Evolution of Temperature Distribution and Microstructure in Multipass Welded AISI 321 Stainless Steel Plates With Different Thicknesses

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Soheil Nakhodchi ◽  
Ali Shokuhfar ◽  
Saleh Akbari Iraj ◽  
Brian G. Thomas
Keyword(s):  
Stainless Steel ◽  
Temperature Distribution ◽  
Residual Stresses ◽  
Arc Welding ◽  
Welding Process ◽  
Steel Plates ◽  
Temperature History ◽  
Transient Temperature ◽  
Multipass Welding ◽  
Aisi 321

Prediction of temperature distribution, microstructure, and residual stresses generated during the welding process is crucial for the design and assessment of welded structures. In the multipass welding process of parts with different thicknesses, temperature distribution, microstructure, and residual stresses vary during each weld pass and from one part to another. This complicates the welding process and its analysis. In this paper, the evolution of temperature distribution and the microstructure generated during the multipass welding of AISI 321 stainless steel plates were studied numerically and experimentally. Experimental work involved designing and manufacturing benchmark specimens, performing the welding, measuring the transient temperature history, and finally observing and evaluating the microstructure. Benchmark specimens were made of corrosion-resistant AISI 321 stainless steel plates with different thicknesses of 6 mm and 10 mm. The welding process consisted of three welding passes of two shielded metal arc welding (SMAW) process and one gas tungsten arc welding (GTAW) process. Finite element (FE) models were developed using the DFLUX subroutine to model the moving heat source and two different approaches for thermal boundary conditions were evaluated using FILM subroutines. The DFLUX and FILM subroutines are presented for educational purposes, as well as a procedure for their verification.

Sequential Transient Numerical Simulation of Inertia Friction Welding Process

2008 ◽  
Author(s):  
Medhat Awad El-Hadek ◽  
Mohammad S. Davoud
Keyword(s):  
Temperature Distribution ◽  
Residual Stresses ◽  
Friction Welding ◽  
Welding Process ◽  
Transient Temperature ◽  
Inertia Friction Welding ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Full Field ◽  
Welding Processes

Inertia friction welding processes often generate substantial residual stresses due to the heterogeneous temperature distribution during the welding process. The residual stresses which are the results of incompatible elastic and plastic deformations in weldment will alter the performance of welded structures. In this study, three-dimensional (3D) finite element analysis has been performed to analyze the coupled thermo-mechanical problem of inertia friction welding of a hollow cylinder. The analyses include the effect of conduction and convection heat transfer in conjunction with the angular velocity and the thrust pressure. The results include joint deformation and a full-field view of the residual stress field and the transient temperature distribution field in the weldment. The shape of deformation matches the experimental results reported in the literature. The residual stresses in the heat-affected zone have a high magnitude but comparatively are smaller than the yield strength of the material.

scholarly journals Thermal and structural modelling of arc welding processes: A literature review

2019 ◽  
Vol 52 (7-8) ◽  
pp. 955-969 ◽  
Author(s):  
Hitesh Arora ◽  
Rupinder Singh ◽  
Gurinder Singh Brar
Keyword(s):  
Temperature Distribution ◽  
Residual Stresses ◽  
Arc Welding ◽  
Weld Zone ◽  
Welding Process ◽  
Thermomechanical Analysis ◽  
Inert Gas ◽  
Welding Distortion ◽  
Structural Modelling ◽  
Welding Processes

This paper presents a state-of-the-art critical review of the thermal and structural modelling of the arc welding process. During the welding process, high temperature in the welding zone leads to generation of unwanted residual stresses and results in weld distortion. Measurement of the temperature distribution was a key issue and challenge in the past decade. Thermomechanical analysis is among the best-known techniques to simulate and investigate the temperature distribution, welding distortion and residual stresses in the weld zone. The main emphasis of this review is the thermal and structural modelling of welding processes and the measurement of welding residual stresses using different techniques. The study also provides information about the various types of heat sources and models used to predict the weld bead characteristics and thermomechanical analysis for different welding processes such as tungsten inert gas welding, metal inert gas welding and shielded metal arc welding.

An analytical solution for transient temperature distribution in fillet arc welding including the effect of molten metal

1997 ◽  
Vol 211 (1) ◽  
pp. 63-72 ◽  
Author(s):  
S. K. Jeong ◽  
H. S. Cho
Keyword(s):  
Temperature Distribution ◽  
Analytical Solution ◽  
Molten Metal ◽  
Arc Welding ◽  
Finite Thickness ◽  
Infinite Plate ◽  
Welding Process ◽  
Transient Temperature ◽  
Fillet Weld ◽  
Transient Temperature Distribution

This paper presents an analytical solution to predict the transient temperature distribution in fillet arc welding, including the effect of the molten metal generated from the electrode. The analytical solution is obtained by solving a transient three-dimensional heat conduction equation with convection boundary conditions on the surfaces of an infinite plate with finite thickness, and mapping an infinite plate on to the fillet weld geometry, including the molten metal with energy equation. The electric arc heat input on the fillet weld and on the infinite plate is assumed to have a travelling bivariate Gaussian distribution. To check the validity of the solution, flux cored arc (FCA) welding experiments were performed under various welding conditions. The actual isotherms of the weldment cross-sections at various distances from the arc start point are compared with those of the simulation result. As the result shows a good accuracy, this analytical solution can be used to predict the transient temperature distribution in the fillet weld of finite thickness under a moving bivariate Gaussian distributed heat source. The simplicity and short calculation time of the analytical solution provides the rationale for using the analytical solution to model the welding control systems or to obtain an optimization tool for welding process parameters.

