Experimental Analysis of Repair Welding Alternatives for Shipbuilding DH36 Plates

2020 ◽  
Vol 64 (04) ◽  
pp. 384-391
Author(s):  
Tetyana Gurova ◽  
Segen F. Estefen ◽  
Anatoli Leontiev ◽  
Plinio T. Barbosa ◽  
Valentin Zhukov ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Best Practice ◽  
Welding Process ◽  
Offshore Structures ◽  
Residual Stress Distribution ◽  
Shipbuilding Industry ◽  
Repair Welding ◽  
Ship Construction ◽  
Repair Techniques

Repair by welding is widely used in the shipbuilding industry during ship construction. The effect of the residual stress distribution induced by the welding process on the ship structure is important for the repair effectiveness. This article presents an experimental study of the residual stress distribution induced by repair welding in the plates that are typically used in ships and offshore structures. Different repair techniques are evaluated to identify the best practice associated with residual stress values. Recommendations for repair welding are discussed, and modifications to the present practice are proposed.

Residual Stress Evaluation of Dissimilar Weld Joint Using Reactor Vessel Outlet Nozzle Mock-Up Model (Report-1)

2008 ◽  
Author(s):  
Itaru Muroya ◽  
Youichi Iwamoto ◽  
Naoki Ogawa ◽  
Kiminobu Hojo ◽  
Kazuo Ogawa
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Welding Process ◽  
Reactor Vessel ◽  
Residual Stress Distribution ◽  
Test Model ◽  
Alloy 600 ◽  
Outlet Nozzle ◽  
Stress Evaluation ◽  
Weld Region

In recent years, the occurrence of primary water stress corrosion cracking (PWSCC) in Alloy 600 weld regions of PWR plants has increased. In order to evaluate the crack propagation of PWSCC, it is required to estimate stress distribution including residual stress and operational stress through the wall thickness of the Alloy 600 weld region. In a national project in Japan for the purpose of establishing residual stress evaluation method, two test models were produced based on a reactor vessel outlet nozzle of Japanese PWR plants. One (Test model A) was produced using the same welding process applied in Japanese PWR plants in order to measure residual stress distribution of the Alloy 132 weld region. The other (Test model B) was produced using the same fabrication process in Japanese PWR plants in order to measure stress distribution change of the Alloy 132 weld region during fabrication process such as a hydrostatic test, welding a main coolant pipe to the stainless steel safe end. For Test model A, residual stress distribution was obtained using FE analysis, and was compared with the measured stress distribution. By comparing results, it was confirmed that the FE analysis result was in good agreement with the measurement result. For mock up test model B, the stress distribution of selected fabrication processes were measured using the Deep Hole Drilling (DHD) method. From these measurement results, it was found that the stress distribution in thickness direction at the center of the Alloy 132 weld line was changed largely during welding process of the safe end to the main coolant pipe.

Comparison of Residual Stress Between MIG Welding and Friction Stir Welding

2012 ◽  
Vol 155-156 ◽  
pp. 1218-1222
Author(s):  
Lei Wang ◽  
Mitsuyosi Tsunori
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Stress Distribution ◽  
Yield Strength ◽  
Room Temperature ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Mig Welding ◽  
Friction Stir ◽  
Friction Stir Welding Process

Residual stress distribution plays a very important role in welded structures, the aim of present work is to find out the effect of different welding methods on the residual stress distribution by means of neutron diffraction measurements and FE models simulation. 4 mm thick DH-36 steel plates were butt welded by MIG welding process and 5 mm thick AA 2024 aluminium alloy plates were butt welded by friction stir welding process. Results show that residual stresses of MIG welding process are higher than those of friction stir welding process. The peak residual stress of MIG weld is close to the room temperature uniaxial yield strength of DH-36 while the peak residual stress of friction stir weld is just about 50% of the room temperature uniaxial yield strength of AA2024. The size effect of MIG welded and effect of welding speeds of friction stir welded on the residual stress distribution have also been studied in the paper.

