scholarly journals Thermo Mechanical Analysis of Hard Faced Circular Grid Plate

2011 ◽  
pp. 55-59
Author(s):  
Shashi Kumar ◽  
Balaguru S ◽  
Vela . murali ◽  
Chellapandi P
Keyword(s):  
Residual Stresses ◽  
Arc Welding ◽  
Base Material ◽  
Deposition Process ◽  
Mechanical Analysis ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Differential Shrinkage ◽  
Grid Plate ◽  
Circular Grid

In this paper, plasma transfer arc welding of hard faced circular grid plate was studied. Hard face deposition made by Plasma Transferred Arc Welding (PTAW) on grid plate at relatively high temperature, generates residual stresses due to differential shrinkage of the molten deposit, process-induced thermal gradients and difference in coefficients of thermal expansion between the deposit and base material. However, the magnitude and distribution of the residual stresses vary depending on the preheat temperature, heat input, deposition process, and the geometry of the component. Finite element analysis of residual stress is performed with commercial FEA package ANSYS 12.0 which includes moving heat source, material deposit, temperature dependent material properties, metal plasticity and elasticity. Coupled thermo-mechanical analysis is done for welding simulation and the element birth and death technique is employed for simulation of filler metal deposition.

Thermo Mechanical Analysis of SS304 Circular Grid Plate Hard Faced with Colmonoy

2012 ◽  
Vol 229-231 ◽  
pp. 710-717 ◽  
Author(s):  
S. Balaguru ◽  
Kumar Shashi ◽  
Murali Vela ◽  
P. Chellapandi
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Arc Welding ◽  
Base Material ◽  
Deposition Process ◽  
Mechanical Analysis ◽  
Element Analysis ◽  
Grid Plate ◽  
Circular Grid ◽  
Ss 304

In this paper, plasma transfer arc welding using hard faced material Colmonoy which is deposited on a annular groove of a circular grid plate made up of SS 304 was studied. Hard face deposition made by Plasma Transferred Arc Welding (PTAW) on a annular groove of a grid plate at relatively high temperature, generates residual stresses due to differential shrinkage of the molten deposit, process-induced thermal gradients and difference in coefficients of thermal expansion between the colmonoy deposit and base material SS 304. However, the magnitude and distribution of the residual stresses vary depending on the heat input, deposition process, and the geometry of the component. Finite element analysis of residual stress is performed with commercial FEA package of ANSYS 12.0 which includes moving heat source, material deposit, temperature dependent material properties, metal plasticity and elasticity. Coupled thermo-mechanical analysis is done for welding simulation and the element birth and death technique is employed for simulation of filler metal deposition. Finally residual stress is evaluated so that annealing is performed accordingly to relieve residual stresses in order to carry out fracture analyses thereafter.

Variation in Residual Stresses due to Thermal Cycling Induced on the Hardfaced Grid Plate in PFBR

2014 ◽  
Vol 591 ◽  
pp. 98-102 ◽  
Author(s):  
S. Balaguru ◽  
K. Saranraj ◽  
Murali Vela ◽  
P. Chellapandi
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Thermal Cycling ◽  
Base Material ◽  
Wear Loss ◽  
Element Analysis ◽  
High Sodium ◽  
Grid Plate ◽  
Nickel Base ◽  
Circular Grid

In sodium cooled fast breeder reactors, the high operating temperature necessitates hard facing of grid plate to avoid galling and to reduce the wear loss of the base material . Nickel-base cobalt-free alloy called Colmonoy-5 has been chosen as the hard facing material for the Prototype Fast Breeder Reactor (PFBR) grid plate. The grid plate (GP) which is a critical component made of 316 LN SS that holds the core subassemblies are hard faced, to prevent galling and also to minimize wear caused by subassembly insertion/removal and erosion due to high sodium velocity at 670 K. Thermal cycling of hard faced circular grid plate made by Plasma Transferred Arc Welding (PTAW) generates residual stresses due to differential shrinkage of the molten deposit and difference in coefficients of thermal expansion between the deposit and substrate material. In this project the effect of thermal cycling of a nickel-base hardfacing alloy deposited on an austenitic stainless steel grid plate was studied. Finite element analysis of hard faced circular grid plate is performed for obtaining residual stress which includes elasto-plastic analysis. Coupled thermo-mechanical analysis is done for thermal cycling of hardfaced circular gridplate to quantitatively estimate the residual stress.

