Gujarat technological university

Birla vishwakarma mahavidhyalaya

Guided by: PROF. R.S.BAROT

RATHOD ANKIT (140070125026)SHAH RUSHI (140070125027)SHAH VRAJ (140070125028) SHIYAL VIKRAM (140070125029)

SUBJECT: METAL JOINING PROCESSES(2162107)

Prepared by :

TOPIC: SUBMERGED ARC WELDING (SAW)

Submerged Arc Welding Submerged arc welding (SAW) is a method in

which the heat required to fuse the metal is generated by an arc formed by an electric current passing between the electrode and the work piece.

There is no visible arc and no sparks, spatter or fume. Arc and molten pool remains completely hidden.

This arc submerged under the loose granular flux.

The submerged arc welding flux feeds through the hopper tube and continuously distributes itself over the seam a short distance ahead of the welding zone. The wire feed mechanism begins to feed the welding into the joint at a controlled rate. An electric arc is established as the current flows between the electrode and the work.

Arc initiation After arranging the polarity ,arc

struck either by touching electrode of w/p or by placing steel ball wool

No withdrawn facilities available for arc initiation , ball of thin wire is placed at working of electrode

So technique adopted for arc initiation is called ball wool wire method.

For arc initiation, electrode touches the ball of thin wire of steel which has very small gauge.

The ball is kept on contact with w/p, the wire ball wool virtually fuse and vaporised by providing electrical supply.

Initially flux works as insulated but it melt as due to arc heat & become conductivity & began to start arc.

Further causing melting and ionization of electrode wire.

Why touch & draw is not used ?In SAW process the wire is fed

automatically by motor only in forward direction only.

For touch & draw method anyone have to add more facilities on m/c for draw , moment will have to be control by motor which makes automation difficult.

Advantages High quality Little risk of undercut and porosity No spatter High current upto 4000A is used High deposition rate upto 20kg/h because arc is

completely confine by granular flux. High thermal efficiency weld upto 75mm thick plates High welding speeds are possible upto 5m/s No edge preparation required Neat appearance

LimitationsPrecise joint preparation requiredNo observation of arc and process during

welding is possibleLimited to flat position .It can not be used for plates less than 5mm

thicknessFlux is subjected to contamination and

absorption of moisture.Flux consumption is high Irregular wire feed.

Applications Fabrication of Boiler Pressure Vessel.

Railroad tank cars.

Structural shapes and cylinders.

Circular welds and Longitudinal pipe welding.

Beam Production.

Ship Building.

Circumferential welding in wind tower

fabrication.

Thank You