Evaluation Study on Angular Distortion and Residual Stress of Stainless Steel Pulsed TIG Weldment

2011 ◽  
Vol 291-294 ◽  
pp. 905-909
Author(s):  
Kuang Hung Tseng ◽  
Hsiang Lin Sung
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Vertical Displacement ◽  
Evaluation Study ◽  
Tig Welding ◽  
Angular Distortion ◽  
Hole Drilling ◽  
Welding Parameters ◽  
Pulsed Current ◽  
Lower Heat

The aim of this study was to investigate the effect of pulsed current welding parameters on angular distortion and residual stress of TIG weldment. Autogenous TIG welding was applied on type 316L stainless steel sheet to produce bead-on-plate welds. Angular distortion was determined using the mean vertical displacement method. Residual stress was determined using the hole-drilling strain- gage method. The results showed that the pulsed current TIG welding has a number of advantages, including lower heat input and consequently a reduction in distortion and residual stress of weldment.

Study of Type 316L Stainless Steel TIG Welding with MoO3 Powder

2011 ◽  
Vol 291-294 ◽  
pp. 901-904 ◽  
Author(s):  
Kuang Hung Tseng ◽  
Ko Jui Chuang
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
316L Stainless Steel ◽  
Tig Welding ◽  
Steel Plates ◽  
Angular Distortion ◽  
Stainless Steel 316L ◽  
Surface Appearance ◽  
Type 316L ◽  
Type 316L Stainless Steel

In the present work, a specific oxide flux was used to systematically investigate the effects of activated tungsten inert gas (TIG) welding on the surface appearance, weld morphology, angular distortion, residual stress, and ferrite structure in type 316L stainless steel plates. MoO3 flux used was packed in powdered form. The results showed that MoO3 flux assisted TIG welding technique can produce a significant improvement in power density of heat source and weld aspect ratio, resulting in low angular distortion and residual stress levels. The MoO3 flux assisted TIG welding associated with a rapid cooling rate of the welds, therefore exhibiting higher ferrite content in austenitic stainless steel 316L weld metals during the solidification after welding.

Study on Welding Parameters Optimization of Duplex Stainless Steel 2205 Based on Orthogonal

2012 ◽  
Vol 472-475 ◽  
pp. 1305-1308
Author(s):  
Zheng Lun Wang ◽  
Zhi Xiang Wang ◽  
Yu Zhang
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Cross Section ◽  
Test Methods ◽  
Orthogonal Test ◽  
Parameters Optimization ◽  
Tig Welding ◽  
Welding Parameters ◽  
Longitudinal Residual Stress

For the duplex stainless steel 2205 used to make into chemical ships in shipyards，TIG welding is used for the welding test of duplex stainless steel 2205. Residual stress on 2 mm thick welding specimen is tested with the slot-cuting method,and the distribution of longitudinal residual stress along weld cross-section has been found. Orthogonal test methods are also used in this paper to optimize welding parameters.

Residual Stresses Prediction for CO2 Laser Butt-Welding of 304-Stainless Steel

2006 ◽  
Vol 3-4 ◽  
pp. 125-130 ◽  
Author(s):  
Khaled Y. Benyounis ◽  
Abdul Ghani Olabi ◽  
M.S.J. Hashmi
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Laser Power ◽  
Travel Speed ◽  
304 Stainless Steel ◽  
Hole Drilling ◽  
Design Matrix ◽  
Butt Welding ◽  
Input Variables

