Designing Shielded Metal Arc Consumables for Underwater Wet Welding in Offshore Applications

1995 ◽  
Vol 117 (3) ◽  
pp. 212-220 ◽  
Author(s):  
A. Sanchez-Osio ◽  
S. Liu ◽  
D. L. Olson ◽  
S. Ibarra
Keyword(s):  
Calcium Carbonate ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Oxide Formation ◽  
Electrode Coating ◽  
Microstructural Refinement ◽  
Underwater Wet Welding ◽  
High Toughness ◽  
Porosity Reduction ◽  
Grain Boundary Ferrite

The use of underwater wet welding for offshore repairs has been limited mainly because of porosity and low toughness in the resulting welds. With appropriate consumable design, however, it is possible to reduce porosity and to enhance weld metal toughness through microstructural refinement. New titanium and boron-based consumables have been developed with which high toughness acicular ferrite (AF) can be produced in underwater wet welds. Titanium, by means of oxide formation, promoted an increase in the amount of acicular ferrite in the weld metal, while boron additions decreased the amount of grain boundary ferrite (GBF), further improving the microstructure. Porosity reduction was possible through the addition of calcium carbonate at approximately 13 wt percent in the electrode coating. However, weld metal decarburization also resulted with the addition of carbonate.

Epoxy Resin as a Binder in the Preparation of Rutile Coated Electrodes

2015 ◽  
Vol 798 ◽  
pp. 419-423 ◽  
Author(s):  
Fernando C. Lage ◽  
Leandro S. Oliveira ◽  
Adriana S. Franca ◽  
Alexandre Q. Bracarense
Keyword(s):  
Weld Metal ◽  
Soybean Oil ◽  
Epoxy Resin ◽  
Acicular Ferrite ◽  
Potassium Feldspar ◽  
Electrode Coating ◽  
Weld Microstructure ◽  
Hydrophobic Polymers ◽  
Coated Electrodes

Coated electrodes are used in manual welding, with the coating being comprised of a variety of ingredients, including the binder, usually sodium or potassium silicate. In recent studies aiming at waterproof electrodes, the usual binders were successfully replaced by hydrophobic polymers. In this study, the use of epoxidized soybean oil (ESO) as well as a commercial epoxy resin (CER) as binders in electrode coating formulations was evaluated in order to verify their suitability as replacements for silicates. The produced electrodes were evaluated for the quality of the weld. Results showed that the use of a CER added of potassium feldspar resulted in favorable weld microstructure, with production of acicular ferrite and martensite elimination. ESO based electrodes still need to be improved through flux modification to reduce carbon and hydrogen content in the weld metal.

THE CHANGE IN THE CHEMICAL COMPOSITION AND TOUGHNESS OF API 5L-X70 WELDS BY ADDITION OF TITANIUM

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1209-1216 ◽  
Author(s):  
BEHROOZ BEIDOKHTI ◽  
AMIR HOSEIN KOUKABI ◽  
ABOLGHASEM DOLATI ◽  
PENG HE
Keyword(s):  
Grain Boundary ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Titanium Content ◽  
Weld Deposit ◽  
Steel Weld Metal ◽  
Metal Properties ◽  
Api 5L X70 Steel ◽  
The Relationship ◽  
Grain Boundary Ferrite

The objective of this work was to study the influence of titanium variations on the API 5L-X70 steel weld metal properties. The relationship between microstructure and toughness of the weld deposit was studied by means of full metallographic, longitudinal tensile and Charpy- V notch tests on the specimens cut transversely to the weld beads. The best combination of microstructure and impact properties was obtained in the range of 0.02-0.05% titanium. By further increasing of titanium content, the microstructure was changed from a mixture of acicular ferrite, grain-boundary ferrite, Widmanstätten ferrite to a mixture of acicular ferrite, grain-boundary ferrite, bainite and ferrite with M/A microconstituent. Therefore, the mode of fracture also changed from dimpled ductile to quasi-cleavage. Titanium-base inclusions improve impact toughness by increasing the formation of acicular ferrite in the microstructure. The amount of manganese in inclusions was decreased with addition of titanium to the weld metal.

