Fig 17 - uploaded by Obeid Obeid
Content may be subject to copyright.
Source publication
The paper presents a nonlinear heat-transfer and mechanical finite-element (FE) analyses of a two-pass welding process of two segments of lined pipe made of a SUS304 stainless steel liner and a C-Mn steel pipe. The two passes consist of the single-pass overlay welding (inner lap weld) of the liner with the C-Mn steel pipe for each segment and the s...
Similar publications
![Mechanical properties of ASTM A276 [8, 9].](profile/Husaini-2/publication/335664090/figure/tbl1/AS:800181805133824@1567789617432/Mechanical-properties-of-ASTM-A276-8-9_Q320.jpg)
![Chemical composition of ASTM A276 [8, 9].](profile/Husaini-2/publication/335664090/figure/tbl2/AS:800181805129728@1567789617460/Chemical-composition-of-ASTM-A276-8-9_Q320.jpg)
Residual stresses are inherently self-balanced stresses that arise due to non-uniform development of Eigen strains during processes like welding. Tensile residual stress in weld joints have a detrimental effect on the structural integrity and life of an engineering component, Accurate estimation and minimization of residual stress is a pre-requisit...
The utility of gray cast iron in engine components remains tied to the mechanical performance and cost. Repair and remanufacturing of castings offer economical and sustainable benefits; however, high thermal input from traditional fusion-based welding is unable to restore the original mechanical quality owing to brittle micro-structures and porosit...
Thermal analyses of girth welded joints of clads have been carried out using both finite element analysis and experimental simulation. Transient temperature curves have been generated for different cladding thicknesses (of stainless steel and mild steel). The welding of the two dissimilar materials has been carried out in-house with the aid of a Tu...
An experimental and numerical investigation on the thermal and mechanical response of a lined pipe (compound pipe) under welding is presented. The welding process consists of a single-pass overlay welding (inner lap-weld) and a two-pass girth welding (outer butt-weld). The influence of the filler material of the girth welding has been examined ther...
Citations
... The welding deformation finite element analysis involved two steps: first, a heat conduction analysis was performed, followed by a mechanical structural analysis based on the temperature history obtained from the heat conduction analysis. Obeid et al. presented a nonlinear heat-transfer and mechanical finite element (FE) analysis of a two-pass welding process of two segments of lined pipe made of SUS304 stainless steel liner and C-Mn steel pipe [4]. Numerous studies have focused on enhancing the efficiency of thermal elasto-plastic finite element analysis in welding applications. ...
In this study, thermal elasto-plastic finite element analysis was conducted to derive the optimal welding sequence to minimize overlay welding deformation on the water wall panels of an SRF (solid refuse fuel) boiler. The water wall panels of an SRF boiler are exposed to high temperatures and corrosive environments, making overlay welding essential. However, because the length of the water wall panels and tubes exceeds 7 m, significant deformation occurs after overlay welding. Additionally, due to the large size of the water wall panels, full-size thermal elasto-plastic analysis requires huge computational costs. Therefore, in this study, the effects of welding sequence on overlay welding deformation were first investigated for a reduced model to derive the optimal welding sequence. Subsequently, an analysis model for the full-size pipe panels was established to compare and analyze the conventional welding sequence with the optimal welding sequence, thereby verifying the validity of the study. According to the welding sequence derived from the reduced model, welding deformation in the full-size model was significantly reduced compared to the conventional sequence. This reduction in deformation was discussed by analyzing the deformation behavior of the structure at each stage of the overlay welding process.
... Significant advancements in FE codes over the last ten years have increased the reliability of the results in weld joints of pipes. Obeid et al. [7] demonstrates a two-pass welding procedure in stainless steel tubing using nonlinear coupled-thermal FE analysis. Zhao et al. [8] built a FE model for joining two dissimilar pipes of thickness 8.9 mm with 4 weld passes. ...