Residual stresses are an integral part of the total stress acting on any component in service. It is important to determine and/or predict the magnitude, nature and direction of the residual stress to estimate the life of important engineering parts, particularly welded components. This work aims to introduce experimental models to predict residual stresses in the heat-affected zone (HAZ). These models specify the effect of laser welding input parameters on maximum residual stress and its direction. The process input variables considered in this study are laser power (1.03 - 1.368 kW), travel speed (26.48 – 68.52 cm/min) and focal point position (- 1 to 0 mm). Laser butt-welding of 304 stainless steel plates of 3 mm thick were investigated using a 1.5 kW CW CO2 Rofin laser as a welding source. Hole-drilling method was employed to measure the magnitude, and direction of the maximum principal stress in and around the HAZ, using a CEA-06- 062UM-120 strain gauge rosette, which allows measurement of the residual stresses close to the weld bead. The experiment was designed based on Response Surface Methodology (RSM). Fifteen different welding conditions plus 5 repeat tests were carried out based on the design matrix. Maximum principal residual stresses and their directions were calculated for the twenty samples. The stepwise regression method was selected using Design-expert software to fit the experimental responses to a second order polynomial. Sequential F test and other adequacy measures were then used to check the models adequacy. The experimental results indicate that the proposed mathematical models could adequately describe the residual stress within the limits of the factors being studied. Using the models developed, the main and interaction effect of the process input variables on the two responses were determined quantitatively and presented graphically. It is observed that the travel speed and laser power are the main factors affecting the behavior of the residual stress. It is recommended to use the models to find the optimal combination of welding conditions that lead to minimum distortion.

Post Welding Heat Treatment Simulation in Welded Stainless Steel Pipe and Comparison with Experiment

2009 ◽  
Vol 83-86 ◽  
pp. 237-243
Author(s):  
Mohammad Sedighi ◽  
B. Davoodi
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Stress Distribution ◽  
Numerical Models ◽  
Welding Process ◽  
Steel Pipe ◽  
Hole Drilling ◽  
Distribution Data ◽  
Stainless Steel Pipe

Due to the intense concentration of heat in the welding process, residual stresses are produced in the specimen. One of the most effective ways to relief welding stress is Post Welding Heat Treatment (PWHT). In this paper, finite element method is employed to model and analyze PWHT for two pass butt-welded SUS304 stainless steel pipe. In this simulation, firstly, the welding process has been modeled. Then the stress distribution of the specimen has been transferred to a second analysis for stress relaxation modeling. Norton law is used to investigate creep in stress relief process. Experimental tests are also carried out to verify the effectiveness of the proposed numerical models. The hole drilling method is used to measure the stress distribution in the specimen. The residual stress distribution data before and after PWHT are compared to investigate the effect of heat treatment on residual stress. Based on the modeling and experimental results, the tensile and compressive stresses distributions have been reduced. They are in a reasonable agreement with each other and prove the capability of the proposed modeling technique to simulate PWHT.

Modeling Residual Stresses in Superduplex Stainless Steel Welded Pipes Using the Finite Element Method

2013 ◽  
Vol 758 ◽  
pp. 1-10
Author(s):  
Fabiano Rezende ◽  
Luís Felipe Guimarães de Souza ◽  
Pedro Manuel Calas Lopes Pacheco
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Welding Process ◽  
Welding Parameters ◽  
Superduplex Stainless Steel ◽  
Mechanical Components ◽  
Element Method

Welding is a complex process where localized and intensive heat is imposed to a piece promoting mechanical and metallurgical changes. Phenomenological aspects of welding process involve couplings among different physical processes and its description is unusually complex. Basically, three couplings are essential: thermal, phase transformation and mechanical phenomena. Welding processes can generate residual stress due to the thermal gradient imposed to the workpiece in association to geometric restrictions. The presence of tensile residual stresses can be especially dangerous to mechanical components submitted to fatigue loadings. The present work regards on study the residual stress in welded superduplex stainless steel pipes using experimental and a numerical analysis. A parametric nonlinear elastoplastic model based on finite element method is used for the evaluation of residual stress in superduplex steel welding. The developed model takes into account the coupling between mechanical and thermal fields and the temperature dependency of the thermomechanical properties. Thermocouples are used to measure the temperature evolution during welding stages. Instrumented hole drilling technique is used for the evaluation of the residual stress after welding process. Experimental data is used to calibrate the numerical model. The methodology is applied to evaluate the behavior of two-pass girth welding (TIG for root pass and SMAW for finishing) in 4 inch diameter seamless tubes of superduplex stainless steel UNS32750. The result shows a good agreement between numerical experimental results. The proposed methodology can be used in complex geometries as a powerful tool to study and adjust welding parameters to minimize the residual stresses on welded mechanical components.

