scholarly journals Thermostructural Analysis of Plate-Type Heat Exchanger Prototypes Considering Weld Properties

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
Kee-nam Song ◽  
Sung-deok Hong
Keyword(s):  
Mechanical Properties ◽  
Heat Exchanger ◽  
Material Properties ◽  
Structural Integrity ◽  
Weld Zone ◽  
Parent Material ◽  
Small Scale ◽  
Hastelloy X ◽  
Weld Properties ◽  
Plate Type

The mechanical properties in a weld zone are different from those in the parent material owing to their different microstructures and residual weld stresses. Welded plate-type heat exchanger prototypes made of Hastelloy-X alloy were manufactured, and performance tests on the prototypes were performed in a small-scale nitrogen gas loop at the Korea Atomic Energy Research Institute. Owing to a lack of mechanical properties in the weld zone, previous research on the strength analyses of the prototypes was performed using the parent material properties. In this study, based on the mechanical properties of Hastelloy-X alloy obtained using an instrumented indentation technique, strength analyses considering the mechanical properties in the weld zone were performed, and the analysis results were compared with previous research. As a result of the comparison, a thermostructural analysis considering the weld material properties is needed to understand the structural behavior and evaluate the structural integrity of the prototype more reliably.

High-Temperture Structural Analysis on a Small-Scale PHE Prototype Considering Mechanical Properties in the Heat-Affected Zone and in the Weld Zone

2012 ◽  
Author(s):  
Kee-Nam Song ◽  
Sung-Deok Hong ◽  
Hong-Yoon Park
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Structural Analysis ◽  
Performance Test ◽  
Weld Zone ◽  
Parent Material ◽  
Small Scale ◽  
Hastelloy X ◽  
Production Of Hydrogen ◽  
Gas Loop

PHE (Process Heat Exchanger) is a key component in transferring the high temperature heat generated from a VHTR (Very High Temperature Reactor) to the chemical reaction for massive production of hydrogen. A performance test on a small-scale PHE prototype made of Hastelloy-X is currently undergoing in a small-scale gas loop at the Korea Atomic Energy Research Institute. Previous researches on the high-temperature structural analysis of the small-scale PHE prototype had been performed using parent material properties over the whole region. In this study, high-temperature elastic structural analysis considering mechanical properties in the weld zone was performed and the analysis result was compared with previous researches.

scholarly journals Effect of Weld Properties on the Crush Strength of the PWR Spacer Grid

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Kee-nam Song ◽  
Sang-hoon Lee
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Structural Component ◽  
Weld Zone ◽  
Base Material ◽  
Instrumented Indentation ◽  
Spacer Grid ◽  
Indentation Technique ◽  
Weld Properties ◽  
Crush Strength

Mechanical properties in a weld zone are different from those in the base material because of different microstructures. A spacer grid in PWR fuel is a structural component with an interconnected and welded array of slotted grid straps. Previous research on the strength analyses of the spacer grid was performed using base material properties owing to a lack of mechanical properties in the weld zone. In this study, based on the mechanical properties in the weld zone of the spacer grid recently obtained by an instrumented indentation technique, the strength analyses considering the mechanical properties in the weld zone were performed, and the analysis results were compared with the previous research.

scholarly journals Effect of Asymmetric Material Flow on the Microstructure and Mechanical Properties of 5A06 Al-Alloy Welded Joint by VPPA Welding

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 120
Author(s):  
Zhaoyang Yan ◽  
Shujun Chen ◽  
Fan Jiang ◽  
Xing Zheng ◽  
Ooi Tian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Boundary ◽  
Material Flow ◽  
Welded Joint ◽  
Weld Zone ◽  
Metal Flow ◽  
Al Alloy ◽  
Average Grain Size ◽  
Weld Properties

The microstructure, texture, and mechanical properties of the asymmetric welded joint in variable polarity plasma arc (VPPA) welding were studied and discussed in this paper. The asymmetric welded joint was obtained through horizontal welding, where the effect of gravity caused asymmetric material flow. The results showed that the grain size and low angle grain boundary (LAGB) at both sides of the obtained welded joint were asymmetric; the grain size differed by a factor of 1.3. The average grain size of the Base Metal (BM), Lower-weld zone (WZ) and Upper-WZ were 25.73 ± 1.25, 37.87 ± 1.89 and 49.92 ± 2.49 µm, respectively. There is discrepancy between the main textures in both sides of the welded joint. However, the effect of asymmetric metal flow on the weld texture was not significant. The micro-hardness distribution was inhomogeneous, the lowest hardness was observed in regions with larger grain sizes and smaller low angle grain boundary. During tensile strength tests, the specimens fractured at the position with the lowest hardness although it has reached 89.2% of the strength of the BM. Furthermore, the effect of asymmetric metal flow and underlying causes of asymmetric weld properties in VPPA horizontal welding have been discussed and analyzed.