This study investigates the mechanical principles that dictate the changes in stress and strain during the welding of pipes, and presents the findings of a thermal-structural analysis of multi-pass welding. The deep-grooved thick pipe is considered to join with MIG welding. These joints need time consuming slow multi-pass welding processes, so, before beginning welding, it is crucial to have a comprehensive plan in place. The existing ANN-based trained data is adopted in FE analysis to maximize the sectional area of the weld bead in order to minimize the number of weld passes. The 3D welding mesh model was developed using Hypermesh and further simulated using Simufact. Data on thermal history, residual stresses, and strain were gathered during the welding process at the outer and inner surfaces of the thick pipe. The results show that the inner surface of welded pipes endures much more axial and hoop compressive plastic strain than the outer surface. After welding the hoop plastic strain experiences significant growth due to thermal shrinkage, while the axial plastic strain on the inner surface increases gradually. Results also demonstrate that the axial stresses are tensile in nature on the inner surface and compressive on the outer surface. The heat-affected zone displays the highest residual stresses, posing a risk of potential weld failure in this area.
Graphical abstract
... The double-ellipsoid heat source distribution model shown in Fig. 1, which can better depict the real welding pool morphology and heat source distribution under actual welding conditions, was adopted in the welding simulation (Obeid et al., 2017). The heat flux distribution in the first semi-ellipsoid can be written as ...
... The radiation heat transfer dominates at the higher temperature near the welding seam, while convection heat transfer dominates at the surface of the welding zone with a lower temperature away from the welding zone. Therefore, the combined boundary conditions in Eq. (5) are used to apply convection and radiation to the surface of the welding zone in the form of convection by a comprehensive heat transfer coefficient H (Obeid et al., 2017), and the initial ambient temperature was set to 20°C. ...
In this work, a finite-element welding model of the X80 pipeline is established, and the residual stress is calculated using a direct thermal–mechanical coupling method through the User Material (UMAT) subroutine of the double-ellipsoid moving heat source. The effects of process parameters on the welding residual stress of the X80 pipelines are discussed. The ultrasonic longitudinal critical refraction (LCR) wave-detecting method is adopted to verify the simulation results. The results show that the residual stress at the inner surface is higher than that at the outer surface, and the peak Mises stress at the welding seam approaches the yield stress. With the increase in welding groove angle and heat input, the peak Mises stress increases at the inner surface and decreases at the outer surface, but the high-stress zone at the outer surface broadens. The residual stresses at the outer surface are more sensitive to the welding parameters. The comparison between the simulated results and ultrasonic LCR detection indicates that the finite-element method is feasible, and the simulation results are credible.
... High strength low alloy (HSLA) steels are used in gas and oil transportation due to their improved mechanical properties, allowing pipes to work with elevated pressure, ensuring high productivity operations. However, in harsh environments, larger volumes of corrosive fluids containing CO 2 and H 2 S need to be transported through pipes, and this demand can be met by using corrosion-resistant alloys (CRA) [1,2]. Therefore, clad pipes were developed, where HSLA steels and CRA are combined to produce pipes with good mechanical and corrosion properties at a lower cost if compared to the solid CRA pipes [3]. ...
Pipes (rigid risers and flowlines) are employed to transport oil and gas from the wells to the platforms. In these pipes, the fluids can be very corrosive and, therefore, corrosion-resistant alloys (CRA) must be chosen. Alloy 625 is a well-known CRA with improved corrosion resistance. However, nickel-based alloys have high cost compared to that of the low alloy steels, thus pipes entirely made of CRA are economically unfeasible. Internal coating with a thin CRA layer is a less expensive and suitable alternative than the solid CRA. An internal coating by overlay manufacturing process can induce phase transformations at the interface. In this work, an alloy 625 cladding layer was deposited in an API X65 steel substrate with an automatic weld overlay system using gas tungsten arc welding (GTAW) process (often referred to as tungsten inert gas (TIG) hotwire). Thus, this study aims at evaluating an API X65 steel pipe cladded with alloy 625. The results show a suitable nickel-based alloy overlay deposited in an API X65 carbon steel substrate.
... The thermal analysis is based on the transient thermal field induced on the material via the TIG welding arc, which is applied as a volumetric heat source having the front and rear ellipsoidal shapes proposed by Goldak et al. [29]. This heat source model is established with a steep temperature gradient in front of the weld and the slow cooling rate at the rear section of the welding torch due to heat convection in the weld pool [30,31]. Figure 4 illustrates the Goldak's heat source. ...
