Compositional Aspects of Cellulosic Electrodes Used for Welding Pipelines

2008 ◽  
Author(s):  
Frank J. Barbaro ◽  
Valerie M. Linton ◽  
Erwin Gamboa ◽  
Leigh Fletcher
Keyword(s):  
Weld Metal ◽  
User Involvement ◽  
Charpy Impact ◽  
Carbon Equivalent ◽  
Welding Parameters ◽  
Line Pipe ◽  
User Input ◽  
Welding Arc ◽  
Simulated Field ◽  
And Performance

The mechanical properties and compositional limits of line pipe for all major pipeline projects are subject to stringent project specific specifications and have substantial user input. The standards for welding electrodes do not have the same level of user involvement and permit significant latitude in terms of alloy design despite the fact that it is known the original electrode design can be markedly altered by elemental transfer as a result of changes in welding parameters and also the condition of the electrodes prior to welding. Several commercially available E8010 consumables have been evaluated under simulated field welding conditions. In addition, the influence of welding arc length and electrode conditioning were investigated. Significant variations in microstructure, hardness and Charpy impact toughness were noted and appear to be primarily related to the final chemical composition of the deposited weld metal. The weld metal carbon equivalent values ranged from 0.20 to 0.42 and all consumables contained additions of Ti and B in the flux coating which resulted in significant levels of B in the final deposited weld metal. It is recommended that the appropriate standards relating to the production and performance of cellulosic consumables be addressed to ensure complete disclosure of consumable formulations to the end user.

The Behaviour of Nitrogen on the Welding Parameters of the Dissimilar Weld Joints between AISI 304 and AISI 316L Austenitic Stainless Steels Produced by Gas Tungsten Arc Welding

2012 ◽  
Vol 248 ◽  
pp. 395-401 ◽  
Author(s):  
Wichan Chuaiphan ◽  
Loeshpahn Srijaroenpramong
Keyword(s):  
Weld Metal ◽  
Nitrogen Content ◽  
Welding Current ◽  
Welding Parameters ◽  
Aisi 316L ◽  
Arc Length ◽  
Aisi 304 ◽  
Dissimilar Weld ◽  
Weld Metals ◽  
Welding Arc

The behavior of nitrogen into the dissimilar joining metal between AISI 304 and AISI 316L Austenitic stainless steel during gas tungsten are welding process was investigated. Studied by using an arc nitrogen atmosphere – controlling in chamber. The relations between nitrogen content of the dissimilar weld metal and the welding parameters, such as the welding current, welding speed, welding arc length and penetration area of weld metals were also evaluated. The results show that the nitrogen content of the weld metals decreased with an increasing welding current, and increasing penetration areas of weld metal, but scarcely depends on the welding arc length. The nitrogen content of the weld metals increased with the welding speed, but decreased penetration areas of weld metals. The role of nitrogen content on the dissimilar weld metals stainless steel is further confirmed by the experimental microstructure, mechanical and corrosion behaviour of the weld metal.

Effect of N2 Addition on Microstructure and Properties of SAF 2507 Duplex Stainless Steels GTAW Welded Joint

2012 ◽  
Vol 724 ◽  
pp. 127-130
Author(s):  
Dong Fang Du ◽  
Jie Liu ◽  
Guo Ping Li ◽  
Jin Ming Liu
Keyword(s):  
Weld Metal ◽  
Impact Energy ◽  
Welded Joint ◽  
Welding Process ◽  
Welding Parameters ◽  
Shielding Gas ◽  
Micro Hardness ◽  
Weld Metals ◽  
Welding Arc ◽  
The Impact

In this paper, SAF2507 duplex stainless steel (DSS) was welded by GTAW with ER2594 as filler wire, and Ar + N2 as shielding gas. The results show that, with increasing the content of N2 in the shielding gas, the amount of austenite in weld metal increase, the micro-hardness drops and impact energy increases; the use of Ar +2 ~ 3% N2 welding parameters, the microstructure and mechanical properties of welded joints are the best, the austenitic rates and impact energy of weld metals are 51%~53% and 75~88 J, respectively, and the welding process is easy to control; when the content of N2 reach 5%, the impact energy of weld metal decreases obviously and the welding arc is unstable.

