Study of flux-cored arc welding processes for mild steel hardfacing by applying high-speed imaging and a semi-empirical approach

2017 ◽  
Vol 61 (5) ◽  
pp. 901-913 ◽  
Author(s):  
G. Wilhelm ◽  
G. Gött ◽  
D. Uhrlandt
Keyword(s):  
Mild Steel ◽  
Arc Welding ◽  
High Speed ◽  
Empirical Approach ◽  
High Speed Imaging ◽  
Flux Cored Arc Welding ◽  
Semi Empirical ◽  
Welding Processes

Optimization of Flux Cored Arc Welding Process Parameter Using Genetic and Memetic Algorithms

2013 ◽  
Vol 13 (4) ◽  
pp. 239-250 ◽  
Author(s):  
T. Kannan ◽  
N. Murugan ◽  
B. N. Sreeharan
Keyword(s):  
Arc Welding ◽  
Welding Process ◽  
Memetic Algorithms ◽  
Optimization Techniques ◽  
Low Carbon ◽  
Robotic Welding ◽  
Bead Width ◽  
Flux Cored Arc Welding ◽  
Arc Welding Process ◽  
Welding Processes

AbstractMost of the manufacturing enterprises indulge in the bonding of metals during the production process. This makes welding one of the most important processes in industries. Subsequently, due to the high usage of welding process, industrial engineers desire to optimize the parameters concerned to achieve the desired weld bead characteristics. This paper focuses on optimization of flux cored arc welding process parameters, which are used for deposition of duplex stainless steel on low carbon structural steel plates. Experiments were conducted based on central composite rotatable design and mathematical models were developed using multiple regression method. Further, optimization with objectives as minimizing percentage dilution, maximizing height of reinforcement and bead width was carried out using genetic algorithm and memetic algorithm. This problem was formulated as a multi objective, multivariable and non-linear programming problem. The algorithms were implemented using basic functions of C language making it highly reliable, adoptable, very user friendly and extendable to other welding processes such as GMAW, GTAW, robotic welding, etc. The adopted optimization techniques were further compared based on various computational factors.

scholarly journals The State of the Art of Underwater Wet Welding Practice: Part 1

2021 ◽  
Vol 100 (4) ◽  
pp. 132-141
Author(s):  
EZEQUIEL CAIRES PEREIRA PESSOA ◽  
◽  
STEPHEN LIU
Keyword(s):  
Research And Development ◽  
Weld Metal ◽  
Arc Welding ◽  
Structural Steels ◽  
Friction Stir ◽  
Underwater Wet Welding ◽  
Class A ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Welding Processes

Developments in underwater wet welding (UWW) over the past four decades are reviewed, with an emphasis on the research that has been conducted in the last ten years. Shielded metal arc welding with rutile-based coated electrodes was established as the most applied process in the practice of wet welding of structural steels in shallow water. The advancements achieved in previous decades had already led to control of the chemical com-position and microstructure of weld metals. Research and development in consumables formulation have led to control of the amount of hydrogen content and the level of weld porosity in the weld metal. The main focus of research and development in the last decade was on weldability of naval and offshore structural steels and acceptance of welding procedures for Class A weld classification according to American Welding Society D3.6, Under-water Welding Code. Applications of strictly controlled welding techniques, including new postweld heat treatment procedures, allowed for the welding of steels with carbon equivalent values greater than 0.40. Classification societies are meticulously scrutinizing wet welding procedures and wet weld properties in structural steels at depths smaller than 30 m prior to qualifying them as Class A capable. Alternate wet welding processes that have been tested in previous decades — such as friction stir welding, dry local habitat, and gas metal arc welding —have not achieved great success as originally claimed. Al-most all of the new UWW process developments in the last decade have focused on the flux cored arc welding (FCAW) process. Part 1 of this paper covers developments in microstructural optimization and weld metal porosity control for UWW. Part 2 discusses the hydrogen pickup mechanism, weld cooling rate control, design, and qualification of consumables. It ends with a description of the advancements in FCAW applications for UWW.

scholarly journals Special Issue on Progress in Welding Processes

2013 ◽  
Vol 7 (1) ◽  
pp. 87-87
Author(s):  
Seiji Katayama
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Fusion Welding ◽  
Double Layers ◽  
Automatic Welding ◽  
Heat Sources ◽  
Hybrid Welding ◽  
Cored Wire ◽  
Shipbuilding Industry ◽  
Welding Processes

