Thermal Simulation and Its Experimental Verifications for Girth Welds in High-Strength Pipelines

2010 ◽  
Author(s):  
Yaoshan Chen ◽  
Yong-Yi Wang ◽  
Vaidyanath Rajan ◽  
Marie Quintana
Keyword(s):  
Thermal Model ◽  
Gas Metal Arc Welding ◽  
Superposition Principle ◽  
High Strength Steels ◽  
High Strength ◽  
Welding Parameters ◽  
Transfer Model ◽  
Thermal Cycles ◽  
Girth Welds ◽  
Welding Processes

Girth welds in high-strength pipeline constructions are often made with mechanized pulsed gas-metal-arc welding (P-GMAW) process. Welding of the high strength steels poses a number of challenges because of the sensitivity of weld mechanical properties to variations in welding parameters and material properties. In addition to the unique characteristics of narrow groove weld geometry and multiple weld passes, the fabrication of P-GMAW girth welds sometimes also employs alternative welding processes such as dual torch or tandem wire in order to increase pipeline construction productivity. In order to understand the dependency of weld properties on welding processes and their parameters, a transient thermal model for multi-pass girth weld had been proposed and successfully developed. The heat transfer model used the superposition principle of heat sources to handle the welding processes with multiple wires or multiple passes. This paper presents the latest development of this numerical approach and its verification against experimental measurements of thermal cycles from X100 girth welds under different welding conditions. A number of X100 pipe girth welds under different welding conditions were made for the verification purpose. The welding conditions include single torch and dual torch P-GMAW process, 1G and 5G welding. Thermocouples were placed in the heat-affected zone (HAZ) and the weld-pool for the measurements of thermal cycles. The measured thermal cycles and cooling times from 800°C to 500°C were compared to those predicted by the thermal model. Very good agreements between the measured results and the numerical prediction by the thermal model were achieved.

Simulation of Microstructure Evolution and Its Experimental Verifications for Girth Welds in High-Strength Pipelines

2010 ◽  
Author(s):  
Yaoshan Chen ◽  
Yong-Yi Wang ◽  
James Gianetto ◽  
Vaidyanath Rajan ◽  
Marie Quintana
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Thermal Model ◽  
Measurement Data ◽  
High Strength ◽  
Welding Parameters ◽  
Thermal Cycles ◽  
Microstructure Model ◽  
Girth Welds ◽  
Welding Processes

Girth Welding of high strength steels such as X80 or X100 poses a number of challenges because of the sensitivity of weld mechanical properties to variations in welding parameters and material properties. This dependency is further complicated by the application of alternative welding processes with multiple wires, tandem wire or dual torch welding, for example. In order to correlate the relation between weld mechanical properties and the welding conditions, an integrated thermal and microstructure model has been developed. Given the welding conditions, the thermal model is able to simulate the local thermal cycles for a girth weld with multiple passes and multiple electrode wires. In the mean time, a microstructure model, using the thermal cycles obtained from the thermal model as input, simulates the microstructure evolution both in the weld metal and the HAZ as the welding progresses. This paper presents the latest development of this microstructure model and its verification against metallurgical measurement data from X100 girth welds. These welds included girth welds made under practical welding conditions and experimental welds made with X100 plates. The measured hardness was compared to the predicted by the microstructure model. The comparison indicated that the microstructure was able to predict the hardness profiles in a multi-pass girth weld and the general trend of variation as a function of welding conditions. In order to improve the accuracy of hardness prediction, the areas of improvement in the microstructure model have been identified.

Microstructure and Properties of High Strength Steel Weld Metals

2012 ◽  
Author(s):  
J. A. Gianetto ◽  
G. R. Goodall ◽  
W. R. Tyson ◽  
F. Fazeli ◽  
M. A. Quintana ◽  
...  
Keyword(s):  
Weld Metal ◽  
Gas Metal Arc Welding ◽  
Large Diameter ◽  
High Strength Steels ◽  
High Strength ◽  
High Productivity ◽  
Metal Arc Welding ◽  
Wide Range ◽  
Girth Welds ◽  
Welding Processes

