Design of TiO2–SiO2–MgO and SiO2–MgO–Al2O3-Based Submerged Arc Fluxes for Multipass Bead on Plate Pipeline Steel Welds

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Lochan Sharma ◽  
Rahul Chhibber
Keyword(s):  
Arc Welding ◽  
Pipeline Steel ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Pressure Vessels ◽  
Welding Parameters ◽  
Chemical Compositions ◽  
Optimization Approach ◽  
Low Alloy Steels ◽  
Submerged Arc

High strength low alloy steels are extensively used in different applications like oil and gas transmission line pipes, pressure vessels and offshore oil drilling platforms. Submerged arc welding (SAW) is mainly used to weld high thickness steel plates. Flux composition and welding parameters play an important role in determining the adequate quality and mechanical properties of the weld. Agglomerated fluxes were formulated based on TiO2–SiO2–MgO and SiO2–MgO–Al2O3 flux system using constrained mixture design and extreme vertices design approach. The chemical compositions of the bead on a plate have been studied using formulated fluxes. Twenty-one beads on plates were applied using submerged arc welding process keeping the parameters: current, voltage, and welding speed constant. Regression models were developed for bead on plate content in terms of individual, binary, and ternary mixture flux constituents for submerged arc multipass bead on plate deposition for pipeline steel (API 5 L X70). In the present study, chemical composition, grain size, and microhardness properties of the multipass bead on a plate (for API 5 L X70 grade pipeline) were optimized using multi-objective optimization approach.

Design of CaO–SiO2–CaF2 and CaO–SiO2–Al2O3 Based Submerged Arc Fluxes for Series of Bead on Plate Pipeline Steel Welds—Effect on Carbon and Manganese Content, Grain Size and Microhardness

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Lochan Sharma ◽  
Rahul Chhibber
Keyword(s):  
Grain Size ◽  
Arc Welding ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Pressure Vessels ◽  
Constant Current ◽  
Welding Parameters ◽  
Chemical Compositions ◽  
Optimization Approach ◽  
Submerged Arc

Submerged arc welding is mainly used to weld high thickness steel plates in various applications such as offshore oil drilling platforms, bridges, building construction, and pressure vessels. Suitable flux composition and welding parameters play an important role in determining the good bead quality, which further affects the mechanical properties of welded joint. Agglomerated fluxes were formulated based on CaO–SiO2–CaF2 and CaO–SiO2–Al2O3 flux system using constrained mixture design and extreme vertices design approach. The chemical compositions of the bead on plate have been studied using formulated fluxes. Twenty one beads on plate experiments were conducted at constant current, voltage, and welding speed using submerged arc welding process. In the present study, chemical composition, grain size, and microhardness properties of series of bead on plate weld deposits (for API 5 L X70 grade pipe line) were optimized by using multiobjective optimization approach.

Development of Exothermic Flux for Enhanced Penetration in Submerged Arc Welding

2020 ◽  
Vol 19 (01) ◽  
pp. 131-146
Author(s):  
Aditya Kumar ◽  
Kulwant Singh
Keyword(s):  
Mathematical Model ◽  
Arc Welding ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Graphical Form ◽  
Welding Parameters ◽  
Weld Penetration ◽  
Agglomeration Process ◽  
Arc Welding Process ◽  
Submerged Arc

An exothermic flux for submerged arc welding process has been developed which is capable of enhancing weld penetration of the joint. For this purpose, thermit mixture in different proportions (20% and 40%) has been added to the parent flux by agglomeration process. Beads on plate were deposited using parent and developed exothermic fluxes for a comparative study. EH14 filler wires in combination with parent and exothermic fluxes were used in this investigation. The effects of welding parameters and exothermic flux on weld penetration were investigated and the results have been presented in this paper. It has been found that the penetration increases from 2.95 to 3.51[Formula: see text]mm with 40% thermit mixture addition to the parent flux. It is further observed that penetration increases with increase in the amount of thermit mixture added. A mathematical model has been developed to predict weld penetration or select suitable welding parameters to obtain the desired penetration. The significance of coefficients was tested using Student’s [Formula: see text]-test and the adequacy of developed model was tested using [Formula: see text]-test. The effects of various parameters on penetration have been presented in graphical form for better understanding.