Prediction of Transient Temperature Distribution, HAZ Width and Microstructural Analysis of Submerged Arc-Welded Structural Steel Plates

2011 ◽  
Vol 316-317 ◽  
pp. 135-152 ◽  
Author(s):  
Aniruddha Ghosh ◽  
Somnath Chattopadhyaya
Keyword(s):  
Temperature Distribution ◽  
Analytical Solution ◽  
Arc Welding ◽  
Submerged Arc Welding ◽  
Electric Arc ◽  
Steel Plates ◽  
Transient Temperature ◽  
Transient Temperature Distribution ◽  
Haz Width ◽  
Submerged Arc

Critical investigation of the transient temperature distribution is important for maintaining the quality of the Submerged Arc Welding of structural steel plates. The aim of this paper is to derive an analytical solution to predict the transient temperature distribution on the plate during the process of Submerged Arc Welding. An analytical solution is obtained from the 3D heat conduction equation. The main energy input that is applied on the plate is taken as the heat lost from the electric arc. The kinetic energy of filler droplets, electromagnetic force and drag force are also considered as input to the process. The electric arc is assumed to be a moving double Central Conicoidal heat source which follows approximately the Gaussian distribution. It is observed that the predicted values are in good agreement with the experimental results. The heat-affected zone (HAZ) width calculation is also done with the help of the analytical solution of the transient 3D heat conduction equation. Analysis of microstructural changes is critically investigated to comprehend the HAZ softening phenomenon and for the validation of the predicted HAZ width.

Residual Stress Improvement in Multi-Layer Welding of Austenitic Stainless Steel Plates by Using Water-Shower Cooling During Welding Process

2006 ◽  
Author(s):  
Nobuyoshi Yanagida ◽  
Hiroo Koide
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Welding Process ◽  
Steel Plates ◽  
Tensile Residual Stress ◽  
Welding Torch ◽  
Measurement Results ◽  
Effective Conditions

To reduce tensile residual stress in a welded region, we have developed a new cooling method that applies a water-shower behind the welding torch. When this method is applied to multi-layer welding of austenitic stainless steel plates, cooling conditions mainly determine how much the residual stress can be reduced. To determine the conditions, we first used FEM to evaluate the effects of water-shower cooling and interpass temperature on the residual stress. In addition, we found effective conditions for reducing tensile residual stress. To verify the validity of the conditions, three plates were welded with or without water shower cooling. Residual stresses of the plates were measured experimentally. It was found that tensile residual stresses occurred on the surface of the welds and that they were reduced when the water-shower was applied at the last pass. These measurement results agree well with the FEM analyses. It can therefore be concluded that water-shower cooling during the last welding pass is appropriate for reducing tensile residual stress in austenitic stainless steel at a multi-pass weld.

Boundary Condition Design to Heat a Moving Object at Uniform Transient Temperature Using Inverse Formulation

2004 ◽  
Vol 126 (3) ◽  
pp. 619-626 ◽  
Author(s):  
Hakan Ertu¨rk ◽  
Ofodike A. Ezekoye ◽  
John R. Howell
Keyword(s):  
Boundary Condition ◽  
Temperature Distribution ◽  
Design Problem ◽  
Manufacturing Industry ◽  
Three Dimensional ◽  
Chemical Deposition ◽  
Iterative Solution ◽  
Conveyor Belt ◽  
Temperature History ◽  
Transient Temperature

The boundary condition design of a three-dimensional furnace that heats an object moving along a conveyor belt of an assembly line is considered. A furnace of this type can be used by the manufacturing industry for applications such as industrial baking, curing of paint, annealing or manufacturing through chemical deposition. The object that is to be heated moves along the furnace as it is heated following a specified temperature history. The spatial temperature distribution on the object is kept isothermal through the whole process. The temperature distribution of the heaters of the furnace should be changed as the object moves so that the specified temperature history can be satisfied. The design problem is transient where a series of inverse problems are solved. The process furnace considered is in the shape of a rectangular tunnel where the heaters are located on the top and the design object moves along the bottom. The inverse design approach is used for the solution, which is advantageous over a traditional trial-and-error solution where an iterative solution is required for every position as the object moves. The inverse formulation of the design problem is ill-posed and involves a set of Fredholm equations of the first kind. The use of advanced solvers that are able to regularize the resulting system is essential. These include the conjugate gradient method, the truncated singular value decomposition or Tikhonov regularization, rather than an ordinary solver, like Gauss-Seidel or Gauss elimination.

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