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.

Optimized Conditions for Tensile Residual Stress Reducing Weld Using Water-Shower Cooling

2003 ◽  
Author(s):  
Nobuyoshi Yanagida ◽  
Kunio Enomoto ◽  
Hideya Anzai
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Heat Input ◽  
Fem Analysis ◽  
Tensile Residual Stress ◽  
Input Quantity ◽  
Preheating Temperature ◽  
Optimized Conditions

To reduce tensile residual stress in a welded region, we developed a new cooling method that applies a water shower behind the welding torch. When this method is applied to the welding of austenitic stainless-steel, the welding and cooling conditions mainly determine how much the residual stress can be reduced. To optimize these conditions, we first used FEM to determine the effects of preheating temperature, heat input quantity, and water-shower area on the residual stress, and found that, to decrease tensile residual stress, preheating temperature should be high, heat input low, and the water-shower large. To confirm the effectiveness of these optimized conditions, residual stresses under optimized or non-optimized conditions were experimentally measured. It was found that the residual stresses were tensile under the non-optimized conditions, but compressive under the optimized ones. These measurements agree well with the FEM analysis. It can therefore be concluded that the optimized conditions are valid and appropriate for reducing residual stress in an austenitic stainless-steel weld.

Development of Residual Stress Improvement for Nuclear Pressure Vessel Instrumentation Nozzle Weld Joint (P-43+P-8) by Means of Induction Heating

2006 ◽  
Author(s):  
Takuro Terajima ◽  
Takashi Hirano
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Induction Heating ◽  
Weld Joint ◽  
Thermal Stresses ◽  
Pressure Vessels ◽  
Weld Joints

As a counter measurement of intergranular stress corrosion cracking (IGSCC) in boiling water reactors, the induction heating stress improvement (IHSI) has been developed as a method to improve the stress factor, especially residual stresses in affected areas of pipe joint welds. In this method, a pipe is heated from the outside by an induction coil and cooled from the inside with water simultaneously. By thermal stresses to produce a temperature differential between the inner and outer pipe surfaces, the residual stress inside the pipe is improved compression. IHSI had been applied to weld joints of austenitic stainless steel pipes (P-8+P-8). However IHSI had not been applied to weld joints of nickel-chromium-iron alloy (P-43) and austenitic stainless steel (P-8). This weld joint (P-43+P-8) is used for instrumentation nozzles in nuclear power plants’ reactor pressure vessels. Therefore for the purpose of applying IHSI to this one, we studied the following. i) Investigation of IHSI conditions (Essential Variables); ii) Residual stresses after IHSI; iii) Mechanical properties after IHSI. This paper explains that IHSI is sufficiently effective in improvement of the residual stresses for this weld joint (P-43+P-8), and that IHSI does not cause negative effects by results of mechanical properties, and IHSI is verified concerning applying it to this kind of weld joint.

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.

Measuring residual stresses in stainless steel—recent experiences within a VAMAS exercise

2009 ◽  
Vol 24 (S1) ◽  
pp. S41-S44 ◽  
Author(s):  
A. T. Fry ◽  
J. D. Lord
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Residual Stresses ◽  
Best Practice ◽  
Test Procedure ◽  
Industrial Plant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Industrial Sectors

Residual stresses impact on a wide variety of industrial sectors including the automotive, power generation, industrial plant, construction, aerospace, railway and transport industries, and a range of materials manufacturers and processing companies. The X-ray diffraction (XRD) technique is one of the most popular methods for measuring residual stress (Kandil et al., 2001) used routinely in quality control and materials characterization for validating models and design. The VAMAS TWA20 Project 3 activity on the “Measurement of Residual Stresses by X-ray Diffraction” was initiated by NPL in 2005 to examine various aspects of the XRD test procedure in support of work aimed at developing an international standard in this area. The purpose of this project was to examine and reduce some of the sources of scatter and uncertainty in the measurement of residual stress by X-ray diffraction on metallic materials, through an international intercomparison and validation exercise. One of the major issues the intercomparison highlighted was the problem associated with measuring residual stresses in austenitic stainless steel. The following paper describes this intercomparison, reviews the results of the exercise and details additional work looking at developing best practice for measuring residual stresses in austenitic stainless steel, for which X-ray measurements are somewhat unreliable and problematic.

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.

Welding Process Development for Spent Nuclear Fuel Canister Repair

2019 ◽  
Author(s):  
Wei Tang ◽  
Stylianos Chatzidakis ◽  
Roger Miller ◽  
Jian Chen ◽  
Doug Kyle ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Nuclear Fuel ◽  
Arc Welding ◽  
Spent Nuclear Fuel ◽  
Welding Process ◽  
Tensile Residual Stress ◽  
304L Stainless Steel ◽  
Welding Temperature ◽  
Stress Direction

Abstract The potential for stress corrosion cracking (SCC) of welded stainless-steel interim storage containers for spent nuclear fuel (SNF) has been identified as a high priority data gap. This paper presents a fusion welding process that was developed for SNF canister repair. Submerged arc welding (SAW) was developed to weld 12.7 mm (0.5 in.) thick 304L stainless steel plates to simulate the initial welds on SNF canisters. The SAW procedure was qualified following ASME Boiler and Pressure Vessel Code requirements. During SAW, the welding temperature was recorded at various locations by using thermocouples. After SAW, weld microstructures were characterized, joint mechanical properties were tested, and the maximum tensile residual stress direction was identified. After SAW procedure qualification, artificial cracks were excavated perpendicular to the maximum tensile residual stress direction in the SAW heat affected zone. Machine cold-wire gas tungsten arc welding (CW-GTAW) was developed and used for repair welding at cracked locations.

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.

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