Microstructure and Toughness of 1000 MPa High Strength Weld Metal

2010 ◽  
Vol 638-642 ◽  
pp. 3441-3446 ◽  
Author(s):  
Wan Sheng Du ◽  
Yun Peng ◽  
Hong Jun Xiao ◽  
Chang Hong He ◽  
Zhi Ling Tian
Keyword(s):  
Electron Microscope ◽  
Weld Metal ◽  
Heat Input ◽  
Welded Joint ◽  
Lath Martensite ◽  
Charpy Impact ◽  
High Strength ◽  
Hardness Test ◽  
Optical Microscope ◽  
Carbon Equivalent

Welding of 1000 MPa high strength alloy steel is difficult because of its welding cold cracking sensitivity and the difficulty in maintaining high joint toughness. In this paper the effects of alloy elements on welding cracking tendency are analyzed, and measures to prevent cold crack are proposed. Welding wires with high strength was deposited into weld metal and welded into joint. Tensile test, micro-hardness test and Charpy impact test were used to evaluate the strength and toughness of weld metal and heat affected zone. Optical microscope, transmission electron microscope and scanning electron microscope were used to analyze the microstructure. It is shown that the weld metal mainly consists of lath martensite, lath bainite, and residual austenite which exists between the laths. The strength of weld metal increases in a small degree with increasing carbon equivalent and its toughness and ductility are not related to carbon equivalent. The toughness and ductility are much sensitive to nonmetallic inclusions. The welded joint has tensile strength of higher than 1000 MPa when welded at heat input of 11 kJ/cm and 15 kJ/cm and the mechanical properties are little influenced by the amount of heat input in this range. The whole welded joint has good comprehensive properties.

Examinations Regarding the Sour Gas Resistance of Girth Welds Carried Out on API Grade X80 Seamless Pipe Steel (Heavy Wall)

2014 ◽  
Author(s):  
Diana Toma ◽  
Jörg Wiebe ◽  
Dorothee Niklasch ◽  
Ashraf Koka
Keyword(s):  
High Strength ◽  
Mechanical Tests ◽  
Carbon Equivalent ◽  
Welding Parameters ◽  
Line Pipe ◽  
Sea Bed ◽  
Steel Grades ◽  
Girth Welds ◽  
Welding Procedure ◽  
Sour Gas

Various accessories such as buckle arrestors and J-lay collars are needed in some cases to successfully lay and secure an offshore pipeline on the sea bed. For such applications the using of high strength seamless pipes in Grade X70 and X80 with heavy wall are necessary. However, there is only small information regarding the welding procedure for such grades in heavy wall dimensions. In comparison to steels used for lower strength level, the chemistry of high strength steel pipes includes higher amounts of micro-alloying elements as well as requires a more complex heat treatment. Due to the higher carbon equivalent these steel grades react more sensitive on heat input during welding. Consequently, the range of welding parameters which ensure suitable mechanical properties has to be adapted. This article presents the results of weldability trials carried out on seamless API X80 heavy wall (> 50mm) line pipe. The welding trials were performed using different preheating temperatures and heat inputs followed by microstructure investigations and mechanical tests of the multilayer welds. The sour gas resistance has to be demonstrated by SSC-tests because it stays challenging to guarantee values below 250 HV10.