Welding is one of the most versatile joining methods for constructing products and structures in nearly all industrial fields. Arc has been widely used as a cheap heat source for welding since carbon arc fusion welding was first applied to join Pb plates in about 1880. New welding technologies have been developed according to social needs or changes since 1960. Therefore, half-automated welding, automatic welding and highefficient welding have been developed for saving man-power and afterward full automation. First, tandem one-side SAW (submerged arc welding), high-speed rotational arc, high-heat input SAW, tandem wire MAG, etc. have been introduced as highly efficient welding processes. On the other hand, as gas-shielding arc welding processes, CO2 gas, MAG, man-power saving automatic welding, the use of a flux-cored wire, AC MIG, MIG with two wires, laser-arc hybrid welding, CMT process have been developed and most widely employed in the industries in conjunction with an advance in the welding heat sources from thyristor to inverter and nowadays digital inverter. Furthermore, robotization has been developed from spot welding robot to squire robot, multi-axes GAM robot, mobile robot, portable many-axes robot and 7 axes robot together with the development in welding sensors such as probe sensor, one-touch sensor, magnetic sensor, arc sensor, laser-slit light sensor, stereo CCD, etc. Recently, novel arc sources are not developed, but deep weld penetration and geometry are controllably obtained in TIG welding by active flux pasted on the plate surface, good use of an active gas and narrow oxidation treatment. Clean MIG process for steels is also developed by use of a unique solid-wire of double layers with different melting temperatures, and different hybrid heat sources of plasma and GMA or laser and MIG. Hybrid welding processes with CO2 laser and MAG, disk laser and MAG, fiber laser and CO2 arc or MAG has recently been applied in the shipbuilding industry. I thank the authors for their generous cooperation to the publication of new development in the welding technologies.

scholarly journals Globular-to-Spray Transition in Cold Wire Gas Metal Arc Welding

2021 ◽  
Vol 100 (4) ◽  
pp. 121-131
Author(s):  
R. A. RIBEIRO ◽  
◽  
P. D. C. ASSUNÇÃO ◽  
E. B. F. DOS SANTOS ◽  
E. M. BRAGA ◽  
...  
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Electrical Current ◽  
Feed Speed ◽  
High Speed Imaging ◽  
Transition Mechanism ◽  
Cold Wire ◽  
Metal Arc Welding

The electrical current required for a transition from globular to spray droplet transfer during gas metal arc welding (GMAW) is determined by the specified wire feed speed in the case of constant-voltage power supplies. Generally, in narrow groove welding, spray transfer is avoided, be-cause this transfer mode can severely erode the groove sidewalls. This work compared the globular-to-spray transition mechanism in cold wire gas metal arc welding (CW-GMAW) vs. standard GMAW. Synchronized high-speed imaging with current and voltage samplings were used to characterize the arc dynamics for different cold wire mass feed rates. Subsequently, the droplet frequency and diameter were estimated, and the parameters for a globular-to-spray transition were assessed. The results suggest that the transition to spray occurs in CW-GMAW at a lower current than in the standard GMAW process. The reason for this difference appears to be linked to an enhanced magnetic pinch force, which is mainly responsible for metal transfer in higher welding current conditions.

Hexavalent Chromium Exposure Levels Resulting from Shipyard Welding

1998 ◽  
Vol 14 (04) ◽  
pp. 246-254
Author(s):  
Bhaskar Kura ◽  
Praveen Mookoni
Keyword(s):  
Hexavalent Chromium ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Task Group ◽  
Health Administration ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Exposure Levels ◽  
The Impact ◽  
Welding Processes

The Occupational Safety and Health Administration is expected to reduce permissible exposure limits of hexavalent chromium from 100 ng/m3between 5 to 0.5 fig/m3. A Navy Industry Task Group study revealed that the impact of proposed regulations on the shipbuilding industry is significant. The estimated cost of compliance by the Navy facilities could be as much as $46 Million/year besides a one-time cost of about $22 Million. Also, the task group estimated that the cost of $9 Million. This paper presents the results of a study undertaken at the University of New Orleans in support of the Navy/Industry Task Group efforts. The study included assessments of Cr(VI) exposure levels for two specific welding processes and three welding scenarios. Airborne particulate matter was collected using personal samplers for two specific welding processes, Gas Metal Arc Welding and Flux-Cored Arc Welding. Two base metals, HY100 and DH36, were considered for Flux-Cored Arc Welding and one base metal, HY100, was considered for Gas Metal Arc Welding. The samples were analyzed for Cr(VI) using OSHA Method 215. Based on the data generated, it can be concluded that Gas Metal Arc Welding and Flux-Cored Arc Welding on HY100 steel result in 8-hr. worker exposures less than 0.5 fig/m3 in a laboratory type setting, though the same levels of exposure may be difficult to be achieved in the field. Flux-Cored Arc Welding on DH36 resulted in exposure above 0.5 ng/m3, again in laboratory type setting.

