Submerged Arc Welding Process

DARSHAK RANA # 27672772
PART - 1
• The weld is taken from a website: [1]
• Product: The weld is for a pressure vessel assembly joining the cylindrical shell and the dome shell.
• The type of the weld: The welding process used is a submerged arc welding process with a butt joint where a groove is made of different shapes and sizes in order that the weld pool may sit in the groove to join the parent metal parts.
The below mentioned figure represents the submerged arc welding used in joining cylindrical shell with the dome of the pressure vessel :

Figure 1 Pressure vessel [1]
• Assessment of the welding process
Submerged arc welding is an automated or a semi - automatic
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Since then more than 15% of the weld joints are produced by this process. [3]
In the manufacturing of a pressure vessels, two different components like the cylindrical shell and the dome structure are casted and then joined by welding. In this process, the arc is submerged under the blanket of flux consisting of silica, manganese oxide or calcium fluoride which is fed into the weld zone through a hopper by a gravity fed controlled nozzle.
The thick layer of flux covers the molten metal preventing the spatter and sparks to spread out as a result of which an insulation is formed promoting a deeper penetration of heat into the workpiece making a stronger weld joint. The insulation of the flux also prevents the oxides and hydrides from the atmosphere getting trapped into the molten weld pool. The consumable electrode is in the form a wire and is fed automatically through a tube. Electric currents vary from 300 A to 2000 A depending upon the penetration of the heat required. The power supply is most often single phase or a three phase with a rating of approx. 440 V which determines the size of the weld pool. Since the welding is to be done a circular part, the part is rotated around the electrode and the unfused flux can be recovered, retreated,
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which is 5 – 10 times higher than the shielded metal arc welding process. The speed rate of welding is also as good as 5 m/min. The quality of the weld such that the uniformity of the properties like toughness and ductility are obtained. The most feasible type of weld for this product is the submerged arc welding because of the size and the quality of the weld required. [6]

Applications of the submerged arc welding process:
1. Since the strength and ductility of the weld joint is uniform with minimal content of nitrogen and hydrogen, this type of process is suitable for the carrying the fluids flowing in the pipes under pressure conditions.
2. Because of the high tensile strength of the joints, this process can be used in joining earth moving equipment and the

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