To Study the Effect of Different Weld Wire Alloying on Metallurgical and Mechanical Properties of Multi Arc SAW Welded HSLA Longitudinal Line Pipes

2019 ◽  
Author(s):  
Dhruvkumar Vavdiya ◽  
T. S. Kathayat ◽  
S. K. Joshi ◽  
Devendra Goyal ◽  
Hiteshkumar Desai
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Volume Fraction ◽  
Weld Line ◽  
High Heat ◽  
Alloying Elements ◽  
Critical Parameters ◽  
Welding Parameters ◽  
Line Pipe ◽  
Lower Temperature

The current scenario of HSLA line pipe welded with critical parameters by Automatic Submerged Arc Welding being widely used in critical services for both onshore & offshore, also challenging to achieve stringent mechanical properties i.e low temperature toughness, hardness, YS/TS ratio, etc. Recent studies proved that the Ti-B wires been widely used to weld line pipes which gives higher fracture toughness values at lower temperature. In this experiment, an attempt has been made to maintain the volume fraction of acicular ferrite by alloying elements in weld metal with variation of low to high heat input range. The purpose of this experiment is to determine the effect of different alloyed wire with respect to critical welding parameters on mechanical & Metallurgical properties. This investigation also includes metallographic changes, role of different alloying elements for improving the microstructure and distribution of inclusions in weld metal, which directly affects the mechanical properties of weld metal. Based on the results, Optimization has been done which is focusing on welding consumables from the existing chemistry to find at what extent the variation of chemistry causes undesired metallurgical changes in the weld metal and also how it influences the mechanical properties of welded line pipe.

Effect of Chemistry on the Fracture Toughness of Low Carbon X70 Girth Weld Heat Affected Zone

2014 ◽  
Author(s):  
M. Rashid ◽  
L. E. Collins ◽  
Y. Bian
Keyword(s):  
Fracture Toughness ◽  
Weld Metal ◽  
Heat Affected Zone ◽  
High Strength ◽  
Carbon Equivalent ◽  
Welding Parameters ◽  
Low Carbon ◽  
Girth Welds ◽  
Ferrite Nucleation ◽  
Linepipe Steel

Addition of alloying elements can alter the properties of high-strength linepipe steel. Particularly the addition of Chromium and Molybdenum acts to suppress ferrite nucleation and promote the formation of acicular bainite microstructures and thereby increase the tensile properties of modern linepipe steel. While chemistry is a factor, welding parameters can also be influential and affect the HAZ toughness. The present work compares the effect of C, Cr, and Mo on the girth weld HAZ fracture toughness of X70 in identical welds. Three pipes of size 48″ OD × 0.528″ WT with different combinations of C, Cr, and Mo were produced. Identical welding procedures were employed to produce two girth welds so that a low-C, Cr pipe (CE = 0.238) was joined to a high-C, Cr pipe (CE = 0.268) which in turn was joined to a low-C, Mo pipe (CE = 0.224). By evaluating the HAZ properties on either side of a weld, it was possible to accurately assess chemistry affects on HAZ properties. These girth welds were subjected to different testing for the evaluation of girth weld HAZ impact and fracture toughness. These included all-weld metal and pipe body tensile testing, micro hardness testing of HAZ, microstructure analysis, Charpy V-notch testing of weld metal and HAZ, and CTOD testing of weld metal and HAZ at −5 °C and −20 °C. In addition, to investigate the transformation behaviour, Gleeble simulations of coarse-grain heat affected zone (CG-HAZ) were conducted using skelp samples, which were taken from the same coils as the pipe samples. The results demonstrated that among the low and high carbon equivalent (CE) alloys, materials with low CE values showed better toughness properties. While among the low CE materials, the material with high Mo performed better in terms of toughness. No clear effect of weld position around the pipe circumference on the CTOD values was observed.

Effect of Nickel on Toughness of Underwater Wet Welds

2003 ◽  
Author(s):  
Faustino Perez ◽  
Stephen Liu ◽  
Charles Smith ◽  
Efrain Rodriguez
Keyword(s):  
Weld Metal ◽  
Water Depth ◽  
Nickel Content ◽  
Charpy Impact ◽  
Tensile Specimen ◽  
Charpy Impact Test ◽  
Offshore Platforms ◽  
Quenching Effect ◽  
Welding Arc ◽  
Similar Yield