Finite element (FE) analysis of welding residual stress and deformation is one of the essential stages in the manufacturing process of mechanical structures and parts. It aids in reducing the production cost, minimizing errors, and optimizing the manufactured component. This paper presents a numerical prediction of residual stress and deformation induced by two-pass TIG welding of Al 2219 plates. The FE model was developed using ABAQUS and FORTRAN packages, Goldak’s heat source model was implemented by coding the nonuniform distributed flux (DFLUX) in user subroutine to represent the ellipsoidal moving weld torch, having front and rear power density distribution. Radiation and convection heat losses were taken into account. The mechanical boundary condition was applied to prevent the model from rotation and displacement in all directions while allowing material deformation. The FE model was experimentally validated and the compared results show good agreement with average variations of 18.8% and 17.4% in residual stresses and deformation, respectively.
... Obeid et al. presented a nonlinear heat-transfer and mechanical finite-element (FE) analyses of a two-pass welding process of two segments of lined pipe made of a SUS304 stainless steel liner and a C-Mn steel pipe [8]. ...
Generally, equipment or mechanical parts are worn out by abrasion, impact, erosion, and environmental corrosion. To reduce these losses, the welding that wears the surface of the material with abrasion or corrosion resistance is called overlay welding. Corrosion and high temperature oxidation are very important factors in overlay welding material selection because they have a great effect on wear rate. Typical equipment is made of carbon steel, stainless steel or a material that is not wear resistant. Therefore, overlay welding is applied to parts where the parts themselves are subject to severe wear or corrosion. The diffusion of chlorine and alkaline ash during the combustion process causes foiling, corrosion, and erosion in the water wall panel & tube which is a heat transfer device. In order to protect the water wall panel & tube from various chemical and physical phenomena occurring during the combustion process, heat-resistant alloy steel such as Inconel is overlay welded on the outer surface of carbon steel pipe. However, since the length of the water wall panel & tube is more than 7 meters, the deformation after overlay welding is very large and the straightening work requires a lot of time and money. Also, since cooling water flows through the pipe during welding, the temperature of the cooling water also affects the welding deformation. In this study, welding process sequence and coolant temperature are optimized to minimize welding deformation during overlay welding.
... However, some discrepancies between the numerical and the experimental results were found because the weld cladding layer under the low alloy steel joint was not taken into account. As a consequence of the lined pipe welding limitation, Obeid et al. [15][16][17] presented a new procedure to simulate a typical lined pipe process including the weld overlay and girth welding. Furthermore, a sensitive analysis to determine the influence of the cooling time between weld overlay and girth welding and of the welding speed has been conducted thermally and mechanically [15]. ...
... As a consequence of the lined pipe welding limitation, Obeid et al. [15][16][17] presented a new procedure to simulate a typical lined pipe process including the weld overlay and girth welding. Furthermore, a sensitive analysis to determine the influence of the cooling time between weld overlay and girth welding and of the welding speed has been conducted thermally and mechanically [15]. However, the effect of the manufacturing procedure for lined pipes on the residual stresses during and after lined pipe welding has not been investigated yet. ...
... A transient heat-transfer analysis during welding, in general, is governed by the classical energy balance equation and its derivative equations to evaluate the thermal history during welding. These equations have been discussed by Obeid et al. [15] whose investigations have included work on the numerical lined pipe welding. In this study, the welding process starts after TFP treatment is completed and the ends of the lined pipe are machined with the whole pipe at room temperature. ...
Experimental tests of multi-pass lined pipe welding are reported and a computational procedure for the determination of the history of temperature, strains and residual stresses is presented in this paper and validated against the experimental test results. The effect of the manufacturing process of the lined pipe on the thermo-mechanical analysis has been investigated. A 3-D FE model using ABAQUS has been developed to simulate a circumferential single-pass weld overlay (lap-weld) and two-pass girth welding (butt-weld). Thermal history and strain fields have been recorded during welding using thermocouples and high temperature strain gauges, respectively. Residual stresses have been measured using residual stress gauges, deep-hole drilling technique and the X-ray diffraction technique along the outer and inner surfaces of the lined pipe. The welding test has been repeated twice to assess the accuracy of thermal and mechanical measurements. Overall, very good correlation has been observed between the experimental and numerical results.
... On the other hand, corrosive production fluids make the use of C-Mn steel pipe for flow line impossible, so that the need for corrosion mitigation is required [2]. One alternative is the use of a lined pipe, consisting of a thinner inner layer (the liner) and outer layer (backing steel) [3]. ...
