scholarly journals Residual Stresses of Explosion Cladded Composite Plates of ZERON 100 Superduplex Stainless Steel and ASTM SA516-70 Carbon Steel

2014 ◽  
Vol 996 ◽  
pp. 500-505 ◽  
Author(s):  
Rogério Varavallo ◽  
Vitor de Melo Moreira ◽  
Vinicius Paes ◽  
Pedro Brito ◽  
Jose Olivas ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Residual Stresses ◽  
Welding Process ◽  
Composite Plates ◽  
Weld Interface ◽  
Hardness Profile ◽  
Superduplex Stainless Steel

In the present work bimetal composite plates of ZERON 100 superduplex stainless steel and ASME SA516-70 carbon steel were produced by explosion welding and submitted to post weld heat treatment for stress relief. The cross section microstructure of the cladded plates was characterized by optical microscopy and scanning electron microscopy and the hardness profile across the weld interface was determined. Residual stress analysis by X-ray diffraction was performed before and after heat treatment on the stainless steel side of the cladded plates. In the as-welded condition, metallography analysis indicated severe plastic deformation at the welded interface and a wavy morphology characteristic of high adhesive strength. Elevated tensile residual stresses were created as a result of the welding process. The heat treatment process applied (6h at 250°C) did not alter hardness at the welded interface nor the residual stress state in the cladded materials.

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.

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.

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.

Reduce the Residual Stress of Welded Structures by Post-Weld Vibration

2005 ◽  
Vol 490-491 ◽  
pp. 102-106 ◽  
Author(s):  
De Lin Rao ◽  
Zheng Qiang Zhu ◽  
Li Gong Chen ◽  
Chunzhen Ni
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Mechanical Vibration ◽  
Welding Process ◽  
Hole Drilling ◽  
Welded Structures ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Before And After

The existence of residual stresses caused by the welding process is an important reason of cracking and distortion in welded metal structures that may affect the fatigue life and dimensional stability significantly. Heat treatment is one of the traditional methods to relieve the residual stresses. But it is often limited by the manufacturing condition and the size of the structures. In this paper a procedure called vibratory stress relief (VSR) is discussed. VSR is a process to reduce and re-distribute the internal residual stresses of welded structures by means of post-weld mechanical vibration. The effectiveness of VSR on the residual stresses of welded structures, including the drums of hoist machine and thick stainless steel plate are investigated. Parameters of VSR procedure are described in the paper. Residual stresses on weld bead are measured before and after VSR treatment by hole-drilling method and about 30%~50% reduction of residual stresses are observed. The results show that VSR process can reduce the residual stress both middle carbon steel (Q345) and stainless steel (304L) welded structures effectively.

Residual Stress Generation and Relaxation in Butt-Welded Pipes

1982 ◽  
Vol 104 (3) ◽  
pp. 188-192 ◽  
Author(s):  
S. Nair ◽  
E. Pang ◽  
R. C. Dix
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Numerical Scheme ◽  
Stress Generation ◽  
304 Stainless Steel ◽  
Thermally Induced ◽  
Steel Pipes

A numerical scheme for the determination of thermally induced local residual stresses and their relaxation behavior during heat treatment in the case of butt-welded pipes is described. The procedure is illustrated by considering 304 stainless steel and SAE 1020 steel pipes. The results are compared with available experimental and numerical results.