High-Temperature Structural Analysis on the Small-Scale PHE Prototype

2012 ◽  
Vol 525-526 ◽  
pp. 465-468
Author(s):  
Kee Nam Song
Keyword(s):  
High Temperature ◽  
Structural Analysis ◽  
Performance Test ◽  
Structural Integrity ◽  
Small Scale ◽  
Nitrogen Gas ◽  
Hastelloy X ◽  
Production Of Hydrogen ◽  
Very High Temperature Reactor ◽  
Gas Loop

PHE (Process Heat Exchanger) is a key component for transferring the high-temperature heat generated from a VHTR (Very High Temperature Reactor) to a chemical reaction for massive production of hydrogen. Korea Atomic Energy Research Institute has established a small-scale nitrogen gas loop for the performance test on VHTR components and has manufactured a small-scale PHE prototype made of Hastelloy-X of high-temperature alloy. A performance test on the PHE prototype is underway in the gas loop. In this study, in order to evaluate the high-temperature structural integrity of the PHE prototype under the test condition of the gas loop, structural analysis on the PHE prototype was carried out to gauge the stiffness of pipelines connected to the PHE prototype in the gas loop.

Comparisons of High-Temperature Structural Analysis Results on the Medium-Scale PHE Prototype under the Steady-State and Trip Conditions of a Small-Scale Gas Loop

2012 ◽  
Vol 525-526 ◽  
pp. 5-8
Author(s):  
Kee Nam Song ◽  
S.D. Hong ◽  
H.Y. Park
Keyword(s):  
Steady State ◽  
High Temperature ◽  
Performance Test ◽  
Structural Integrity ◽  
Small Scale ◽  
Nitrogen Gas ◽  
Hastelloy X ◽  
Medium Scale ◽  
Production Of Hydrogen ◽  
Gas Loop

PHE (Process Heat Exchanger) is a key component for transferring the high-temperature heat generated from a VHTR (Very High Temperature Reactor) to a chemical reaction for massive production of hydrogen. Recently, Korea Atomic Energy Research Institute (KAERI) has manufactured a medium-scale PHE prototype made of Hastelloy-X of high-temperature alloy and a performance test on the PHE prototype is scheduled in a small-scale nitrogen gas loop established at KAERI. In this study, in order to evaluate the high-temperature structural integrity of the PHE prototype under the steady-state and trip conditions of the gas loop before the performance test on the PHE prototype, elastic and elastic-plastic structural analyses on the PHE prototype were carried out and the analyses results were compared each other.

Material Property Identification and Sensitivity Analysis Using Micro-Indentation

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Long Ge ◽  
Nam H. Kim ◽  
Gerald R. Bourne ◽  
W. Gregory Sawyer
Keyword(s):  
Mechanical Properties ◽  
Sensitivity Analysis ◽  
Material Properties ◽  
Numerical Technique ◽  
Response Surfaces ◽  
Small Scale ◽  
Test Statistics ◽  
Indentation Experiment ◽  
The Difference ◽  
Micro Indentation

Mechanical properties of materials in small-scale applications, such as thin coatings, are often different from those of bulk materials due to the difference in the manufacturing process. Indentation has been a convenient tool to study the mechanical properties in such applications. In this paper, a numerical technique is proposed that can identify the mechanical properties using optimization and evaluate the robustness of identified material properties using sensitivity analysis. First, two response surfaces are constructed for loading and unloading curves from the indentation experiment of a gold film on the silicon substrate. Unessential coefficients of the response surface are then removed based on the test statistics. Unlike the traditional methods of identification, the tip geometry of the indenter is included because its uncertainty significantly affects the results. In order to validate the accuracy and stability of the method, the sensitivity of the identified material properties with respect to each coefficient is analyzed. It turns out that the plastic hardening parameter is the most sensitive to the experimental data. In addition, all material parameters are sensitive to the coefficients of higher-order bases. However, their effects are diminished because the magnitudes of these coefficients are small.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

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