Evaluation of the Fracture Characteristics with Thermal Aging on Dissimilar Welds in Reactor Coolant System

2005 ◽  
Vol 297-300 ◽  
pp. 1691-1697
Author(s):  
Jae Do Kwon ◽  
Seung Wan Woo ◽  
Young Hwan Choi
Keyword(s):  
Thermal Aging ◽  
Cooling System ◽  
Weld Zone ◽  
Accelerated Aging ◽  
Mechanical Tests ◽  
Fracture Characteristics ◽  
Dissimilar Weld ◽  
Dissimilar Welds ◽  
Reactor Operating ◽  
Cast Stainless Steel

A dissimilar weld zone exists between the pipe and nozzle in a primary reactor cooling system (RCS). Thermal aging is observed in cast stainless steel, CF8M used in a pipe as the RCS is exposed for a long period of time to a reactor operating temperature between 290 and 330°C. No effect is observed in low-alloy steel. SA508 cl.3 is used in a nozzle. The artificially accelerated aging specimens are prepared to maintain for a temperature of 430°C for 300, 1800, and 3600hrs, respectively. Then, various mechanical tests such as hardness, tension, impact test, are performed in virgin and aged specimens in order to determine the existence of dissimilar weld zones. The specimens for elastic-plastic fracture toughness tests are prepared for one type, where a notch is created in the heat affected zone of CF8M. From the experiments, it was found that J-integral values decrease as age increases.

The Study on Effects of Thermal Aging of Dissimilar Weld Zone in a Primary Reactor Cooling System

2004 ◽  
Vol 261-263 ◽  
pp. 1689-0 ◽  
Author(s):  
Jae Do Kwon ◽  
Seung Wan Woo ◽  
Y.H. Choi
Keyword(s):  
Thermal Aging ◽  
Cooling System ◽  
Operating Temperature ◽  
Weld Zone ◽  
Accelerated Aging ◽  
Mechanical Tests ◽  
Dissimilar Weld ◽  
Long Period ◽  
Reactor Operating ◽  
Cast Stainless Steel

In a primary reactor cooling system(RCS), a dissimilar weld zone exists between austenitic-ferritic duplex cast stainless steel(CF8M) in a pipe and low-alloy steel(SA508 cl.3) in a nozzle. Thermal aging is observed in CF8M as the RCS is exposed for a long period of time to a reactor operating temperature between 290 and 330°C, while no effect is observed in SA508 cl.3. An investigation of the effect of thermal aging on the various mechanical properties of the dissimilar weld zone is required. The purpose of the present investigation is to find the effect of thermal aging on the dissimilar weld zone. The specimens are prepared by an artificially accelerated aging technique maintained for 100, 300, 900, 1800 and 3600 hrs at 430°C, respectively. The various mechanical tests for the dissimilar weld zone are performed for virgin and aged specimens.

Fracture Toughness with Thermal Aging in CF8M/SA508 Welds

2006 ◽  
Vol 321-323 ◽  
pp. 570-573
Author(s):  
Seung Wan Woo ◽  
Jae Do Kwon ◽  
Young Hwan Choi
Keyword(s):  
Fracture Toughness ◽  
Thermal Aging ◽  
Cooling System ◽  
Weld Zone ◽  
Accelerated Aging ◽  
Dissimilar Weld ◽  
System A ◽  
Elastic Fracture ◽  
Reactor Operating ◽  
Cast Stainless Steel

In a primary reactor cooling system, a dissimilar weld zone exists between cast stainless steel (CF8M) in a pipe and low-alloy steel (SA508 cl.3) in a nozzle. Thermal aging is observed in CF8M as the RCS is exposed for a long period of time to a reactor operating temperature between 290 and 330, while no effect is observed in SA508 cl.3. The aged specimens are prepared by an artificially accelerated aging technique maintained for 300, 1800 and 3600 hrs at 430, respectively. The specimens for elastic-plastic fracture toughness tests are prepared two types, which notch is created in the center of deposited zone and the heat affected zone of CF8M. From the experiments, the plastic-elastic fracture toughness values (JIC) with the increase of aging time decrease as the notch is created in the HAZ of CF8M, while that is different slightly as the notch is created in the deposited zone. Also, JIC values in the deposited zones are smaller than the HAZ of CF8M at all aged specimens.

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

scholarly journals Preparation and Characterization of Composites Materials with Rubber Matrix and with Polyvinyl Chloride Addition (PVC)

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1978
Author(s):  
Dan Dobrotă ◽  
Valentin Petrescu ◽  
Cristinel Sabin Dimulescu ◽  
Mihaela Oleksik
Keyword(s):  
Substantial Reduction ◽  
Accelerated Aging ◽  
Mechanical Tests ◽  
Point Of View ◽  
Rubber Matrix ◽  
The Finite Element Method ◽  
Composites Materials ◽  
Before And After ◽  
Conveyor Belts

