Adjusting And Setup of Welding Equipment

Objectives:

•The students will recap on safety in the shop & welding procedures.•The students will be able to recognize parts and tools used for welding.•Students will be able to define terms used in welding.•Students will be able to describe the welding process.

Terms And Definitions

Arc Welding – Process of using an electric arc as the source of heat to join two or more pieces of metal by the fusion process.

Terms and Definitions

Arc – flow of electric current across a narrow gap.

Terms and Definitions

Base metal – metal to be welded.

Terms and Definitions

Flux – Chemical coating on electrodes; used to promote fusion of metals during welding.

Terms and Definitions

Bead Weld – Weld made by one pass of the electrode.

Terms and Definitions

Pad – piece of practice metal on which parallel beads are deposited side by side.

Terms and Definitions

Tack Weld – Small weld used to hold base metals together temporarily.

Terms and Definitions

Slag – Nonmetallic by-product of welding process; made of flux and nonmetallic impurities.

Terms and Definitions

Spatter – Deposit of small spots or particles of metal on the base metal long side of the bead.

Terms and Definitions

Porosity – Condition caused by a trapped gas pocket in a weld as it solidifies.

Kinds of shielded metal Arc Welding Machines

• Alternating Current (AC) – Machine that alternates direction of flow of electric current 120 times per second.

Kinds of shielded metal Arc Welding Machines

• Direct Current (DC) machine in which the electric current flows in one direction.

Kinds of shielded metal Arc Welding Machines

• Alternating / direct current (AC/DC) – Machine that is capable of supplying AC or DC current for welding.

Common Arc Welding Equipment

• Welding Machine • Electrode holder with lead

Common Arc Welding Equipment

• Ground clamp with lead • Welding Helmet

Common Arc Welding Equipment

• Leather Gloves • Chipping Hammer

Common Arc Welding Equipment

• Eye Protection • Wire Brush

Common Arc Welding Equipment

• Electrodes

Meanings of Characters in the AWS Electrode Classification System

• Tensile

• Strength• (Thousands Welding• of pounds Position• Electrode Welding Current• And / Or Depth Of• Penetration

• E 6012• 1. Letter E – denotes that electrode is for arc welding.• 2. First two numerals – indicates tensile strength in thousands of pounds

per square inch.• 3. Third numeral – indicates position to be used.• 4. Fourth numeral – gives code for special characteristics of electrode.

Purposes Of Flux

• 1. Stabilizes arc• 2. Shielding molten

puddle from air.• 3. Floating impurities

out of puddle.• 4. Forming slag, which

slows cooling.• 5. Increasing speed.

Methods of establishing arc

• 1. Scratching (similar to striking a match)

• 2. Tapping

Characteristics of proper arc length

• 1. End of electrode is same distance from base metal as diameter of electrode.

• 2. Steady hum from welding machine and “frying” sound at the arc.

Arc Welding Safety

• Always weld in a well ventilated area. If proper ventilation is not available, go outside.

Arc Welding Safety

• Never look at a welding arc with the naked eye.

• Do not strike an arc until you are sure those in the vicinity have protective equipment or have turned their eyes away from the arc.

Arc Welding Safety

• Use eye protection when chipping slag from a weld.

• Always wear suitable clothing (long sleeves, gloves, heavy pants, heavy boots) to protect the body from arc burns and spatter of hot metal.

Arc Welding Safety

• Don not weld around

combustible materials.• Do not weld on containers

that may contain combustible substances.

Arc Welding Safety

• Do not leave electrode holder on the table or in contact with a grounded metal surface.

• Do not use the welder on or around wet surfaces.

Arc Welding Safety

• Place hot electrode stubs in a metal container for disposal. Never throw them on the floor.

• Make sure all connections are tight before welding.