron dose. The potential effects of reactor coolant environment on the fracture toughness of austenitic SS welds are also discussed.

Effects of thermal aging on the low cycle fatigue behavior of austenitic–ferritic duplex cast stainless steel

2001 ◽  
Vol 206 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Jae-do Kwon ◽  
Seung-wan Woo ◽  
Yong-son Lee ◽  
Joong-cheul Park ◽  
Youn-won Park
Keyword(s):  
Stainless Steel ◽  
Thermal Aging ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cycle Fatigue ◽  
Cast Stainless Steel

scholarly journals Charpy Impact Properties of Hydrogen-Exposed 316L Stainless Steel at Ambient and Cryogenic Temperatures

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 625 ◽  
Author(s):  
Le Thanh Hung Nguyen ◽  
Jae-Sik Hwang ◽  
Myung-Sung Kim ◽  
Jeong-Hyeon Kim ◽  
Seul-Kee Kim ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Low Temperatures ◽  
316L Stainless Steel ◽  
Charpy Impact ◽  
Cryogenic Temperatures ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Charging Time ◽  
The Impact

316L stainless steel is a promising material candidate for a hydrogen containment system. However, when in contact with hydrogen, the material could be degraded by hydrogen embrittlement (HE). Moreover, the mechanism and the effect of HE on 316L stainless steel have not been clearly studied. This study investigated the effect of hydrogen exposure on the impact toughness of 316L stainless steel to understand the relation between hydrogen charging time and fracture toughness at ambient and cryogenic temperatures. In this study, 316L stainless steel specimens were exposed to hydrogen in different durations. Charpy V-notch (CVN) impact tests were conducted at ambient and low temperatures to study the effect of HE on the impact properties and fracture toughness of 316L stainless steel under the tested temperatures. Hydrogen analysis and scanning electron microscopy (SEM) were conducted to find the effect of charging time on the hydrogen concentration and surface morphology, respectively. The result indicated that exposure to hydrogen decreased the absorbed energy and ductility of 316L stainless steel at all tested temperatures but not much difference was found among the pre-charging times. Another academic insight is that low temperatures diminished the absorbed energy by lowering the ductility of 316L stainless steel.

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