Underwater wet welding has been used as an option for the repair of offshore platforms. Rutile-grade electrodes are typically used to carry out the underwater repairs because of their good arc stability, bead appearance, and bead morphology. However, the main problems to overcome are porosity and reduction of toughness and strength as the water depth increases. During wet welding, the welding arc decomposes water into hydrogen and oxygen, which results in the formation of oxides and pores in the weld metal. The loss of alloying elements in the oxidation process and the fast cooling rate due to the quenching effect of water surrounding the weld are responsible for the deterioration in mechanical properties. This paper presents evidence of toughness improvements on wet welds made with experimental rutile-grade electrodes. Experimental electrodes with nickel added to the flux covering (0, 1.2, 2.3, and 3.0 wt. pct.) were extruded. A commercial rutile electrode was used for comparison. Bead-on-plate and multipass V-groove wet welds were made at 1 ft. water depth in fresh water. Charpy impact test specimens were machined from the V-groove welds and tested at four temperatures. The toughness measured at −50°C of wet welds with 3.0 wt pct. nickel was improved by a factor of four over the wet welds without nickel content. Smaller improvements were obtained with 2.3 wt. pct. nickel at −50°C. At higher temperatures, the toughness did not increase with nickel additions. All-weld-metal reduced-size tensile specimens made from the wet welds deposited with the commercial and experimental electrodes presented similar yield and tensile strength. The tensile specimen with 3.0 wt. pct. nickel presented lower ductility.

scholarly journals Influence of the Heat Input on the Dendritic Solidification Structure and the Mechanical Properties of 2.25Cr-1Mo-0.25V Submerged-Arc Weld Metal

2021 ◽  
Author(s):  
Hannah Schönmaier ◽  
Ronny Krein ◽  
Martin Schmitz-Niederau ◽  
Ronald Schnitzer
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Heat Input ◽  
Stress Rupture ◽  
Pressure Vessels ◽  
Rupture Time ◽  
Solidification Structure ◽  
Welding Parameters ◽  
Austenite Grain Size ◽  
Submerged Arc

AbstractThe alloy 2.25Cr-1Mo-0.25V is commonly used for heavy wall pressure vessels in the petrochemical industry, such as hydrogen reactors. As these reactors are operated at elevated temperatures and high pressures, the 2.25Cr-1Mo-0.25V welding consumables require a beneficial combination of strength and toughness as well as enhanced creep properties. The mechanical properties are known to be influenced by several welding parameters. This study deals with the influence of the heat input during submerged-arc welding (SAW) on the solidification structure and mechanical properties of 2.25Cr-1Mo-0.25V multilayer metal. The heat input was found to increase the primary and secondary dendrite spacing as well as the bainitic and prior austenite grain size of the weld metal. Furthermore, it was determined that a higher heat input during SAW causes an increase in the stress rupture time and a decrease in Charpy impact energy. This is assumed to be linked to a lower number of weld layers, and therefore, a decreased amount of fine grained reheated zone if the multilayer weld metal is fabricated with higher heat input. In contrast to the stress rupture time and the toughness, the weld metal’s strength, ductility and macro-hardness remain nearly unaffected by changes of the heat input.

Usage of ICT Tools in New Product Development

2010 ◽  
pp. 76-91 ◽  
Author(s):  
Kristina Risom Jespersen ◽  
Nuka Buck
Keyword(s):  
Product Development ◽  
New Product Development ◽  
User Involvement ◽  
New Product ◽  
Performance Expectations ◽  
Strategic Emphasis ◽  
Innovative Climate ◽  
The Social ◽  
Ict Tools ◽  
And Performance

Involvement of users in new product development is needed more than ever due to the technological and the social progression in recent years. Usage of ICT tools is one approach forwarded in literature discussing user-involvement. This chapter explores the antecedents of ICT usage in NPD. We utilize five groups of factors: innovative climate, strategic emphasis on ICT tools, ICT champions, competencies and performance expectations. To this end three case studies were conducted. The case findings demonstrate that the most significant antecedents for sustained user-involvement in NPD with ICT tools are strategic emphasis, competencies and the type of ICT champion.

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