An experimental and numerical investigation on the mechanical response of a lined pipe (compound pipe) under a dynamic impact is presented. The influence of the impact energy has been studied in terms of the depth of the dent formed, and of the strains and residual stresses. To this end, a three-dimensional explicit dynamic non-linear finite element model has been developed and successfully validated against the results of impact-test experiments conducted on pipes made of AISI 10305 steel, with and without the AISI304 stainless steel liner. The validation was made by comparing numerically computed strains with those measured by strain gauges, as well as in terms of permanent deformation. The model is then utilized to evaluate the residual stresses, the amount of energy dissipation and the velocity of impact process as a function of different pipes (i.e. with or without liner) and of the free drop heights.
... Even so, it is worth noting that the technique used to move the heat source around the weld overlay to fix and seal the liner at the pipe ends and then around the girth weld to join two specimens of lined pipe has not been reported yet. Consequently, Obeid et al. [11] presented a new procedure to simulate a typical lined pipe process including the weld overlay and girth welding. Furthermore, a sensitivity analysis to determine the influence of the cooling time between weld overlay and girth welding and of the welding speed has been conducted thermally and mechanically. ...
... Accounting for the rotational movement of the welding torch along the circumference, the power density can be given as a function of position and time as follows [11]: ...
... Through careful observation of Fig. 15(a) and (b), it can be clearly seen that the axial stress distributions around the welding direction have an almost homogenous distribution on the outer and inner surfaces. Consequently, the axial residual stress distributions do not strongly depend on the angular position [11]. ...
This paper investigates numerical thermal fields and residual stresses induced by single-pass weld overlay (lap-weld) and girth welding (butt-weld) in lined pipe using Tungsten Inert Gas (TIG) welding. A distributed power density of the moving heat source based on Goldak’s ellipsoid heat flux distribution is used in a Finite Element (FE) simulation of the lined pipe welding process. In addition, radiation and convection have been incorporated in heat transfer coefficient user-subroutines for the FE code ABAQUS. The 3-D FE model approach has been validated using previous experimental results published for butt-welds of similar sections of carbon-manganese C-Mn steel pipe lined with stainless steel. The FE model has been developed to determine the thermal isotherms and residual stress distributions from weld overlay and girth welding. The use of an inner layer known as a liner has a considerable influence on the thermal history and residual stress distributions. Furthermore, the influence of the weld overlay has been examined thermally and mechanically as it is a key factor that can affect the quality of lined pipe welding.
... Furthermore, no study has investigated the influence of different factors on lined pipe welding. Consequently, Obeid et al. [12] presented a new procedure to simulate a typical lined pipe process including the weld overlay and girth welding. Furthermore, a sensitivity analysis to determine the influence of the cooling time between weld overlay and girth welding and of the welding speed has been conducted thermally and mechanically. ...
... During the lined pipe welding process, the effects of volumetric change and the change in the yield stress value (the transformation plasticity) due to the metallurgical phase transformation, namely the martensitic phase transformation, have been neglected in this work because the volume dilation [16] and the reduction in the yield stress value [5] due to the phase transformation is small. Therefore, the increment of the total strain, dε ij , has been broken down into three components as follows [12]: ...
... In the kinematic hardening rule, the Bauschinger effect considers that the size and shape of the yield surface keep the same with translating in the stress space. Consequently, a linear kinematic hardening rule has been assumed for both materials C-Mn and AISI304 [12], with the hardening parameter obtained from the temperature-dependant yield stress reported in Fig. 6, when the plastic strain of C-Mn [9] and AISI304 [8] is equal to 1%. ...
Welded lined cylindrical structures such as boilers, pressure vessels and transportation pipes are widely used in the oil and gas industries because an inexpensive outer layer is protected from corrosion by a thinner expensive layer, which is made of a corrosion resistant alloy (CRA). Welding in the lined pipe is of two different types, where the first one, so called weld overlay (lap-weld), is deployed to seal the liner with the outer pipe whilst the other one, known as girth welding (butt-weld), is deposited to join two specimens of lined pipe together. Therefore, the precise prediction of the thermal and residual stress fields due to the combination of two different types of circumferential welding is a major concern regarding welded lined pipes to avoid sudden failure during service. Six parametric studies have been conducted primarily to examine the influence of welding properties (weld overlay and girth welding materials), geometric parameters (weld overlay and liner) and welding process parameters (heat input) on the thermal and residual stress fields. All predicted results obtained from a 3-D FE model based on the ABAQUS code are validated against small-scale experimental results. Furthermore, in this study, the effect of mesh size has been investigated.