With an industry trend towards application of modern high strength steels for construction of large diameter, high pressure pipelines from remote northern regions there is a need to develop high-productivity welding processes to reduce costs and deal with short construction seasons. Achieving the required level of weld metal overmatching together with adequate ductility and good low temperature toughness is another major challenge for joining high strength X80/100 pipes. It is important to develop an improved understanding of weld metal systems that are required for the successful production of high strength pipeline girth welds that are needed for such demanding pipeline construction. In this investigation a range of weld metal (WM) compositions based on (i) C-Mn-Si-Mo, (ii) C-Mn-Si-Ni-Mo-Ti and (iii) C-Mn-Si-Ni-Cr-Mo-Ti was selected for more detailed evaluation of experimental plate welds complemented by specimens simulated by Gleeble® thermal cycling. Five specially-designed experimental plate welds were made with a robotic single torch pulsed gas metal arc welding (GMAW-P) procedures with wire electrodes applicable for joining X100 pipe. The procedures consisted of three initial fill passes deposited at 0.5 kJ/mm and a final deep-fill pass at 1.5 kJ/mm to just fill the narrow-gap joint. An important part of the research focused on development of WM Continuous Cooling Transformation (CCT) diagrams to establish the influence of composition and thermal cycle (cooling time) on formation of fine-scale, predominantly martensite, bainite and acicular ferrite (AF) microstructures. For the relatively wide range of cooling times investigated (Δt800−500 = 2 to 50 s), the lowest-alloyed WM (LA90) exhibited microstructures dominated by bainite with martensite to AF, whereas the highest-alloyed WM (PT02) formed large fractions of martensite with bainite to AF. Weld metal toughness was evaluated using both through-thickness notched 2/3 sub-size Charpy-V-notch (CVN) specimens as well as full-size surface-notched specimens. Post-test metallographic and fractographic examinations of selected fractured specimens were used to correlate WM microstructure and notch toughness.

Cooling Curve Based Estimation of Mechanical Properties in High Strength Steel Welds

2016 ◽  
Vol 879 ◽  
pp. 1760-1765 ◽  
Author(s):  
Rahul Sharma ◽  
Uwe Reisgen
Keyword(s):  
Mechanical Properties ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Structural Steels ◽  
Cooling Time ◽  
Cooling Curve ◽  
Welding Parameters ◽  
Steel Welds ◽  
Welding Processes

The application of high strength steels in welded structures relies on easy to use quality assurance concepts for the welding process. For ferritic steels, one of the most common methods for estimating the mechanical properties of welded joints is the cooling time concept t8/5. Even without experimental determination, the calculation of cooling time with previously introduced formulas based on the welding parameters leads to good results. Because high strength structural steels and weld metals with a yield strength of 960 MPa contain higher quantities of alloying elements, the transformation start temperature Ar3 is found to be outside of the range of 800 °C to 500 °C. This leads to inadequate estimation results, as the thermal arrest caused by the microstructural transformation in this case is not considered. In this work the usage of the well-proven cooling time concept t8/5 is analyzed using high strength fine grained structural steels and suitable welding filler wires during gas metal arc and submerged arc welding processes. The results are discussed taking into account the microstructure and the transformation behavior. Based on the experimental work, an improved concept is presented.

Feasibility study of welding dissimilar Advanced and Ultra High Strength Steels

2020 ◽  
Vol 59 (1) ◽  
pp. 54-66
Author(s):  
Francois Njock Bayock ◽  
Paul Kah ◽  
Antti Salminen ◽  
Mvola Belinga ◽  
Xiaochen Yang
Keyword(s):  
Heat Input ◽  
High Strength Steel ◽  
Gas Metal Arc Welding ◽  
Base Material ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Hardness Test ◽  
Welding Parameter ◽  
Welding Parameters

AbstractThis study concerns the weldability of dissimilar Ultra high-strength steel (UHSS) and advanced high-strength steel (AHSS), which is used in the modern machine industry. The materials offered superior strength as well as relatively low weight, which reduces microstructure contamination during a live cycle. The choice of the welding process base of the base material (BM) and welding parameters is essential to improve the weld joint quality. S700MC/S960QC was welded using a gas metal arc welding (GMAW) process and overmatched filler wire, which was performed using three heat input (7, 10, and 15 kJ/cm). The weld samples were characterized by a Vickers-hardness test, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The test reveals a decrease of softening areas in the HAZ and the formation of the stable formation of Bainite-Ferrite for S700MC and Bainite-martensite for S960QC when the heat input of 10 kJ/cm is used. It is recommended to use the GMAW process and Laser welding (Laser beam-MIG), with an optimal welding parameter, which will be achieved a high quality of manufacturing products.