Effect of Welding Sequence on the Residual Stress Distribution in a Stiffened Plate

2016 ◽  
Author(s):  
Bai-Qiao Chen ◽  
C. Guedes Soares
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Lower Layer ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Steel Plates ◽  
Tension Zone ◽  
Welding Sequence

This work investigates the temperature distribution, deformation and residual stress in steel plates as a result of different sequences of welding. The single-pass gas tungsten arc welding process is simulated by a three dimensional nonlinear thermo-elasto-plastic approach. It is observed that the distribution of residual stress varies through the direction of plate thickness. It is concluded that the welding sequence affects not only the welding deformation but also the residual stress mainly in the lower layer of the plates. An in-depth discussion on the pattern of residual stress distribution is presented, especially on the width of the tension zone. Smaller residual tension zone and slightly lower compressive stress are found in thicker plate.

scholarly journals 16.29: Determination of the residual stress distribution of steel bridge components by modelling the welding process

ce/papers ◽  
2017 ◽  
Vol 1 (2-3) ◽  
pp. 4276-4282
Author(s):  
Evy Van Puymbroeck ◽  
Wim Nagy ◽  
Ken Schotte ◽  
Zain Ul-Abdin ◽  
Hans De Backer
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Steel Bridge

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.

SCC Assessment Based on Probability Fracture Mechanics Considering SCC Initiation and Propagation Under Residual Stress Fields Generated by Machining and Welding Process of Pipes

2013 ◽  
Author(s):  
Masahito Mochizuki ◽  
Ryohei Ihara ◽  
Jinya Katsuyama ◽  
Makoto Udagawa
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Crack Growth ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Initiation Time ◽  
Butt Welding ◽  
Surface Machining ◽  
Inner Surface ◽  
Growth Analyses

Stress corrosion cracking (SCC) has been observed near the welded zones of pipes made of austenitic stainless steel type 316L. Residual stress is an important factor for SCC. In the joining processes of pipes, butt welding is conducted after surface machining. Residual stress is generated by both processes, and the residual stress distribution by surface machining is varied by the subsequent butt-welding process. In this study, numerical analysis of the residual stress distribution by butt welding after surface machining was performed by the finite element method. The SCC initiation time was estimated by the residual stress obtained at the inner surface. SCC growth analyses based on probability fracture mechanics were performed by using the SCC initiation time and the residual stress distribution. As a result, the residual stress distribution in the axial direction due to butt welding after surface machining has high tensile stress exceeding 1000 MPa at the inner surface. The effect of SCC initiation on leakage probability is not as significant as the effect of plastic strain on the crack growth rate. However, to perform crack growth analyses considering SCC initiation, evaluation of the residual stress due to surface machining and welding is important.

Standardized Through-Wall Distributions of Dissimilar Metal Weld Residual Stress

2015 ◽  
Author(s):  
John E. Broussard
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Crack Growth ◽  
Welding Process ◽  
Wall Stress ◽  
Residual Stress Distribution ◽  
Analytical Models ◽  
Stress Distributions ◽  
Dissimilar Metal

The residual stresses imparted by the welding process are a principal factor in the process of primary water stress corrosion cracking (PWSCC) of Alloy 82/182 nickel-alloy (i.e., dissimilar metal or DM) piping butt welds in PWRs. While Section XI of the ASME Code requires that residual stresses are considered in crack growth calculations, there is little guidance or requirement on how to calculate them. Analytical models are frequently used to simulate the welding process in order to predict the residual stress distribution in the weld and base material as an input to crack growth calculations. The crack growth calculations, in turn, have demonstrated a high sensitivity to the welding residual stress distribution inputs. While significant progress has been made in understanding and reducing the variability in calculated residual stress among modelers as well as the variability in measured residual stress among different techniques, there remains some uncertainty regarding any given measured or calculated distribution. A feasible alternative to calculating through-wall stress distributions with analytical models on a case-by-case basis is to develop a set of standardized through-wall stress distributions that are applicable to DM welds. Examples of standardized through-wall distributions for residual stress are found in numerous consensus code and standards. The benefit of established through-wall stress distributions is that evaluations for flaws in welds would start from a uniform basis on one of the key inputs to the crack growth calculation, reducing the time required to perform and review flaw evaluations. This paper presents and describes the technical basis for a set of through-wall distributions for common DM welds found in the US nuclear industry. The basis of the distributions include the results of analytical models, including uncertainty, as well as measured data for through-wall stress in DM welds.

scholarly journals Influence of Interlayer Temperature and Welding Sequence on the Temperature Distribution and Welding Residual Stress of the Saddle-Shaped Joint of Weldolet-Header Butt Welding