Crack Analysis of a Pressure Vessel Using the API 579-1/ASME FFS-1

2017 ◽  
Author(s):  
Jose de Jesus L. Carvajalino ◽  
José Luiz F. Freire ◽  
Vitor Eboli L. Paiva ◽  
José Eduardo Maneschy ◽  
Jorge G. Diaz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Duplex Stainless Steel ◽  
Pressure Vessel ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
The Other ◽  
Austenitic Steels

This paper presents a structural integrity evaluation of a duplex stainless steel pressure vessel containing several flaws detected in a longitudinal weld. The evaluation had the objective of determining whether the pressure vessel was suitable to continue in operation or whether it should be immediately repaired or even replaced. Due to timely issues, a first analysis was conducted in accordance with the 2007 edition of the API 579-1/ASME FFS-1 Standard [1]. A second analysis was later repeated based on the 2016 edition [1]. Results obtained from both analyses were compared and presented relevant differences caused by the other calculation procedures used to determine residual stresses generated in the longitudinal welding. The assessment was based on the Failure Assessment Diagram (FAD). The existing indications were detected by ultrasonic examination and were located in one longitudinal weld. The assessment evaluations used stress intensity factors for the opening mode I, KI, obtained for two cases: 1) the combination of the several supposedly interacting cracks into an equivalent crack using the interaction criteria presented in [1]; 2) the allocation of the multiple cracks into a finite element model that took into consideration, more realistically, the interaction among the individual cracks. The total loads and stresses considered in the analysis resulted from a superposition of the design pressure stress and the residual stresses induced by the welding process. Due to lack of information on the material fracture toughness for the duplex stainless steel used in the vessel, the material toughness was estimated using a lower bound value suggested in [1] for common welded stainless austenitic steels, although higher values can be predicted for duplex steels by extending the use of a transition master curve as presented and discussed elsewhere [2–7] and by employing specific Charpy test results for the vessel material. One of the key aspects of the problem was the calculation of the residual stress distribution imposed by the welding process. Two procedures were adopted: one available in the API/ASME Standard issued in 2007, and the other in the 2016 release. The results presented in this paper have demonstrated that the limits of the Standard 2007 are conservatively satisfied when the Level 3 assessment is applied. The re-analysis of the vessel when subjected to the residual stress distribution presented in the newest 2016 edition leads to consider the vessel safe under an assessment Level 2. The overall conclusion was that the damaged pressure vessel could continue in service under restrictions of the development of an inspection plan to verify the absence of future crack growth.

Residual Stress Generation and Relaxation in Butt-Welded Pipes

1982 ◽  
Vol 104 (1) ◽  
pp. 42-46 ◽  
Author(s):  
S. Nair ◽  
E. Pang ◽  
R. C. Dix
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Numerical Scheme ◽  
Stress Generation ◽  
304 Stainless Steel ◽  
Thermally Induced ◽  
Steel Pipes

A numerical scheme for the determination of thermally induced local residual stresses and their relaxation behavior during heat treatment in the case of butt-welded pipes is described. The procedure is illustrated by considering 304 stainless steel and SAE 1020 steel pipes. The results are compared with available experimental and numerical results.

Thermal Recovery of Plastic Deformation in Dissimilar Metal Weld

2014 ◽  
Vol 783-786 ◽  
pp. 2857-2862
Author(s):  
Dong Xiao Qiao ◽  
Xing Hua Yu ◽  
Wei Zhang ◽  
Paul Crooker Yu ◽  
Stan David ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Stress Corrosion ◽  
Strain Hardening ◽  
Stress Corrosion Cracking ◽  
Thermal Recovery ◽  
Plastic Strains ◽  
Dissimilar Metal