Feasibility Studies on the Modeling and Evaluation of Residual Stresses in Arc Welded Butt Joints

2006 ◽  
Author(s):  
K. Satyambabu ◽  
N. Ramachandran
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Arc Welding ◽  
Thermal Loading ◽  
Submerged Arc Welding ◽  
Pressure Vessels ◽  
Welding Parameters ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Submerged Arc

Many important engineering applications such as nuclear reactors, ships, pipes and pressure vessels are shell-like structures made with weldments. For such a structure, a major problem is the development of residual stress and distortion due to welding. Residual stresses in weldments significantly affect stress corrosion cracking, hydrogen-induced cracking and fatigue strength in welded structures. As-welded components generally have certain amount of residual stresses caused by the application of intense heat or thermal loading at the weld joint, formed due to non-uniform cooling rates at different points in the weld metal and heat affected zones. Presence of residual stresses in a component is detrimental as they may lead to failure below the design stress value and also affect many important properties including the life of a welded component. Welding induced residual stresses can significantly increase the fracture driving force in a weldment and also contribute to brittle fracture. The thermal cycle imposed on any welded object causes thermal expansions and contractions which are not uniform. Quantitative measurement of residual stresses is essential to take remedial measures such as change in the welding technique, optimizing welding parameters (heat input, electrode diameter etc,), change in the weld groove design and post-weld heat treatment for minimizing the residual stresses. Residual stress measurements after post-weld treatment would also ensure the adequacy of stress relief treatment. To have an investigation into these aspects, residual stresses due to Manual Metal Arc Welding and Submerged Arc Welding were measured nondestructively with Ultrasonic technique. Residual stress distribution for Shielded Metal Arc Welding and Submerged Arc Welding were compared and the present studies emphasized, that Shielded Metal Arc Welding gave higher compressive stresses than Submerged Arc Welding. Further, to substantiate the studies, commercial finite element analysis software ANSYS 5.6 was used for modeling of manual metal arc welded joint. The results obtained by ANSYS were compared with those by Ultrasonic method.

Development of Welding Procedures for X90-Grade Seamless Pipes for Riser Applications

2012 ◽  
Author(s):  
Hiroyuki Nagayama ◽  
Masahiko Hamada ◽  
Mark F. Mruczek ◽  
Mark Vickers ◽  
Nobuyuki Hisamune ◽  
...  
Keyword(s):  
Weld Metal ◽  
Arc Welding ◽  
Mechanical Test ◽  
Welding Process ◽  
High Strength ◽  
Submerged Arc Welding ◽  
Welding Parameters ◽  
Flux Cored Arc Welding ◽  
Welding Procedure ◽  
Submerged Arc

Ultra-high strength seamless pipes of X90 and X100 grades have been developed for deepwater or ultra-deepwater applications. Girth welding procedure specifications (WPSs) should be developed for the ultra-high strength pipes. However, there is little information for double jointing welding procedure by using submerged arc welding process for high strength line pipes. This paper describes mechanical test results of submerged arc welding (SAW) and gas shielded flux cored arc welding (GSFCAW) trials with various welding consumables procured from commercial markets. Welds were then made with typical welding parameters for riser productions using high strength X90 seamless pipes. The submerged arc weld metal strength could increase by increasing alloy elements in weld metal. The weld metal with CE (IIW) value of 0.74 mass% achieved fully overmatching for the X90 pipe. The weld metal yield strength (0.2% offset) was 694 MPa, and the ultimate tensile strength was 833 MPa. It was also confirmed that the reduction of boron in weld metal can improve low temperature toughness of high strength weld metal. Furthermore, it was confirmed that the HAZ has excellent mechanical properties and toughness for riser applications. In this study GSFCAW procedures were also developed. GSFCAW can be used for joining pipe and connector material for riser production welding. The weld metal with a CE (IIW) value of 0.54 mass% could meet the required strength level for X90-grade pipe as specified in ISO 3183. Cross weld tensile testing showed that fractures were achieved in the base metal. Good Charpy impact properties in weld metal and HAZ were also confirmed.

Improvements in the Welding Technology for Heavy Wall Pressure Vessels 2 ¼ Cr 1Mo ¼ V Low Alloy Steels

2017 ◽  
Author(s):  
Fausto Fusari ◽  
Paolo Marangoni ◽  
Michele Musti ◽  
Stefano Alberini
Keyword(s):  
Weld Joint ◽  
Arc Welding ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Pressure Vessels ◽  
Narrow Gap ◽  
Welding Technology ◽  
Gap Technique ◽  
Single Bead ◽  
Submerged Arc

The standard practice recommended for high pressure vessels, having heavy walls, requires the implementation of weld joint preparation with narrow gap technique; this generally calls for a ‘two beads per layer’ sequence alongside the use of the submerged arc welding process. This process provides a high quality and uniformed weld joint whilst also reducing the residual stresses after welding. In refinery equipment that are subjected to high pressures and are exposed to hydrogen environment, high strength materials such as 2 1/4 Cr 1 Mo 1/4 V are commonly used. A recent study conducted on this material, and the process of submerged arc welding with narrow gap technique ‘two beads per layer,’ had identified a potential issue in complying with ASME Code specified creep resistance properties. In another setting, with regards to the properties of toughness in weld joints, other possible inconsistencies, in the narrow gap weld joint, between the weld centerline and center bead, were found. In order to overcome the deficiencies stated above, an innovative welding technology is presented in this paper which is based on the preparation of a narrower groove than the commonly used narrow gap technique. Such groove has been designed to implement the ‘single bead per layer’ approach. This paper illustrates that the use of this new technique results in improved quality of weld seams as applied in heavy wall high pressure vessels used in creep regime. The welding process considered is that of tandem submerged arc welding with two wires. The mechanical characteristics and results obtained by comparing the two techniques ‘two beads per layer’, and the new innovative one ‘single bead per layer’ will be evidenced and discussed.

