Weld Metal Chemistry of Mineral Waste Added SiO2–CaO–CaF2–TiO2 Electrode Coatings for Offshore Welds

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Waris Nawaz Khan ◽  
Rahul Chhibber
Keyword(s):  
Weld Metal ◽  
Structural Integrity ◽  
Offshore Structures ◽  
Tio2 Electrode ◽  
Shielded Metal Arc Welding ◽  
Electrode Coating ◽  
Metal Chemistry ◽  
Metal Arc Welding ◽  
Welding Consumables ◽  
Mineral Waste

Abstract Offshore structures in recent time are witnessing the increased application of dissimilar metal welds for enhanced structural integrity. Offshore structures are complex systems. Fabrication, maintenance, and repair of these structures require conventional and advanced welding technologies along with suitably chosen welding consumables. The present work aims at the design and development of shielded metal arc welding (SMAW) electrode coating using extreme vertices design methodology. This work also attempts to study weld metal chemistry along with microstructure and microhardness. Red ochre, a mineral waste from iron ore is added in the coating composition. Multi response optimization has been carried out to obtain optimum flux composition and to study the effect of individual constituents and their interactions on the weld chemistry and microhardness.

Experimental investigation on dissimilar weld between super duplex stainless steel 2507 and API X70 pipeline steel

2021 ◽  
pp. 146442072110130
Author(s):  
Waris N Khan ◽  
Rahul Chhibber
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pipeline Steel ◽  
High Strength ◽  
Super Duplex Stainless Steel ◽  
Shielded Metal Arc Welding ◽  
Electrode Coating ◽  
Dissimilar Weld ◽  
Metal Arc Welding ◽  
Welding Electrode

This work investigates the microstructure and mechanical properties of 2507 super duplex stainless steel and API X70 high strength low alloy steel weld joint. This joint finds application in offshore hydrocarbon drilling riser and oil–gas pipelines. Coated shielded metal arc welding electrodes have been designed and extruded on 309L filler and their performance compared with a commercial austenitic electrode E309L. Filler 309L solidifies in ferrite-austenite (F-A) mode with a resultant microstructure comprising skeletal ferrites with austenite distributed in the interdendritic region. Results of tensile and impact tests indicate that weld fabricated with laboratory-developed electrodes has higher ductility and impact energy than the commercial electrode. The tensile strength and weld hardness of commercial electrodes are superior. The laboratory-made electrode’s microhardness is lower than the commercial electrodes, making the former less prone to failure. An alternative welding electrode coating composition has been suggested through this work and found to be performing satisfactorily and comparable to the commercially available electrodes.

Transformation Temperatures and Welding Residual Stresses in Ferritic Steels

2007 ◽  
Author(s):  
J. A. Francis ◽  
H. J. Stone ◽  
S. Kundu ◽  
R. B. Rogge ◽  
H. K. D. H. Bhadeshia ◽  
...  
Keyword(s):  
Residual Stress ◽  
Arc Welding ◽  
Structural Integrity ◽  
Steel Plates ◽  
Stress Distributions ◽  
Metal Arc Welding ◽  
Thick Steel ◽  
Steel Welds ◽  
Welding Consumables ◽  
Filler Metals

Residual stress in the vicinity of a weld can have a large influence on structural integrity. Here the extent to which the martensite-start temperature of the weld filler metal can be adjusted to mitigate residual stress distributions in ferritic steel welds has been investigated. Three single-pass groove welds were deposited by manual-metal-arc welding on 12mm thick steel plates using filler metals designed to have different martensite-start temperatures. Their residual stress distributions were then characterised by neutron diffraction. It was found that a lower transformation temperature leads to a potentially less harmful stress distribution in and near the fusion zone. The experimental method is reported and the results are interpreted in the context of designing better welding consumables.

Fracture Mechanics of Conventional and Narrow Groove Pulse Current Gas Metal Arc Welds of HSLA Steel

2012 ◽  
Vol 710 ◽  
pp. 451-456
Author(s):  
Ravi Ranjan Kumar ◽  
P. K. Ghosh
Keyword(s):  
Fracture Toughness ◽  
Weld Metal ◽  
Tensile Properties ◽  
Arc Welding ◽  
Hsla Steel ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Compact Tension ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding

Mechanical and fracture properties of 20MnMoNi55 grade high strength low alloy (HSLA) steel welds have been studied. The weld joints were made using Gas Tungsten Arc Welding (GTAW), Shielded Metal Arc Welding (SMAW) and Pulse Gas Metal Arc Welding (P-GMAW) methods on conventional V-groove (V-Groove) and Narrow groove (NG-13). The base metal and weld metal were characterised in terms of their metallurgical, mechanical and fracture toughness properties by following ASTM procedures. The J-Integral fracture test was carried out using compact tension C(T) specimen for base and weld metal. The fracture toughness and tensile properties of welds have been correlated with microstructure. In conventional V-groove welds prepared by P-GMAW shows the improvement in initiation fracture toughness (JIC) as compared to the weld prepared by SMAW. Similar improvements in tensile properties have also been observed. This is attributed to reduction in co-axial dendrite content due to lower heat input during P-GMAW process as compared to SMAW. In the narrow groove P-GMA weld prepared at f value of 0.15 has shown relative improvement of JIC as compared to that of the weld prepared by SMAW process.

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