Covered Electrodes Temperature Variation During Wet Welding and Its Influence on Weld Metal Porosity

2005 ◽  
Author(s):  
Ezequiel C. P. Pessoa ◽  
Alexandre Q. Bracarense ◽  
Stephen Liu ◽  
Faustino Peres Guerrero ◽  
Eduardo M. Zica
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Weld Bead ◽  
Electrode Temperature ◽  
Charpy Test ◽  
Underwater Wet Welding ◽  
Porosity Reduction ◽  
Covered Electrodes

The objective of this work was to evaluate the porosity variation along weld bead and its relation with weld metal mechanical properties and electrode heating during underwater wet welding. Three commercial covered electrodes were used to make bead-on-plate welds. V-groove welds were also made using two electrodes at 50 and 100 meters depth in three different steels. Electrode temperature and weld metal porosity measurements and mechanical tests were performed. The results of temperature measurements indicated that electrode temperature increases during underwater wet welding. Simultaneously, porosity reduces along the BOP and V-groove weld beads. Mechanical tests showed that the mechanical properties are better at the end of welds. Additionally, the load supported by side bend tests samples extracted from 50 meter welds were higher than that measured for the 100 meter welds. Tensile test results also showed similar trend. Charpy test did not reveal any relation between the absorbed energy and porosity reduction along weld bead. However presented the same trend of bend and tensile tests at 50 and 100 m depth.

A Decade of Progress in Underwater Wet Welding Using the SMAW Process (1990-2003)

2004 ◽  
Author(s):  
Stephen Liu
Keyword(s):  
Weld Metal ◽  
Nickel Content ◽  
Cost Savings ◽  
Significant Cost ◽  
Electrode Coating ◽  
Underwater Wet Welding ◽  
Recent Developments ◽  
Weld Metal Microstructure ◽  
Metal Microstructure ◽  
Repair Techniques

It is well established that underwater wet welding (UWW) offers significant cost savings over other repair techniques for submerged structures such as petroleum production platforms, ships, and piers. Due to the deleterious effect of increased pressure on weld quality, innovative consumables are required for the production of quality wet welds. Manganese was added to the electrode coating to replenish its loss from the weld pool. Titanium and boron were added to control the molten metal oxygen potential and refine the as-solidified and reheated weld metal microstructure. Rare-earth metals (REM) were added to control the weld metal oxygen content. Finally, weld metal nickel content was optimized to improve impact toughness. Selected results of these approaches are presented in this work. These recent developments clearly demonstrate that it is possible to achieve significant progresses in wet welding using shielded metal arc (SMA) consumables, if these are designed following sound metallurgical principles.

On the disperse acicular ferrite formation in the structure of cold-resistant joints under temperatures up to –70°С in MMA welding of 10KhSND steel. Part 1

2020 ◽  
pp. 17-29
Author(s):  
G. N. Sokolov ◽  
T. R. Litvinova ◽  
I. V. Zorin ◽  
V. O. Kharlamov ◽  
A. A. Artemyev ◽  
...  
Keyword(s):  
Weld Metal ◽  
Acicular Ferrite ◽  
Cumulative Effect ◽  
Steel Part ◽  
Detonation Synthesis ◽  
Titanium Nitrides ◽  
Low Carbon ◽  
Electrode Coating ◽  
Diamond Nanopowder ◽  
Extreme North

The article presents an analysis of the metallurgical techniques that provide high quality electrodes for manual arc welding of low-carbon low-alloyed cold-resistant steels. It is shown that it is possible to improve technological and operational properties of welded joints at very low climatic temperatures up to –70°C implementing micro-alloying of the weld metal with nitrogen, titanium, cerium oxide and diamond nanopowder produced by detonation synthesis. The composition introduced into the electrode coating modifier mixture is identified. The cumulative effect of its components on the weld impact strength under temperature testing within the range from –20 up to –70°C was established. The matrix of the weld metal is composed mainly of disperse acicular ferrite, hardened by nanoparticles allegedly nitrides and carbonitrides of titanium and aluminum. It is shown that the centers for the crystallization of acicular ferrite are micro-sized non-metallic inclusions formed on ultrafine titanium nitrides. It was revealed that the toughness of the weld metal at low climatic temperatures is higher than toughness of joints welded by massively imported Japanese KOBELCO electrodes LB-52U. The results of the study make it possible to increase the cold resistance of welded structures for petrochemical plants and other facilities located in the Extreme North of the Russian Federation.Part 2 of the article will be devoted to the study of the welding and technological properties of coated electrodes.