scholarly journals Measurement of the Residual Stresses and Investigation of Their Effects on a Hardfaced Grid Plate due to Thermal Cycling in a Pool Type Sodium-Cooled Fast Reactor

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
S. Balaguru ◽  
Vela Murali ◽  
P. Chellapandi
Keyword(s):  
Residual Stresses ◽  
Thermal Cycling ◽  
Arc Welding ◽  
Plate Model ◽  
Element Analysis ◽  
Scale Down ◽  
Grid Plate ◽  
Lower Dose Rate ◽  
Plasma Transferred Arc Welding ◽  
Pool Type

In sodium-cooled fast reactors (SFR), grid plate is a critical component which is made of 316 L(N) SS. It is supported on core support structure. The grid plate supports the core subassemblies and maintains their verticality. Most of the components of SFR are made of 316 L(N)/304 L(N) SS and they are in contact with the liquid-metal sodium which acts as a coolant. The peak operating temperature in SFR is 550°C. However, the self-welding starts at 500°C. To avoid self-welding and galling, hardfacing of the grid plate has become necessary. Nickel based cobalt-free colmonoy 5 has been identified as the hardfacing material due to its lower dose rate by Plasma Transferred Arc Welding (PTAW). This paper is concerned with the measurement and investigations of the effects of the residual stress generated due to thermal cycling on a scale-down physical model of the grid plate. Finite element analysis of the hardfaced grid plate model is performed for obtaining residual stresses using elastoplastic analysis and hence the results are validated. The effects of the residual stresses due to thermal cycling on the hardfaced grid plate model are studied.

Thermomechanical Model of Spot Welding for Calculating Residual Stresses

2003 ◽  
Author(s):  
Lijun Xu ◽  
Jamil A. Khan
Keyword(s):  
Residual Stresses ◽  
Heat Generation ◽  
Spot Welding ◽  
Welding Process ◽  
Mechanical Analysis ◽  
Temperature Dependent ◽  
Thermomechanical Model ◽  
Faying Surface ◽  
Proposed Model ◽  
Electrode Interface

A comprehensive axisymmetric model of the coupled thermal-electrical-mechanical analysis predicting weld nugget development and residual stresses for the resistance spot welding process of Al-alloys is developed. The model estimates the heat generation at the faying surface, the workpiece-electrode interface, and the Joule heating of the workpiece and electrode. The phase change due to melting in the weld pool is considered. The contact area and its pressure distribution at both the faying surface and the electrode-workpiece interface are determined from a coupled thermal-mechanical model using a finite element method. The knowledge of the interface pressure provides accurate prediction of the interfacial heat generation. For the numerical model, temperature dependent thermal, electrical and mechanical properties are used. The proposed model can successfidly calculate the nugget diameter and thickness, and predict the residual stresses and the elastic-plastic deformation history. The calculated nugget shape and the deformation of sheets based on the model are compared with the experimental data. The computed residual stresses approach the distribution of experimental measurement of the residual stress.

scholarly journals Effect of Pulsed Laser Ablation on the Increase of Adhesion of CRN Coating-Substrate

2018 ◽  
Vol 26 (43) ◽  
pp. 61-70
Author(s):  
Paulína Zacková ◽  
Lucia Števlíková ◽  
Ľubomír Čaplovič ◽  
Martin Sahul ◽  
Vitali Podgurski
Keyword(s):  
Laser Ablation ◽  
Residual Stresses ◽  
High Speed ◽  
Substrate Surface ◽  
Base Material ◽  
High Speed Steel ◽  
Cobalt Content ◽  
Deposition Process ◽  
Adhesion Behavior ◽  
Surface Laser

Abstract The contribution deals with analysis of the influence of the substrate surface laser ablation before deposition process to improve the adhesion of coating-substrate system. The coatings were applied to the high-speed steel 6-5-2-5 (STN 19 852) and WC-Co cemented carbide with cobalt content of 10 wt%. LAteral Rotating Cathodes (LARC®) process was chosen for evaporation of individual CrN layers. Influence of laser ablation on the substrate morphology, structure, roughness, presence of residual stresses inside the substrates and layers and their adhesion behavior between the layers and the base material was studied. Scanning electron microscopy fitted with energy dispersive spectroscopy was utilized to investigate morphology and fracture areas of substrates with CrN layers. X-ray diffraction analysis was employed to detect the residual stresses measurements. Adhesion between the coatings and substrate was analyzed using “Mercedes” testing.

