Report Arc Welding

TITLE: ARC WELDING (SHIELDED METAL ARC WELDING AND GAS METAL ARC WELDING)

INTRODUCTION: Arc welding is one of alternative for joining process in manufacturing. Arc welding process had done by create an electric arc between electrode and the base material to melt the metal at the welding point using welding power supply. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas and sometime adds by an evaporating filler material. Shielded metal arc welding (SMAW), also known as manual metal arc (MMA) welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. They can use either direct current (DC) or alternating current (AC) from a welding power supply, 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 vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.

Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semiautomatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used. There are four primary methods of metal transfer in GMAW, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.

OBJECTIVES ● To know about SMAW and GMAW theoretically and practically. ● To know the different between SMAW (DCRP), SMAW (DRSP) and GMAW in term of spatter, welded bead, and undercut. ● To learnt about terminology in welding. ● To learnt theoretically and practically how to use arc welding.

THEORY : In arc welding, basically the principle is heating and melting of base metal using electric arc. The electric arc formed when there is a voltage difference between metal coating (on the electrode) and surface of the metal to be welding. The arc will produce enough heat to melt the base metal and end of the electrode to form point of molten metal. Shielded Metal Arc Welding (SMAW) Shielded metal arc welding (SMAW), also known as manual metal arc (MMA) welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. They can use either direct current (DC) or alternating current (AC) from a welding power supply, 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 vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.

Gas Metal Arc Welding (GMAW) Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semiautomatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used. There are four primary methods of metal transfer in GMAW, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.

SAFETY: Welding is a process involving with electricity and high temperature (heat), so we must take precaution in doing this process to as precaution. The safety are: 1) Wear safety equipment such as head shield, glove and apron (safety jacket) before start welding. 2) Do not watch the ultraviolet rays spatter when welding using eye without a head Shield. 3) Carry Out at a comfortable area and where the is good welding will be done away from the flammable materials. 4) Do not disturb other student that are still work. 5) Do not use tools that we do not recognize.

APPARATUS: 1) Glove. 2) Wire brush. 3) Chipping hammer 4) Safety jacket 5) Head shield. 6) Electrode holder. 7) Pieces of metal. 8) SMAW main apparatus (electrode, power supply, etc.) 9) GMAW apparatus.