An important problem that arises at present refers to the increase in performances in the exploitation of the conveyor belts. Additionally, it is pursued to use some materials, which can be obtained by recycling rubber and PVC waste, in their structure. Thus, the research aimed at creating conveyor belts using materials obtained from the recycling of rubber and PVC waste. Under these conditions, conveyor belts were made that had in their structure two types of rubber and PVC, which was obtained by adding in certain proportions of reclaimed rubber and powder obtained from grinding rubber waste. In order to study the effect of adding PVC on properties, four types of conveyor belts were made, with the structure of rubber, PVC and textile reinforcement. These have been subjected to certain mechanical tests, also being analyzed from the point of view of the behavior of the accelerated aging. The results obtained showed that the addition of PVC lead to a decrease in tensile stress for the strips made, but also an increase in the tensile strain. Additionally, the elasticity tests performed before and after the accelerated aging showed that the presence of PVC in the structure of the conveyor belts determined a substantial reduction of the aging process of the rubber in the conveyor belts. Under these conditions, it has been established that the use of PVC in the structure of rubber matrix conveyor belts is beneficial if conveyor belts are to be produced that are less subject to mechanical stress, but that work in conditions that can cause accelerated aging of materials. An analysis with the finite element method (FEM) of the test samples was also performed.

scholarly journals Mechanical and Thermal Influences on Microstructural and Mechanical Properties during Process-Integrated Thermomechanically Controlled Forging of Tempering Steel AISI 4140

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5772
Author(s):  
Bernd-Arno Behrens ◽  
Kai Brunotte ◽  
Tom Petersen ◽  
Julian Diefenbach
Keyword(s):  
Mechanical Properties ◽  
Cooling System ◽  
Mechanical Tests ◽  
Integrated Treatment ◽  
Fine Grained ◽  
Bainitic Microstructure ◽  
Aisi 4140 ◽  
Steel Aisi ◽  
Intermediate Cooling ◽  
Different Characteristics

Thermomechanical treatment (TMT) describes the effect of thermal and mechanical conditions on the microstructure of materials during processing and offers possible integration in the forging process. TMT materials exhibit a fine-grained microstructure, leading to excellent mechanical properties. In this study, a two-step TMT upsetting process with intermediate cooling is used to demonstrate possibilities for a process-integrated treatment and corresponding properties. A water–air-based cooling system was designed to adjust different phase configurations by varying the target temperature and cooling rate. Four different thermal processing routes and four combinations of applied plastic strains are investigated in standardized mechanical tests and metallographic analyses. The applied TMT results in a finely structured bainitic microstructure of the investigated tempering steel AISI 4140 (42CrMo4) with different characteristics depending on the forming conditions. It can be shown that the demands of the standard (DIN EN ISO 683) in a quenched and tempered state can be fulfilled by means of appropriate forming conditions. The yield strength can be enhanced up to 1174 MPa while elongation at break is about 12.6% and absorbed impact energy reaches 58.5 J without additional heat treatment when the material is formed after rapid cooling.

Evaluation of Residual Stresses in Dissimilar Weld Joints

2011 ◽  
Vol 681 ◽  
pp. 182-187 ◽  
Author(s):  
Alix Bonaventur ◽  
Danièle Ayrault ◽  
Guillaume Montay ◽  
Vincent Klosek
Keyword(s):  
Residual Stresses ◽  
Weld Joint ◽  
Safety Issue ◽  
Austenitic Steels ◽  
Hole Drilling ◽  
Primary Coolant ◽  
Pressurized Water ◽  
Dissimilar Weld ◽  
Dissimilar Welds ◽  
Water Reactors

Dissimilar metal joints between pipes of ferritic and austenitic steels are present in primary coolant circuit of pressurized water reactors. Over the last years in particular in USA and Japan, stress corrosion cracks, often associated with weld repairs, have been observed for some dissimilar welds made with an Inconel filler metal. The integrity of this type of components is thus a major safety issue. In this context, the goal of this work is to evaluate the welding residual stresses field for a dissimilar weld joint. A representative bi-metallic tubular weld joint was fabricated and residual stresses profiles in the different weld zones were evaluated by means of the hole drilling and neutron diffraction methods.

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

Deformation and Fracture of Bone Analogue Biomaterials Having Different Polymer Matrices

2008 ◽  
Vol 47-50 ◽  
pp. 1391-1394
Author(s):  
Min Wang ◽  
Ya Liu ◽  
Chun Ling Au ◽  
Pik Ki Lai ◽  
Lai Yee Leung ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Tissue Repair ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Hard Tissue ◽  
Fracture Characteristics ◽  
The Past ◽  
Reinforced Polymer ◽  
Deformation And Fracture ◽  
Biological Assessments

By mimicking the microstructure of human cortical bone, a variety of bioactive particle reinforced polymer composites have been developed for hard tissue repair. Apart from biological assessments, these composites must be fully evaluated in terms of their mechanical performance before they can be used in patients. The bioactive particles in these composites are normally hard (relative to matrix materials) and brittle bioceramics such as hydroxyapatite (HA), tricalcium phosphate (TCP), Bioglass, etc. The matrices can be either “biostable” polymers such as high density polyethylene (HDPE) and polysulfone (PSU) or biodegradable polymers such as polyhydroxybutyrate (PHB) and poly(L-lactide) (PLLA). These polymers on their own possess different mechanical properties and display different deformation behaviours. With the incorporation of various amounts of particulate HA, TCP or Bioglass, the bone analogue polymeric composites exhibit a spectrum of deformation and fracture characteristics. In our systematic studies of HA/HDPE, Bioglass/HDPE, HA/PSU, HA/PHB, TCP/PHB and a few other bone analogues biomaterials over the past fifteen years, mechanical tests were conducted under a variety of loading conditions (tension, compression, bending, torsion, etc.). Comparisons of deformation and fracture behaviours of these composites were made and presented. The insights that have been gained are important for developing other bioactive ceramic-polymer composites.

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