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5980
Author(s):  
Chunliang Mai ◽  
Xue Hu ◽  
Lixin Zhang ◽  
Bao Song ◽  
Xiongfei Zheng
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Stress Distribution ◽  
High Stress ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Welding Residual Stress ◽  
Two Stage ◽  
Welding Sequence ◽  
Simulation Results

In this paper, based on Simufact Welding finite element analysis software, a numerical simulation of the temperature and residual stress distribution of the weldolet-header multi-layer multi-pass welding process is carried out, and the simulation results are verified through experiments. The experimental results are in good agreement with the numerical simulation results, which proves the validity of the numerical simulation results. Through the results of the numerical simulation, the influence of the welding sequence and interlayer temperature on the temperature and residual stress distribution at different locations of the saddle-shaped weld was studied. The results show that the temperature and residual stress distribution on the header and weldolet are asymmetric, and the high-stress area of the saddle-shaped welded joint always appears at the saddle shoulder or saddle belly position. When the interlayer temperature is 300 °C, the peak residual stress reaches a minimum of 428.35 MPa. Adjusting the welding sequence can change the distribution trend of residual stress. There is no high-stress area on the first welding side of the two-stage welding path-2. The peak values of residual stresses for continuous welding path-1 and two-stage welding path-2 are 428.35 MPa and 434.01 MPa, respectively, which are very close to each other.

Finite Element Modeling of Transient Temperature and Residual Stress Distribution Analysis in Multi-Pass Welding Process

2012 ◽  
Author(s):  
Guang-Ming Fu ◽  
Chen An ◽  
Marcelo Igor Lourenço ◽  
Meng-Lan Duan ◽  
Segen F. Estefen
Keyword(s):  
Residual Stress ◽  
Temperature Distribution ◽  
Stress Distribution ◽  
Heat Source ◽  
Welding Process ◽  
Source Model ◽  
Residual Stress Distribution ◽  
Transient Temperature ◽  
Fe Model ◽  
Transient Temperature Distribution

The residual stress and deformation due to the welding process have significant influences on the service performance of the welded deepwater platform hull. An exact prediction of transient temperature distribution is the important prerequisite to ensure the simulation accuracy of the welding residual stress and deformation fields, especially in the multi-pass welding process. Although the transient temperature distribution and residual stress distribution was studied in the past by various authors, the literature on 3D finite element (FE) simulation of multi-pass welding process is limited. In this paper, a FE model is developed to analyze the transient temperature and residual stress distribution of AH36 steel sheets in multi-pass welding process. A moving heat source model based on Goldak’s double-ellipsoidal heat flux distribution is employed for the heated plates. The addition of the volumetric heat source into the FE model and its movement along the welding pass are realized through a dedicated FORTRAN subroutine. The element birth and death technique in Abaqus/Standard is employed to simulate the weld filler variation with time in welded joints. The transient temperature calculated in the first stage is utilized as the input to the residual stress and distortion due to thermal shrinkage during the welding process and subsequent cooling. The results show good agreements between the temperature distribution and the geometry of weld pool obtained in the present work and those previously reported. Finally, a parametric study is performed to investigate the effect of welding variables, such as geometric parameters of Goldak’s heat source model, welding speed, pre-heat temperature and power input in the multi-pass welds, on the residual stress and distortion of the steel sheets.

Analysis of Temperature and Residual Stress Distribution in Laser Welding for Ta/Mo Lap Joints Using FEM

2013 ◽  
Vol 820 ◽  
pp. 220-224
Author(s):  
Liang Jin ◽  
Fang Fang Song ◽  
Guo Qiang Wei ◽  
Qi Guo
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Laser Welding ◽  
Weld Zone ◽  
Welding Process ◽  
Physical And Mechanical Properties ◽  
Element Model ◽  
Lap Joints ◽  
Residual Stress Distribution ◽  
Laser Welding Process

A nonlinear transient three-dimensional finite element model for the laser welding process is developed to investigate the temperature and residual stress distribution. All the major physical phenomena associated to the laser welding process, including temperature dependent thermo-physical and mechanical properties are taken into account in the model. The heat input to the model is assumed to be a Gaussian heat source. Results show that the temperature distribution of laser welding is consistent with the actual, and along-welding line longitudinal stress and transverse stress are retained in the weld zone after laser welding and cooling to the room temperature.

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