Stainless steel has been widely used in challenging environments typical to nuclear power plant structures, due its excellent corrosion resistance. Nickel filler metals containing high chromium concentration, including Alloy 82/182, are used for joining stainless steel to carbon steel components to achieve similar high resistance to stress corrosion cracking. However, the joint usually experience weld metal stress corrosion cracking (SCC), which affects the safety and structural integrity of light water nuclear reactor systems. A primary driving force for SCC is the high tensile residual stress in these welds. Due to large dimension of pressure vessel and limitations in the field, non-destructive residual stress measurement is difficult. As a result, finite element modeling has been the de facto method to evaluate the weld residual stresses. Recent studies on this subject from researchers worldwide report different residual stress value in the weldments [5]. The discrepancy is due to the fact that most of investigations ignore or underestimate the thermal recovery in the heat-affect zone or reheated region in the weld. In the current study, the effect of heat treatment on thermal recovery and microhardness is investigated for materials used in dissimilar metal joint. It is found that high equivalent plastic strains are predominately accumulated in the buttering layer, the root pass, and the heat affected zone, which experience multiple welding thermal cycles. The final cap passes, experiencing only one or two welding thermal cycles, exhibit less plastic strain accumulation. Moreover, the experimental residual plastic strains are compared with those predicted using an existing weld thermo-mechanical model with two different strain hardening rules. The importance of considering the dynamic strain hardening recovery due to high temperature exposure in welding is discussed for the accurate simulation of weld residual stresses and plastic strains. Finally, the experimental result reveals that the typical post-buttering heat treatment for residual stress relief may not be adequate to completely eliminate the residual plastic strains in the buttering layer.

Microstructure and Residual Stress Analysis of Dissimilar Metal Composite Plates Produced by Explosion Welding

2014 ◽  
Author(s):  
Rogério Varavallo ◽  
Vitor de Melo Moreira ◽  
Vinicius Paes ◽  
Pedro Brito ◽  
José Olivas ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Composite Plates ◽  
Base Plate ◽  
Explosion Welding ◽  
Inconel 625 ◽  
Metal Composite ◽  
Superaustenitic Stainless Steel ◽  
Clad Metals ◽  
Superduplex Stainless Steel

In the present work, different corrosion resistant materials (AL-6XN superaustenitic stainless steel, ZERON 100 superduplex stainless steel and Inconel 625 Ni alloy) were joined with ASME SA516-70 carbon steel by explosion welding to form bimetal composite plates. The microstructure of cladded plates was characterized by optical and scanning electron microscopy and the hardness variation across the interface was determined by applying Vickers microhardness. The residual stresses generated by the cladding process were determined by X-ray diffraction. All materials adhered well to the ASME SA516-70 base plate and the cladded interface exhibited the wavy morphology usually associated with strong bond strengths. Hardness increased near the interface due to strain hardening caused by plastic deformation and tensile residual stresses were found to develop on all clad metals.

Numerical Analysis of Residual Stresses in V-Butt Welded Joint of Two Dissimilar Pipes

2013 ◽  
Author(s):  
Gurinder Singh Brar ◽  
Gurdeep Singh
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Residual Stresses ◽  
Filler Metal ◽  
Welded Joint ◽  
Low Carbon Steel ◽  
Stress Distributions ◽  
Low Carbon

In this paper a three-dimensional welding simulation was carried out by commercially available finite element software to predict temperature and the residual stress distributions in V-butt welded joint of two dissimilar pipes. Low carbon steel and stainless steel pipe welding is widely used in a variety of engineering applications such as oil and gas industries, nuclear and thermal power plants and chemical plants. Inelastic deformations during heat treatment are the major cause of residual stress. Heat during welding causes localized expansion as some areas cool and contract more than others. The stress variation in the weldment can be very complex and can vary between compressive and tensile stresses. The mismatching (in the weld in general) occurs due to joint geometry and plate thickness. Welding procedures and degree of restraints also influences the residual stress distributions. To understand the behavior of residual stress, two dissimilar pipes one of stainless steel and another of low carbon steel with outer diameter of 356 mm and internal diameter 240 mm were butt welded. The welding was completed in three passes. The first pass was performed by Manual TIG Welding using ER 309L as a filler metal. The remaining weld passes were welded by Manual Metal Arc Welding (MMAW) and ER 309L-16 was used as a filler metal. During each pass, attained peak temperature and variation of residual stresses and magnitude of axial stress and hoop stress in pipes has been calculated. The results obtained by finite element method agree well with those from Ultrasonic technique (UT) and Hole Drilling Strain-Gauge (HDSG) as published by Akhshik and Moharrami (2009) for the improvement in accuracy of the measurements of residual stresses.

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