Flux-cored arc welding processes analysis of a shipyard

2016 ◽  
pp. 801-805
Author(s):  
P Lameira ◽  
C Benjamin ◽  
E Loureiro ◽  
H Moraes ◽  
N Figueiredo ◽  
...  
Keyword(s):  
Arc Welding ◽  
Flux Cored Arc Welding ◽  
Welding Processes

A Processing Approach Incorporating Copper Backing-Wheel Device in Submerged Arc Welding for Manufacturing Cryogenic Storage Tanks

2014 ◽  
Vol 705 ◽  
pp. 106-111
Author(s):  
Supphachan Rajsiri ◽  
Mayuree Chomjanngam ◽  
Sittiphun Tuntawiroon
Keyword(s):  
Arc Welding ◽  
Submerged Arc Welding ◽  
Storage Tanks ◽  
Welding Temperature ◽  
New Approach ◽  
Cryogenic Storage ◽  
Processing Approach ◽  
Flux Cored Arc Welding ◽  
Welding Processes ◽  
Submerged Arc

A processing approach using a copper backing-wheel device was developed to aid the fabrication process of industrial cryogenic storage tanks manufactured under the ASME Section VIII Division 1. This research focused on the welding processes related to the cylindrical-body assembly. Two processing steps involving the root-run formation and the replacement with a sound outer-circumference joint were studied. Initially, tank fabrication is achieved through the application of both flux-cored arc welding and submerged arc welding. A new processing approach was proposed with the modified method in cross-section preparation, and a low-cost reusable copper backing-wheel device was developed to facilitate the root-run formation using only submerged arc welding. Temperature gradient through the device components along the heat-conduction path was monitored to assure the conductivity of the backing device. The results suggest that the proposed approach reduced manufacturing time by removing the initial flux-cored arc welding process used in the conventional welding method. As an effect, the new approach show promise reduces the overall manufacturing cost of tank fabrication. Based on radiographic testing of tanks fabricated using the new approach found that circumference joints required little or no welding repair suggesting higher joint quality.

Investigation of Microstructure and Hardness Properties of Hardfacing Surface on SCM 440 Alloy Steel by Using Metal Active Gas and Flux Cored Arc Welding Processes

2017 ◽  
Vol 728 ◽  
pp. 31-35 ◽  
Author(s):  
Siva Sitthipong ◽  
Prawit Towatana ◽  
Amnuay Sitticharoenchai
Keyword(s):  
Alloy Steel ◽  
Arc Welding ◽  
Welding Process ◽  
High Strength ◽  
Side Plate ◽  
Weld Metals ◽  
Flux Cored Arc Welding ◽  
The Difference ◽  
Arc Welding Process ◽  
Welding Processes

This research aimed to investigate the microstructure and hardness properties of hardfacing surface on SCM440 alloy steel by using metal active gas and flux cored arc welding processes. Due to the difficulty of welding the high strength steel, the changes in base metals’ microstructures were found after welding. Preheating the specimens at 350°C and post weld heat treatment the specimens at 550°C were performed for 1 hour, to reduce the residual stresses and avoid the undesired formation of microstructures. The weld metals’ microstructures that were found from both welding processes are acicular ferrite, polygonal ferrite and side plate ferrite. The hardness value of weld metal resulted from flux cored arc welding process is higher than that of the metal active gas welding process. Each welding process produced different quantities of weld metals’ microstructures, causing the difference in hardness values. The data will be used for investigating and improving parameters of shaft repairing, in order to use it more effectively.

Development of a Hybrid Laser Arc Welding System for Pipeline Construction

2008 ◽  
Author(s):  
D. Begg ◽  
G. Beynon ◽  
E. Hansen ◽  
J. Defalco ◽  
K. Light
Keyword(s):  
Arc Welding ◽  
High Speed ◽  
Large Diameter ◽  
Primary Objective ◽  
Construction Costs ◽  
Hybrid Laser Arc Welding ◽  
Pipeline Construction ◽  
Girth Welding ◽  
Pipeline Welding ◽  
Welding Processes

The construction costs for a northern pipeline will represent approximately half of the project costs and will be extremely challenging with much of the work being carried out in harsh winter conditions at temperatures, as low as −55°C. The welding costs are a major component of the overall construction costs and industry continues to seek future generation pipeline welding technologies to achieve additional improvements in productivity and enable significant cost savings. The current state-of-the-art welding processes for onshore pipelines involve mechanized gas metal arc welding (GMAW). The dual tandem pulse GMAW process provides the greatest productivity to date with four welding arcs operating simultaneously on each welding carriage. Based on the progression of laser welding technology, it is highly likely that the next generation of automated pipeline welding equipment will be built around hybrid laser arc welding (HLAW). The primary objective of this project is to develop, test, and validate a “field ready” HLAW system for full circumferential girth welding of large diameter (NPS30 and above) high strength pipe. The system is based on both robotic and direct clamp-on platforms where potential applications include double jointing operations in pipe mills and as well for onshore and offshore pipeline construction projects. The pipe grades evaluated include both X80 and X100, with wall thicknesses of 10.4mm and 14.3mm, respectively. Lab trials include high speed root pass, high speed root pass with laser assisted GMAW for fill and cap passes, and, single pass complete joint penetration girth welding. This paper discusses the approach to the development of the HLAW system, however at the time the paper was submitted no mechanical testing or system validation trials had been completed. It is expected results will be available for the conference presentation.

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