Three-Dimensional Transient Finite Element Analysis for Microstructure Formation and Residual Stresses in Laser-Aided DMD Process

Volume 3 ◽  
2004 ◽  
Author(s):  
S. Ghosh ◽  
J. Choi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Process Parameters ◽  
Deposition Process ◽  
High Energy ◽  
Material Behavior ◽  
Process Conditions ◽  
Element Analysis ◽  
Energy Beam

Despite immense advances in Laser-Aided Direct Material Deposition process, many issues concerning the adverse effects of process parameters on the stability of variety of properties and the integrity of microstructure have been reported. Macroscopic aspects are important in predicting macroscopic defects or optimizing process conditions, while microstructural features such as phase appearance, morphology, grain size, spacing, or micro-defects are certainly no less important in determining the ultimate properties of the solidified product. Traditional solidification theories as applied to castings or related processes are inappropriate in describing solidification in high-energy beam processes involving significantly greater cooling rates. Due to the complexity and nonlinearity of this process, analytical solutions can rarely address the practical manufacturing process. This paper is an attempt towards a methodology of finite element analysis for the prediction of solidification microstructure and macroscopic as well as microscopic thermal residual stresses in this process. The computer simulation which is based on metallo-thermomechanical theory and finite element analysis for coupled temperature, solidification, phase transformation and stress/strain fields can prove to be a very useful tool in predicting the material behavior and optimizing the process parameters to obtain the best material properties. This model would reduce long and cumbersome experimental routes to predict the material behavior under similar loading conditions.

Finite Element Analysis of Residual Stresses on Butt Welded Joints

2006 ◽  
Author(s):  
Enrico Armentani ◽  
Renato Esposito ◽  
Raffaele Sepe
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Fusion Zone ◽  
Welded Joints ◽  
High Strength Steels ◽  
High Strength ◽  
Heat Of Fusion ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Welding Processes

Localized heating during welding, followed by rapid cooling, usually generates residual stresses in the weld and in the base metal. Residual stresses in welding processes give significant problems in the accurate manufacture of structures because those stresses heavily induce the formation of cracks in the fusion zone in high strength steels. Therefore, estimating the magnitude and distribution of welding residual stresses and characterizing the effects of certain welding conditions on the residual stresses are deemed necessary. In this work, residual stresses and distortions on butt welded joints are numerically evaluated by means of finite element method. The FE analysis allows to highlight and evaluate the stress field and his gradient around the fusion zone of welded joints, higher than any other located in the surrounding area. Temperature-dependent material properties, welding velocity, external mechanism constraints, technique of ‘element birth and death’ and latent heat of fusion are also taken into account. Some numerical results are compared with experimental data showing a very good correlation.

The Temperature and Residual Stress Distributions of Butt Weld Pass on Nickel Alloy 690 Plate

2013 ◽  
Vol 690-693 ◽  
pp. 2651-2654
Author(s):  
Chun Ho Yin ◽  
Chao Ming Hsu ◽  
Jao Hwa Kuang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Nickel Alloy ◽  
Welding Parameters ◽  
Stress Distributions ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Butt Weld ◽  
Alloy 690 ◽  
Solidification Processes

The variations of temperature profile and residual stress distribution in the single V butt welds were studied in this work. The thermal elastic-plastic model of ANSYS finite element analysis software is employed in this study to simulate the melting and solidification processes of two clamped nickel alloy 690 plates with different welding parameters; i.e. the welding speed and the number of weld passes. The temperature dependent material properties are used. The effects of these welding parameters on the residual stresses around the weld are investigated. Numerical results reveal that these welding parameters may affect the distribution of residual stresses significantly.

scholarly journals Simulation of Multipass Welding With Simultaneous Computation of Material Properties

2000 ◽  
Vol 123 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Lars Bo¨rjesson ◽  
Lars-Erik Lindgren
Keyword(s):  
Residual Stresses ◽  
Microstructure Evolution ◽  
Material Properties ◽  
Base Material ◽  
Steel Plates ◽  
Filler Material ◽  
Temperature History ◽  
Temperature Dependent ◽  
Butt Welding ◽  
Thick Steel

Multipass butt welding of two 0.2 m thick steel plates has been investigated. The objective is to calculate residual stresses and compare them with measured residual stresses. The material properties depend on temperature and temperature history. This dependency is accounted for by computing the microstructure evolution and using this information for computing material properties. This is done by assigning temperature dependent material properties to each phase and applying mixture rules to predict macro material properties. Two different materials have been used for the microstructure calculation, one for the base material and one for the filler material.

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