Combining CaO–SiO2–TiO2 and CaO–SiO2–Al2O3 ternary phase systems for design of bimetallic welds

2021 ◽  
Vol 235 (8) ◽  
pp. 1271-1283
Author(s):  
Deepak Bhandari ◽  
Rahul Chhibber ◽  
Lochan Sharma ◽  
Navneet Arora ◽  
Rajeev Mehta
Keyword(s):  
Weld Metal ◽  
Power Plants ◽  
Ternary Phase ◽  
Desirability Function ◽  
Manganese Content ◽  
Research Work ◽  
Welding Process ◽  
Delta Ferrite ◽  
Electrode Coating ◽  
Phase Systems

The bimetallic welds are frequently utilized for pipeline transport system of the nuclear power plants. The occurrences of welding defects generally depend on the filler electrode as well as the electrode coatings during shielded metal arc welding process. This study involves the design of austenitic stainless steel welding electrodes for SS304L–SA516 bimetallic welds. The objective of research work includes the novel design of Al2O3–TiO2–CaO–SiO2 coatings by combining two ternary phase systems using extreme vertices mixture design methodology to analyze the effect of key coating constituents on the weld metal chemistry and mechanical properties of the welds. The significant effect of electrode coating constituent CaO on weld metal manganese content is observed which further improves the toughness of bimetallic weld joints. Various regression models have been developed for the weld responses and multi objective optimisation approach using composite desirability function has been adopted for identifying the optimized set of electrode coating compositions. The role of delta ferrite content in promoting the favourable solidification mode has been studied through microstructural examination.

Development of Hot Rolled Ship Plate with High Strength and High Toughness

2013 ◽  
Vol 690-693 ◽  
pp. 106-109 ◽  
Author(s):  
Xiang Dong Huo ◽  
Lin Guo ◽  
Jin Song Feng ◽  
Chao Luo ◽  
Jun Qu
Keyword(s):  
Acicular Ferrite ◽  
Precipitation Hardening ◽  
High Strength ◽  
Experimental Methods ◽  
Polygonal Ferrite ◽  
High Toughness ◽  
Microstructural Constituent ◽  
Lath Width ◽  
Nanometer Particles ◽  
Hot Rolled

A new hot-rolled ship plate with high strength and high toughness is successfully developed through chemical composition design and TMCP process. Experimental methods, such as OM, TEM and X-EDS, were used to study the microstructure and precipitates of steel. The primary microstructural constituent is acicular ferrite, quasi-polygonal ferrite with second constituents along grain boundaries. Lath width of acicular ferrite is about 1μm. Cubic particles about several hundreds nanometers and nanometer particles exist in experimental steel. It can be concluded that acicular ferrite is the main reason for high strength and super toughness. precipitation hardening due to dispersed precipitations of carbonitrides can not be overlooked.

scholarly journals The Use of Compressed Air for Micro-Jet Cooling After MIG Welding

2016 ◽  
Vol 61 (3) ◽  
pp. 1405-1408
Author(s):  
D. Hadryś ◽  
T. Węgrzyn ◽  
J. Piwnik ◽  
Z. Stanik ◽  
W. Tarasiuk
Keyword(s):  
Weld Metal ◽  
Acicular Ferrite ◽  
Compressed Air ◽  
Steel Weld ◽  
Low Alloy Steel ◽  
Mig Welding ◽  
Jet Cooling ◽  
Metal Deposit ◽  
Steel Weld Metal ◽  
First Time

AbstractThe material selected for this investigation was low alloy steel weld metal deposit (WMD) after MIG welding with micro-jet cooling. The present investigation was aimed as the following tasks: obtained WMD with various amount of acicular ferrite and further analyze impact toughness of WMD in terms of acicular ferrite amount in it. Weld metal deposit (WMD) was first time carried out for MIG welding with micro-jet cooling of compressed air and gas mixture of argon and air. Until that moment only argon, helium and nitrogen were tested as micro-jet gases for MIG/MAG processes. An important role in the interpretation of the results can give methods of artificial intelligence.

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