Residual Stress Measurements and Modelling for Temper Bead Qualification

2013 ◽  
Author(s):  
Xavier Ficquet ◽  
Vincent Robin ◽  
Ed Kingston ◽  
Stéphan Courtin ◽  
Miguel Yescas
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Hole Drilling ◽  
Stainless Steel Surface ◽  
Element Analysis ◽  
Stress Measurements ◽  
Welding Processes

This paper presents results from a programme of through thickness residual stress measurements and finite element analysis (FEA) modelling carried out on a temper bead mock-up. Emphasis is placed on results comparison rather than the measurement technique and procedure, which is well documented in the accompanying references. Temper bead welding processes have been developed to simulate the tempering effect of post-weld heat treatment and are used to repair reactor pressure vessel components to alleviate the need for further heat-treatment. The Temper Bead Mock-up comprised of a rectangular block with dimension 960mm × 189mm × 124mm was manufactured from a ferritic steel forged block with an austenitic stainless steel buttering and a nickel alloy temper bead cladding. The temper bead and buttering surfaces were machined after welding. Biaxial residual stresses were measured at a number of locations using the standard Deep-Hole Drilling (DHD) and Incremental DHD (iDHD) techniques on the Temper Bead Mock-up and compared with FEA modelling results. An excellent correlation existed between the iDHD and the modelled results, and highlighted the need for the iDHD technique in order to account for plastic relaxation during the measurement process. Maximum tensile residual stresses through the thickness were observed near the austenitic stainless steel surface at 298MPa. High compressive stresses were observed within the ferritic base plate beneath the bimetallic interface between austenitic and ferritic steels with peak stresses of −377MPa in the longitudinal direction.

Residual Stress Depth Distributions for Atmospheric Plasma Sprayed MnCo1.9Fe0.1O4 Spinel Layers on Crofer Steel Substrate

2017 ◽  
Vol 905 ◽  
pp. 174-181 ◽  
Author(s):  
Hyoung C. Back ◽  
Markus Mutter ◽  
Jens Gibmeier ◽  
Robert Mücke ◽  
Robert Vaßen
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Stress Analysis ◽  
Ferritic Stainless Steel ◽  
Steel Substrate ◽  
Atmospheric Plasma ◽  
Cathode Side ◽  
Hole Drilling ◽  
Residual Stress Analysis ◽  
Depth Distributions

In solid oxide fuel cells (SOFC) for operating temperatures of 800 °C or below, the use of ferritic stainless steel can lead to degradation in cell performance due to chromium migration into the cells at the cathode side [1]. Application of a coating on the ferritic stainless steel interconnect is one option to prevent Cr outward migration through the coating. MnCo1.9Fe0.1O4 (in the following designated as MCF) spinels act as a diffusion barrier and retain high conductivity during operation [2]. Knowledge about the residual stress depth distribution throughout the complete APS coating system is important and can help to optimize the coating process. This implicitly requires reliable residual stress analysis in the coating, the interface region and in the substrate.For residual stress analysis on these specific layered systems diffraction based analysis methods (XRD) using laboratory X-ray sources can only by applied at the very surface. For larger depths sublayer removal is necessary to gain reliable residual stress data. The established method for sublayer removal is electrochemical etching, which fails, since the spinel layer is inert. However, a mechanical layer removal will affect the local residual stress distribution.As an alternative, mechanical residual stress analyses techniques can be applied. Recently, we established an approach to analyse residual stress depth distributions in thick film systems by means of the incremental hole drilling method [5, 6]. In this project, we refined our approach for the application on MCF coatings with a layer thickness between 60 – 125 μm.

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