Welding of Ultra High Strength Steels

2013 ◽  
Vol 849 ◽  
pp. 357-365 ◽  
Author(s):  
Paul Kah ◽  
Markku Pirinen ◽  
Raimo Suoranta ◽  
Jukka Martikainen
Keyword(s):  
Electron Beam Welding ◽  
Research Work ◽  
High Strength Steels ◽  
High Strength ◽  
Welding Parameters ◽  
Heavy Equipment ◽  
High Strength Level ◽  
Ultra High Strength Steels ◽  
New Generation ◽  
Welding Processes

The ongoing need to reduce the weight of products while increasing strength has resulted in new generation steel manufacturing using special heat treatments to produce High Strength Steels (HSS) and Ultra High Strength Steels (UHSS) with up to 1700 MPa tensile strength. The high strength level of these steels makes it possible to produce structures with a considerable weight and cost reduction, and such steels have been adopted in the automotive industry and for mobile heavy equipment. Welding of UHSS is, however, not without its complications and welding processes for these steels need careful attention. For instance, their high susceptibility to cracking and Heat Affected Zone (HAZ) softening are risks that need to be borne in mind when choosing welding parameters. This research work discusses the difficulties and challenges of successful welding of UHSS. Common welding methods used in welding of UHSS are briefly reviewed to gain a better understanding of the effects of different welding parameters and methods. The paper finds that UHSS can be satisfactorily welded with laser welding, electron beam welding, resistance welding, and conventional arc welding methods, but the quality of the weld is dependent on appropriate control of several parameters and variables of the welding processes.

scholarly journals Numerical modeling of two-dimensional heat-transfer and temperature-based calibration using simulated annealing optimization method: Application to gas metal arc welding

2016 ◽  
Vol 20 (2) ◽  
pp. 655-665
Author(s):  
Miso Bjelic ◽  
Karel Kovanda ◽  
Ladislav Kolařík ◽  
Miomir Vukicevic ◽  
Branko Radicevic
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Simulated Annealing ◽  
Gas Metal Arc Welding ◽  
Source Parameters ◽  
Optimization Method ◽  
Calibration Procedure ◽  
Welding Parameters ◽  
Transfer Model ◽  
Welding Processes

Simulation models of welding processes allow us to predict influence of welding parameters on the temperature field during welding and by means of temperature field and the influence to the weld geometry and microstructure. This article presents a numerical, finite-difference based model of heat transfer during welding of thin sheets. Unfortunately, accuracy of the model depends on many parameters, which cannot be accurately prescribed. In order to solve this problem, we have used simulated annealing optimization method in combination with presented numerical model. This way, we were able to determine uncertain values of heat source parameters, arc efficiency, emissivity and enhanced conductivity. The calibration procedure was made using thermocouple measurements of temperatures during welding for P355GH steel. The obtained results were used as input for simulation run. The results of simulation showed that represented calibration procedure could significantly improve reliability of heat transfer model.

scholarly journals PC-GMAW effect on the welding thermal cycle and weld metal geometry for high strength steels

2020 ◽  
Vol 1 ◽  
pp. 5-16
Author(s):  
Anatoliy Zavdoveev ◽  
Valeriy Poznyakov ◽  
Hyuong Seop Kim ◽  
Massimo Rogante ◽  
Mark Heaton ◽  
...  
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Low Frequency ◽  
High Strength Steels ◽  
Welding Current ◽  
High Strength ◽  
High Amplitude ◽  
Depth Of Penetration ◽  
Temper Ature Range ◽  
Welding Processes

Welding of medium carbon alloy steels used in the manufacture of special-purpose machinery imposes to solve two mutually exclusive problems – to increase the depth of penetration of the base metal and to reduce the width of the thermal impact zone of the welded joints. To successfully solve this problem, it is necessary to use arc welding processes with a concentrated heat source. One of these processes is pulsed current gas metal arc welding (PC-GMAW). The present researches have allowed estab-lishing, that with PC-GMAW change of welding current is a difficult character, namely: on high-frequency impulse signal (60 kHz), impulses of the current of low frequency (from 90–150 Hz) are imposed. The change in the values of the mean welding current at PC-GMAW is achieved by increasing the pause current and the frequency of high-amplitude current pulses. It is shown that the PCGMAW allows reducing the amount of metal splashing, to increase the depth of penetration (almost 2 times) in comparison with stationary welding. At the same time, the cooling rate of HAZ metal in the temper-ature range 600–500°C decreases almost 1.5 times, which allowed to reduce the width of HAZ by 40%.

scholarly journals Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa

2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Joint Strength ◽  
Solid Phase ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Friction Stir ◽  
Welding Processes

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.

