Reduction of Manufacturing Distortion in Arc Welded Ship Panels Using Thermal Tensioning

2008 ◽  
Vol 24 (04) ◽  
pp. 177-179
Author(s):  
Ruth Sanderson ◽  
Bill Lucas ◽  
Roy Pocock

Large sheet or thin plate steel structures invariably suffer from distortion especially when fabricated using an arc welding process. The cost of reworking in shipbuilding is high. Low-stress no-distortion (LSND) welding has been demonstrated to effectively prevent distortion. The technique has been show to work well by rapidly cooling the weld with atomized water or liquid CO2 immediately after solidification. However, this can be expensive and difficult to apply in the fabrication of large structures. In this work, only a thermal tensioning technique is presented. The technique controls distortion by applying thermal stresses in front of the weld pool to counteract the stresses induced in the structure by welding. A combination of finite element modeling and experimentation has been used to find a thermal tensioning arrangement that reduces distortion by 50% in 4 mm butt welded steel plates using arc welding.

2002 ◽  
Vol 124 (3) ◽  
pp. 695-701 ◽  
Author(s):  
Y. M. Zhang ◽  
S. B. Zhang ◽  
M. Jiang

The welding industry is driven to improve productivity without sacrificing quality. For thick material welding, the current practice is to use backing or multiple passes. The laser welding process, capable of achieving deep narrow penetration, can significantly improve welding productivity for such applications by reducing the number of passes. However, its competitiveness in comparison with traditional arc welding is weakened by its high cost, strict fit-up requirement, and difficulty in welding large structures. In this work, a different method, referred to as double-sided arc welding (DSAW) is developed to improve the arc concentration for arc welding. A sensing and control system is developed to achieve deep narrow penetration under variations in welding conditions. Experiments verified that the pulsed keyhole DSAW system developed is capable of achieving deep narrow penetration on a 1/2 inch thick square butt joint in a single pass.


2012 ◽  
Vol 3 (3) ◽  
pp. 228-233
Author(s):  
R. Dhollander ◽  
S. Vancauwenberghe ◽  
W. De Waele ◽  
N. Van Caenegem ◽  
E. Van Pottelberg

The assembly of large structures made out of thick steel plates requires a welding process bywhich multiple wires can be used simultaneously. To reproduce these industrial processes in a researchenvironment, OCAS has invested in a multiwire submerged arc welding (SAW) setup. In this multiwiresetup, up to five wires in tandem configuration can be used.The objective of this master thesis is to establish a deeper knowledge of process parameters used to weldsteel plates in a thickness range of 12,7 up to 25 mm, by means of the submerged arc welding process.Based on literature, a test matrix is composed in which the number of wires, the plate thickness and otherweld parameters are the variables. In addition, a specific plate preparation for each plate thickness isderived from the literature. The preformed weld trails will be evaluated on weld bead geometry andmetallographic properties. There is further experimental examination required, which will result in therevising of the matrix.


Author(s):  
Ankush Choudhary ◽  
Munish Kumar Gupta ◽  
Manoj Kumar

In this paper, a novel developed water-cooled advanced submerged arc welding (WASAW) process has been designed and established. The developed WASAW process can be utilized for higher preheating currents at 100% duty cycle. Subsequently, a multi-pass welding investigation has been carried out on AISI 1023 steel plates as per the L8 Taguchi orthogonal array by varying WASAW input factors namely voltage (V), wire feed rate (WFR), welding speed (WS), nozzle to plate distance (NPD), and preheat current (I), respectively. The relationships between selected WASAW process parameters and responses namely tensile strength (TS), yield strength (YS), percentage elongation (E), and weld metal hardness (H) has been established with statistical regression analysis and ANOVA method. Then, the effect of each input factor and their interactions on selected responses was analyzed using single effect and 3D surface plots. Lately, the fractography analysis of tensile fractured surfaces has been carried out to study the failure in all weld metals. Finally, Jaya and genetic algorithms have been applied to optimize the WASAW performance. Overall, the outcomes reveal that developed WASAW process yields a substantial enhancement in the mechanical behavior of all weld metals.


2011 ◽  
Vol 284-286 ◽  
pp. 2469-2472
Author(s):  
Aniruddha Ghosh ◽  
Somnath Chattopadhyaya ◽  
S. Mukherjee

In Submerged Arc Welding process involves critical set of variables which are needed to control. An attempt has been made in this paper to find out- the influence of the heat input and bead volume on HAZ Hardness for Submerged Arc Welding Process of Mild steel plates. Mild steel plates are welded by changing input variables (current, voltage, travel speed, i.e. heat input) and Rockwell hardness no. has been observed on welded portion and at the zone adjacent to the welded portion. A detailed analysis of the microstructure changes is carried out to understand the HAZ softening phenomenon.


2010 ◽  
Vol 43 (4) ◽  
pp. 44
Author(s):  
Malladi V. V. N. Sriram ◽  
Somnath Chattopadhyaya ◽  
Aniruddha Ghosh

2010 ◽  
Vol 3 (6) ◽  
pp. 41
Author(s):  
Alfonso Patarroyo ◽  
Elvis Solano ◽  
Fabio Cueca ◽  
Fernando Rojas ◽  
Alfredo Morales

Repairs and changes of steel plates in the structure of the vessels where it is possible to find steels with a high degree of deterioration need reliable welded joints in naval steel of the type ASTM A–131 Gr. A new to old. Due to the fact that the variables associated to the weldability of the materials to be repaired are not known, it is necessary to make a study on the weldability of steel ASTM A131 Gr A, in full penetration seams or junctures, under the various parameters involved in the welding process, to determine the influence of the corroding residues that affect the application of welding compounds through the analysis of the metallurgical reactions of liquid condition in order to select the contributing materials with the alloy elements that are able to prevent these phenomena and to recommend the best practices for the electric arc welding process with tubular electrode with FCAW flux core.


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