Electroslag welding
The Electroslag welding process is actually originated in Russia when the Paton welding institute performed the basic research to perfect Electro slag welding.
Later, this process was developed in many European countries and in the U.S.A so that thick sections of steel could be used as a very effective tool for welding. The Electroslag welding process is an arc welding process in which co-fabrication is produced by molten slag that melts the filler metal and work surfaces to be welded.
Concept of Electroslag welding
The Electroslag welding process is initiated by introducing an arc between the filler metal/electrode and the work. This arc heats the flux and melts it to form slag.The arc is eliminated and the conductive slag is maintained in a liquefied state, due to its resistance to the flow of electric current between the electrode and the work the molten slag remains between the electrode and the work
The molten slag remains between the electrode and the work. The molten metal pool is shielded by molten lava that moves along the complete cross-section of the joint as the welding progresses.
How it works
The arc is ignited between the electrode and the joint floor with the help of a piece of steel wool. Welding flux is added and It is melted by the heat of the arc. The temperature of this molten slag pool is about 1650 degrees centigrade on the surface and 1930 degrees centigrade below the surface.
When a sufficiently thick layer of hot flux or molten slag is formed, the arc action stips and the electric current passes through the conductive slag pool in the workpiece from the electric current. The conductive lava pool remains molten due to the resistance to electric current between the electrode and the work.
This much heat is sufficient to fuse the edges of the workpiece and the welding electrode.The liquid metal and hot base metal coming from the welding electrode collects in a pool under the slag bath and slowly freezes, forming a weld bead joining the two workpieces.