Performance Evaluation of Alternating Current Square Waveform Submerged Arc Welding as a Candidate for Fabrication of Thick Welds in 2.25Cr-1Mo Heat-Resistant Steel

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Uttam Kumar Mohanty ◽  
Yohei Abe ◽  
Takahiro Fujimoto ◽  
Mitsuyoshi Nakatani ◽  
Akikazu Kitagawa ◽  
...  
Keyword(s):  
High Pressure ◽  
Arc Welding ◽  
Submerged Arc Welding ◽  
Pressure Vessels ◽  
Heat Consumption ◽  
Welding Parameters ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Flux Consumption ◽  
Submerged Arc

Abstract The paper evaluates the performance of alternating current (AC) square waveform submerged arc welding (SAW) as a candidate technology for manufacturing thick welds for high-pressure vessels. A new mathematical formulation for calculating melting efficiency in square waveform arc welding is presented. The melting efficiency and the heat consumption are presented as a mathematical model of welding parameters, namely welding current, welding speed, current frequency, and electrode negativity (EN) ratio. The proposed approach is demonstrated through the welding of 2.25Cr-1Mo heat-resistant steel performed over a wide range of welding parameters. The investigation provides deeper insights into the interplay between process parameter, total heat consumption, and melting efficiency. The effect on flux consumption is also explained. The melting efficiency is inversely proportional to flux consumption. The welding heat does not necessarily promote the plate melting. Improper use of welding heat may lead to decreased melting efficiency and increased unwanted melting and consumption of welding flux. Compared to the conventional direct current (DC) power sources, the AC square waveform welding achieves almost the same order of melting efficiency with added advantages of better weld bead shape and flux consumption in a desirable range. The two additional parameters (frequency and EN ratio) of the AC square waveform power source provide more freedom to fine-tune the process and thereby efficiently use welding heat. The results of this investigation will be advantageous to the designers and fabricators of high-pressure vessels using AC square waveform welding.

Effects of Chemical Compositions of the Submerged Arc Welding Wires on Impact Toughness of the Weld Metals for the Pipeline Steel

2007 ◽  
Vol 353-358 ◽  
pp. 385-388
Author(s):  
De Liang Ren ◽  
Fu Ren Xiao ◽  
P. Tian ◽  
X. Wang ◽  
L.Y. Zhang ◽  
...  
Keyword(s):  
Impact Toughness ◽  
Arc Welding ◽  
High Efficiency ◽  
Pipeline Steel ◽  
Submerged Arc Welding ◽  
Chemical Compositions ◽  
Weld Metals ◽  
Temperature Impact ◽  
Low Temperature Impact Toughness ◽  
Submerged Arc

With the development of high toughness pipeline, it is necessary to develop new welding wires for high-efficiency submerged-arc welding, to produce weld metals whose properties can match corresponding ones of the base metal, such as strength, toughness, H2S corrosion resistance, etc. In this paper, the weld wires with variations of elements have been designed, and the effects of alloy elements on the microstructures and low temperature impact toughness are discussed.

scholarly journals Parametric Design on Weld Characteristics of Submerged Arc Welding Process Parameters

2018 ◽  
Vol 7 (2.23) ◽  
pp. 467
Author(s):  
Sailender Mamunuri
Keyword(s):  
Arc Welding ◽  
Parametric Design ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Pressure Vessels ◽  
Manganese Steel ◽  
Deep Penetration ◽  
Low Carbon ◽  
Joint Quality ◽  
Submerged Arc

A low carbon with manganese steel is apt for the fabrication of pressure vessels welds, which is designed for low-temperature service requirement. Submerged Arc Welding (SAW) is chosen process, due to incessant sound joint requirement and its inherent qualities like smooth bead, deep penetration and sound joint quality and reliable. SAW is renowned by huge quantity of parameters, which acts collectively influence the outputs performance, subsequently affects the joint quality. The objective is to optimize the variables parametrically for various outputs. Taguchi’s orthogonal array, which is a design of experiment, is adopted to optimize as well for their effects on desired outputs. The author modified the process by introducing ‘purging gas’ in SAW. ‘Purged’ SAW results are contrasted against the traditional ‘as-is’ of SAW. Identified the variable significance effect is through analysis of variance with their contribution. Correlations between parameters and performance outputs are established via Regression Analysis. Build models competency are checked with F-test; determined quantitatively and showed graphically, for discussion of their effects to achieve the required quality. Using confirmation tests, the models are validated and found the outcomes are in the confines.  

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