ARC WELDING
Aim: To prepare a butt joint with the specimens by Arc Welding.
Equipment and Material Required: D.C Welding machine, Bench vice, Tensile testing machine, M.S. Plates of 100x50x5(2), Metallurgical microscope.
Tools Required: Hack saw, Chipping hammer, wire brush, safety goggles, Hand gloves, Face shield, Files.
Procedure:
1. Given 2 M.S. plates are filled at an angle of 45degree at 2 surfaces to be joined (V groove is formed)
2. Electrode is fixed to electrode holder.
3. Connections to be given such that electrode- negative and work piece positive.
4. Welding is to be done carefully for the half-length of the plates.
5. The work piece is to be cut into two halves by power hacksaw.
6. The beads are polished, etched with two percent natal solution and studied under the microscope whose magnification factors 10X for the heat effected zone.
7. By gripping the beads b/w the jaws pf Tensile testing machine and load is applied until the work piece breaks and the readings is to be noted.
8. The same procedure is repeated for the remaining half which is welded by reverse polarity and the results are to be compared
Precautions:
1. Edge preparation should be done very carefully.
2. Before welding ensure the surfaces are extremely clean.
3. While welding always use face shields or goggles.
Result: The effect of polarity on weld strength and heat effected zone in arc welding was studied.