Study on Arc welding process

 

Experiment Name: Study on Arc welding process.

Theory:  Shielded Metal Arc Welding, also known as Manual Metal Arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. An electric current, in the form of either alternating current  or direct current  from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapours that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.

Apparatus: 

A) Welding Machine: This is the term used to describe the machine which converts 120-240 volt AC directly to welding voltage, typically 40-70 volts AC, but also the range of DC voltages. It generally consists of a large, heavy transformer a voltage regulator circuit, an internal cooling fan, and an amperage range selector.

B) Welding Rods: These are the insulated copper conductors which carry the high amperage, low voltage electricity to the work piece that is being welded.

C) Rod Holder: Is the device on the end of the lead that holds electrode.

D) Ground Clamps: This is the lead that grounds, or completes the electrical circuit, and specifically, the clamp that is attached to the work to allow the electricity to pass through the metal being welded.

E) Amperage or Amps: This is an electrical term, used to describe the electrical current supplied to the electrode.

F) Electrodes: There are many specialized welding electrodes, used for specific alloys and types of metals, such as cast or malleable iron, stainless steel, aluminium and tempered or high carbon steels. A typical electrode consists of the wire rod in the center covered with a special coating which burns as the arc is maintained, consuming oxygen to prevent the base metal from  oxidizing.

Safety Equipment:

Welding Shield

Welding gloves

Work boots

Working Procedure:

1) At first gather the tools and materials we will need to begin welding. This means the welding machine, electrodes, cables and clamps and the metal to be welded.

2) Set up a safe work area, preferably with a table constructed of steel or other non-flammable material.

3) Prepare the metal to be welded.

4) Attach claps to hold the metal pieces together.

5) Attach the ground clamp to the larger piece of stock that is being welded.

6) Select the correct rod and amperage range for the work we are attempting.

7) Turning on the welding machine.

8) Hold the stinger in our dominant hand by insulated handle.

9) Hold welding shield up just high enough so we can able to see move the electrode to within a few inches of the work piece, ready to flip in down to protect our eyes.

10) Selecting the point is very important where we wish to weld.

11) Strike the electrode against the surface of the metal.

12) Travel across path of weld with the electrode, move at a consistent speed, and in line with the path we want to weld.

Conclusion :  >>>>>>>>>>>>>>>>>>