Solid Freeform Fabrication of Al-Li 2199 via Controlled-Short-Circuit-MIG Welding

2011 ◽  
Vol 409 ◽  
pp. 843-848
Author(s):  
David W. Heard ◽  
Julien Boselli ◽  
Raynald Gauvin ◽  
Mathieu Brochu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Solid Freeform Fabrication ◽  
Short Circuit ◽  
Lithium Concentration ◽  
Gas Metal Arc Welding ◽  
Fusion Welding ◽  
Welding Parameters ◽  
Freeform Fabrication ◽  
Metal Arc Welding ◽  
Welding Processes

Aluminum-lithium (Al-Li) alloys are of interest to the aerospace and aeronautical industries as rising fuel costs and increasing environmental restrictions are promoting reductions in vehicle weight. However, Al-Li alloys suffer from several issues during fusion welding processes including solute segregation and depletion. Solid freeform fabrication (SFF) of materials is a repair or rapid prototyping process, in which the deposited feedstock is built-up via a layering process to the required geometry. Recent developments have led to the investigation of SFF processes via Gas Metal Arc Welding (GMAW) capable of producing functional metallic components. A SFF process via GMAW would be instrumental in reducing costs associated with the production and repair of Al-Li components. Furthermore the newly developed Controlled-Short-Circuit-MIG (CSC-MIG) process provides the ability to control the weld parameters with a high degree of accuracy, thus enabling the optimization of the solidification parameters required to avoid solute depletion and segregation within an Al-Li alloy. The objective of this study is to develop the welding parameters required to avoid lithium depletion and segregation. In the present study weldments were produced via CSC-MIG process, using Al-Li 2199 sheet samples as the filler material. The residual lithium concentration within the weldments was then determined via Atomic Absorption (AA) and X-ray Photoelectron Spectroscopy (XPS). The microstructure was analyzed using High Resolution Scanning Electron Microscopy (HR-SEM). Finally the mechanical properties of welded samples were determined through the application of hardness and tensile testing.

Development of High Steel Grade Seamless X100 Weldable

2008 ◽  
Author(s):  
Alfonso Izquierdo ◽  
Hector Quintanilla ◽  
Gilles Richard ◽  
Ettore Anelli ◽  
Gianluca Mannucci ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Limit State ◽  
High Strength Steels ◽  
High Strength ◽  
Steel Grade ◽  
Technological Evolution ◽  
Complex Design ◽  
Exploration And Production ◽  
Girth Welds

The technological evolution in the offshore sector points out a trend towards an increasing use of high strength steels (grade 80ksi and higher), for both pipelines and risers. Pipeline specifications for deepwater offshore fields demand developments in design criteria (i.e. limit state design), welding, installation, and laying technologies. As long as the market goes deeper in offshore exploration and production, the market trend is to use heavier pipes in steel grade X65/X70 and some technological limits from several fronts are faced and more attractive becomes for the market to have a lighter high strength 100ksi seamless steel grade. The joint industrial program (JIP), termed “Seamless 100 ksi weldable” launched by Tenaris in order to address the complex design issues of high strength Q&T seamless pipes for ultra deep water applications has been finalized. The 100ksi steel grade has been achieved in two wall thickness 16 mm and 25 mm. The main results from both phase I devoted to the development and production of seamless pipes with minimum 100ksi and phase II devoted to evaluate the high strength seamless pipe weldability will be addressed in this paper. Main microstructural features promoting the best strength-toughness results obtained from phase I and the results from phase II, where the heat affected zone (HAZ) characterization made using stringent qualifying configuration such as API RP2Z and the promising results after qualifying the girth welds simulating a typical offshore operation and the Engineering Critical Assessment for installation will be addressed. The results from this development are of interest of all oil & gas companies who are facing as an output from the design project analysis the need to have high strength seamless pipes.

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