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Manufacturing Process Lab Lab Experiments

To prepare a butt joint with the specimens by Arc Welding


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.



  1. Given 2 M.S. plates are filled at an angle of 450 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


  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.

Applications of welding:

Industries:Welding processes are a foundational aspect of all large-construction industries, ensuring strong, sustainable connections within buildings, bridges and other infrastructures.

Electrical:In the electrical and electronics industries, discharge capacitor (DC) welds are preferred for use with the thinner sheet metals associated with smaller, more delicate electronics systems. This welding option is used throughout the electrical system build-out process in numerous specialty applications, such as medical labs and small appliance fabrications. CD welding neatly bonds components like switchboards and switches in cabinets and on panels, fix fascia panels, add buttons and instruments, and attach printed circuit boards.

Mechanical:For more rugged applications that involve thicker metal dimensions, arc stud welding provides the control and effectiveness necessary to firmly bond heavier pieces together. In the automotive industry, arc welds bond heat shields, exhaust systems and hydraulic lines to the chassis. Metal furniture pieces like office desks, file cabinets and shelving units are often welded. Heating, ventilation and air conditioning units are usually constructed using welding processes.

Shipbuilding:Welding has been the traditional shipbuilding construction method used since the advent of the Industrial Age. Ensuring a water-tight surface is essential. Inside the ship, welding processes secure hatches, fluid lines, control panels and many other components critical to a safe and seaworthy vessel.

Equipment:Most, if not all, of today's industries rely on properly functioning equipment, and welding processes are vital to the success of those machines.

Farm equipment:In agriculture, farm machines that plow, plant, seed and harvest are fundamental to the country’s food supply. Those machines are welded throughout their frames and processes. On the chassis, the cab frame, fenders and brackets are formed by welds. Motor structure and electrical functions are fused, as are the features of specialized tools such as threshers and spreaders.

Lawn and garden:Lawn mowers, trimmers, power saws and other garden equipment have long lives due to the strength of their welded frames. Other metal garden features enhance the enjoyment of outdoor life, such as barbecue grills, enclosures, seating and watering systems.